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Science, Mathematics, & Technology Timeline

Modern Present - 1950

Summary of change:

Environmental: Humans and their livestock (mostly pigs and cows) now have 22 times the mass than wild mammals. Domesticated birds have two times the mass of wild birds. Plant mass has halved since civilization began.


Wild fires in California kill 88 and destroy ... Wild Fires graph

Japan's Hayabusa2 spacecraft dropped multiple probes onto the surface of the Ryuga Asteroid. The probes hop across the asteroid: take pictures, measure temperatures, magnetism, look for water and organic molecules. The main spacecraft will land three times and collect samples to return to Earth in 2020. Source See Hayabusa1.

NASA announced its Mars rover found evidence for ancient life and methane in Mars’ atmosphere, suggesting microbes have existed and still might exist today.

The B-52 bomber is still flying. By Gordon F. Sander January 20, 2018

Somalian plate is separating from the African Continent See Africa’s Big Break. by Shannon Hall in Discover magazine May 2018.

Co2 in atmosphere passed 400 parts per million.

Wheat genome sequenced. Source


First artificial species created

Mycoplasma mycoides JCVI-syn3.0 has 473 genes and was created by J. C. Venter. He started with the living organism Mycoplasma genitalium, the smallest organism (has 525 genes) and the first organism to be sequenced, by removing and adding genes until it sustained life and reproduced.

First time police use a robot to kill a suspect

After a sniper killed 12 police officers in Dallas, police armed a small robot with a bomb and detonated it next to the shooter.

2016 March

The Great Math Mystery

According to Mario Livio, all numbers (one, two, ...) are invented concepts, and humans have discovered that numbers have all kinds of intricate relationships. Humans invented the concept and then discovered the relations among the different concepts. Therefore, math is both invented and discovered. It may feel like it's already there, but it comes from the creativity of human beings. Source

Cruise ship Crystal Serenity along with 100 tourists steamed from Alaska to New York through the Northwest Passage for the first time in recorded history.


Paris agreement on climate change.


Higgs boson discovered at CERN on July 4, 2012.

Peter Ware Higgs, a theoretical physicist proposes the electro weak theory and broken symmetry could explain the origin of elementary particle mass in general and W and Z bosons in particular through a Higgs mechanism. This same mechanism was proposed by other physicists about the same time and it predicted the existence of a new particle, the Higgs boson. Both discoveries add support for the Standard Model of particle physics.

On March 14, 2013, the Higgs boson was tentatively confirmed to be + parity and zero spin. Making it the first known fundamental scalar particle to be verified in nature.

Curiosity arrives on Mars and begins to sift soil and rock samples for organic molecules. in 2015 from two different sites it finds evidence of a goopy fossilized building block (kerogen) for oil and gas on Earth were found, sulfur bearing carbon rings, and traces of methane in the atmosphere rise and fall with the season.

Voyger I entered intersteller space on August 25, 2012. In another 40,000 years it will leave the solar system and the Sun's gravitational influence. Source Ed Stone

Google brain project created an algorithm that was capable of learning to identify a cat.


First spacecraft to land on an asteroid and return to Earth is Japan's Asteroid Explorer Hayabusa (MUSES-C). It traveled to Itokawa asteroid and brought back samples. It also was the first to use ion engines to navigate. Source


Scalbard Global Seed Vault on the island of Spitsbergen near Longyearbyen Norway opens. It was created to preserve a wide variety of plant seeds as spare copies held as a worldwide gene bank in case of a regional or global crises. Source


The number of people living in urban areas (cities) is greater than the number of people living in rural areas.


First mammal, Dolly the sheep, is cloned. Followed by dogs, rabbits, pigs, and primates in 2018, with Zhongshan Zhongshan and Hua Hua.


Self flying plane (autonomous vehicle)

A Boeing 737 with a Global positioning system (GPS) landed itself 110 times in a row. Source


Congress killed the Superconducting Super Collider


Confirmed microwave background radiation of the big bang

The COBE ( NASA's Cosmic Background Explorer satellite) team announced they detected the three-degree Kelvin electromagnetic background radiation in all directions of the sky that was emitted 380,000 years after the Big Bang.


Al Gore introduced legislation to create ARAPANET, a public network that became the internet. See 1990, 1989.


Hubble telescope launched April 24, 1990.

The Hubble telescope will collect millions of observations of space objects expanding the size and the universe and the number of known objects in it. See NASA for great photos and more about Hubble.

Tim Berners-Lees and Robert Cailliau utilize ideas of a server, TCP, DNS, HTTP, HTML, URL, and a browser to make the WWW and the first web page at: http://info.cern.ch/hypertext/WWW/TheProject.html

See 1989, 1991.



Tim Berners-Lee designs the Distributed Information System (internet) for particle physicists to communcate more effectively and efficiently. See 1990 and 1991.


Treaty to ban chlorofluorocarbons, to protect the ozone layer, is ratified by 197 countries.


Organ Transplant

Organ transplants were largely unsuccessful because the body rejected the new organ. Thomas Starzl worked for many years to improve on transplant success. First with the drug cyclosporine, approved by the FDA in 1983. Later with tacrolimus, approved by the FDA in 1994. Over his career he investigated: preservation, immunosuppression, infectious diseases, oncology, growth factor physiology, and immunology. The Puzzle People: Memoirs of a Transplant Surgeon. University of Pittsburgh Press.


Micro Computers


Diamond v. Chakbrabarty - Can life be patented

Asked to rule if a patent for a human-made, genetically engineered bacterium capable of breaking down crude oil, a property which is possessed by no naturally occurring bacteria could be patented.

  1. At questions is: are living things patentable?
  2. Does a micro-organism constitutes a manufactured or composition of matter?

Ruled, it was a nonnaturally occurring organism that was manufactured or a composition of matter of human ingenuity with a distinctive name and character of use.

Referenced: 1930 Plant Patent Act, allowed protection of certain asexually reproduced plants and the 1970 Plant Variety Protection Act, protected certain sexually reproduced plants.



Global positioning system (GPS)

Brad Parkinson and his team had proof of the concept for a global positioning system (GPS) . Source


Gossamer Condor, became the first nonstop human-powered flight in 1977. The Condor designed and built by Paul MacCready stayed aloft for seven minutes and flew a figure eight course. The flight won a prize of $100,000, which was offered by British industrialist Henry Kremer 18 years earlier. The Condor now hangs in the National Air and Space Museum in Washington, D.C. More about Paul and ...

Have Blue, the first stealth aircraft designed and built at Lockheed's Skunk Works took flight over Nevada. More

Voyger 1 is launched and continues its voyage.

  • Voyger 1 was launched Septeber 5, 1977.
  • In 1990 the blue dot photo 2,was taken.
  • On February 17, 1998 it became the most distant human made object
  • In 1998 it crosses the termination shock
  • On February 13, 2010 it passes the reach of the solar wind
  • On August 25, 2012 in reaches interstellar space

Pale Blue Dot image

Photo of Earth taken by Voyager 1 between Uranus and Neptune. Original: NASA JP

Three domains: bacteria, archaea, eukaryotesTangled Tree cover Carl R. Woese discovered cells whose 16S rRNA genetic materials were evolutionary older than known bacteria. This discovery resulted in a three-domain (archaea, bacteria, & eukaryote) biological classification system and understanding of how evolutionary differences can be used for classification. His work lead to the separation of prokaryotes into two groups: Bacteria and Archaea. Woese reasoned the differences in genes of these two groups and the eukaryotes (multicellular fungi, plants, & animals) to be classified as three separate domains.

Source The Tangled Tree by David Quammen


First use of precision guided bombs

On July 23rd, laser-guided bombs were used to target and destroy the Than Hoa Bridge and Longbien Bridge. The Than Hoa Bridge was destroyed by a 3,000-pound laser-guided bomb dropped by an F-4 Phantom jet, and Longbien Bridge was destroyed by a 2,000-pound TV-guided bomb. Source


Decoded how DNA is transribed into RNA to build proteins.

Har Gobind Khorana, found that DNA’s four letter codes: A, T, C and G are transcribed into RNA and then translated, three at a time, to build proteins with amino acids. He studied nucleic acids, molecules that make genes, and confirmed the 64 unique three-letter words that determine the order of amino acids needed to make specific proteins.

In 1972, Khorana made a second breakthrough, constructing the world’s first synthetic gene. In 1976 he injected the gene into a living bacterium. Source The Gene


Discover microwave background radiation of the big bang

Detected electromagnetic background radiation that seemed to be coming from all directions of the sky. Thought to be emitted 380,000 years after the Big Bang. See 1992

16 October 3 pm China detonated its first atomic bomb and announces its policy of no first use in a conflict.

Qian Xuesen was born in China. Received a scholarship to MIT gained a security clearance and worked on classified weapons research in the U.S. During the Red scare the FBI revoked his clearance and put him under house arrest. He returned to China and worked on their nuclear weapon program, ballistic missle program, aerodynamics, and systems engineering to control social science and engineering problems (Three Gorges Dam on the Yangtze River). Setting the stage for state ran surveillance to control reality later in 2016. Source

James F. Holland researches and develops combination chemotherapy as a treatment of acute leukemia in children based on two key concepts: first, cancer cells are naturally resistant to chemotherapy, and second, resistance can be overcome more effectively when multiple drugs are given at the same time instead of one after another. His research changes acute lymphoblastic leukemia from an incurable illness to one with a high survival rate.


Treaty to ban atmospheric nuclear testing to eliminate radioactive fallout as s source of pollution is signed.


Silent Spring cover Rachel Carson

Rachel Carson publish Silent Spring where she claims that everything is connected, that we all share the same molecules, and humans have the capacity to destroy nature.
PBS Rachel Carson video 2017 (1:53:11) and Life & Legacy of Rachel Carson

  • Created the environmental movement
  • At 10 she wins a prize for her story published in St. Nicholas Magazine 1918.
  • Graduated Parnassus, Pa. High School 1925
  • Graduated Pennsylvania College for Women (Chatham University) 1929
  • Woods Hole Marine Biological Laboratory
  • Johns Hopkins University MA in zoology in 1932.
  • Wrote 52 short radio programs on marine life called Romance Under the Waters in 1935.
  • Undersea Atlantic Monthly article published in 1937
  • Works at the U.S. Fish and Wildlife Service as a fish & aquatic marine biologist 1939-1951
  • Reader's Digest turned down her article on DDT effects on the environment because it was thought to be too controversial. Chemical companies claimed it was only harmful to bugs.
  • The Sea Around Us prize winning book, published in 1952, a study of the oceans. Followed by The Edge of the Sea in 1955.
  • Japanese seamen on board the Lucky Dragon die of radiation exposure 1954. She asked. How does it take to harm life? How much to kill? Strontium 90. leukemia, birth defects...
  • Help Your Child to Wonder. 1956
  • Our Ever-Changing Shore. 1957
  • Silent Spring published 1962 Relates pesticide effects to radioactive build up. What is a wise use of pesticides?
  • CBS Reports with Eric Sevareid airs The Silent Spring of Rachel Carson on national television 1963. Aired in spite of the fact all sponsers with drew commercial support.
  • Who does the land, air, forest, water belong to? What is the commons?
  • She set out to save a species ... Us.

Big box store architecture can be tracked to 1962 when Walmart, Target, and Kmart stores open a few months apart. Inside stores with huge areas of undivided retail space for customers to purchase large supplies of retail goods and outside big parking lots with easy access to highways to attract shoppers.

Two Telstar communication satellites were launched. The first in July 1962 and the second in May 1963. They enabled the first TV signals, telephone calls, fax images and live transatlantic feed to be relayed from space.


December 1961. President Kennedy authorized the use of defoliants in Vietnam.


The Green Revolution, and Norman Borlaug developed new strains of wheat and rice to use in developing countries for higher yields. He first developed a short strain of wheat and other varieties for Mexico, which increased wheat production three times.

Later, India and Pakistan ask him to help their countries with their agricultural revolution.

He developed techniques to create mutations for finding new hybrids, which he used to develop different strains of wheat, rice, sorgum, millet, cassova, triticale, maize, and tubers. It is estimated these varieties were able to save billions of people from starvation. The down side is the large amounts of chemical fertilizers and pesticides required to maintain the high yields. Source

Laser (light amplification by stimulated emission of radiation) is invented.

Laser is a device that amplifies coherent light by energizing electromagnetic radiation.

The first laser was built by Theodore H. Maiman at Hughes Research Laboratories, based on ideas by Charles Hard Townes and Arthur Leonard Schawlow.

Later applications include: laser pointers, laser surgery, tatoo removal, cutting materials, welding, fiber-optics, optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, instruments to mark targets, instruments to measuring range and speed, laser lighting displays ...


America enters space age

ARPA launched America's first communication satellite (SCORE) into orbit aboard an American Atlas rocket. A previously recorded meassage was loaded onto the satellite before being launched. On December 19, 1958 with a second attempt a radio signal from Earth was able to turn it on and President Eisenhower's pre recorded speech was broadcasted on a short-wave radio frequency from outer space. Message below: Source

This is the President of the United States speaking. Through the marvels of scientific advance, my voice is coming to you from a satellite circlin g in outer space. My message is a simple one. Though this unique means, I convey to you and all mankind, America’s wish for peace on earth and good will to men everywhere.

NASA launced its first satellite, Explorer 1, into space on January 31, 1958 aboard a Jupiter C rocket developed by the team headed by Dr. Wernher von Braun. The primary scientific purpose was to measure cosmic ray radiation in Earth orbit.The experiment, conducted by Dr. James Van Allen, measured a lower cosmic ray count than expected. This lead to the discovery of the Van Allen Belts of charged particles concentrated in space by Earth's magnetic field. Source

Nuclear research

ARPA funded research to investigate the possibility of creating an electron shield, to destroy enemy intercontinental ballistic missiles (icbm), by exploding atomic bombs in the atmosphere. The funding included an actual icbm launch with an atomic bomb that was exploded in the atmosphere to test feasibility (ARGUS test). Source

Investigate the creation of a space vehicle powered by hundreds of nuclear bombs (Orion).

Anthropocene Epoch (present - .01 mya)

Anthropocene Epoch (present - .01 mya) can be identified by the measurement of radioactive traces in organic materials that was alive during the atomic bomb tests of the 1950's and 60's. Might be considered as a sign post, along with the introduction of plastic into the environment, for the extinction of many species. Will humans be among them?


The start of the Space Age
Sputnik launched by the Soviet Union
on October 4, 1957

Sputnik 1, the earth’s first artificial satellite, was launched. Shortly after, two more Soviet satellites were launched, one with a dog, into space. The satellites orbited Earth approximately once every 90 minutes.

Strategic Air Command (SAC) south of Omaha, NE 1957

Under General LeMay SAC employed nearly a quarter of a million men and its hangars contained over 2,000 strategic aircraft, including over 700 B-52s.


Shipping container

was invented and patented in 1956 by Malcolm Mc Lean. He was a trucker who owned and operated a large fleet of trucks.


Solar cell

On April 25, 1954, Bell Labs announces the invention of the first practical silicon solar cell. Originated from Aleksandr Stoletov the first solar cell based on the photoelectric effect in 1894. Source Timeline solar cells

See article on how variation of Sun angle, duration effects the amount of Solar radiation energy (insolation).


MUexperimentStanley Miller created amino acids. His experiment put an electrical charge in a flask with methane, ammonia, hydrogen and water. The results may explain how organic materials were created on Earth billions of years ago.

By The original uploader was Carny at Hebrew Wikipedia (Transferred from he.wikipedia to Commons.)

James Watson and Francis Crick demonstrated a model for deoxyribonucleic acid (DNA) as a double helix twisted ladder. Essential for understanding how genes control the chemical processes within living organisms.


Maria Tharp discovered the Mid-Atlantic Ridge from mapping data.

When Maria transferred data from a 5000 foot scroll onto onto sheets of white linen mapping the bottom of the Atlantic Ocean a length rift valley appeared. Such a ridge was suggested by Wegner's theory of continental drift. However, most people believed continents were to massive to drift so she was told by her superior to redo her work. Later when she did and the results were compared to another map by Bruce Heezen both described rift valleys in the mid-ocean ridge. The results were published and read in 1957, by the ocean explorer Jacques Cousteau. He doubted Tharp’s conclusions and tacked her map to the dining room wall of his ship, determined to prove her wrong. However, after viewing film he took of the Atlantic Ocean floor, he saw a deep valley ridge where Tharp had mapped it. Source "Connect the Dots: Mapping the Seafloor and Discovering the Mid-ocean Ridge" by Marie Tharp, Chapter 2 in Lamont-Doherty Earth Observatory of Columbia

Great London Fog or Big Smog

A five day air-pollution event in the United Kingdom caused by cold weather and a lack of wind to move massive amounts of smoke created by the buring of coal and other fossil fuels for home use, transportation, and industry was believed to have killed 12,000 and sickened 25,000. It led to the Clean Air Act 1956. Source

First amino acid sequence of a protein

Frederick Sanger found a protein is a genetically created sequence of amino acids. He used this ideas to determine the complete amino acid sequence of two polypeptide [protein] chains - bovine insulin A (1951) and bovine insulin B (1952). Next he he determine how amide groups were distribed, and the location of the disulphide linkages which completed his deduction of the structure of insulin, in 1954. Source


Henrietta Lacks died of cervical cancer on October 4, 1951, at age 31. Cells were taken from her body and used to create the HeLa cell line. These cells were found to grow quickly, were very hardy and survived longer than usual human cells. They became widely used in thousands of medical research experiments (cancer, polio vaccine, HIV, effects of toxins and radiation on cells, gene mapping, testing sensativity of cosmetics and other substance on cells, invitro fertilization, ... ). Since the cells were taken without her or her families permission their use and ownership eventually began discussion on ethical and legal use of peoples cells and genetic material. Source


Manhattan Project's Trinity test successfully detonated the first atomic bomb in Alamogordo, New Mexico on July 16, 1945, at 5:29:45 a.m.


Frozen food Clarence Birdseye learned from the Inuit that trout caught through holes in the ice could be frozen instantly in the air (which was 30 degrees below zero) tasted like it was fresh trout when it was cooked later. Unlike when food was frozen in the more usual way. Later in 1944 he developed a flash freezing method to create frozen meals and vegetables and changed the way the world would eat. Provided peole with quality food that wasn't in season. Source and more.

Erwin Schrodinger publishes What Is Life. He answers: " ... how can the events in space and time which take place within the spatial boundary of a living organism be accounted for by physics and chemistry?"


First digital speech encryption system, SIGSALY or The Green Hornet, was developed by Bell Telephone Laboratories and built by Western Electric. The communication was from Washington to London and during WWII. Confidential talks between British Prime Minister Winston Churchill and US President Roosevelt. The system used the highly-secure One-Time Pad (OTP) encryption. Source


Space age

The V-2 missile is fired successfully from Peenemund island off Germany’s Baltic coast. Overseen by German rocket scientist Wernher von Braun.


Penicillin Howard Florey and Ernst Boris Chain isolated, purified, and created a injectable form of penicillin to use as an antibiotic.


A study showed bacteria could develop a resistance to penicillin. Even before penicillin was used to treat infections. However, the idea of killing bad bacteria and an increase in the discovery of antibiotics would accelerate the use of antibiotics in ways to contribute to resistant microbes rather than considering a more targeted and efficient use of antibiotics to reduce the evolution of drug resistant organisms.


DDT was found to kill insects and began to be used extensively as an insecticide. Sprays attached to mowers to spray yards before picnics, shelf paper with DDT embedded, paint, varnish, there were no limits on its use. Thought it would raise the standard of living, rid the world of malaria, fire ants and other pests that caused disease and harmed crops.

DDT poster


1936 - 1938

City planning for green space and community ...

Greenbelt, Maryland, was constructed from 1936 to 1938 by thousands of laborers, through the New Deal programs. Clarence S. Stein was a consultant and created design guidelines. Later Stein worked to preserve the town as an example of socially and environmentally responsible community design that could be a prototype for future desgins. Designs that combined superblocks of houses and apartments that had pedestrian walkways through communal green space which joined to a central area with commercial and recreational structures separate from roads for automobile travel. In addition, the federal government promoted cooperative enterprises and associations in Greenbelt as a way to foster affordability and an enduring sense of community. While the cooperative nature of the towns were deemed a failure, the physical layout of the town was replicated by private developers. Source information related to the political aspects of this social experiment.


Sulfa drug and antibiotics

Sulfa, also called sulfonamide, a synthetic antibiotic with a sulfanilamide molecular structure was the first chemical substances systematically used to treat and prevent bacterial infections in humans. Their effects were first observed in 1932, by Gerhard Domagk who noticed that red dye Prontosil killed Streptococcus infections in mice. Later researchers found the active agent was sulfanilamide, or para-aminobenzenesulfonamide, a metabolic product of Prontosil.


Edwin P. Hubble supported the expansion of the universe with his measurements of shifting spectral lines of light emitted from distant galaxies.


Penicillin. Alexander Fleming accidentally contaminated colonies of bacteria with penicillium and noticed the bacteria in those areas did not grow. He isolated the mold, grew it, and found it contained a substance capable of killing many bacteria that infect humans.

Dirac and the electron wave equation and the positron

In 1928 Dirac presented to the Royal Society of London a relativistic wave equation for the electron. His equation required four wave functions and introduced spins. It included an extra set of solutions with negative values of energy. In 1931 Dirac suggested this implied the existence of the antielectron, or positron. Laer discovered in cosmic rays by Carl Anderson.

The Dirac equation as a path to the concept of quanta, and its role in quantum electrodynamics. by Mario Bacelar Valente


Hans Berger invented the EEG (electroencephalograph) that recorded brain waves. He also discovered the alpha wave.

Atomic 1920 - 1860


Army ward Kansas 1918Influenza pandemic of 1918-1919

An influenza (Spanish flu H1N1) pandemic from 1918-1919. It was the deadliest in modern history. It infected around 500 million people worldwide (one-third of Earth's present population) killing 18-20 million in India and between 20-50 million worldwide. The first case was identified at the U.S. Army infirmary in Fort Riley, Kansas. The point of origin was a farm in Haskell County, Kansas. The story of how this epidemic changed the world is in Pale Rider. More people died from this epedemic than died in World War I. It was the most devastating epidemic in recorded history. See vaccination fact sheet
See also Pandemic related Pod casts with first person accounts and more:
Going Viral: The Mother of all Pandemics


Chemistry: fertilizer, chlorine gas, and zyklon B gas.

Fritz Haber and his team weaponized chlorine gas, which was the first large scale use in, Ypres France, in 1915.

He and Jeroen Bosch created the Haber process, which makes ammonia fertilizer (NH3) from atmospheric nitrogen and hydrogen gas (1909). The first agricultural fertilizer that was not natural (not from animal sources). This creation provided food that saved millions of people from starvation and earned Haber the Nobel Prize in Chemistry in 1918.

Haber left Germany for Switzerland and died in exile in 1933. Nazi scientists found his notes that described a gas called Zyklon B, which Haber’s team had developed as a pesticide. The Nazis used this gas to kill millions in the Holocaust. Source

A commercial video on the social and ethical consequences of scientific work related to Haber's decisions. (35:00 minutes)


X-ray crystallography was found by William Bragg and his son William Lawrence Bragg when they found X-rays could be used to reveal the structure of salt and diamonds. Later in late 1950s the process was extended to discover the structures of proteins and later protein complexes.


Suture technique



Alexis Carrel and Charles Guthrie solved the problem of how to sew (suture) two blood vessels together. Blood vessels being tubular were difficult to sew for several reasons, which were solved by their triangular suture method. Source







Vitamins as essential for health were recognized by Casimir Funk, who collected information about human diseases, beriberi, scurvy, and pellagra, and concluded they were caused by a chemical deficiency of amine compounds. Thus, he called them vital amines. Which was later shortened to vitamin when it was found not all vitamins contain amines. See the discovery stories five vitamins:

  1. The Case of the Night-blind Fishermen - vitamin A
  2. The Case of the Wobbling Hens - vitamin B1, thiamin
  3. The Case of the Volunteer Victims - vitamin B3, niacin
  4. The Case of the Pine Needle Soup - vitamin C, ascorbic acid
  5. The Case of the Invisible Rays - vitamin D


Ford assembly line

Henry Ford used standardized parts and an efficient assembly line to create an affordable car for the common man. A car every 22 seconds rolled off the line.

Critical discovery to measure the size of the universe with variable stars

Henrietta Swan Leavitt observed Cepheid variable stars in the Small Magellanic Cloud and discovered their brightness was greater the longer it took them to complete one cycle. This period-luminosity function of Cepheid variable stars provided a way to move beyond the use of parallax to measure distances to stars.


The pure food and drug act was the first consumer protection law to protect the American food supply. It was the passed by Congress. American women, doctors, and editors helped Congress to pass the bill.

The Jungle by Upton Sinclair kept public attention on the importance of food inspection laws to insure a safe meat supplly from meat packing plants.

Later congress created the Food and Drug Administration (FDA) to ban foreign and interstate traffic in contaminated and mislabeled food and drug products. To achieve this:

  • It directed the U.S. Bureau of Chemistry to inspect products and refer offenders to prosecutors.
  • It required labels to identify active ingredients
  • Required products to be within purity levels established by the United States Pharmacopeia or the National Formulary.
  • Today the FDA is responsible for protecting and promoting public health through the control and supervision of food safety, tobacco products, dietary supplements, prescription and over-the-counter pharmaceutical drugs/medications, vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices, cosmetics, animal foods & feed, and veterinary products. Source

The Poison Squad is a book that tells the story of how its first chief chemist: Harvey Washington, citizens, and government can work together in meaningful ways for consumer protection.


Nettie Stevens Discovers male chromosome determines sex

Stevens observed a difference between female and male mealworm sex cells. She noticed the sperm had two versions of their 20th chromosome: a smaller version and a largeer one. She then concluded the spermatozoa, which contains the smaller chromosome determines a male mealworn, while spermatozoa that contains 10 equal sized chromosomes determines a female mealworm. She did not call them X and Y chromosomes. That terminology was coined later. Source

1902 +

Chemical fertilizer (Nitrogen)

Haber developed a process that used nitrogen (N2) and methane (CH4) gas to make ammonia (NH3) economically. Bosch conducted more than 20 000 experiemnts to find a catalyst and industrialize the process. It has been used to produce so much fertilizer that about 50% of all nitrogen atoms in humans today come from the Haber-Bosch process.

Wilhelm Ostwald used the ammonia (NH3) from Haber's process and developed an additional process to produce nitric acid (HNO3).

Nitric acid ammonia can be mixed to make a more neutral compound ammonium nitrate. It is a good fertilizer because it has a high concentration of nitrogen and can be stored and blended with other fertilizer components. Source


The era of big oil began ( January 10, 1901, ) when a well at Spindletop (Beaumont, Texas) struck oil at a depth of 1 139 ft. The Lucas Gusher went 150 feet in the air and blew 100,000 barrels (4 200 000 gallons) per day for nine days before it was capped. Beaumont became a boomtown as its population grew from 10 000 to 50 000 in three months.


One in 38 railroad employees was injured on the job - and 1:399 died. Source Doctors Derailed: How Railway Surgeons Advanced Medicine. Discover Magazine. July/ August 2016.


The Chlorine Revolution started in Jersey City, NJ when the water supply from the Passaic River was contaminated. To provide a clean water supply the city contracted Patrick H. Flynn to develop a new source. Twenty-three miles west of the city on the Rockaway River a dam was built to create a reservoir. However, after the contstruction there were several times a year rain would cause the sewage system to overflow and contaminate the water. The city claimed the engineer should have planned better and refused to pay for the construction. Flynn consulted with Dr. John L. Leal who believed bacteria contaminated the water and suggested it could be treaated with chloride of lime (chlorine). The water was treated succesfully, the judge accepted the soution, and ordered the city to pay for the construction. Source The Chlorine Revolution: Water Disinfection and the Fight to Save Lives, by Michael McGuire, 2013. Purified water has saved millions of lives and raised life expectancies by some estimates forty years. See Chlorination and public health


The Food ExplorerDavid Fairchild was a botanist, financed by Barbour Lathrop who convinced James Wilson, the Secretary of Agriculture, to accept seeds and plant cuttings David ships to DC to distribute to farmers to diversify American food production. He shipped magoes and dwarf oranges from Jamaica, avocadoes from Santiago, Chile, fava beans and broccoli from Venice, Italy along wiht seedless grapes: purple sultanina, and light-green varieties to become raisins. Kale from Croatia and hops from Polepy, Czech Republic. He also brought Cherry trees from Japan as ornamentals for his garden that became the inspiration for the DC tidal basin cherry blossoms that was a gift from the city of Tokyo.

Source The Food Explorer: The true adventures of the globe-trotting botanist who transformed what America eats. by Daniel Stone


Radio waves

Guglielmo Marconi, an electrical engineer explored long-distance radio transmission, and developed Marconi's law and a radio telegraph system. Often credited as the inventor of radio, An entrepreneur, businessman, and founder in Britain in 1897 of The Wireless Telegraph & Signal Company. Later the Marconi Company, built on the work of previous experimenters and physicists, and became a commercial success in radio.


First fiber glass. Charles V. Boys used a cross bow, a hot glass rod as an arrow that he heated to the point of melting, and then fired it. The result was a few microns diameter thread 30 m long. He found it to be very strong and used it to build devices to measure radiation and gravity. Unknown to him it was the first fiber glass. Source


First book on soap bubbles: Soap -Bubbles and the Force which mould them


First use of the term scientist. The British philosopher, William Whewell, at the British Association for the Advancement of Science. suggested that since the practitioners of art are called artists, then the practitioners of science ought to be called scientists. Suggesting they should no longer be called philosophers.


Pullman Company town

Pullman's philosophy was, happy workers make more productive workers and the quality of his company owned and maintained houses were good for worker housing. As a result the majority of Pullman employees lived in his houses, which contained two to seven rooms with each having direct access to a private yard, woodshed and paved alley. A variety of housing types were available within each block and from block to block designed to meet different income, status, and family makeup. Source

1880 + -

Light bulb and electrical systems. Joseph Swan installed light bulbs in homes and landmarks in England in the early 1880's. His house was the first in the world to be lit by a lightbulb and the first house in the world to use hydroelectric power. Others who worked on the light bulb: Henry Woodward, Matthew Evans, William Sawyer and Albon Man.

The home of Lord Armstrong at Cragside was also among the first houses to be lit by electricity. He started his company and lit the Savoy Theatre in the City of Westminster, London making it the first public building in the world to be lit entirely by electricity.

Around the same time Edison found how to make longer burning light bulbs using: 1. a more effective incandescent material, 2. creating a higher vacuum in the bulb, and 3. using a high resistance. Higher resistance also allowed power to be distributed from a central source, making an economical sytem. This lead to a completly integrated system of electric lighting with a centrally located massive generator and a parallel-distribution system. All built by the Edison Illuminating Company of New York that could supply electricity to 59 customers in a square-mile area of lower Manhattan. Thus Edison's genius was not only the light bulb, but the system to make it work in a community.



Andrew Carnegie returned from England in 1872 having learned about the Bessemer process for making steel. He increased the scale of the furnace and built his first steel mill, Edgar Thomson Steel Works, in 1875 in Braddock, Pennsylvania, (near Pittsburgh).

For the first time steel could be mass produced inexpensively. This first mill was so successful Carnegie was able to use the profits to buy other Pittsburgh steel mills and create the Carnegie Steel Company in 1892.


Barbed wire. Joseph Glidden was granted a patent for barbed wire on November 24, 1874. He went into partnership with a merchant, Isaac Ellwood, and they formed The Barb Fence Company. Source of invention.

DDT was synthesized in 1874. However, it was not until 1939 that it was discovered it could be used as an insecticde.


National Weather Service established


Transcontinental railroad was opened for through traffic on May 10, 1869 with a ceremonial driving of the last spike. The spike, referred to as the golden spike, was driven with a silver hammer, at Promontory Summit, Utah.

Riverside, Illinois was the first planned suburb, and the Chicago suburbs of the mid-19th century weren’t exactly suburbs yet but towns near the downtown.

Periodic Table of Elements was created by Demitri Mendeleev. Source

Mendeleev’s , Demitri Mendeleev, presented to the Russian Chemical Society in March, 1869 his Periodic Law. He stated, “... elements arranged according to the value of their atomic weights [today atomic mass or number is more accurate] present a clear periodicity of properties.”

His version had 70 elements with gaps where he believed unknown elements belonged. Using the properties of periodicity he successfully predicted properties for three or the gap elements. Source

Periodic table today


First Planned suburb

Riverside, Illinois was the first planned commuter suburb. It was a suburb of Chicago Illinois accesible by train. Although at the time it wasn't known as a suburb, but as a town near the downtown. While towns were designed in a familiar checker board fashion, Riverside was the first where roads were curvalinear and didn't meet wiht 90 degree angles. Designed by Frederick Law Olmsted. Source

First Canned meat

Deviled ham meat spread was first canned in 1868 by the Underwood Deviled Ham company. The company was found in 1822 by William Underwood who then packed food in glass containers. In 1836 he changed to steel cans coated with tin.

Underwood® Devil logo is thought to be the oldest food trademark. Source

Underwood Deviled Ham Spread Ad


Speed of light, was measured as 298 000 km/s by Léon Foucault who used an improved method to measure the speed of light.

1861 +

Maxwell's electric and magnetic equations:
James Clark Maxwell's
published equations to describe how electric and magnetic fields are generated, interact, and are changed by each other and their charges and currents.

Explanation of Maxwell equations

Industrial 1860 - 1500


Oil well
he first successful oil wells was drilled in northwestern Pennsylvania. Known as the Drake Well, after "Colonel" Edwin Drake. It began an international search for oil and energy use for the next hundred... years... Source


Can opener invented
Ezra J. Warner invented and received a patent for the first can openerin 1858. It used by the US military in the civil war.

In 1866 William Lyman improved it with a wheel that rotated along the top rim of the can and received a patent for it in 1870. Source

1855 + -

Elevator, lifting devices with ropes and pulleys were described and used by Archimedes, in the Roman Colosseums, Louis XV, and others. However, they were slow and unreliable with the use of ropes, which could wear out and fail. In 1852, Elisha Graves Otis invented a safety break in 1852 that changed that. If there was a cable break, a spring would push pawls on the car into position racks on the sides of the shaft and hold the car in place. Such a devise was installed at a five-story department store in New York City in 1857.

Commercial passenger elevators allowed the building of the world’s first skyscrapers opening cities to an explosion of population and real estate value as building rose literally hundreds of floors. The Otis Elevator Company, is a subsidiary of United Technologies Corporation, the world's largest manufacturer of vertical transport systems. Source



Dr. John Snow investigated the death of over 500 people, in the Golden Square neighborhood of London. He collected data on where the dead people had lived, mapped it, and his analysis lead him to discover a geographic relationship to indicate the source of the cholera epidemic as a local well. He recommended the removal of the pump handle, which the St. James Parish ordered done.


Dr John Gorrie, found that when yellow fever patients were cooled with ice, they had a better chance of recovering. Being in the south ice was only available when it was imported from New England. To make ice available all year he explored how make ice with refrigeration and cool rooms with air conditioning. His invention was granted a patent for a machine that made ice by compressing and cooling air. Source


A Drop of London Water, from Punch, 1850

Drop of water



Guano as fertilizer
Europe and other countries with depleated soils sought ways to keep their soils fertile. One was to add manure to the soil. A recent discovery of on Peru's Chincha Islands was mountains of bird excrement several hundred feet deep in places. The guano deposits were high quality and with a high demand, the idea that a fortune could be made sent investors to the region to mine and sell guano as fertilizer. Soon countries were exploring the world for other areas rich in Guano and claiming mining rights. Wars and territorial disputes developed.


Friedrich Wilhelm Bessel used parallax to calculate the distance to the star, 61 Cygni, and concluded it was 10.3 light years.


England deliberately exterminated beavers in the Oregon Bridge Creek to keep trappers (particularly U.S.) from going into Oregon and claiming the Territory for the United States.


Renѐ Laennec was a muscian and physician who invented the stethoscope. He recorded his first observations of the heart as musical notation and pioneered listing to chest sounds to diagnose various medical conditions.


Preservation of food was perfected by Nicolas Appert who preserved fruits, vegetables, meat, soup, and milk by boiling and storing them in airtight glass containers. It was developed so Napoleon could feed his troops in the field. Source


Eli Whitney invents the cotton gin and its effect on slavery

Whitney had a genius ability to reconize an develop innovations. In South Carolina he observed how hard it was to remove seeds from cotton so he invented the cotton gin, a machine that could clean ten times as much cotton as a slave by hand. Source


James Madison recognizes that a census could be a scientific method to decide how to distribute political power. If a census were conducted every ten years, the data could be used to determine how many representatives each state would have. Therefore, a way to guarantee the House of Representatives would equably represent future population changes.

  • His idea was mandated by Article I, Section 2 of the United States Constitution.
  • The first census of the United States that recorded the population of the United States as of Census Day, August 2, 1790.
  • A scientific accurate census can provide information to make wise social, economic, health, medical research, technological, and other important decisions.
  • If conducted well it becomes a valuable source to create representative samples for quality research.


Immanuel Kant (1724-1804) Philosopher

Kant claimed that everything we know is a construction by our perceptions, which are shaped by our minds abilities and lack of abilities, of what we percieve as our observations of the world. It is our empirical intuition and subjective reasoning about these perceptions we synthesize and recognize as our consciousness and existence and understanding in the world with our observation and reasoning. That pure reasoning (rationalism) without observable data would lead to illusion about the world. Understanding is a function of imagination that bridges thought and perception of observable data to allow us to believe our consciousness exists and there are objects and events in our world which we can discover and understand with our reasoning.

Critique of Pure Reason (1781).



Steam engine

James Watt improved a Thomas Newcomen version of the steam engine making it available for work and the industrial age. He added a separate condenser so the cylinder could be kept heated with each stroke, a shaft that rotated instead of movint up and down, and other improvements to make it practical for multiple uses.


Emile cover Jean-Jacques Rousseau - (1712 -1778)

Wrote and published Emile or a Treatise on Education.

The book is considered the first educational philosophy book as well as the first child psychology book.

Rousseau claims children have a natural goodness and can become critical life long learners and educated citizens if they can survive a corrupted society.

Rousseau is sometimes referred to as the father of modern child psychology.

Also: Education timeline - Rousseau


Washington Crop rotation

George Washington experimented with crop rotation on a three year cycle and five year cycle. He drew elaborate charts that showed how he divided his fields and the amounts of crops was equalized with flax, hay, clover, buckwheat, turnips, and potatoes being rotated through different fields. Later he expanded to a seven year cycle as shown in the table. See also Townshend crop rotation.

Washington's crop rotation table


Classification system

Carl Linnaeus created a systematic framework for the classification of animals and plants based on visual observation of related properties among organisms. Any classification system opens debate to how general or specific the differences between the relationships used for classification should be. Deciding if properties should be widened or narrowed to include more or less species of organisms in a group.


Townshend Crop rotation

Charles Townshend, investigated a crop rotation based on Dutch and Flemish farming practices. His experiments found crops grew better with fewer weeds, fewer pests, and returned nutrients to the soil when he rotated crops through four years: wheat in the first year, clover (or ryegrass) in the second, oats or barley in the third, and turnips or rutabagas in the fourth. See also Washington crop rotation.


Principia Mathemaatica coverIsaac Newton

  1. Published Principia Mathematica
  2. First claimed ... Forceg = G * ((M1 * M2) / d2)
  3. 1660's demonstrated white light is all colors.





Adapted from Isaac Newton [Public domain], via Wikimedia Commons


Leeuwenhoek microscopeAntonie van Leeuwenhoek used a simple magnifying glass to observe the quality of fabric. He later ground lenses and refined his method for better magnification. He left 247 microscopes and 172 lenses, nine microscopes are known to have survived with a magnification of up to 200 times. The best microscopes of the time. He was the first to observe and noted: protozoa, bacteria, red blood cells, spermatozoa, and closer observations of other organisms. The microscope provided the technology necessary for microbiology and cell biology. Thanks ... Antonie van Leeuwenhoek


Boyle's Gas law and a vacuum

Robert Boyle and Charles Hooke used a vacuum pump, invented by Otto von Guericke (1649), to investigate the properties of air and properties of a vacuum: sound does not travel through a vacuum, but magnetism does, liquids vaporized quicker in a vacuum, animals died in a vacuum (see famous public bird demonstrations), and animals could be frozen. The importance of the relationship of temperature and pressure wasn't realized until much later with refrigeration and heat pumps.

Their first discovery of air properties is Boyle’s Law. They used a glass tube and filed it with different amounts of mercury to vary the pressure on a fixed weight of air. They discovered that pressure times volume equals a constant (p*v=c) if temperature was constant. In other words, when you increase the pressure on a gas, the gas’s volume shrinks proportionally. It would be a few years before Charles discovered the next gas law in 1787.

Boyle's air pressure experiment


First vacuum & first barometer

Evangelista Torricelli used a suggestion by Galileo and filled a 4 foot glass tube with mercury and inverted it into a dish of mercury. He observed some mercury flowed out of the tube and left a space in the tube above the mercury. Being sealed he concluded the empty space was a vacuum. From his day to day observations and observations from moving it up a moutain side, he concluded the variation of the height of the mercury was caused by changes in the amount of air above dish of mercury pushing down on it, atmospheric pressure. His experiments on air and vacuums explained why water pumps at that time were unable to raise water more than about 33 feet. His ideas would related to Boyles Gas law and engines.


First printing press in the American Colonies is assembled at Harvard College.


Bacon image

Sir Francis Bacon (1561-1626) published his Novum Organum, where he describes a system of logic he believes is superior to Aristotle's syllogism (360 BCE ) or deductive reasoning. It becomes known as the Baconian method, inductive reasoning and the scientific method. Bacon may have been inspired by Ibn al-Haytham’s Optics (Kitāb al-manāẓir).

He believed it was the best way to draw conclusions about the natural world. An inductive approach of skeptical observation and experimentation with facts and explanation leading to conclusion. Because of this he has been called the father of empiricism and the father of the scientific method.

"British - Francis Bacon - Google Art Project" by British (School, Details of artist on Google Art Project) - UwEFEzZpMHs4JA at Google Cultural Institute, zoom level maximum. Licensed under Public Domain via Commons.


Galileo Galilei (1564-1642) Published Starry Messenger (1610).

  • Turned his telescope upward and observed the mountains of the moon, additional stars, planets orbiting the Sun, and four moons orbiting Jupiter; then wrote about it in Starry Messenger.
  • His stance that facts should govern life not belief and support of the Copernican theory (Earth orbits the Sun) got him put under house arrest, forbade him to write any more, and wasn't allowed visits by mathematicians. 1633. Source
  • Dropped different sized canon balls of the Tower of Pisa and demonstrated that heavy and light objects fall at the same rate.
  • Explored inertia and friction. Source

Pre industrial revolution

Co2 in atmosphere was 270 parts per million.


The Gregorian calendar / Western calendar / Christian calendar, is named for Pope Gregory XIII, who introduced it in October 1582.


Nicolas Copernicus used his calculations to support the idea the Sun was the center of the solar system with planets orbiting around it.


In the late 1400's on the Murano island, (Venice) glassmakers developed cristallo, a transparent colorless glass, that could be made into plate glass, polished, and backed with lead and antimony to make a rough surface with a dim reflection.

In 1507 Andrea & Domenico d'Angelo del Gallo brother glassmakers on Murano improved the method by applying a mercury-tin amalgamon the backside of the high quality transparent glass. This revolutionary technique was so valuable the Republic of Venice forbade any glassmaker from leaving the island. Eventually the technique made its way to France and beyond.

The production of high quality mirrors lead to study and experiement with light in new ways as wel as to artist who culd study their own images and create for the first time self-portraits.


Printing with movable type

Johannes Gutenberg, invented printing with movable type. Small metal prisms (lead) that were cast precisely and in large quantities so they could be set into a grid, used, reset, and used again. He also used a new press, similar to those used in wine making, new papermaking and bookbinding techniques, and an oil-based printing ink. All improvements to Chinese or Korean printing, or current European printing by stamping letters on a surfaces or woodblock printing. Source


Black Death wiped out half of Europe. The Black Death or bubonic plague, is caused by the bacterium Yersinia pestis transferred from wild rodents to humans.


Glassmaking becomes industrialized when the Venetian Republic, thought the 1 000 degree furnaces for the city’s mostly wooden buildings might be a problem. The solution was to order glassmakers to move their foundries to the small island of Murano nearby. The move brought many glassmakers together and Murano became a hot spot for glassmakers to develop and maintain their craft and art of quality glass making to today. Source


Magnetic compass

Chinese scholars discovered a needle could be heated till red, held in a north south orientation, and cooled. Then when it was floated in liquid or suspended on a silk thread it would point north and south. Therefore, it was valuable for navigation and used by the Song Dynasty, China, for military navigation around 1040 and later for maritime navigation around 1111.

Earlier, around 206 BC, magnetic devices were used to divine wisdom in the Han Dynasty around. Source Smith College Museum of Ancient Inventions


Book cover Optics

Optics was written between 1028 & 1038

Ibn al-Haytham’s most important work: Optics (Kitāb al-manāẓir).

  • Described scientific discovery as observation reasoned with induction in a cautious manner to make conclusions without being swayed by opinion. Influenced Roger Bacon
  • Combined experiments with mathematical reasoning.
  • Includes an accurate model of vision, laws of reflection, refraction with the relationship between angles of incidence and refraction, and describes motion in mediums with different densities.


See: 1001 Inventions and the World of Ibn Al-Haytham and A Journey of Science from Darkness into Light.

City state and Agriculture: 1 000 C. E. - 10 000 BCE


Mysterious fog plunges Europe, the Middle East, & west Asia into darkness for 18 months.

"For the sun gave forth its light without brightbness, like the moon, during the whole year" Procopius

Temperatures fall lower temperatures cause snow in the summer, crop failure, people starve, Irish and record wheat failure from 536-539. Later in 541 a plague in Pelusiam, Egypt (known as the Plague of Justinian) spread killing 33-50% of the eastern Roman empire population, contributing to its collapse. Tree ring esearch in 1990 supported that summers around 540 were unusually cold. Later in 2018 ice from Swiss glaciers suggest a cataclysmic volcano erupted in Iceland in 536 and two more massive eruptions in 540 and 547. It is believed these eruptions caused economic problems that reduced trade and manufacturing until around 640 where ice samples indicate and increase of airborne lead from silver smelting. Source


Mouth harp discovered in the Altai Mountains in Russia measured about 4.3 inches long and 3.3 inches wide and can still make music. Source

300 - 400

Hun's range


Nomadic tribes of Northern Asia invaded China, eastern Asia, and Europe. With superior horse skills and the stirrup destroyed villages, the current political structures, and changed peoples lives.


Mount Vesuvius, near the Bay of Naples in Italy, erupts in 79 and buries Pompeii in ash preserving artifacts to be found later to see how Romans lived during this time. Source

The ancient Roman town of Baia, a fashionable resort for Romans, on the shore of the Gulf of Naples, sank into the sea also as a result of Vesuvius volcanic action.

C. E. -------------------- B. C. E.

37 BCE

Cement - Romans made cement and used it to make concret for water pipes, docks in harbors ... Source

240 BCE

Calculated size of the Earth

Eratosthenes, heard of a well in Syene that on summer solstice (June 21) the Sun light up the well right down to the water and cast no shadow on the side (meaning the sun was directly overhead [zenith]). On the same day the Sun, in Alexandria, was 7 degrees off the zenith (point directly overhead). Using geometry he calculate the Earth's diameter as 12,800 km or about 8ooo miles around the poles and equator. Source explanation of measurement

310 BCE

Sun centered solar system

Aristarchus of Samos, built on Herakleides Sun centered theory and described accurate orbits of Earth and the Sun's other planets encircling it and the orbit of the Moon around the Earth. This symbolically marks the end of Greek scientific philosophy as those who came after stuck to myths that put the Earth at the center.

350 BCE

Babylonians use a trapazoid to predict Jupiter's motion across the sky.

Numbers inscribed in a clay tablet calculate the distance Jupiter travels by charting the plantet's motion (velocity) over 60 days. The results forms a right-angled trapezoid with a downward slanting top. With the area equal to the distance Jupiter traveled. See Babylonians Tracked Jupiter with Fancy Math. By Megan Gannon, February 1, 2016: Scientific American.

360 BCE

Aristotle - 380 - 322 BCE

Explanation with rhetoric and logic. While Socrates and Plato used reasoning Aristotle developed a system of rules and strategies, syllogism, that was the begining of logical deductive reasoning (as opposed to inductive reasoning). Reasoning in which a conclusion is drawn (validly or not) from propositions (premises) that share an idea not present in the conclusion, for example. Categorical syllogism, uses two premises and a conclusion:

  • All humans are vertebrates; no insect is a vertebrates; therefore no humans are insects.
  • All dogs are mammals, all mammals are animals, therefore, all dogs are animals.

Believed there was a natural order to the world that could be determined with logic without observation. Objects would naturally come to rest (without a force acting on them). Solid objects would fall to Earth, because that was their natural place to be. Believed forces were requird to keep things moving. He had no concept of inertia. See Galileo and Newton.

Aristotle claimed heredity needs a message and material to explain how traits were passed from parent to children to grandchildren and beyond. He recognized Pythagoras ideas needed to be extended to include information from the mother and ancesters from both sides of the parents. He claimed there was mutual contributions of information passed in the male in the semen and female in the blood.

380 BCE

Petra is an acient city carved in rocks by the Nabataeans in the desert of southern Jordan. See - Nova video (53:05)
Nabataeans created an irrigation system for their city's water needs. To do so they needed to solve several problems so water could be moved a long distance. They needed to find what shape and size of pipes, how to manage sediment and clogging, how smoothness of pipes and flow rate delivered appropriata amounts of water. For example, rapid flow creates ripples and reduces water volume compared to a smooth flow; and shape, size, smoothness, and slope of pipes affect flow. Nabataeans learned how to manage these problems and found a 2.5 degree slope worked for an efficient water flow. Excavations show how the Nabataeans created a water supply system for the desert city, an artificial oasis, with flood control multiple dams, storage in cisterns, and water transported in conduits from sources miles away. Source for detailed descriptions of Petra's Water supply and distribution.

Image source Bernard Gagnon (Own work) [GFDL or CC BY-SA 3.0], via Wikimedia Commons

More information and images for Petra.

400 BCE

The idea of atoms

Democritus - 470 - 370 BCE

Democritus considered all matter was made of atoms, which were small, invisible, surrounded by space, could not be subdivided, and lasted forever. There were an infinite number of them that make up the physical world. They were different in shape, arrangement, position, and magnitude. He also believed space was a void or vacuum that was infinite. Source


A horseshoe is essential to protect the foot of horses if they are to be used productively for agriculture and transportation. They protect the foot from repeated wear and cracking in dirt, mud, and on rock.

Early protection was created with leather or other materials wrapped around the foot and fastened with thongs. Sometimes metal or other materials were inserted inside the boot shaped material. Literature includes early reports of shoes of bronze, silver, and gold being on horses of important leaders.

With the development of iron it would provide a much better material and along with the idea of fastening to the foot with nails. Sine iron was valuable and could be melted and reused, it makes discovery of it in archaeological digs more unlikely.

Sculptures of horses with shoes are rare, but a few are known.

Four bronze horseshoes with nail holes were found in an Italian tomb dated around 400 B.C.E. Source

What are the pros and cons between horses, mules, and oxens as what is best for ... Consider strength, speed, health, and food requirements ...

415 BCE

Hippocratic oath

Hippocrates is a Greek physician who is regarded as the father of medicine. Around 60 medical writings have survived with his name, many probably not written by him.

  • First written information about the flu 412 BCE
  • Best known for the Hippocratic Oath, which bears his name, but he may not have written, and the high ethical standards it sets.

407 BCE

Plato and Socrates

Explanation through Dialectic reasoning or dialectics (Socratic method, Hindu, Buddhist, Medieval, Hegelian dialectics, Marxist, Talmudic, and Neo-orthodoxy.), and modern debate. All involve conversations between two or more people arguing different points of view for the purpose of establishing truth with reasoned argument.

Socrates valued truth as the highest value. Truth discovered through conversation with reason and logic (dialectic reasoning). Logic, not emotion, to discover truth for persuasion and make choices to guide one's life. To Socrates, truth, not art, was the greater good to guide one's life. Therefore, Socrates opposed the sophists and their teaching of rhetoric as art and as emotional oratory requiring neither logic nor proof.

480 BCE

Sophists - 480 - 390 BCE

The first teachers of rhetoric, the art (arte) and process of effective public speaking, in the Greek world were known as the Sophists, or wise men. They taught by example skills of civic life and explored a wide range of human experience within Greek culture. Not being of Athens they often clashed culturally and philosophically with the Athenians.

Rhetoric is a method or art of speaking or discourse/ conversation to persuade, inform, or motivate an audience. Concepts of rational appeal (logos), emotional appeal, (pathos), and ethical appeal (ethos) are all intentionally used to persuade and convince people of a particular idea or argument.

They taught art had the highest value in life and it should be used to make choices and to seek it out in all things. To them the artistic quality of a speech or oration was its power to motivate, influence, and please people. Therefore, oration was taught as an art form, which was used to please, motivate, and influence other people through quality speaking. Maybe the historical basis for Declamations which are students interpretations of famous speeches they regive to demonstrate their ability to understand and apply the purpose and power of the speech and skill in public speaking. Samples

500 BCE

Buttress Source

Parmenides, (515-430BCE) Greek philosopher, is known to use logic with an extended arguments for his views rather than just a view of reality. However, he never systematically studied or formed logical principals, proofs, for valid arguments.

530 BCE

Pythagoras lived in Croton, Greece. His work included.

  • Made famous a theorem for the area of right triangles.
  • Explained the similarities between parents and children were caused when semen travels throughout a male body, where it absorbs mystical vapor from all parts of the body to create a blueprint to build a baby so when the semen is transported to the mother to provide a message with instructions for the female to provide the matter to build and nourish the fetus. Which he wrongly thought was the only purpose of a female in reproduction. This became known as spermism. See Aristotle

750 BCE

The Great Dam of Marin on on the Wadi Adhanah watershed, near the ancient city of Ma'rib the capital of Saba (a prosperous trading nation, with control of the frankincense and spice routes in Arabia and Abyssinia) was built in eighth century BCE may be the oldest dam. Source

1 450 BCE

First artificial hand? Bronze and gold artifacts that resemble a hand may have been used for rituals. Source

1 500 BCE

Mediterranean Sea MapWater and sewer system

Minoan plumbing, sewer, and storm drainage was well developed when the Minoan civilization flourished on the Isle of Crete in the Mediterranean Sea from 2600 to 1600 BCE. Source

  • About 1540 BCE a Volcano on Thera, an island 70 miles away from Crete, caused earthquakes and tsunamies that severely impacted Minoan settlements in the Mediterranean.

1 754 BCE

Water regulations

King Hammurabi, wrote a code to regulate water usage:

  1. The distribution of water based on the acres farmed.
  2. Required each farmer to maintain the canals on his property.
  3. Required the collective administration of the canal by all users.

1 920 BCE

China's Great Flood

China's first Emperor, Yu, is said to have tamed a great flood. Researchers have found evidence of a landslide and flood on the Yellow River around 1920 BCE. Source Finding China’s Great Flood New study finds truth in an ancient myth. By Bridget Alex|Wednesday, December 21, 2016

2 000 BCE

Iron production has been dated to 1500 BC at a variety of sites in Niger where production sites and iron objects were found and dated around 2000 BCE +- 500 years. Source

Atlantis symbolAtlantis

Greek philosopher Plato wrote about Atlantis in 360BCE in his dialogues where he describes it as an island city by the straits of the Pillars of Hercules, today Straits of Gibraltar. Over the years people have searched for this lost city. Recent research suggests it might have been located near Spain.

Image is symbol for Atlantis.


2 650 BCE

First dentist Hesy-Re's tomb had panels that described him as chief of dentist and physicians. Source

1 000 - 4 000 BCE

Cities founded

  • 1045 Bejing
  • 1100 Kirkuk
  • 1500 Balkh
  • 4000 Faiyum
  • 4200 Sosa

2 480 - 3 000 BCE

Stonehenge near Amesbury, UK is built. Source

4 000 BCE

Irrigation Nileometer image

Egypt and Mesopotamia (present day Iraq and Iran) use flood water from the Nile or Tigris/Euphrates river to water crops.

The Egyptians use a verticle column (Nilometer) and a series of stairs to measure the depth of water. Several still exist and can be seen today. Source Image source: Baldiri (Own work) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons

3 000 BCE The first reservoir may have been made by King Menes along with dams and canals to diverted water from the Nile into Lake Moeris. Source

Eribil became a city.

4 000 BCE or ≈ 6 000 years ago

5 500 years ago

Horse domestication might have begun on the Kazakh steppe with the Botai. Riding horses vastly changed human civilization and as humans changed the horse genome changed. Source

6 400 years ago

Feline domestication, as indicated by DNA, began in southwestern Asia through southeast Europe 6 400 years ago.

7 000 years ago

Breeding of dogs in Siberia. Skulls were measure and their ratios of snout height to skill length and cranium height to skull length distinguished them as dogs. Dogs werebred to be large enough to pull a sled, but not too large to overheat. Source

8 000 years ago

Rock art with dogsRock art shows domesticated dogs used to hunt. Dogs on leash were maybe being trained. Source Science

Potato domesticate in Peru.

Catalhoyuk, Turkey citizens lived in houses that were built and supplied in a manner that suggest equality with no apparent leadership. Artifacts also suggest domestication and use of clay appears to have affected the environment in harmful ways: as evidence of deforestation, extensive burning, erosion and of large-scale grazing were also found. Source

9 000 years ago

Kennewick man lives in Washington and shares DNA to today's Native American tribes of the Coville Reservation as suggested by his skeleton found in Washington.

Olmec Domesticate maize, corn.

Jericho became a city.

10 000 years ago

Domestication of sheep in the Mesopotamian area for: food, clothing and shelter. The use of wool developed over time as the quality of wool needed to be bred for more fleece with finer fibers and less kemp. Source Sheep industry fact sheets

Hunter gatherers: prior 10 000 BCE

.01 million (10 000) years ago (Cenozoic Era, Quaternary Period, Holocene Epoch .01-1.8 mya )

Measurements of Greenland ice packs show an increase of temperature, as measured by hydrogen chemistry, that shows an end of the ice age.

10 000 years ago ...

Food production center of the world

One might think many hunter gatherer societies stumbled upon domestication and took up farming. However, this seems to have happen only nine places around the world: Fertile Crescent, China, Mesoamerica, Andes/Amazonia, eastern United States, Sahel, tropical West Africa, Ethiopia and New Guinea.

History from now until today includes many tales of hunter gatherer societies being driven out, infected, conquered, and exterminated by farming societies where farming is possible. Except the Huns and Atilla see 300-400 & 1225.

Hunter gatherers of the Fertile Crescent domesticated wheats, barley, peas, sheep, goats, cows and pigs to become the first farmers and herders, beginning around 8500 BC. This led to major changes: shorter birth intervals (from four years to one year) political changes (social classes, kings, soldiers, empires, professional armies), and technology (metal tools, writing, ...). These were tools of conquest and allowed them to spread into Europe, North Africa, western India, and central Asia. However, having no other advantages power shifted to Greece then Italy and then to northwest Europe. While human societies in the Fertile Crescent inadvertently committed slow ecological suicide as low rainfall caused deforestation, soil erosion and salinization.

Source Nature, Jared Diamond

11 000 years ago

First Temple?

A temple at Gobekli Tepe, Turkey is where hunter gatherers congregate to share in spiritual celebrations. The artifacts at the site suggest religion predates agriculture and possible permanent settlements built while while humans were still hunters and gatherers. Artifacts carved on the surfaces represent images of foxes, lions, scorpions, vultures, and T shaped pilars that some believe represent humans. Findings suggest early people had beliefs and those beliefs evolved and centered on human's place in nature.

  • Humans as spirits in a spiritual world among animals, weather, and other Earthly spirits.
  • Humans with nature.
  • Humans as master of nature.
  • Humans as servants of nature.
  • Three skulls were found with red ochre, grooves, circular holes that seem to be cut at time of death or near death as there was no indication of healing. Could have been suspended by cords for ritual situations. Source


11 500 years ago ...

Skull of Luzia Woman dated to around 11, 5000 years ago was found in a cave at Lapa Vermelha, Pedro Leopoldo, Great Belo Horizonte, Brazil in 1975.

An infant is at the Upward Sun River in the Tana River Basin in Alaska. The infant bones, date to around 11 500 year ago. The site was found in 2008. The infant's genetics suggest her ancestors settled Beringia and her descendants headed south into North America. Science January 5, 2018.

12 000 - 13 000 years ago ...

Extinction of Wooly mammoth may have been the last of the large animals that became extinct. Others included: Columbian mammoth, American mastodon, Beautiful armadillo, Stag moose, Giant beaver, Jefferson's ground sloth, Harlan's ground sloth, Flat-headed peccary, & short-faced bear. Source

13 000 years ago and maybe earlier ...

Naia, a teenage girl explores an underwater cave in the Yucatan Peninsula, Mexico. Where her skeleton was found and dated to 13,000 years ago. Her DNA indicates she descended from early Native Americans, who likely crossed the Bering Strait. Source
Learn more about Naia on Nova First Face of America February 7, 2018.

Humans began to farm rather than maintain a hunting and gathering existance. A belief farming was superior to hunting gathering is probable inaccurate as farming required more work, lower adult status and resulted in worse nutritional conditions, poorer sanitation, and more disease. What ever the circumstances farming causes changes in plants, animals, and human behaviour as they interacted with each other and humans build and inhabit cities. Source Evolution, consequences and future of plant and animal domestication, by Jared Diamond.

It may be the food supply of the wild animals was shrinking to a point of unsustainability as 100's of large mammals are hunted to extinction by humans. Source Sapien

Cooking, grinding, leeching, soaking

Wheat, barley, seeds with non shattering seed pod or head

Goats, sheep, cattle, chicken, pigs, For the species which were not domesticated. Is the reason that it was difficulty to domesticate each of those species?, or Were the indigenous people that lived where the species was native not inclined to domesticate them?

13 200 years ago

Ancient American West coastal dwellers left a footprint on Calvert Island British Columbia and fish hooks on Cedros Island, Mexico believed to be America's oldest. Source. On the Trail of Ancient Mariners by Lizzie Wade

13 800 years ago and maybe earlier ...

Archaeological evidence indicates a village was established off the Central Coast of British Columbia, Canada on the ancestral grounds of the Heiltsuk Nation. The findings support their oral tradition that claims the tribe lived along the coast in a land that didn't freeze during the ice age. Source

14 000 years ago

Humans arrive to the Americas by boat by island hopping down the west coast. Source. On the Trail of Ancient Mariners by Lizzie Wade

15 000 years ago

Domestication of dogs range to possible 30 000 years ago. Source

Dog breeding and rock art 8 000 years

23 000 years ago

At the Ohalo II agricultural site, located on the shore of Galilee, people cleared land, sowed wheat and barley and harvested them 23 000 years ago. Ehud Weiss and his team collected 150 000 specimens of plant remains from the site and dated them to this time. The find suggests human migration to North America was along the coast instead of overland.

38 000 years ago

Beringia, a the land bridge connects Siberia to Alaska at this time, the last Glacial Maximum. Sea levels are around 400 feet lower than today and humans may have crossed it before it sunk into the ocean about 20 000 years ago.

40 800 years ago

European cave art in El Castillo cave is created. The cave art is dated to 40 800 years ago. Indicating Homo Sapien & Neanderthals are both capable of artistic self expression. Source Discover Magazine January / February 2013

Cave art

Other old drawings were found on the island of Sulawesi, in Indonesia. at least 35,400 years old. Source

42 000 years ago

Mungo man lives as indicated by a skeleton found in the dunes of a long gone lake, Lake Mungo in Australia, that is dated to 42 million years old.

43 000 years ago

Flute, maybe the oldest known musical instrument created from bird bone and mammoth ivory was found in a cave in southern Germany and dated to 43 ooo years ago.

64 800 years ago

Art created in three caves in Iberia, Spain. Art found was dated to 64 800 years ago. The date implies the art has a Neandertal origin, since humans did not arrive until about 20 000 years ago. Source Science. U-Th dating of carbobate crusts reveals Neanderthal origin of Iberian cave art 2-22-2018

65 000 years ago

Humans arrived in Australia and created stone tools, ground ochre, slabs of ochre, and ochre in crayon form. These artifacts were found at Madjebdebe, Australia and dated to 65 000 years ago. Source A find in Australia hints at very early human exit from Africa

50 000 - 700 000 years ago

Homo floresiensis (hobbit) is alive as indicated by fossils:

  • fossils dating 50 000 years ago found in Liang Bua cave in Indonesia.
  • fossils dating to 700 000 years old found at Mata Menge.

See Discover magazine stories

100 000 years ago

Remains were found in caves of Qafzeh, east of Nazareth, Israel and classified as Homo sapiens Qafzeh and dated at 92 000 years old. Other remains were found at Skhul, on Mount Carmel, Israel they were labeled as Homo sapiens Skhul and dated at 115 00 years old. These remains indicate lanky slender bodies adapted to hot moist climates and unsuitable for a cooler ice age that arrived around 75 000 years ago, which may have resulted in their extinction. Evidence also suggests Neanderthal, built more stocky, were better able to retain heat and survive through ice ages. While none of these may have meet during this time in this area of the world it does suggest their existence overlapped. Source When Neanderthals Replaced Us by Theodora Sutcliffe.

Ochre carving

Blombos Cave South Africa artifacts suggest it was a red ochre factory. Artifacts incuded: grindstones, pebbles dipped in ochre used as a stamp, abalone shells used as containers to mix ochre with bone, charcoal, quartz, and other materials to make paint, and the above artifact may be the earliest piece of art. Ochre was used as a cosmetic, sunscreen, mosquito repellent, medicine, antiseptic, tanning and preserving hides.

Remains of campfires were found in a South Africa cave. Source

180 000 years ago

Misliya-1, earliest homo sapien outside Africa. An upper jawbone with teeth was found at Misliya Cave, at Mount Carmel in Israel. Source

“While all of the anatomical details in Misliya-1 are fully consistent with modern humans, some features are also found in Neanderthals and other human groups ... ” Dr. Rolf Quam,

200 000 years ago

Homo sapiens evolved in Africa about 200 000 years ago. Genetic similarities between Eurasians, Oceanians, and Americans indicate all non-African humans descended from a small population that left Africa about 60 000 years ago.

Dispersal nao from Africa Source Science December 8, 2017

300 000 years ago

Jebel Irhoud, Morocco. Oldest fossils of early Homo sapiens with middle stone aged (MSA) tools. Science June 9, 2017

307 000 years ago

Olorgesailie, Kenya site found pieces of ochre with marks of human alteration and obsidian that came from about 60 miles away Indicating humans ranged further than previously thought and possible traded with others. Pigment of Our Imagination: The story of human evolution is written in ochre. by Gemma Tarlach Discover April 2018. See also Blombos Cave.

780 000 years ago

Magnetic poles flippled orientation. Source The Spinning Magnet by Alanna Mitchell

900 000 years ago

Olorgesailie, Kenya is a prehistoric site where artifacts have been found dated from 1.2 million years ago - 499 000 years ago. A skill cap of a Homo erectus was found along with big Acheulean hand axe and scrapers used to butcher meat that dated to about 900 000 years ago.

1.6 million years ago

Homo ergaster is thought to be the first hominid with long striding legs. Campable of long sustained walking and running.

Human chimp musclulature evolution

1.8 million years ago (Cenozoic Era, Quaternary Period, Pleistocene Epoch .01-1.8 mya )

Stone tools

Homo erectus intentionally formed stone tools into teardrop shapes. Acheulean hand axes. Creation of these tools required sensory motor control, memory, visualizing an object within an object, hence, planning. Source

First humans, mammoths, mastodons, saber-toothed cats.

2 million years ago

Homo erectus used fire to cook meat many years before Homo Sapien appeared.

2.6 million years ago (Cenozoic Era, Miocene Epoch 24 - 1.8 mya)

It appears humans began to eat meat and use weapons, around this time period as stone tools were found at Gona in Ethiopia and dated to 2.6 million years ago.
These tools match tools known as the Oldowan, named after Olduvai Gorge in Tanzania, where Louis Leakey found similar tools in the 1930s. Those tools were so well knapped that they were believed to have evolved from a less technological tool-making culture.

A strong similarity between marks these tools made and the marks on fossil zebra bones, indicates stone tools were used to butcher animals by at least 2.6 million years ago. Humans and food source

Stone tools

2.8 million years ago

Fossilized jaw found at Ledi-Geraru, Ethiopia was dated as 2.8 million years old and classified as Homo genus.

3.18 million years ago


Discovered in 1974 Lucy classified as Australopithecus afarenis. Upright a terrestrial hunter and gatherer that probable spent some time in trees. It has been speculated that fractures she suffered might have been from falling.

"Afarensis was small and completely non-technological. No one has ever argued that they were predatory. They are bipedal, ground-eating apes," Michael Bisson

3.3 million years ago

Stone tools at the Lomekwi site near Kenya's Lake Turkana were found by Sonia Harmand and her team, which were dated to 3.3 million years old . Source

3.3 - 3.5 million years ago

A hominin jawbones was dated and classified as Australopithecus deyiremeda. They were found in the Afar region in Ethiopia. Source & image

Animals bones dated to 3.4 million years ago suggest Australopithecus butchered meat. Source

3.6 million years ago

Footprints at Laetoli near Olduvai. Believed the first evidence of bipedalism. Thought to be from three Australopithecus afarensis hominids who walked on volcanic ash, which was preserved, until Mary discovere them in 1978.

3.67 million years ago

South Africa Sterkfontein Cave a hominid skeleton named Little Foot a female Australopithecus afarensis or A. prometheus was discovered in 1997 and exposed over the next twenty years. It has become the most complete skeleton of it kind found and dated to about 4 million years old. Australopithecus afarensis is believed to have lived aroung 2.9 million to 4.1 million years ago. Source & images

3.9 million years ago

Australopithecus appears. First sheep, cattle, modern whales, bears, mice, rats, apes, monkeys, dogs, modern birds appear.

5.3 million years ago (Cenozoic Era, Tertiary Period, Pliocene Epoch 1.8-5.3 mya )

23.8 million years ago (Cenozoic Era, Tertiary Period, Miocene Epoch 5.3-23.8 mya )

33.7 million years ago (Cenozoic Era, Tertiary Period, Oligocene Epoch 23.8-33.7 mya )

54.8 million years ago (Cenozoic Era, Tertiary Period, Eocene Epoch 33.7-54.8 mya )

65 million years ago (Cenozoic Era, Tertiary Period, Paleocene Epoch 54.8-65 mya )

First deer, cats, pigs, tapirs, and rhinos, elephants, horses, owls, shrews, hedgehogs, and rabbits evolve.

EarthViewer - An interactive application to explore what the Earth looks like at different times. Explore what Earth looks like 250 million years ago? Or 1 billion years ago? Or 4.5 billion years ago? EarthViewer lets you see continents grow and shift as you scroll through billions of years and explore changes in atmospheric composition, temperature, biodiversity, day length, and solar luminosity over deep time.

Beginning -
Mesozoic era, Paleozoic era, & Precambrian


Mesozoic era includes three periods

  1. Cretaceous period is between 65.5 and 145.5 million years ago.
  2. Jurassic period 144-208 mya, &
  3. Triassic period 208-245 mya

Paleozoic era about 251 - 540 million years ago

  1. Permian Period 245 - 280 mya
  2. Carboniferous Period 280 - 360 mya
  3. Devonian Period 360 - 408 mya
  4. Silurian Period 408 - 438 mya
  5. Ordovician Period 438 - 505 mya
  6. Cambrian Period 500 - 540 mya

Precambrian 540 mya - 4.6 billion years ago includes about 90% of the time the Earth has existed.

Summary of change

The Earth itself evolved over a very long time period, compared to human life spans. The millions of years eventually provided conditions and materials for habitats suitable for life to evolve complex organisms: most recently Homo sapien.

  • A geological period is a basic unit of geological time in which a single type of rock system is formed.
  • A geological era is a time period of two or more periods.

More information on eras, periods, and evolution of life see Earth science Australia

Mesozoic era 65.5 - 250 million years ago

66 million years ago (Mesozoic Era, Cretaceous Period 65.5 - 145.5 mya )

First flowering plants, snakes, crocodilians.

Mass extinction at the end of this period kills dinosaurs, and others.
Known as the K-T extinction (Cretaceous - Tertiary extinction) and K-Pg (Cretaceous - Paleogene)

Cretaceous period Paleocene era can be labeled as a critical boundary at 66 million years ago.

The boundary a result of an asteroid strike wiping out the dinosaurs, which can be measured by the strong trace of the element iridium located in rocks as a result of the impact of the asteroid.

The asteroid, about 6 miles or 10 km diameter, crashed in Chicxulub, Mexico creating a crater about 110 miles (180 km) in diameter. The explosion released as much energy as 100 trillion tons of TNT, more than a billion times more energy than the bombs that destroyed Hiroshima and Nagasaki.

The event was at the end of the Mesozoic Era Cretaceous Period and the extinction of the dinosaurs who were among the 80% of life on Earth that were unable to survive during this time known as one of the six mass extinctions. See PBS and what killed the dinosaur?

85 million years ago

Australia breaks away from Antarctica

200 million (Mesozoic Era, Jurassic Period 144-208 mya)

Oceans full of fish, squid, ammonites, the great ichthyosaurs and long-necked plesiosaurs. Huge plant-eating dinosaurs roam the Earth and eat huge ferns, palm-like cycads, and a type of seed plant, bennettitaleans. Smaller carnivores hunt the herbivores. Vertebrates take to the air, like the pterosaurs and the first birds.

245 million years ago (Mesozoic Era, Triassic Period 208-245 mya )

First mammals, dinosaurs, frogs, turtles, crocodyloformes.

Paleozoic era about 251 - 540 million years ago

280 million years ago (Paleozoic Era, Permian Period 245-280 mya )

Sail-back reptiles. Amphibians abundant. Pangaea forms. Ends with mass extinction.

300 million years ago

Both oxygen and ozone levels reach current levels with many different kinds of complex land plants and animals.

360 million years ago (Paleozoic Era, Carboniferous Period 280-360 mya)

Widespread coal swamps. First reptiles, winged insects.

408 million years ago (Paleozoic Era, Devonian Period 360-408 mya)

First amphibians, sharks, bony fish, ammonoids, and spiders. Many fish.

438 million years ago (Paleozoic Era, Silurian Period 408-438 mya )

First insects, vascular plants on land.

450 million years ago

The ozone level was close to its present value as land plants evolved.

505 million years ago (Paleozoic Era, Ordovician Period 438-505 mya )

First land plants, corals, Nautiloids. End in mass extinction.

540 million years ago (Paleozoic Era, Cambrian Period 500 to 540 mya )

Evolution of many life forms. First shellfish, primitive fish, trilobites, corals, mollusks.

Precambrian 540 million years ago

The Precambrium (a geologic time) starts with the Earth's formation, 4.6 billion years ago and lasts to the beginning of the Paleozoic Era Cambrian Period, 540 mya.

The Precambrian is not considered a geologic eon, era, period, or epoch, it is simplied referred to as Precambrian or Precambrian Time. It spans most of the Earth's history (90%).

Oxygen concentration increased to about ten percent of the current level.

3.5 billion years ago

Cyanobacteria, an oxygen-producing organism evolves. These organisms use carbon dioxide and water for photosynthesis and release oxygen as a waste product. Over time, the oxygen they produce accumulate in the atmosphere where some is converted to ozone, which is important for the development of life on land, because it protects Earth's surface from too much ultraviolet radiation that is fatal to life.

3.8 - 4.3 billion years ago

First life on Earth. Microfossils of tiny creatures were found locked in different samples of rock from northern Canada. One sample dated from 3.8 - 4.3 billion years and another sample dated to 3.95 billion years.

4.6 billion years ago

The Earth's primitive atmosphere and oceans evolve complex molecules that the will evolve into the first living cells.

13.8 billion years ago

Big bang ... The creation of the Universe. Creation logically has three options:

  1. a creation that is a cataclysmic event (most likely),
  2. a non creation event with the Universe always being in existence, or
  3. a Universe that is an illusion and doesn't exist as a physical entity.



Dr. Robert Sweetland's notes
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