- Evolution - The process of change
- Evolution applies to the universe also. Matter and the nature of matter has changed over time
- Evolution applies to life, implies that life is not static, but responds to the environment.
- Previous western thought held the universe, earth animals, and man were created by God.
- Held the earth and life were created in the thousands of years in the past..
- Life and the earth were thought to be static and unchanging.
- Modern evolution holds that the universe is billions of years old (between 9-12b years)
- Earth was created approx 4.5b years ago.
- Human existence is only a small fraction of time since the beginnings of the universe.
Cosmic Calendar (From The Dragons of Eden - Carl Sagan)
Pre-December Dates
| Big Bang | January 1 |
| Origin of Milky Way Galaxy | May 1 |
| Origin of the solar system | September 9 |
| Formation of the Earth | September 14 |
| Origin of life on Earth | ~ September 25 |
| Formation of the oldest rocks known on Earth | October 2 |
| Date of oldest fossils (bacteria and blue-green algae) | October 9 |
| Invention of sex (by microorganisms) | ~ November 1 |
| Oldest fossil photosynthetic plants | November 12 |
| Eukaryotes (first cells with nuclei) flourish | November 15 |
December
Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday |
| 1 Significant oxygen atmosphere begins to develop on Earth. | 2 | 3 | 4 | 5 Extensive vulcanism and channel formation on Mars. | 6 | |
| 7 | 8 | 9 | 10 | 11 | 12 | 13 |
| 14 | 15 | 16 First Worms. | 17 Precambrian ends. Paleozoic Era and Cambrian Period begin. Invertebrates flourish. | 18 First oceanic plankton. Trilobites flourish. | 19 Ordovician Period. First fish, first vertebrates. | 20 Silurian Period. First vascular plants. Plants begin colonization of land. |
| 21 Devonian Period begins. First insects. Animals begin colonization of land. | 22 First amphibians. First winged insects. | 23 Carboniferous Period. First trees. First reptiles. | 24 Permian Period begins. First dinosaurs. | 25 Paleozoic Era ends. Mesozoic Era Begins. | 26 Triassic Period. First mammals. | 27 Jurassic Period. First birds. |
| 28 Cretaceous Period. First flowers. Dinosaurs become extinct. | 29 Mesozoic Era ends. Cenozoic Era and Tertiary Period begin. First cetaceans. First primates. | 30 First evolution of frontal lobes in the brains of primates. First hominids. Giant mammals flourish. | 31 End of Pliocene Period. Quaternary (Pleistocene and Holocene) Period. First humans. |
December 31
| Origin of Proconsul and Ramapithecus, probable ancestors of apes and men | ~ 1:30 p.m. |
| First humans | ~ 10:30 p.m. |
| Widespread use of stone tools | 11:00 p.m. |
| Domestication of fire by Peking man | 11:46 p.m. |
| Beginning of most recent glacial period | 11:56 p.m. |
| Seafarers settle Australia | 11:58 p.m. |
| Extensive cave painting in Europe | 11:59 p.m. |
| Invention of agriculture | 11:59:20 p.m. |
| Neolithic civilization; first cities | 11:59:35 p.m. |
| First dynasties in Sumer, Ebla and Egypt; development of astronomy | 11:59:50 p.m. |
| Invention of the alphabet; Akkadian Empire | 11:59:51 p.m. |
| Hammurabic legal codes in Babylon; Middle Kingdom in Egypt | 11:59:52 p.m. |
| Bronze metallurgy; Mycenaean culture; Trojan War; Olmec culture; invention of the compass | 11:59:53 p.m. |
| Iron metallurgy; First Assyrian Empire; Kingdom of Israel; founding of Carthage by Phoenicia | 11:59:54 p.m. |
| Asokan India; Ch'in Dynasty China; Periclean Athens; birth of Buddha | 11:59:55 p.m. |
| Euclidean geometry; Archimedean physics; Ptolemaic astronomy; Roman Empire; birth of Christ | 11:59:56 p.m. |
| Zero and decimals invented in Indian arithmetic; Rome falls; Moslem conquests | 11:59:57 p.m. |
| Mayan civilization; Sung Dynasty China; Byzantine empire; Mongol invasion; Crusades | 11:59:58 p.m. |
| Renaissance in Europe; voyages of discovery from Europe and from Ming Dynasty China; emergence of the experimental method in science | 11:59:59 p.m. |
| Widespread development of science and technology; emergence of global culture; acquisition of the means of self-destruction of the human species; first steps in spacecraft planetary exploration and the search of extraterrestrial intelligence | Now: The first second of New Year's Day |
Darwin & Natural Selection
- Modern evolutionary thought arose through the inquiries of Charles Darwin.
Charles Darwin
- Darwin was a Naturalist aboard an exploration ship called the HMS Beagle.
- Collected and catalogued biological specimens for return to England.
- Was fascinated by the species of Finches he observed in the Galopagos Islands.
- Found that these birds were quite similar to a species found on mainland South America. However they differed significantly in the shapes of their beaks.
Galapagos Finches
- Darwin reasoned that these species of finches arose from a common ancestor, and gradually changed over to accommodate their particular diets.
- Led him to develop his theory of evolution through Natural Selection.
Natural selection
The notion of evolution was dominated by 2 theories. - Lamarckian Theory of Inheretance of acquired characteristics
- Held that traits acquired throughout life of an organism would be passed on to offspring.
- "Use it, or lose it principle"
- Eg. If you lifted weights during your life, your children would be stronger or, if you did'nt exercise your children would be weaker
- Theory has been replaced by Darwin's theory of natural selection.
- Natural selection:
- Based on following premises:
- There are not enough resources for all organisms to survive.
- Some organisms are more "fit" to survive.
- Fitness refers to:
- The ability of an organism to survive in its environment.
- The ability of an organism to survive long enough to reproduce.
- Natural pressures "weed-out" those individuals "less fit" to survive. Thus changing a species over time.
- New genes/traits arise from random mutations.
- Most are either Neutral (no effect), or disadvantageous (decrease an organism's chance for survival).
Natural Selection : The Peppered Moth:
The peppered moth
- The peppered moth is a species of moth which uses camouflage against tree bark to avoid being eaten by birds. It is normally a light grey color.
- During England's industrial revolution, pollution caused a darkening of the bark of the trees.
- There was a natural variation in moth coloration with some being darker than others.
- Those moths of a lighter color, were easier to spot and eat by birds. And were eaten at a faster rate.
- The survivors tended to be darker, and when they mated, their offspring tended thus to be darker also.
- Over time, this resulted in the species becoming darker in color.
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