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30 Cards in this Set
- Front
- Back
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What is creationism? |
- Young Earth (less than 10,000 yrs) - All organisms are created spontaneously a supreme being over 6 days - All organisms are immutable (unchanged/fixed) - Humans are most important form of life (closest to God)
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who are Hutton & Lyell? |
- Both are geologists (studied rock formations) - Hutton was 1st to challenge the "young Earth" view in the late 1700s - Proposed "uniformitarianism": Earth must have formed over millions of years of gradual changes - Lyell just popularized the idea |
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Who is George Cuvier? |
- Pioneer of paleontology (study of fossils) - 1st to challenge the 'fixed-species' idea - Concluded that species could go extinct (mammoths, dinosaurs, etc.) and get replaced by new "creations"/spontaneous generation - Also suggested the Earth must be extremely old - Proposed "catastrophism" to explain extinctions |
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Who is Linnaeus? |
- Was a naturalist (studied the diversity of living things) - Linnaeus invented taxonomy: the modern classification system of living things grouping clustered by similarities - Linnaeus suggested some new species may arise by "hybridization" between existing species |
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Who is Buffon? |
- was a naturalist - Buffon suggested that species are mutable and DO change over time - Buffon even suggested similar species may share common ancestry … i.e. were not created - BUT, he had no theory to explain this … |
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Who is Jean Lamarck? |
- A student of Buffon, but believed in creationism - He proposed that species can change over time to better suit their environment |
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What did Lamarck props? |
- Proposed theory of “Inheritance of Acquired Characteristics” a ) organisms “uses or lose” a trait according to need b) repeated use causes enhanced features c) these “ acquired trait “ are passed to the next generation d) individuals change to better “adapt to the environment “ E.g Giraffe neck length stretches for feeding |
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Charles Darwin's major observations |
Major observations on 5-year voyage: 1. Distantly related species on different continues wit similar niches have similar appearances 2. Island clusters had many closely related, but different looking species occupying different niches 3. Fossils show that species change over time. What we see now is related to what was there before 4. Species can go extinct, but new ones arise |
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What did Charles Darwin do? |
- 1st to propose that ALL life has descended from one or few common ancestors, over a very long period of time - He saw the environment as the driving force of evolutionary change - Proposed the theory of “Natural selection” |
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Does real evolution happen on an individual scale or population scale? |
real evolution doesn’t happen on an individual scale but it happens on a population level |
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What is natural selection? |
the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution. |
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Who proposed Natural selection? |
Darwin |
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5 points of Natural Selection |
1. Organisms produce offsprings with different (random mutation and DNA was discovered later) 2. There is a struggle for survival due to limited resources (ie. competition ) 3. The environment selects the most “fit” individuals to survive and reproduce: “survival of the fittest” 4. The traits that allow survival and reproduction are passed on and inherited by the next generation 5. The environment is always changing… so the population either has the traits to survive the changes or goes extinct i.e species gain traits by chance and selection NOT by need |
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7 proofs of evolution |
1. Fossil records (see the history of evolution) 2. Comparative Anatomy (common structures in different species) 3. Embryology (common process during early development) 4. Biogeography ( comparing species by geographic locations) 5. Molecular Biology ( comparing DNA sequences and protein structures vs function) 6. Artificial selection (breeding experiments) 7. Modern day examples |
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What are the fossil records |
- 1000s of layered rock deposits from around the world all consistently show the same trend from simple fossil form to more complex fossils form - However, fossil formation is a rare event… ∴ we can never expect to find every fossil of every organism |
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Pattern of fossils |
Fish —> amphibians —> reptiles —> mammals —> humans —> birds No reversals of this pattern have ever been found! e.g.: a bird fossil being found in a deeper layer than the first reptile fossils |
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What is a fossil between species? |
- Intermediate fossils (“in between” species with traits from 2 different groups) show the evolution of vertebrates from - These intermediate fossils are called “transitional forms” |
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Whale to wolf evolution |
Hind limbs: - Reduction and eventual loss of in hind limbs Body length: - Elongated body (longer spine) Fingers: - Fingers get longer and closer together Head position: - Head more in line with spine Shape of vertebrae: - Vertebrae elongate vertically (dorsally), making a more rounded back (instead of flat) Inner ear: - Reductionof the semi-circular canals in the inner ear (*backof page) Head & snout: - Elongatedhead and snout Nostrils: - Migrationof nostrils upwards and above eyes |
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Advantages of wolf to whale evolution |
More streamlined / less drag More powerful swimmer Less sensitive to motion sickness - able to do more acrobatic swimming without feeling nauseous Able to breathe while keeping eyes under water to watch for prey |
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What is comparative anatomy? |
a) mutations can only modify existing structures, forming new structures functions b) Harmful or energetically costly structures are reduced or eliminated |
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What are the two different patterns in Evolution of anatomy? |
1. Divergent: closely related groups develop different outward appearances/traits 2. Convergent: Distantly related groups develop similar outward appearances/traits Example( bats and birds, same trait and appearance but different anatomy ) |
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What are the two types of Evidence for Divergent Evolution |
Homologous structures and Vestigial structure |
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What is a Homologous structure? |
Homologous structures: similar internal structures in different species that may be used for a smilier or different purpose (only for anatomy, internal) |
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Where did the ear bones come from? |
- reptiles double-hinged jaw bones are homologous tot he single jaw bone & Hammer & Anvil bones in ears of mammals ∴ ear bones are from modified jaw bones of reptiles |
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Examples of Homologous structures? |
1. Whales & Pakicetus have homologous ear bones & tooth shape ∴ common descent with modification 2. Front limbs of amphibians, reptiles, mammals & birds ALL have some basic bones in the same relative pattern ∴ a single common ancestor 3. Mammals have ear bones, but reptiles don't … but aren't they related? |
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Examples of Vestigial structures? |
Examples in Humans: -ear muscles -appendix -tail bones -3rd eyelid - wisdom teeth - goose bumps Examples in other animals: -leg bones in pythons -leg bones in whales -some toes/digits on the legs of 4 legged runners: cat, dogs, pigs , horses -Eyeless fish/salamanders in underground caves |
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What is a Vestigial structure? |
Vestigial structure: a similar structure in different species that has reduced or no function in some of the species |
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Evidence of Convergent Evolution |
Analogous structures |
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What are Analogous structures? |
Analogous structures: structures with a similar function or external appearance but whose internal organization is completely different - Selection can favor the development of a similar trait more than once! |
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Examples of Analogous structures |
Wings evolved 4 times: insects, pterosaurs, birds and bats |
