Evolution. The theory that organisms have changed gradually over time. Evidence to support the Theory of Evolution. Fossil Record - Law of Superposition Comparative Anatomy: Homologous Structures Analogous Body Structures Vestigial Body Structures Comparative Embryology
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The theory that organisms have changed gradually over time.
2. Analogous Structures – similar in function and appearance, but not in origin.
Illustrate convergent evolution – things becoming more similar.
Similar organic compounds (proteins, etc.)
Humans and chimp DNA – 98% similar
Humans and other mammals – 80% similar
Descent with Modification
2. Studied Charles Lyell – Geologist who said,
“The present is the key to the past.” The same forces acting on earth in the past are continuing today.
1. Overproduction of Offspring (more produced than can survive)
2. Variation within a population
3. Struggle to survive creating competition
4. Successful reproduction - Individuals with better adaptations pass these on to offspring (survival of the fittest)
Darwin envisioned the tree of life
Each new offspring in a population draws its genes from the same gene pool.
Which trait was a better adaptation and so selected for?
How did this affect the frequencies of the different alleles?
Primordial soup hypothesis: Primitive atmosphere filled with carbon, hydrogen, nitrogen, water vapor - bombarded by lightning and uv radiation, producing organic compounds and precursors to first cells, which ended up in oceans