Give me some proof! Evidence for Evolution. 1. Studies of Fossils What are Fossils? –Fossils are...
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Transcript of Give me some proof! Evidence for Evolution. 1. Studies of Fossils What are Fossils? –Fossils are...
Fossil evidence• Shows history of life on Earth.
• Shows how different organisms have changed over time.
• Fossils appear in a particular order.
What can fossils tell us?
• Finding the age of a fossil will show us how long ago that organism existed.
2. Comparison of Structures
• We can compare body structures of different living organisms to determine evolutionary relationships.
2A. Homologous Structures
Homologous Structures: structures that share a common ancestor.
•The structures can be different sizes & serve different functions.
•Similarities and differences among the homologous structures help determine how recently species shared a common ancestor.
2B. Analogous Structures
Analogous Structures: Structures that serve the same function in different species, but evolved independently (NOT from a common ancestor).
Example
• The Wings of Birds, Bats, & Butterflies
• Wings serve similar function but did NOT evolve from a common organism.
2C. Vestigial Structures
Vestigial Structures: Structures with NO known functions.
•Inherited from ancestors
•Structures are remnants of organism’s evolutionary past
Example in humans: appendix, tailbone, wisdom teeth (Individuals still have them because they must not affect the organisms fitness)
2D. Developmental Structures
• Developmental structure patterns show evolutionary relationships.
• The more closely related show the organisms descended from a common ancestor.
• Example:– Human Embryos & Chicken Embryos are very similar
at 4 days– Thus, must have evolved from common ancestor
3. DNA & proteins
• The universal genetic code provides evidence of common descent.
• We can also compare similarities in gene sequencing and protein production between organisms.
• We also know that heritable variation on which natural selection operates may be caused by mutations or the reshuffling of genes during sexual reproduction.