6.6 Evidence of Evolution

Evidence of Evolution

the fossil record

comparative morphology

biogeography

Fossil Record

fossils are remains or traces of past organisms

the fossil record gives a visual of evolutionary change over time

fossils can be dated by examining the rate of carbon 14 decay and the age of rocks where the fossils are found

gives geographical data for the organisms found

Comparative Morphology

analysis of the structures of living and extinct organisms

Includes homology

Homology

characteristics in related species that have similarities even if the functions differ

Embryonic homology

many species have similar embryonic development

Vestigial Structures

structures that are conserved even though they no longer have a use

ex. tailbone, appendix, and wisdom teeth in humans

Molecular Homology

many species share similar DNA and amino acid sequences

Homologous Structures

characteristics that are similar in 2 species because they share a common ancestor

ex. arm bones of many species

(arise from shared ancestor, similar anatomy, but may have different functions like arm bones in different speciess may share similar structure but serve different functions ex. flying, swimming, grasping, etc.)

Convergent Evolution

similar adaptations that have evolved in distantly related organisms due to similar environments

includes analogous structures

Analogous Structures

structures that are similar but have separate evolutionary origins

ex. wings in birds vs bats vs bees

each species as wings, but the wings did not originate from a common ancestor

(different anatomy but similar