Evidence for Evolution Evidence of Evolution Darwin had

Evidence for Evolution

Evidence of Evolution • Darwin had to have evidence to support his theory of natural selection/ evolution – Why did people have a hard time accepting this idea? • Darwin waited almost 25 years to publish his theory of Evolution

Fossil record

Fossil record • The fossil record is a history of life on Earth – The earth is millions of years old • Which scientists proposed this? – Fossils that are found in different rock layers show the evolution of living species over millions of years

Fossil Record • Transitional fossils-document various intermediate stages in the evolution of modern species

Geographic distribution • when a population gets separated difference selective pressures will work on the populations and cause changes • Divergent Evolutionpopulations evolve separately – Formation of new species

Geographic distribution • The environment selects for specific adaptations – If the environment is the same in 2 different locations we see the evolution of similar but unrelated species – Convergent evolution of shared traits in unrelated species • Bats and birds

Homologous body structures Homologous structures: variations on a body structure that was present in their common ancestor

Vestigial Organs • Vestigial organs- homologous structures that do not serve an important purpose in the organism today.

Similarities in Embryology • The early stages of development are similar in different species – All animals with backbones • The same groups of embryonic cells develop in the same order and pattern – Cause for homologous structures