Evidence for Evolution Evolution The theory of evolution

Evidence for Evolution

Evolution • The theory of evolution states that all organisms on Earth have descended from a common ancestor.

The Support for Evolution • The Fossil Record • Derived traits: are new evolved features, such as feathers, that do not appear in the fossils of common ancestors. • Ancestral traits: more primitive features, such teeth and tails, that do appear in ancestral forms.

The Support for Evolution • Comparative Anatomy – Homologous Structures: • Anatomically similar structures inherited from a common ancestor.

The Support for Evolution • Comparative Anatomy – Vestigial Structures: • Structures that are the reduced forms of functional structures in other organisms.

The Support for Evolution • Comparative Anatomy – Analogous Structures: • Structures that can be used for the same purpose and can be superficially similar in construction, but are not inherited from a common ancestor

The Support for Evolution • Comparative Embryology – Vertebrate embryos exhibit homologous structures during certain phases of development but become totally different structures in adult forms.

The Support for Evolution • Comparative Biochemistry – Evolutionary theory predicts that molecules in species with a recent common ancestor should share certain ancient amino acid sequences. – The more closely related the species are, the greater number of sequences will be shared.