Morphology and Homologous, Analogous, and Vestigial Structures

Analogous Structures

Analogous structures are when two organisms have different structures but serve a similar function.

How do analogous structures support evolution?

Animals with no common ancestor but with a shared environment all become similar because it is effective in that environment.

Examples of Analogous Structures

Flippers/fins/wing on aquatic animals

Homologous Structures

Homologous structures are when two organisms have a similar structure but have a different function.

What is the difference between homologous and analogous structures?

Homologous structures share an ancestor but serve a different function but analogous structures serve a similar function but do not share an ancestor.

Examples of Homologous Structures

Mammalian forelimbs (monkeys, humans...)

How do vestigial structures support evolution?

Our ancestors used the in the past and it provided an advantage for them but as the species evolved the trait stayed but became ineffective to a changed environment.

How do homologous structures support evolution?

Structures are similar, which shows a common ancestor.

Vestigial Structures

Vestigial structures are traits that our ancestors needed but no longer serve a purpose in our environment.

Examples of Vestigial Structures

Whale Pelvic Bones, appendix, tailbone, wisdom teeth in humans, muscles that can move ears.