Biology: Evidence for Evolution Notes

homologous structures

similar characteristics between related species that have different functions

analogous structures

features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature

vestigial structures

body parts or organs that have lost their original function through evolution

Fossils

preserved pieces of dead organisms

How do scientists date fossils

the layer of rock they are found in. this is knows as the law os superstition. they can also date them using radioactive decay.

transitional forms

fossils that are in-between two species

Embryos

early stages of development

Why is it hard to distinguish an embryo during early stages?

They have homologous structures including a tail, eye, spots, and gills

What does the presence of DNA suggest

we all evolved from a single ancestor

biogeography

the study of the distribution of organisms on Earth.

species with common features can be found…

in similar environments

When can we see evolution happen quickly?

High rate if reproduction and strong selective pressure.