organs or skeletal elements of animals and organisms that, by virtue of their similarity, suggest their connection to a common ancestor. These structures do not have to look exactly the same, or have the same function.

The form and structure of an organisms traits, its characteristics.

Similar embryological development in different organisms indicating a common ancestry or evolutionary origin.

Preserved remains or evidence of ancient organism.

A characteristic of different organisms that have similar function but not necessarily the same structure and did not come from the same common ancestor.

States that layers of sediment and rock are older at the bottom levels of younger as they move up to the surface.

Similar DNA sequence between different organisms indicating a common ancestry or evolutionary origin.

Father of Evolution, wrote origins of species and studied organisms from Galapagos to support his proposal that natural selection occurs.

Any change in the traits of an organism that allows it to survive and reproduce more effectively in its environment.

Serves no useful purpose in the modern organism but did in its ancestral form.