Theme 1 Topic 6

Natural Selection

The process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Homologies

Similarities arising from a shared evolutionary ancestor, which can be morphological, embryonic, vestigial, or molecular.

Morphological Homologies

Physical resemblances between species that represent variations on a structural theme found in a common ancestor.

Embryonic Homologies

Similarities in embryonic development among different species that indicate a shared evolutionary ancestor.

Vestigial Structures

Remnants of structures that were functional in an organism’s ancestors; they provide evidence of evolutionary change.

Molecular Homologies

Similarities in the DNA and proteins of different species, suggesting a common evolutionary ancestor.

Fossil Record

A historical timeline of species, showing gradual evolutionary transformations and providing evidence of extinction and origin of new groups.

Transitional Fossils

Fossils that document the existence of intermediate forms between different groups of organisms, acting as 'missing links' in evolutionary history.

Biogeography

The study of the geographical distribution of living organisms and fossils, which reflects historical processes like continental drift.

Endemic Species

Species that are native to a specific geographic area and are not found naturally anywhere else.