B.9A Evidence of Common Ancestry on level – 04

Identical crocodile fossils were found on both Africa and South America, thousands of miles apart. This shows that the crocodiles lived there when the continents were joined. The continents split after these crocodiles died and their bones became fossils.



Homologies
Homology refers to the similarities in body structures, body functions, and development of different species of living things. These similarities are evidence that living things have a common ancestor.
Homologous Anatomical Structures
Homologous structures are similar physical features in organisms.

Molecular Homology
Molecular homology is the similarities in the genome of different organisms.
A genome is an organisms complete set of genes. Scientists can compare genomes of different organisms to see how similar or different they are from each other. Any time there is a change in the gene sequence of an organism, those changes are passed on to the offspring. By looking at the changes in the gene sequence between organisms, scientists can determine how closely or distantly those organisms are related to a common ancestor.