Evidence for Evolution

Biogeography- the study of where organisms live now and where they and their ancestors lived in the past.

Many recently discovered fossils form series that trace the evolution of modern species from extinct ancestors.

The greatest shark to have ever lived The greatest shark to have ever lived! An apex predator, the Carcharodon megalodon comes from the Greek word for “big tooth”. This shark was as big as a bus at a length of 60 feet and estimated to weigh between 30-60 tons. Their skeletons were made of cartilage, like those of modern sharks. This resulted in poor to no fossilization of their skeletons and therefore is rarely found in the fossil record.

2. Comparative Anatomy A. Homologous Structures- similar structures that are different in function

b. Vestigial Structures Structures that serve no apparent purpose in the organism that has it

Pelvis and Femur in Humans

Do you have a Tail? The true human tail upon birth is caused by a lack of cell destruction of the distal end of the embryonic tail 

Pelvis and Femur in Whales

Sightless eyes

c. Analogous Structures Similar structures in unrelated organisms

3. Embryological Development The comparative study of embryos during development at various stages

4. Homologous Molecules Comparisons of DNA sequences and amino acid sequences in proteins * Amino acid sequence of cytochrome c in human and chimp differs by one amino acid!

Activity: Timing is Everything