10.4 Evidence for Evolution

Question 1

Paleontology

Answer 1

Different layers of rock correspond to different geological eras, forms a sequence from oldest to youngests, fossils embedded within, showing how organisms have changed over time

1. simplest organisms found in the oldest rocks
2. sequence matches ecological links for exmaple plant fossils found before animal fossils
3. show how closely related organisms have evloved from a common ancestor eg. horses and zebras
4. relationships between extinct and living organsims can be investigated

BUT the fossil record is incomplete: soft bodied organisms would have decayed, conditions needed not often present, fossils destroyed by the Earths movements.

Question 2

Comparative Anatomy

Answer 2

1. similarities and differences in the anatomy of different species
2. homologous structure appears superficially different and may perform different functions, but has the same underlying structure eg. pentadactyl limb of vertebrates- same bones adapted to carry out a range of functions- horse, mole, bat.
3. This provides evidence for divergent evolution: different species with different adaptive features have all evolved from a common ancestor. Happens when closely related species diversify to adapt to new habitats as a result of migration or habitat loss

Question 3

Comparative biochemistry

Answer 3

1. similarities and differences in the proteins and other molecules that control life processes
2. Cytochrome C, rRNA, order of DNA bases, order of amino acids in a protein.