Question

What are the evidences for evolution?

Answer 1

• Paleontology is the study of ancient life, studied through fossil records.
• Fossils are studied in different sedimentary layers. Evidence indicates-

1. The time period in which the organisms lived.
2. Life forms varied over time.
3. Some life forms are similar to the present day animals.

• Ernst Heckel observed certain embryological characteristics common to all vertebrates, for example gill slits that are behind the head.
• Disproved by Karl Ernst Von Baer.
• Homologous organs- Similar anatomical structure but different function

1. Examples- Forelimbs of different animals like bats, whales, thorn of Bougainvillea and tendril of Cucurbita.
2. These have common ancestry and it is evidence of divergent evolution.

• Analogous organs- Organs that are different in anatomy but have similar function

1. Examples- Wings of butterflies and wings of bats, eye of octopus and eye of mammals.
2. These species lived in the same habitat, resulting in selection of similar adaptive features towards the same function. This is evidence of convergent evolution. Protein and sequences of nucleotides in certain animals like apes and humans show similarity. Indicates common ancestry