Download Evidences of Evolution

Evidence for Evolution
1. Anatomical Evidence-Based on anatomy, which is the body structure of a living
organism. when scientists see similar structures between two anatomies of organisms
they are either related or have a common ancestor. The similar structure of a lion's
foreleg, bat's wing and a dolphin's fin mean they are homologous. Homologous
means when body parts are similar in structure.
Cotylosaur branched off into many different animals and dinosaurs including
mammals, birds, snakes, turtles
2. Fossil Evidence-Fossils are imprints or remains of plants and animals. By
matching the structures of their bones they can match their evolution. Whales had two
hind legs and could walk on land - scientists know that these fossils are whale
ancestors because they had whale like skulls.
3. Radioactive Dating-Method used to measure age of a fossil/rock. Carbon14 is a
radioactive form of carbon. The half life is 5770 years and carbon14 is in living things
and it decays at the half life rate. Half life is the time it takes for half of the element
to decay.
4. Relative Dating -Fossils are compared by the rock layers in which they are found.
Sedimentary rock layers in the Grand Canyon show how old the rock is by how far
down the layer is.
5. Fossil Record-Most complete biological record of all time. Contains all fossil
evidence ever collected by scientists. In the Eohipphus, an ancestor of the horse, but
the Mesohipphus was similar in forefoot and skull yet larger, and ultimately the Equus
largest yet but with similar forefoot and skull.
6. Embryological Evidence-Embryology is the study of developing organisms.
Scientists compare embryos of different species to see the relations. Embryos of
chicken, fish, rabbit and human all appear similar however the fish begins to changes
during development and show it's differences.
7. Chemical Evidence-chemicals in DNA from two different organisms are compared
looking for similarities and differences in the genetic sequence. If they are very
similar they are either closely related or have a shared ancestor. For example the zebra
and quagga share a common ancestor.
8. Molecular Clock-Scientists look at the similarities or differences in protein
structure (amino acids).