2. E, marsupials began in North America.
3. They show convergent evolution. They evolved separately into the same environment, so they have structures in their body that work similarly, but are made up of completely different things.
4. DNA sequencing compares the genetics of different organisms to see how similar they are. If two organisms have a more recent common ancestor, then their DNA will be more similar than with an organism whose shared common ancestor is further back down the line. Our lab proved that chimpanzees are more closely related to humans than gorillas are because their DNA is closer to ours. Gorillas, on the other hand, are more genetically similar to a different common ancestor that is further back from humans and chimpanzees. The genetic similarities prove that we are in some way related to gorillas and chimpanzees, and therefore verify evolution.
5. Homologies are structures that are similar in many organisms because they were inherited from a common ancestor. In Your Inner Fish, Shubin elaborates on the one bone-two bone-blobs-digits structure that most animals have in their arms. It can be seen everywhere from early animals like Tiktaalik (although it was very primitive, because it was one of the first fish to venture on land) to modern birds, whales, dogs, and humans, to name a few. This essential homology connects us with our many shared ancestors and is essential for living on land.
