Thursday, September 26, 2013

Answers for Evolution Quiz #1

1. Explain the following picture in terms evidence for evolution.

  This picture demonstrates the evolution of modern whales. The Mesonychid's living condition began switching from terrestrial to aquatic from around 55 million years ago, while its homologous structure changes as well. 3 million years later, the Ambulocetus it evolved to has a more flexible backbone and hind limbs in order to walk on land and swim. 6 million years later,  the Ambulocetus evolved to Rodhocetus, which its limbs could not support it to walk on land, and swam in an up-and-down motion. 4 million years later, Basilosaurus has more reduced limbs than those of Rodhocetus, and its size was bigger than Rodhocetus, which was closer to the sizes of the modern whale today.

2. Which of the following continents did marsupials begin from?

  E, North America

3. Comparing a dragonfly, bird, bats - explain the type of evolution that these organisms show

  Dragonfly, bird and bats have wings for their ability to fly. However, their underlying structures are different since they evolved from different ancestral structures. The bats has fingers on their wings, and the bird only has a single forelimb, while the dragonfly almost has none. This is why they show a type of convergent evolution.

4. Explain how the Common Descent Lab shows DNA evidence and ancestry as evidence for evolution. Include examples of Primates.

  In the Common Descent lab, we were looking for the similarities and differences of the hemoglobin strands in DNA of humans, chimpanzees, gorillas, and their common ancestor. We found out that the human DNA has the least similarity with DNA of the common ancestor, while it share the most similarities with Chimpanzee DNA. comparison of DNA sequences can be a useful tool to find out the similarities between species. Therefore, it can be a strong evidence for evolution.

5. Explain homology using some examples from your readings.

  Homology is the similarities in the structures of organisms of same or different species because of their common ancestor. For example, tiktaalik has same backbone structure as fish, and modern whale has same tail and backbone structure as Basilosaurus.

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