Evolution --- Quiz

Evidence of Evolution Quiz 

1. The following picture presents one of the evidences for evolution, which is the fossil record. The comparison between these fossils shows us that present-day species have morphological features of species in the past. These features further prove that present-day species have been modified from ancestral form. Fossil record is an important evidence for evolution. Even though fossil record is incomplete, fossils can show many evolutionary changes. Some of these changes are gradual, such as the following picture. The picture shows revolutionary changes of species from terrestrial to aquatic.Besides fossil record, homology is also an important evidence for evolution. In this case, limb is the homologous structure between Mesonychid, Ambulocetus, Rodhocetus, and Basilosaurus. Despite Mesonychid lives on land and Basilosaurus lives in water, this picture clearly presents the gradually evolutionary change from the limbs of Mesonychid to the fins of Basilosaurus. 

2. Marsupials begun from North America.  

3. Dragonflies, birds and bats all have the ability to fly. Between birds and bats, limbs under their wings are homologous. This homologous structure proves that they are descendants from a common ancestor. Although dragonflies have legs, they do not have limbs under their wings.This difference of dragonflies' underlying structure indicates that dragonflies are evolved from different ancestral structure. However, dragonflies do contain many similarities of birds and bats. They are all able to fly, and they all have light, broad surfaces. These organisms present convergent evolution. 

4.  During the Common Descent Lab, we are able to link species together by examing the amino acid sequence in the protein, Cytochrome C. Gens are made of DNA and are inherited from parent to offsprings. Some DNA sequences code for the amino acid sequence of proteins. Therefore, by comparing the amino acid sequences, we are able to make a cladogram to show the relationships between species. With the help of cladogram, we are able to see the evolutionary changes between species. For example, the difference between amino acid sequences of cow's and horse's is only, which indicates that cows and horses might be evolved from a common ancestor. This is the reason why the Common Descent Lab shows DNA as evidence of evolution. 

5. As mentioned in Inner Fish, Dr, Shubin found a perfect transitional organism between fish and amphibians, Tiktaalik. In order to prove that Tiktaaklik is the missing link between fish and amphibians, Dr. Shubin proved himself by applying homology. Homology is the study of similar body structures. These similarities imply that single ancestral species branch into many closely related cpecies. For Tiktaalik, the most amazing thing is that instead of having fins on the sides, it has short forearms that enable it to do push-ups. These forearms are similar to the limbs of amphibians. By comparing these homologous structures, we could define Tiktaalik as the perfect transitional organism between fish and amphibians.