Evolution Blog

A fossil is formed through a long process. First of all, the organism must be dead. Its body is eaten by scavengers. The hard parts of the body such as bones can be remained and buried in sedimentary rocks. After millions of years of movement of the rocks and layers, older bones are buried in lower layers and newer remains are buried in upper layers. The fossils can be discovered on the surface of the earth by being weathering out from the wind, water, and sand.

Archaeologists and biologists use fossils as evidence for the Evolution theory. A theory is formed through a process with hypothesis, observation, evidence, and conclusion. Homology classification is created by observing similar structures of different organisms that can be used to conclude that they have common ancestors. Through millions of years of evolution in order to adapt to different living environments, organisms change their body structures even though they share common ancestor. Analogous structures have similar functions but the organisms have different body structures underneath the surface. For example, both a bird and a dragonfly have wings but their skeletons are different.

The evolution theory can be tested in the evidence of Tiktaalik, a type of fish that has certain amphibian characteristics. Different from the fish’s head, Tiktaalik’s head is flatter and its eyes are on the sides, allowing it to float above the water surface to look for prey. Tiktaalik’s limbs are different from fish’s fins in that they allow Tktaalik to go to shallow water area and not to be stuck, paving the way to becoming an amphibian animal.

Another method to test the Evolution theory is from biomedical evidence such as DNA and proteins in different organisms. Through comparing the Cytochrome C sequence in different organisms, we can draw a cladogram to see which organisms are closely related. The fewer differences in amino acid sequence, the more closely related the organisms are because the DNA mutations happen in less time and they are closer to their common ancestor.