Week 9

I think the most important subject in the geologic era is the fossils. I thinks its important to know and learn about who or what was living before us. I also think its important to know who they are and what they look like. The subject about fossils is pretty interesting as well. In the future we may or may not find out more about the fossils in the past thousands or maybe millions of years.

Week 8

Directional selection is when individuals at one end of the curve higher fitness than individuals in the middle or at the end. Stabalizing selection is when individuals near the center of the curve have higher fitness than individuals at either end of the curve. Disruptive selection is when individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle.

Week 7

To understand how radical Darwin's thoughts appeared, you must understand a few things about the world in which he lived. Most Europeans in Darwin's day believed that the Earth and all its forms of life had been created only a few thousand years ago. Since that original creation, they concluded, neither the planet or its living species had changed.

Week 6

Convergent evolution has occurred time and time again in both animals and plants. Consider swimming animals, for example. An animal can move through the water rapidly with the least amount of energy if its body is streamlined and if it has body parts that can be used like paddles.

Week 5

As new species evolve, populations become reproductively isolated from eachother. Speciation in the Galapagos finches occurred by founding of a new population, geographic isolation, changes in the new population's gene pool, reproductive isolation, and ecological competition.

Week 4

Individual organisms differ, and some of the variations are heritable. Organisms produce more offspring than can survive, and many that do survive do not reproduce. Because more organisms are produced than can survive, they compete for limited resources. Each unique organism has different advantages and disadvantages in the struggle for existence. Individuals best suited to their environment survive and reproduce most successfully. These organisms pass their heritable traits to their offspring. Other individuals die or leave fewer offspring. This process of natural selection causes species to change over time. Species alive today are descended with modification from ancestral species that lived in the distant past. This process, by which diverse species evolved from common ancestors, unites all organisms on Earth into a single tree of life.