Sunday, June 5, 2011

Theories of Evolution

Evolution is the series of random changes of inherited changes over time. The inherited traits range from anatomical features, biochemical, and behavioral characteristics. Evolution happens over many generation; it is a series of tiny changes which cause noticeable mutations.

Mutation- Changes in the gene sequence that create permanent alterations in the genome. Mutation is caused by radiation, viruses, and mutagenic chemicals. Mutations can be inherited from parents or develop during one's lifetime. When the chromosome number changes, larger mutations take place.

Intelligent Design- Unlike natural selection, intelligent design seeks to make sense of seemingly random changes in the genome. Intelligent design states that certain features of the universe and living organisms are explained by intelligent cause rather than natural selection. Intelligent design disagrees with the theory that all mutations are only caused by features in the natural word. It is controversial because of its religious implications (rather than weighing it as the only evidence). Intelligent design theologists argue that there are no natural or material methods to explain the origin and diversity of life.

Creationism- This is a belief that the supernatural created humanity, Earth, life, and the universe. Every culture has their own myths or legends to explain the natural world. The Christian explanation says that God created Adam and Eve the first people. All humans are descendants from Adam and Eve.

Natural Selection- Biological traits become more prevalent in populations due to the fact that only certain members get to survive and reproduce. The environment acts as the selector to which traits get passed down. Over long periods of time this creates lasting changes on the species. For example, the peppered moth is quite common in the UK. It comes in dark and light color variations. During the Industrial Revolution soot would cling to the trees. Dark moths could blend in better with darkened trees. They became more common. After the Clean Air Act the trees returned to their natural shade of brown. Lighter moths flourished rather than dark ones.

Genetic Drift- Certain members of a population leave more descendants. They may not be the stronger one with greater advantages. This means future generations will have their genes. It happens to all populations.

Gene Flow- Synonymous with migration, gene flow is the movement genes from one population to another. It is the mixing of two different populations which causes future genetic differences they did not have originally.

Sources: http://www.intelligentdesignnetwork.org/
http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/genemutation
http://en.wikipedia.org/wiki/Evolution#Mutation

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