Patterns of Evolution

Patterns of Evolution….

Evolutionary Processes

Have you ever wondered why Earth is filled with such diversity? One main reason is because of the evolution of living organisms. Evolution allows a species to change. It is based on genetic inheritance. A change in the genotype of an organism is passed down from parent to offspring again and again. The genes in a population change, and the phenotype of an organism is altered. This evolutionary process occurs in two different ways.

Gradualism. Many evolutionary theorists agree with Darwin, who believed that evolution was a slow and steady process of changes to a species; this is called gradualism. The cheetah didn’t instantaneously become the world’s fastest animal. Its species gradually gained greater speed. The evolution of a species in gradualism is slow, consistent, and constant.

Punctuated equilibrium. Theorists Niles Eldredge and Stephen Jay Gould suggested evolution occurs by punctuated equilibrium. They believed that a species hardly ever changes. It can be millions of years before a species goes through a significant change. If change does occur, it occurs in spurts, like within a few tens of thousands of years the species will change and evolve into a new species. Most change occurs due to mutation of genes that benefit the organism in its environment. When this occurs, the mutated organism is most likely to do better in its environment and reproduce more often, evolving the population. The species then settles and doesn’t change again for a long while. Other rapid changes may occur due to a drastic change in environment. For instance, insects are becoming more and more tolerant to the various pesticides used against them. It’s not that they suddenly grow an immunity to the pesticide; instead, the majority that aren’t tolerant die off, and the very few which already have an immunity live and reproduce, changing the gene pool and population of the species. As you can see, variation of a species definitely helps with its survival.

Patterns of Evolution

Adaptive radiation. Natural selection is a mechanism in evolution that suggests the genes that are passed on more often are the stronger genes of a population because those species strongest in their environment survive and are able to reproduce more. Over time, the gene pool changes and the population is made up of those favorable genes for that specific environment. The perfect example of natural selection is evident in Darwin’s finches. Charles Darwin, the Father of Evolution and a firm believer in natural selection, observed the many different species of finches on the Galapagos Islands. Each species’ characteristics seemed to fit with their environment and diet

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