READ: Charles Darwin and Natural Selection
4. Introduction
Introduction
Biological evolution is change in species over time. The idea of evolution was proposed by many people before Charles Darwin began collecting evidence for the idea. Scientists for hundreds of years had hypothesized that species change over time. But it was not until Darwin published his research and detailed analysis that the idea of evolution started to gain widespread acceptance. Darwin’s theory of evolution by natural selection brings all fields of biology together and illuminates nearly every aspect of biology. As one famous biologist said, "Nothing in biology makes sense except in the light of evolution."
Charles Darwin was one of the most influential scientists who has ever lived. Darwin introduced the world to the theory of evolution by natural selection, which laid the foundation for how we understand the living world today.
Evolution by natural selection explains:
- The tremendous variety of organisms on Earth.
- Why some organisms that resemble each other are distantly related.
- Why some organisms that do not resemble each other are closely related.
There are three parts to Darwin’s Theory of Evolution by Natural Selection.
- Evolution, which is change in species over multiple generations.
- Natural selection, in which individuals of a population that are most likely to survive and reproduce are also most likely to pass on traits that have a genetic basis to any offspring.
- Adaptation, which are traits that help a plant or animal survive and reproduce in a particular environment. Adaptations are the result of natural selection. For example, light-colored moths on dark trees might be easier for birds to see and catch than dark moths on dark-colored trees. If the moths' color has a genetic basis, then after many generations of birds catching more light moths than dark moths, the population of moths will consist mostly of dark moths.
Humans and the other apes in this drawing all evolved from a common apelike ancestor.
In everyday English, "evolution" simply means to "change" or a "stepwise change from simple to complex." In biology, evolution means change in the inherited traits of a group of organisms over multiple generations. Biological evolution has changed biologists' understanding of all life on Earth.
Human earlobes may be free or attached. You inherited the particular shape of your earlobes from your parents. Inherited traits are influenced by genes, which are passed on to offspring and future generations. Your summer tan is not passed on to your offspring. Natural selection only operates on traits like earlobe shape that have a genetic basis, not on traits like a summer tan that are "acquired."
CK-12 Foundation, Biology. http://creativecommons.org/licenses/by-nc-sa/3.0/