WEIT 2012 Chap1

WHAT IS EVOLUTION

What is the definition of Evolution?

Evolution is a gradual process in which something changes into a different and usually more complex or better form.

Life on earth changed gradually, beginning with one primitive species. Taking millions of years, it branched out over time, throwing off many new and diverse species. This mechanism of evolutionary change is called natural selection. When you break that statement down, you find that it really consists of six components.

What are the six components?

The six components are evolution, gradualism, speciation, common ancestry, natural selection, and nonselective mechanisms of evolutionary change. Let see each of these components closer.