WEIT 2012 Chap1

WHAT IS EVOLUTION

What is the definition of Evolution?

Evolution is a gradual process in which the biological populations change into a different and usually more complex or better form. Life on Earth began with a universal common ancestor. It changed gradually, taking several millions of years. This universal common ancestor, named LUCA (Last Universal Common Ancestor), 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.

put these terms in bold--Pierre.brawand 28 mars 2012 à 13:34 (CEST)

What is evolution?

Evolution is the fact that a species undergoes genetic change over time.

a SPECIES or a POPULATION? Be very precise with this definition--Pierre.brawand 28 mars 2012 à 13:34 (CEST) The differences are based on the changes into the DNA, which originate as mutations. All the species evolve but not at the same rate. The theory of evolution doesn't predict that species will constantly be evolving, or how fast they will change when they do. It depends on the evolutionary pressures they experience.

What is gradualism?

Gradualism is the fact that it takes many generations to produce a substantial evolutionary change. The evolution of new features can take over hundreds or thousands (even millions) of generations. A species evolve faster or slower as evolutionary pressures wax and wane. Also, when the natural selection is strong, evolutionary change can be fast. But once a species becomes well adapted to a stable habitat, evolution often slows down. Many living species share fundamental traits such as biochemical pathways that we use to produce energy, our standart four letters DNA code, and how that code is read and translated into proteins. This tells us that every species goes back to a single common ancestor (who had those traits and passed them on to its descendants).

What is speciation?

???--Pierre.brawand 28 mars 2012 à 13:34 (CEST)

What is common ancestry?

???--Pierre.brawand 28 mars 2012 à 13:34 (CEST)

What is natural selection?

???--Pierre.brawand 28 mars 2012 à 13:34 (CEST)

What is nonselective mechanisms of evolutionary change?

good start but you should now increase the production in order to finish on time this part.--Pierre.brawand 28 mars 2012 à 13:34 (CEST)

You'll have to define the term THEORY here... see page 15. Very important point.--Pierre.brawand 28 mars 2012 à 13:34 (CEST)

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