Evolutionary Mechanics

So, how do changes cause new species?

Natural Selection is one mechanism of Evolution.  

Let's take a look at some others.

We've already seen that Natural Selection is one of the evolutionary mechanisms we've investigated, and we've seen how this can work (using  the peppered moth and the Stick Insect color as just two examples of this),  but we've also seen that the environment isn't the only thing that can put pressure on the characteristics of an organism.  We've already seen that females can be pretty choosy about who they mate with, and they can help select traits they want in a mate.  By doing this, they become a driving force in evolution.


So our loist can start with these two mechanisms:

  1. Natural Selection

  2. Sexual Selection


But there are still more ways that evolution gets changes into poulations.  We'll learn about a couple of these in this section.


Before we get into the details, let's take an overview of Evolution (MacroEvolution)


We've already seen the video above, and we need to consider these questions:

  • List the mechanisms of Evolution.

  • How do each of these mechanisms work?

  • What is a species?

  • How can one type of animal evolve into a whole new species of animal?

  • Why is it necessary for organisms produce an excess of offspring for evolution to occur?

  • How does selection occur?

  • Why is uniqueness necessary for Evolution?

  • Why is the DNA of each individual slightly different?

  • How does an excess of offspring increase diversity in a species?

  • Define Heredity.