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Updated Biology Courses cardella

General Biology
Prof. Bryan Cardella, M.Ed.

ap biology eaton

AP Biology 
Dr. Carleen Eaton, M.D.

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  • Study Guides


  • When Darwin proposed his theory of evolution by natural selection, he believed it helped explain the origin of the many species found on earth. For a new species to form, the passage of genes between two groups of organisms must be blocked.

  • Once each gene pool is isolated, natural selection can act on each population independently. If the populations encounter different conditions, they may evolve in different ways.

  • In this activity, we'll look at the types of barriers that can divide a population into separate species. We'll introduce the different ways a new species can evolve. We'll see what happens if two related species come into contact and breed with each other. Then, we'll look at the rate at which new species develop.