Evolution Darwins Theory of Evolution 1 Individual organisms

Darwin’s Theory of Evolution 1. Individual organisms in nature differ from one another. Some

• Darwin also saw that when humans choose organisms with specific characteristics as

–Example of artificial selection in animals: dog breeding German shepherd Hundreds to thousands of

2. Organisms in nature produce more offspring than can survive. Leopard Frog

3. Because more organisms are produced than can survive, members of each species must

4. Because each organism is unique, each has different advantages and disadvantages in the

5. Individuals best suited to their environment survive and reproduce most successfully. The characteristic

6. Species change over time. This is natural selection. Over long periods of time,

7. Species alive today have descended with modifications form species that lived in the

8. All organisms on Earth are united into a single tree of life by

Phylogenetic Tree – Hand out Phylogenetic Tree and Homologous Structures Worksheet 1. Which two

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Evolution

Darwin’s Theory of Evolution 1. Individual organisms in nature differ from one another. Some of this variation is inherited. Natural variation – differences among individuals of a species

• Darwin also saw that when humans choose organisms with specific characteristics as breeding stock, they are performing the role of the environment –This is called artificial selection –Example of artificial selection in plants: five vegetables derived from wild mustard

–Example of artificial selection in animals: dog breeding German shepherd Hundreds to thousands of years of breeding (artificial selection) English springer spaniel Golden retriever Yorkshire terrier Minidachshund Ancestral dog

2. Organisms in nature produce more offspring than can survive. Leopard Frog

3. Because more organisms are produced than can survive, members of each species must compete for limited resources.

4. Because each organism is unique, each has different advantages and disadvantages in the struggle for existence. Peppered Moths

5. Individuals best suited to their environment survive and reproduce most successfully. The characteristic that make them best suited to their environment are passed on to offspring. Individuals whose characteristics are not as well suited to their environment die or leave fewer offspring.

6. Species change over time. This is natural selection. Over long periods of time, natural selection causes changes in the characteristics of a species, such as in shape and form. New species arise, and other species disappear.

7. Species alive today have descended with modifications form species that lived in the past. Jackal Thousands to millions of years of natural selection • These five canine species evolved from a common ancestor through natural selection African wild dog Fox Coyote Wolf Ancestral canine

8. All organisms on Earth are united into a single tree of life by common descent. C A B A is more closely related to B than to C

Phylogenetic Tree – Hand out Phylogenetic Tree and Homologous Structures Worksheet 1. Which two modern organisms are likely to be most closely related? 2. What was the most recent common ancestor of organisms 2 and 3? 3. Now do this one on your own. Then complete the rest of your worksheet.

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