BM #2 "Describe how biological evolution accounts for species diversity, adaptation, natural selection, extinction, and change in organisms over time

1. Understand and describe that with all of the species alive today similarities in internal structures, chemical processes, and common ancestry suggest a unity.

2. Understand that diversity today is the result of changes over many generations. These changes that provide pathways for diversity are mutations. Sometimes these variations in a population provide unique characteristics for adaptation.

3. Describe how adaptations of structures, behaviors, or physiology enhance survival of the species. Environmental changes impact the survival of organisms.

4.Understand the descendants can be different from their ancestors through differential or selective breeding

5. Understand that extinction is common and final. Fossil records support this.

6. Explain that remains found in the fossil record of sedimentary rocks demonstrate a continuum of change. More recent fossil deposits most likely resemble existing species.

Evolution- A change of hereditary factors in a species over time.

Species- A group of organisms with similar characteristics whose members successfully reproduce among themselves.

-Darwin: observed how some organisms changed over generations. He attributed the changes to differences in inherited characteristics.

-Natural Selection- organisms with traits best suited to their environments are more likely to survive.

Chief Characteristics:

1. Organisms produce more offspring than can survive.
2. Variations are found among individuals of a species
3. Some variations enable members of a population to survive and reproduce better than others (survival advantage)
4. Over time, offspring of individuals with helpful variations make up more and more of a population.

Variation- is the appearance of an inherited trait that makes an individual different from other members of the same species. They can be helpful or harmful.

Sources of variation: Always tied to the environment

1. Mutations
2. Mixing of populations/ movement
3. Geographical isolation

Evolution: the rate of evolution varies. There are two ideas which are both supported by evidence: Gradual and Punctuated Equilibrium

Fossil Evidence

1. Types of fossils
2. Fossil Record (page 164 in text)
3. Vestigial structures
4. Embryology
5. DNA: