EVOLUTIONA gradual change over a period of time

What is a theory?

• Theories are statements or models that have been tested and confirmed many times

• They explain a wide variety of data and observations

• They can be used to make predictions

What is a theory?

• They are not absolute, they serve as a model of understanding the world and can be changed as the world view changes

• The term "Theory" does not express doubt.

Charles Darwin

• Naturalist that observed many species

• Many trips to the Galapagos Islands

• Observed finches, mockingbirds, turtles

• Wrote the Origin of Species

Theory of Evolution by Natural Selection

1.  Variation exists among individuals in a species

2. Individuals of species will compete for resources (food and space) called Struggle for Existence

3. Some competition would lead to the death of some individuals while others would survive called Survival of the Fittest

Theory of Evolution by Natural Selection

4. Individuals that had advantageous variations are more likely to survive and reproduce.

5. This process he describes came to be known as Natural Selection.

Decent with Modifications

Darwin noted that all the finches on the Galapagos Island looked about the same except for the shape of their beak. His observations lead to the conclusion that all the finches were descendents of the same original population. The shape of the beaks were adaptations for eating a particular type of food (Ex. long beaks were used for eating insects, short for seeds)

Darwin’s Finches

Evidence of Evolution

• Fossil Evidence

Evidence of Evolution• Homologous

Structures - structures that are embryological similar, but have different functions, the wing of a bird and the forearm of a human

Evidence of Evolution

• Vestigial Structures – lost most or all of function do to lack of use

Evidence of Evolution

• Biochemistry and DNA

Evidence of Evolution

• Early Embryonic Development

Genetic Variation

• How Genetic variation and the Environment influence Natural Selection

Summary of Darwin’s Theory

• Organisms differ; variation is inherited• Organisms produce more offspring than

survive• Organisms compete for resources• Organisms with advantages survive to pass

those advantages to their children• Species alive today are descended with

modifications from common ancestors

Natural Selection

• The environment determines which traits are favorable for survival

Natural Selection is responsible for Antibiotic Resistance to

Bacteria

MRSA

CLASSIFICATION

• The grouping of information or objects based on similarities

• Named using to words from Latin or Greek

• Felis Catus

Dichotomous Key

• A device used to easily and quickly identify an unknown organism.

• The user of the key is presented with a sequence of choices between two statements based on characteristics of the organism. By always making the correct choice, the name of the organism will be revealed.

Here is an example from your book

Phylogenetic Treeor Cladogram

Phylogenetic Tree• Is a branching diagram or tree showing the

evolutionary relationships among various biological species based upon the physical and/or genetic characteristics