1. Theories of Evolution Type I – Cheetahs can reach top speeds of up to 60 mph; however, they were not always this fast. Explain how/why cheetahs may have evolved to be such fast animals.

2. Lamarck Jean Baptiste Lamarck (1744 – 1829) One of the first to propose a theory of evolution. – First to state that organisms change over time, meaning newer generations of organisms are modified versions of older generations of organisms. Theory is based on observed changes in the fossil record for the same species Believed that organisms could pass down acquired traits which are traits not determined by genes; traits gained by experience or behavior Ex: Cheetahs exercised and increased leg strength, then passed it on to their offspring.

3. Teleology Comes from the root “telos” meaning end. Teleology – idea that evolution is purposeful or has a pre-determined result. Belief that everything happens for a reason. Ex: Cheetahs were meant to become top predators, so they had to become faster to catch their prey.

4. Creationism/Intelligent Design Belief in a “creator” or “higher power”. Creationism – Belief in the literal meaning of the Bible and other religious documents. – Do not believe that species change significantly over time. Intelligent Design – Belief that creator began the process of life. – Recognize that species change over time, but do not believe that new species are created. Ex: Cheetahs were created by “God” to be fast runners.

5. Darwin Charles Darwin – attended medical school and studied for the clergy Hired as a naturalist for an expedition in 1831 – sailed on the H.M.S. Beagle – traveled through South America and South Pacific Read books on geology. – Geologic changes take place over millions of years. Organisms must adapt to these changes. Collected specimens and recorded data from various locations. – Noted differences between similar species living in different locations. Why were they different? Developed a theory called evolution by natural selection. – Now most widely accepted evolutionary theory in scientific community.

6. Darwin’s Theory Based on Descent with Modification – newer species are modified descendents of older species. – Different from Lamarck’s idea of descent with modification – Believed that all species descended from a few original types of organisms. Idea supported by Darwin’s observations from his specimens and travels – Similar species showed different characteristics in different locations. – Ex: Galapagos finches – compared birds on different islands Beaks shaped differently when different food sources present – Large, wide beak for cracking seeds. – Small, thin beak for catching insects.

8. Darwin’s Theory continued… Darwin proposed the theory of Evolution by natural selection – Proposed hypothesis for how evolution happens. He observed that environment can limit the size of populations. – Most populations do not grow unchecked. 2 ways to limit population growth. – Increased death rate – Decreased reproduction rate

9. Natural Selection Main points of Darwin’s theory 1.All populations contain some variation – Not all individuals are the same within a group. 2.Some organisms are more “fit” for their environment. Fitness – the ability of an organism to survive and reproduce in its environment 3.More fit organisms will have greater reproductive success. (Have more offspring!!) 4.As a result, genes for these traits will be passed on more often. 5.After time, the population as a whole may change. Adapt – a species changing genetically over time to become better suited for the environment EX: Cheetahs who were fast were more fit for the environment and more likely to survive and reproduce.

10. Important to Remember Evolution acts on populations, NOT individuals! – Individuals do not change spontaneously. – Changes may be seen in the population as a whole over millions of years. Evolution is NOT purposeful! – Traits that are favorable in some environments may not be favorable in others. – Change in the environment may cause change in populations.