1. Reminders Lab Reports- Example, Average, Comments – Hypothesis, using numbers, variables, materials/procedure, wording Lab Notebook? Test Grades Evolution Unit Plan

2. Warm Up: On your stickey note, write down three of the craziest/weirdest things you have heard about ‘The Theory of Evolution’

3. Microevolution: Unique Gene Pools

4. Charles Darwin Charles Darwin (1809-1882) is credited with proposing that the mechanism for the process of evolution is natural selection. Darwin spent five years on a voyage that took him around the world with the majority of his time spent in South America and its neighboring islands. Darwin published his theory with compelling evidence for evolution in his 1859 book On the Origin of Species, overcoming scientific rejection of earlier concepts of transmutation of species. 4

5. Charles Darwin He established that all species of life have descended over time from common ancestors, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. 5

6. Charles Darwin By the 1870s the scientific community and much of the general public had accepted evolution as a fact. However, many favored competing explanations and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. In modified form, Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life. 6

7. Darwin’s Observations Populations change over time as evidenced by the fossil record. There are always more offspring produced than the preceding generation. Populations, if left unchecked, grow at a geometric rate rather than an arithmetic rate. Darwin used an example involving elephants to illustrate the points above. He estimated that if elephants underwent unrestricted reproduction, that in 740-750 years there would be 19 million elephants produced from just one original pair.

8. Darwin’s Observations Summarize the graph and explain the patterns

9. Darwin’s Elephant Problem “There is no exception to the rule that every organic being naturally increase at so high a rate that if not destroyed, the earth would soon be covered by the progeny of a single pair.... The Elephant is reckoned to be the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase: it will be under the mark to assume that it breeds when thirty years old, and goes on breeding till ninety years old, bringing forth three pairs of young in this interval; if this be so, at the end of the fifth century there would be alive fifteen million elephants, descended from the first pair.” (Darwin, 1859 p.64) 9

10. Darwin’s Observations 10 There is variation within a given species and the majority of this variation is inherited. This litter of kittens vary with respect to coat pattern and color. Any variation may, to some degree, affect the ability of an organism to reproduce and contribute genes to the gene pool, thus affecting evolutionary success. Species change over time. These changes are related to traits that are inherited or arise from an alteration of the genetic code. Some inherited traits are beneficial and contribute to survival. Whether a trait is beneficial or not is a function of the environment in which it lives What is the difference between heredity and mutation?

11. Adaptations and Fitness An adaptation is a genetically controlled trait that is favored by natural selection and gives the organism a reproductive advantage ensuring the trait is passed on to its descendants. This trait may also allow the individual to survive longer thus increasing the reproductive rate of that individual. Compare and contrast these hares and identify the differences in their traits 11

12. Adaptations and Fitness The antelope hare lives in the desert, and the snowshoe hare lives in the mountains. Explain how the differences in their traits enhance their ability to survive in their respective environments. Evolutionary success or fitness refers to the contribution of genes to the gene pool and NOT how long an organism lives. 12

13. The Effect of Environmental Change 13 Earth’s environment is NOT STATIC, but rather ever changing. As a consequence, traits or adaptations that were favorable may become unfavorable. The peppered moth, Biston betularia is native to England and exists in two forms, one is dark and the other light with a “peppered” appearance. Birds are its main predator. Prior to the industrial revolution, only 2% of the moths were dark. The industrial revolution produced vast amounts of sulfur dioxide and soot from the burning of coal which altered the environment. Fifty years later 95% of the moths were dark. Propose an explanation!

14. Industrial Melanism 14 England has since regulated the burning of coal and as a result, the trees are returning to their original state (A). Consequently, the coloring among the population of moths in Britain has shifted back so that the peppered moths are once again favored.

15. Evolution Defined Evolution is defined as a change in the inherited characteristics of biological populations over successive generations. – More simply: Genetic change over time Evolutionary processes give rise to diversity at every level of biological organization, from the molecular to the macroscopic. As a result diversity is prevalent among molecules such as DNA as well as individual organisms and species of organisms. 15

16. Microevolution Microevolution is simply a change in gene frequency within a population. Evolution at this scale can be observed over short periods of time such as from one generation to the next. Example: The frequency of a gene for pesticide resistance in a population of crop pests increases. Predict some reasons why these changes would come about 16

17. Microevolution Microevolution is simply a change in gene frequency within a population. Evolution at this scale can be observed over short periods of time such as from one generation to the next. Example: The frequency of a gene for pesticide resistance in a population of crop pests increases. Such a change might come about because – natural selection favored the gene – the population received new immigrants carrying the gene (gene flow) – nonresistant genes mutated into a resistant version of the gene – of random genetic drift from one generation to the next 17

18. Microevolution A gene is a sequence of DNA nucleotides that specify a particular polypeptide chain. Genes code for proteins. An allele is a particular form of a gene. For example: B represents the allele for black coat color and b for white coat color. Selection acts on phenotype because differential reproduction and survivorship depend on phenotype not genotype. Natural selection acts on individuals, but only populations evolve. 18