Which of the following principals is NOT part of

1. Which of the following principals is NOT part of • Darwin’s theory of evolution by natural selection? • Evolution is a gradual process that occurs over • long period of time. • b. Variation occurs among individuals in a • population. • c. Mutations are the ultimate source of genetic • variation. • d. More individuals are born than will survive. • e. Individuals that posses the most favorable • variations have the best chance of reproducing. Answer: c

2. In a certain group of African people, 4 percent are • born with sickle cell anemia. What percentage of • the group has the selective advantage of being • more resistant to malaria than those individuals • who are homozygous for normal hemoglobin or • for sickle cell anemia? • 2% • 4% • 8% • 16% • 32% Answer: e

3. Do Now September 12, 2013 • CONTEMPORANEOUS: existing during the same time • Task: Develop definitions for the following. Do NOT look up the definitions. Create them on your own – individually – without assistance from others. • Genetic drift • Population bottleneck • Founder effect

4. 15 Mechanisms of Evolution

5. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory • Biological populations change over time, or evolve. • Evolutionary change is observed in laboratory experiments, in natural populations, and in the fossil record.

6. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory Evolutionary theory—understanding the mechanisms of evolutionary change. It has many applications: study and treatment of diseases, development of crops and industrial processes, understanding the diversification of life, and how species interact. It also allows us to make predictions about the biological world.

7. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory Theory—In everyday speech, an untested hypothesis or a guess. Evolutionary theory is not a single hypothesis, but refers to our understanding of the mechanisms that result in genetic changes in populations over time and to our use of that understanding to interpret changes in and interactions among living organisms.

8. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory Even before Darwin, biologists had suggested that species had changed over time, but no one had proposed a convincing mechanism for evolution.

9. Linnaeus Lamarck Wallace

10. E. O. Wilson American biologist recognized as the world’s leading authority on ants. He was also the foremost proponent of sociobiology, the study of the genetic basis of the social behavior of all animals, including humans.

11. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory Charles Darwin was interested in geology and natural history.

12. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory In 1831, Darwin began a 5-year voyage around the world on a Navy survey vessel, the HMS Beagle.

13. Figure 15.1 The Voyage of the Beagle

14. Galapagos

15. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory From the observations and insights made on the voyage, and new ideas from geologists on the age of the Earth, Darwin developed an explanatory theory for evolutionary change: • Species change over time. • Divergent species share a common ancestor. • The mechanism that produces change is natural selection.

16. Natural Selection

17. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory In 1858, Darwin received a paper from Alfred Russel Wallace with an explanation of natural selection nearly identical to Darwin’s. Both men are credited for the idea of natural selection. Darwin’s book, The Origin of Species, was published in 1859.

18. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory By 1900, the fact of evolution was established, but the genetic basis of evolution was not yet understood. Then the work of Gregor Mendel was rediscovered, and during the 20th century, work continued on the genetic basis of evolution. A “modern synthesis” of genetics and evolution took place 1936–1947.

19. Figure 15.2 Milestones in the Development of Evolutionary Theory

20. Concept 15.1 Evolution Is Both Factual and the Basis of Broader Theory The structure of DNA was established by 1953 by Watson and Crick. In the 1970s, technology developed for sequencing long stretches of DNA and amino acid sequences in proteins. Evolutionary biologists now study gene structure and evolutionary change using molecular techniques.

21. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Biological evolution refers to changes in the genetic makeup of populations over time. Population—a group of individuals of a single species that live and interbreed in a particular geographic area at the same time. Individuals do not evolve; populations do.

22. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution The origin of genetic variation is mutation. Mutation—any change in nucleotide sequences. Mutations occur randomly with respect to an organism’s needs; natural selection acts on this random variation and results in adaptation.

23. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Mutations can be deleterious, beneficial, or have no effect (neutral). Mutation both creates and helps maintain genetic variation in populations. Mutation rates vary, but even low rates create considerable variation.

24. Variation among members of a species (Heritable)

25. Polymorphism

26. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Because of mutation, different forms of a gene, or alleles, may exist at a locus. Gene pool—sum of all copies of all alleles at all loci in a population. Allele frequency—proportion of each allele in the gene pool. Genotype frequency—proportion of each genotype among individuals in the population.

27. Figure 15.3 A Gene Pool

28. A gene pool is the genetic make-up of a specific population, and is the combination of all the alleles for all traits members of the population exhibit. For example, in a population of mice, the gene pool consists of all the alleles of the genes for each individual mouse. In the gene pool above, 60% of the alleles are black (B) and 40% are white (b). The percent of alleles in a pool is known as an allele frequency. The sum of all alleles in any pool must be 100%.

29. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Many of Darwin’s observations came from artificial selection of domesticated plants and animals. Selection on different characters in a single species of wild mustard produced many crop plants.

30. Figure 15.4 Many Vegetables from One Species

31. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Darwin bred pigeons and recognized similarities between selection by breeders and selection in nature.

32. Figure 15.5 Artificial Selection

34. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Laboratory experiments also show genetic variation in populations. Selection for certain traits in the fruit fly Drosophila melanogaster resulted in new combinations of genes that were not present in the original population.

35. Figure 15.6 Artificial Selection Reveals Genetic Variation

36. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Natural selection: Far more individuals are born than survive to reproduce. Offspring tend to resemble their parents, but are not identical to their parents or to one another. Differences among individuals affect their chances to survive and reproduce, which will increase frequency of favored traits in the next generation.

37. Competition for limited resources Overproduction of young

38. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Adaptation—a favored trait that evolves through natural selection. Adaptation also describes the process that produces the trait. Individuals with deleterious mutations are less likely to survive and reproduce and to pass their alleles on to the next generation.

39. Adaptations "Fitness"

40. Natural selection has no intentions or senses; it cannot sense what a species “needs.” If a population happens to have the genetic variation that allows some individuals to survive a particular challenge better than others, then those individuals will have more offspring in the next generation, and the population will evolve. If that genetic variation is not in the population, the population may still survive (but not evolve much) or it may die out. But it will not be granted what it “needs” by natural selection.

41. Do Now September 16, 2013OBSTREPEROUS: noisy, unruly Task: Read the following and select the most appropriate answer. In your notebook, write the answer and your reasoning in selecting that. In which of the following scenarios are allele frequencies are likely to change, leading to evolution, according to Hardy–Weinberg assumptions: a. An isolated and highly endangered population of 50 woodland caribou b. A large population of lizards whose males have red, blue, or green tails; females preferentially mate with red-tailed males c. A large population of fish in an isolated lake; every 5 years a flood results in some fish from a population in an adjacent lake mixing with this population d. All of the above e. None of the above

42. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Migration of individuals between populations results in gene flow, which can change allele frequencies.

43. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Genetic drift—random changes in allele frequencies from one generation to the next. In small populations, it can change allele frequencies. Harmful alleles may increase in frequency, or rare advantageous alleles may be lost.

44. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution A population bottleneck—an environmental event results in survival of only a few individuals. Genetic drift can change allele frequencies. Populations that go through bottlenecks loose much of their genetic variation.

45. Figure 15.7 A Population Bottleneck

46. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Founder effect—genetic drift changes allele frequencies when a few individuals colonize a new area.

47. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Nonrandom mating: Selfing, or self-fertilization is common in plants. Homozygous genotypes will increase in frequency and heterozygous genotypes will decrease.

48. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Sexual selection—mates are chosen based on phenotype, e.g., bright-colored feathers of male birds. There may be a trade-off between attracting mates (more likely to reproduce) and attracting predators (less likely to survive).

49. Concept 15.2 Mutation, Selection, Gene Flow,Genetic Drift, and Nonrandom Mating Result in Evolution Or, phenotype may indicate a successful genotype, e.g., female frogs are attracted to males with low-frequency calls, which are larger and older (hence successful). Studies of African long-tailed widowbirds showed that females preferred males with longer tails, which may indicate greater health and vigor.

50. Figure 15.8 What Is the Advantage?