Final Stretch! Who was Charles Darwin? HW: Begin Evolution Study Guide w/Word Bank

1. Final Stretch! Who was Charles Darwin? HW: Begin Evolution Study Guide w/Word Bank Agenda: 1. Turn in Genetic Disorder Brochures 2. Discuss EOCT Review Tue & Thur 3. Discussion: Charles Darwin and Theory of Evolution Georgia Performance Standards: SB 5: Evaluate the role of natural selection in the theory of evolution

2. Evolution Chapter 15 15.1 Darwin’s Theory of Natural Selection Darwin on the HMS Beagle • His job was to collect biological and geological specimens during the ship’s travel.

3. What can explain the large extent of biological diversity on earth? • Evolution – change over time • How life has changed over time

4. Evolution Chapter 15 15.1 Darwin’s Theory of Natural Selection The Galápagos Islands • Darwin began to collect mockingbirds, finches, & other animals on the 4 islands. • He noticed that the different islands seemed to have their own, slightly different varieties of animals. • Later called descent with modification

5. The Galapagos Islands • West of South America • Group of islands each with different climates • Tortoises varied from island to island in neck length and shell shape • Finches varied in beak shape • Characteristics of plants and animals varied from island to island

6. Evolution Chapter 15 15.1 Darwin’s Theory of Natural Selection

7. Evolution 15.1 Darwin’s Theory of Natural Selection Darwin Continued His Studies • Darwin inferred that if humans could change species by artificial selection, then perhaps the same process could work in nature. • Think of Biotechnology and Agricultural Engineering today!!

8. Journal Entry January 7, 2010 • How life has changed over time is: • Natural Selection b. Descent with modification c. Evolution • 2. According to Darwin, the fact that plants & animals may look similar but show variation is due to • a. Natural Selection b. Descent with modification c. Evolution • 3. The process, or driving force, that causes organism to gradually change in response to their environment is: • Natural Selection b. Descent with modification c. Evolution • 4. The use of biotechnology today can be considered an example of: • a. Natural Selection b. Artificial Selection c. Derived trait • 5. Charles Darwin took his voyage aboard the HMS _______________ and did most of his research in______________. • a. Bagel; Australia b. Evolution; South Africa c. Beagle; Galapagos

9. What did Darwin call the process by which an individual changes over time? Agenda: 1. Review: Natural Selection 2. Discuss Support/Evidence for Evolution Georgia Performance Standards: SB 5: Evaluate the role of natural selection in the theory of evolution

10. Evolution Chapter 15 15.1 Darwin’s Theory of Natural Selection Natural Selection • Individuals in a population show variations. • Variations can be inherited. • Organisms have more offspring than can survive with available resources. • Variations that increase reproductive success will have a greater chance of being passed on. • “Survival of the Fittest”

11. Evolution Chapter 15 15.1 Darwin’s Theory of Natural Selection The Origin of Species • Darwin published On the Origin of Species by Means of Natural Selectionin 1859. • It is a means of explaining how evolution works.

12. Lamarck’s Theory • Pre-Darwin scientist • Inheritance of acquired traits due to use and disuse of features • Structures not used would shrivel and disappear • Early scientist to recognize that organisms had changed over time

13. Evolution Chapter 15 15.2 Evidence of Evolution Support for Evolution • The fossil record • Provide a record of species that lived long ago. • Show that ancient species share similarities with species that now live. Armadillo Glyptodont

14. Evolution Chapter 15 15.2 Evidence of Evolution Support for Evolution • Biological Molecules • Nucleotide changes (mutation) cause a change in amino acid sequences • Species with a common ancestor will have fewer differences in their genes and amino acids.

15. Evolution Chapter 15 15.2 Evidence of Evolution Support for Evolution • Geographic Distribution • The distribution of plants and animals that Darwin saw first suggested evolution to Darwin. Rabbit Mara

16. Evolution Chapter 15 15.2 Evidence of Evolution • Derived traits are newly evolved features, such as feathers, that do not appear in the fossils of common ancestors. • Ancestral traits are more primitive features, such as teeth and tails, that do appear in ancestral forms.

17. Homologous Structures • Anatomically similar structures inherited from a common ancestor

18. Evolution • Same function but different structure • NOT inherited from common ancestor. Chapter 15 Analogous Structures

19. Evolution • Evolutionary theory predicts that features of ancestors that no longer have a function for that species will become smaller over time until they are lost. Chapter 15 15.2 Evidence of Evolution Vestigial Structures • Structures that are the reduced forms of functional structures in other organisms.

20. Evolution Chapter 15 15.2 Evidence of Evolution • Comparisons of the similarities in organisms are seen in comparative anatomy and in the fossil record. • Organisms with closely related morphological features have more closely related molecular features.

21. More Terms • Fitness – ability of an individual to survive and reproduce in a specific environment • Adaptation – inherited characteristic that increases an organism’s chance of survival • Can be physical traits as well as behavioral traits

22. Evolution Chapter 15 15.2 Evidence of Evolution Camouflage • Allows organisms to become almost invisible to predators Leafy sea dragon

23. Evolution Chapter 15 15.2 Evidence of Evolution Mimicry • One species evolves to resemble another species. California kingsnake Western coral snake

24. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Natural Selection • Acts to select the individuals that are best adapted for survival and reproduction

25. Evolution Chapter 15 15.3 Shaping Evolutionary Theory • Stabilizing selectionoperates to eliminate extreme expressions of a traitwhen the average expression leads to higher fitness. • Ex. Siberian Husky

26. Evolution Chapter 15 15.3 Shaping Evolutionary Theory • Directional selectionmakes an organism more fit. • Favors the extremes • Ex. Greyhound Dog

27. Evolution Chapter 15 15.3 Shaping Evolutionary Theory • Disruptive selectionis a process that splits a population into two groups. • Ex. Black, White, & Gray Rabbits

28. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Mechanisms of Evolution • Population genetics • Hardy-Weinberg principle states that when allelic frequencies remain constant, a population is in genetic equilibrium.

29. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Write these down & know these!

30. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Genetic Drift • A change in the allelic frequencies in a population that is due to chance and random mating • In smaller populations, the effects of genetic drift become more pronounced, and the chance of losing an allele becomes greater. • Marble Example

31. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Nonrandom Mating • Promotes inbreeding & could lead to a change in allelic proportions favoring individuals that are homozygous for particular traits

32. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Founder Effect • The loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population Island 1 Island 2 Mainland Island 3

33. Evolution 15.3 Shaping Evolutionary Theory Bottleneck • a significant percentage of a population or species is killed or otherwise prevented from reproducing and can rebound later • Often caused by a natural disaster

34. What is a gene pool? • Gene pool – combined genetic info of all members of a population • Contains two of more alleles (genes) for the same trait • Allele frequency – number of times an allele occurs in a gene pool compared to the number of times another allele occurs (expressed in percents)

35. Relative Frequencies of Alleles Section 16-1 allele for brown fur allele for black fur Sample Population 48% heterozygous black Frequency of Alleles 16% homozygous black 36% homozygous brown

36. Gene Flow • Genes entering or leaving a population • AKA. Migration • Emigration Genes LEAVING a population • Immigration INCOMING genes in a population

37. What are sources for genetic variation? • Mutations – random change in the DNA, may cause evolution in future populations • Genetic shuffling – occurs in meiosis when gametes are formed

38. Evolution Chapter 15 15.3 Shaping Evolutionary Theory • Sexual selection operates in populations where males and females differ significantly in appearance.

39. Evolution Chapter 15 15.3 Shaping Evolutionary Theory • Prezygotic isolationprevents reproduction by making fertilization unlikely. • In behavioral isolation, patterns of courtship may be different. • In temporal isolation, different groups may not be reproductively mature at the same season, or month, or year. • In ecological isolation, not in the same habitat where they are likely to meet. Eastern meadowlark and Western meadowlark

40. Evolution • Postzygotic isolationoccurs when fertilization has occurred but a hybrid offspring cannot develop or reproduce. Chapter 15 15.3 Shaping Evolutionary Theory • Prevents offspring survival or reproduction Liger

41. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Allopatric Speciation • A physical barrier divides one population into two or more populations. Kaibab squirrel Abert squirrel

42. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Sympatric Speciation • A species evolves into a new species without a physical barrier. • The ancestor species and the new species live side by side during the speciation process.

43. Evolution • Can occur in a relatively short time when one species gives rise to many different species in response to the creation of new habitat or some other ecological opportunity Chapter 15 15.3 Shaping Evolutionary Theory Adaptive Radiation

44. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Coevolution • The relationship between two species might be so close that the evolution of one species affects the evolution of the other species. • Mutualism • Coevolutionary arms race

45. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Convergent Evolution • Unrelated species evolve similar traits even though they live in different parts of the world.

46. Evolution Chapter 15 15.3 Shaping Evolutionary Theory Rate of Speciation • Evolution proceeds in small, gradual steps according to a theory called gradualism. • Punctuated equilibrium explains rapid spurts of genetic change causing species to diverge quickly.

47. Evolution Chapter 15 15.3 Shaping Evolutionary Theory