UNIT VII POPULATION GENETICS & CLASSIFICATION

1. UNIT VII POPULATION GENETICS & CLASSIFICATION

2. I. EVOLUTION VOCABULARY • Evolution • Change in the _________________ ___________________________ of organisms over time • Descent with modification • Natural Selection • Populations of organisms can change over the generations if individuals having certain _________________ _____________ leave more offspring than others • ___________________ reproductive success • Evolutionary adaptations • A prevalence of inherited characteristics that ______________ organisms’ ______________ and _____________________ in __________________ environments November 24, 1859

3. II. A HISTORY OF EVOLUTIONARY THEORY • Carolus Linnaeus (1707-1778) • “Father of __________________” • Grouped similar species into a hierarchy of increasingly general categories • Had no evolutionary reasoning behind this • James Hutton (1726-1797) • Theory of ___________________ • Profound change is the cumulative product of slow but continuous processes • Jean-Baptiste de Lamarck (1744-1829) • ________________________ • Body parts used extensively become larger & stronger while those that aren’t used deteriorate (ex. Blacksmith or Giraffe neck) • Inheritance of __________________ Characteristics

4. II. A HISTORY OF EVOLUTIONARY THEORY, cont • Thomas Malthus (1776-1834) • Populations • Charles Lyell (1792-1875) • Theory of ______________________________ • Geologic processes have not changed throughout Earth’s history, so the forces and the rates at which these forces operate are the same today as in the past • Gregor Mendel (1822-1884) • “Father of ________________” • Inheritance patterns • Alfred Wallace (1823-1913) • Independently developed evolutionary theory • Not 1st to publish = little to no credit

5. II. A HISTORY OF EVOLUTIONARY THEORY, cont

6. II. A HISTORY OF EVOLUTIONARY THEORY, cont • Charles Darwin (1809-1882) • Naturalist • HMS Beagle • _____________________ Islands • Darwin’s _______________: New species of finches arose from gradual accumulation of adaptations due to variations in food supply, terrain • The Origin of Species 1) 2)

7. III. DARWIN’S CONCLUSIONS • Descent with Modification • Summary of Observations • Members of a population often _________ greatly in their traits. • Traits are inherited from parents to offspring. • All species are capable of producing _______ offspring that their environment can _________. • Owing to a _________ of food or other resources, many of these offspring do not ______________.

8. III. DARWIN’S CONCLUSIONS, cont • Decent with Modification • Summary of Inferences • Individuals whose inherited traits give them a ________________________ _____________________ of surviving and reproducing in a given environment tend to leave _________ offspring than other individuals. • This unequal ability of individuals to survive and reproduce will lead to the accumulation of _______________ ____________ in the population over generations.

9. IV. EVIDENCE FOR EVOLUTION • Direct Observation • Antibiotic/Drug Resistance • Coloration in Guppies • Endler’s Experiments • Fossil Record • Succession of forms over time • Transitional Links

10. IV. EVIDENCE FOR EVOLUTION, cont • Homology • ____________________ structures – similar in characteristic resulting from _____________ ancestry (not necessarily the same function) • Ex. Forelimbs of humans, cats, whales, bats, etc. • ___________________ organs- remnants of structures that had important functions in ancestors • Ex. Snake Pelvis & Pharyngeal Pouches (gill slits) • Does NOT apply to convergent evolution • Independent evolution of similar features in different lineages • _____________________ structures – similar structure/ function between two species that are not closely related

11. IV. EVIDENCE FOR EVOLUTION, cont • Comparative ________________ • Pharyngeal Pouches (gill slits) • Post Anal Tail • Molecular Biology • Similarities in DNA, proteins, genes, & gene • products • Common genetic code

12. IV. EVIDENCE FOR EVOLUTION, cont • Biogeography • Geographical distribution of species • Continental Drift • Pangaea • Islands are inhabited by organisms most closely resembling nearest land mass

13. V. POPULATION GENETICS • Population Genetics • The study of genetic changes in populations • Population • Species • Gene pool • Population’s genetic make-up

14. V. POPULATION GENETICS, cont • Hardy-Weinberg Principle • Predicts ______________________ ____________________ in a non-evolving population; that is, a population in ___________________ • Can be used to determine if a population is evolving • States that allele frequencies in a population will remain constant from generation to generation if _________ conditions are met

15. V. POPULATION GENETICS, cont • Five Conditions for Hardy-Weinberg Equilibrium • If any of these conditions are not met, evolutionary change will occur

16. V. POPULATION GENETICS, cont • Hardy-Weinberg Equation • ________________________ (think phenotype) • p = dominant phenotype(AA or Aa) • q = recessive phenotype (aa) • ________________________ (think genotype) • p2 = % of AA as a decimal • 2pq = % of Aa as a decimal • q2 = % of aa as a decimal

17. V. POPULATION GENETICS, cont Hardy-Weinberg Practice Problems • If you know that you have 16% recessive fish (bb), calculate the frequency of each genotype using Hardy-Weinberg

18. V. POPULATION GENETICS, cont • Hardy-Weinberg Practice Problems, cont 2. If in a population of 1,000, 90 show recessive phenotype (aa), use Hardy-Weinberg to determine frequency of allele combinations.

19. VI. MICROEVOLUTION • A change in the ____________________ of a population over a succession of generations • Five main causes (opposite of HWE): • _________________ • _________________ • _________________ • _________________ • _________________

20. VI. MICROEVOLUTION, cont • Genetic Drift • Changes in the gene pool due to_______________. • More commonly seen in ____________ population sizes. • Usually reduces genetic variability. • There are _________ situations that can drastically reduce population size: • ___________________________: type of genetic drift resulting from a reduction in population (natural disaster) such that the surviving population is no longer genetically representative of the original population • ___________________________: type of genetic drift attributed to colonization by a limited number of individuals from a parent population; Gene pool is different than source population

21. VI. MICROEVOLUTION • Gene Flow • Genetic exchange due to the migration of __________ individuals or gametes between populations • Tends to reduce differences between populations • Natural Selection • Differential success in _________________________ • Only form of microevolution that adapts a population to its _______________ • Mutations • A change in an organism’s __________ (gametes; many generations) • Original source of genetic variation (raw material for natural selection) • Nonrandom Mating • Inbreeding and selective mating both can change allele frequencies of different genotypes

22. VII. VARIATIONS IN POPULATION • Polymorphism • Coexistence of 2 or more distinct forms of individuals _______________ within the same population • Applies only to _______________ characters • Geographical Variation • Differences in genetic structure between populations • _____________: graded change in some trait along a geographic axis • Mutation and Recombination • Occur by _________ & process of ____________ & fertilization

23. VII. VARIATIONS IN POPULATION Tendency of natural selection to reduce variation is countered by mechanisms that ________________ or ________________ variation • Diploidy • 2nd set of chromosomes hides variation in the ____________________ • Balanced Polymorphism • Heterozygote Advantage • _______________________________________ _________________________________________ __________________________________________ _________________________________________ • Frequency-Dependent Selection • _______________________________________ __________________________________________ __________________________________________ __________________________________________ __________________________________________ __________________________________________ • Parasite/host – evolutionary race

24. VII. VARIATIONS IN POPULATION • Adaptive Evolution due to Natural Selection • _________________________ - Contribution an individual makes to the gene pool of the next generation • 3 ways in which natural selection alters variation • ____________________ • ____________________ • ____________________

25. VII. VARIATIONS IN POPULATION • Sexual Selection • Can result in ___________________ ____________________________ - secondary sex characteristic distinction that does not directly relate to sex • Explains why males & females often look different other than the obvious reproductive structures • _____________________ Selection • “within the same sex” • Direct competition between individuals of the same sex • _____________________ Selection • Mate choice/female choice

26. VIII. MACROEVOLUTION • _____________________- Origin of new taxonomic groups • Speciation • ______________________ - accumulation of heritable changes transform existing species into new species • ________________ - branching evolution; budding of new species from a parent species that continues to exist • Basis of biological diversity

27. VIII. MACROEVOLUTION • Biological Species Concept • Ernst Mayr - 1942 • ‘Working Definition of a Species’ - population or group of populations whose members have the potential to interbreed and produce viable, fertile offspring, but cannot produce viable fertile offspring with members of other species • AKA….. similar organisms that can make babies that can make babies  • Can be difficult to apply to certain organisms… • Reproductive Isolation • Prevents closely related species from interbreeding when their ranges overlap. • 2 types • Prezygotic - _______________________________________________ • Postzygotic - ______________________________________________

28. VIII. MACROEVOLUTION

29. VIII. MACROEVOLUTION

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31. VIII. MACROEVOLUTION • Speciation • _______________________________ - Fossil record shows evidence of bursts of many new species, followed by periods of little change • _______________________________ - Other species appear to change more gradually • Fits model of evolution proposed by Darwin

32. VIII. MACROEVOLUTION • Modes of Speciation • Based on how gene flow is interrupted • ____________________________ • Populations segregated by a geographical barrier; can result in ________________________ • Ex. island species • ____________________________ • Reproductively isolated subpopulation in the midst of its parent population • Ex. cichlid fishes