UNIT VII POPULATION GENETICS & CLASSIFICATION

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

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

II. A HISTORY OF EVOLUTIONARY THEORY, cont Thomas Malthus ( ) o Populations Charles Lyell ( ) o Theory of ______________________________ o 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 ( ) o “ Father of ________________” o Inheritance patterns Alfred Wallace ( ) o Independently developed evolutionary theory o Not 1 st to publish = little to no credit

II. A HISTORY OF EVOLUTIONARY THEORY, cont

Charles Darwin ( ) – 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)

III. DARWIN’S CONCLUSIONS Descent with Modification o 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 ______________.

III. DARWIN’S CONCLUSIONS, cont Decent with Modification o 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.

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

IV. EVIDENCE FOR EVOLUTION, cont Homology o ____________________ structures – similar in characteristic resulting from _____________ ancestry (not necessarily the same function) o Ex. Forelimbs of humans, cats, whales, bats, etc. o ___________________ organs - remnants of structures that had important functions in ancestors  Ex. Snake Pelvis & Pharyngeal Pouches (gill slits) o 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

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

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

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

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

V. POPULATION GENETICS, cont Five Conditions for Hardy-Weinberg Equilibrium 1) 2) 3) 4) 5) If any of these conditions are not met, evolutionary change will occur

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

V. POPULATION GENETICS, cont Hardy-Weinberg Practice Problems 1.If you know that you have 16% recessive fish ( bb ), calculate the frequency of each genotype using Hardy-Weinberg

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.

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

VI. MICROEVOLUTION, cont Genetic Drift o Changes in the gene pool due to _______________. o More commonly seen in ____________ population sizes. o Usually reduces genetic variability. o 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

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

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

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 o _______________________________________ __________________________________________ o Parasite/host – evolutionary race

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  ____________________

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

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

VIII. MACROEVOLUTION Biological Species Concept  Ernst Mayr  ‘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 o Prevents closely related species from interbreeding when their ranges overlap. o 2 types  Prezygotic - _______________________________________________  Postzygotic - ______________________________________________

VIII. MACROEVOLUTION

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

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