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ANT 3514 – Intro to Bio Anth Lab. Megan Hosford mhosford@anthro.ufl.edu B329 and B301 MWR (2:00-3:15). ANT 3415C Lab Policies Rules for Turlington B304 NO food or drinks allowed in the room. NO cell phones or pagers during lab session – these must be turned off.
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ANT 3514 – Intro to Bio Anth Lab Megan Hosford mhosford@anthro.ufl.edu B329 and B301 MWR (2:00-3:15)
ANT 3415C Lab Policies Rules for Turlington B304 NO food or drinks allowed in the room. NO cell phones or pagers during lab session – these must be turned off. Handle and treat all teaching materials in the room with utmost care and respect. Bone and fossil casts are breakable (and expensive)! COURSE WEBSITE www.clas.ufl.edu/users/krigbaum/3514 Attendance Lab sessions are MANDITORY. Attendance will be taken at the beginning of each session. If you plan on missing a lab, you must notify your TA at the beginning of the week and you must have a legitimate reason. The TA will place you into another appropriate session for that week. There will be no lab make-up opportunities except under the following situations: (1) serious sickness/injury with official doctor/infirmary letter to Prof. Krigbaum; (2) military or athletic excuses with official documents; (3) other emergencies (talk to your TA or the Prof. Krigbaum for approval). Grading There will be 6 lab sessions (20 points each) and 3 lab quizzes (2 in-class and 1 take-home, 10 points each). The three lab quizzes will be given BEFORE exams. Lab homework is due at the beginning of next week’s lab. Lab questions will be drawn from reading materials as well as those based on materials provided during lab hours and lecture. You may turn in the answers of a lab you missed, but answers for in-lab questions will NOT be credited.
Lab 1 Principles of Evolution Part 1: Natural Selection
Evolution The change in gene frequency over time. • Natural Selection – • The mechanism that determines: • which characteristics (physical or behavioral) are best suited to the environment • will persist in succeeding generations, given a stable environment • advantageous characters become numerous in future populations at the expense of less favorable characteristics
Measuring ‘fitness’ • Natural selection acts on genetic variation so that the genes for ‘fit’ phenotypes increase in a population. • Who is the most fit? • A professional athlete (7-digit income) who is in good health, single, and has no children. • A single parent (minimum wage income) who is in fair health and struggling to raise 2 children. • A foster parent (modest income) who is in good health and parenting an adopted child.
Lamarkian vs. Darwinian Evolution (LOOK AT QU 1-3) Lamark (~1800) • Variation exists b/c of environment, in response to a specific demand • An individual’s efforts affected its physical structure inherited • Individual level • Goal – oriented • Directionality • Darwin (1859) • Variation naturally exists • Offspring inherent characteristics from parents • Depending on environment, some characteristics more beneficial than others • Population level • Not goal – oriented • No directionality
Darwin’s War • Randomized gene pool • Each person maintains a population of 10 individuals • In this environment, higher-ranking cards are being selected for, aces represent the suite of characteristics best suited for this current environment • Play war, randomly select competition – keep ‘fit’ cards, replace ‘unfit’ ones • At the end of 10 rounds (generations), see how final population is different from your original population • Record population demography prior to each round (Round 1 is your original hand) • Hand in data sheet, I will email class population results
DNA Structure • Deoxyribonucleic acid • Main component of chromosomes • Double-stranded molecule • Contains genetic codes Synthesizes protein • Made of two chains of nuclieotides— sugar, phosphate, base (A,T,C,G) LOOK AT QUESTION 7
Terminology • Gene • Chromosome autosome & sex chromosome • Allele • Diploid & haploid
Cell Division • Mitosis- somatic cell DNA replication simple cell division (1 into 2) exact replication of the original DNA
Cell Division • Meiosis- sex cell DNA replication in ovary & testis 2 divisions (1 into 4) random assortment recombination (cross-over) gamete
Mendelian Genetics • Gregor Mendel (1822-1884) • Dominance vs. Recessiveness • Homozygous vs. Heterozygous • Medelian traits • Principle of Segregation Principle of Independent Assortment (LOOK AT QUESTION 11)
Principle of Segregation: Genes (alleles) occur in pairs (because chromosomes occur in pairs). During gamete production, the members of each gene pair separate, so that each gamete contains one member of each pair. During fertilization, the full number of chromosomes is restored, and members of gene or allele pairs are reunited. Principle of Independent Assortment: The distribution of one pair of alleles into gametes does not influence the distribution of another pair. The genes controlling different traits are inherited independently of one another.
Evolution–change in gene frequency over time • acts on a population Forces of Evolution - factors that produce and redistribute variation: 1.Natural Selection 2. Gene Flow 3. Genetic Drift 4. Mutation (Recombination) (LOOK AT QUESTION 13)
Gene Flow The exchange of genes between populations - migrations (group or individual-level) Inherent mechanism within human and non-human species - Social taboos against incest - Fundamental basis for sex-specific patterns of philopatry & migration
Genetic Drift (LOOK AT QUESTION 15) Changes in allele frequencies due to: • Random factors • Small population size • Founder effect – prevents gene flow genetic bottleneck • - colonization • - disasters Examples: - Cheetahs – decreased reproductive potential - Taiwanese macaques – geographic isolation
Mutation • Changes of alleles, A a • Mutation rates are usually low in big pop’ • Natural selection determines the frequency of the mutated allele • Basic creative force in evolution—the ONLY way to produce new genetic variation • LOOK AT QUESTION 14
Types of Selection • 1. Stabilizing: when environment is stable, maintains genotypic and phenotypic status quo • 2. Directional: responses to environmental change and productive shifts in composition of a population’s gene pool and collective phenotypes LOOK AT QUESTION 9 and 16!
Hardy-Weinberg Theorem • Predicts the distribution of genotypes in subsequent generations of a population • p2+2pq+q2=1, where p2 : % homozygous dominant 2pq : % heterozygous q2 : % homozygous recessive LOOK AT QUESTION 17
Hardy-Weinberg Theorem Assumptions: • A large population • Random mating • Equal numbers of males and females • Absence of natural selection • No mutation, genetic drift or gene flow • No migration in or out What will happen if H-W Theorem holds?
Species Concepts • Biological Species Concept–a group of individuals capable of producing fertile offspring • Based on gene flow and reproductive isolation • Limitations? Doesn’t allow for hybrids (e.g. baboons) Reproductive behavior can’t be traced through the fossil record • Ecological Species Concept – a group of organisms exploiting a single niche • - Stresses the role of natural selection • - Limitations? Does a niche define a species, or does a species define a niche? No easy answer – not necessarily mutually exclusive!
READ QUESTION 18 AND LISTEN CAREFULLY ABOUT THE NEXT THREE SLIDES
Speciation • The process by which a new species evolves from a prior species • The most basic process in macroevolution
Speciation • Anagenesis: one species evolves into another A B • Cladogenesis: ancestral species evolves into branches of descendent species B A A’
Models of Speciation • Gradualism: New species evolves by gradual changes from the original one • Punctuating equilibrium: Not unidirectional