Biol 3350 1st editionExam # 3 Study Guide Lecture 15 (March 10)What are some effects of genetic drift?- Changes in the distribution of genetic information- Variation within demes becomes variation among demes- An allele can go to fixation or to extinction by chance alone; not a result of selection- This could make the organism less likely to survive t in the environment- Promotes population subdivision and can result in speciationo When the demes become different enough from each other, they are no longer able to interbreed and become different speciesWhat is drift-migration equilibrium?- Balance between loss of alleles due to genetic drift and introduction of alleles from migrantso When the gene flow and drift lines cross = drift-migration equilibriumo Migration can be really important in small populations because it can counter theeffects of drift and help small populations to maintain variabilityLecture 16 (March 24)What does the term “aniosgamy” refer to?- Males produce small gametes- Females produce large ones (the female egg is the largest single cell in the human body)What other factors aid in reproductive success of an organism other than successful insemination?- Select a mate- Convince potential mate to select you- Successful fertilization- Provide sufficient resources for offspring successLecture 17 (March 26)What are some ways in which men compete to attract mates?- Risky sports- Brawls- Jealousy-induced fights with other men- Competition for statusWhat is the difference between intrasexual selection and intersexual selection?- Intrasexual Selection – competitive interactions within members of the same sex to gainaccess to the other sexo typically (but by no means exclusively) male-male competition- Intersexual Selection – mate choice; selection of mates with goal of producing high-quality offspringo typically expressed as female choice of a mating partnerLecture 18 (March 31)What is the difference between adaptive and altruistic behaviors?- Adaptive:o Cooperative and selfisho Increase own fitnesso Favored by natural selection- Altruistic:o Altruistic and spitefulo Decreases own fitnessAccording to Hamilton’s rule, what are the coefficients of relatedness for relatives?- Parent-offspring = 0.5- Full siblings = 0.5- Grandparent-grandchild = 0.25- Half siblings = 0.25- Uncle-nephew = 0.25- Cousins = 0.125Lecture 19 (April 2)What are the four different mechanisms of kin recognition?o Spatial proximity (learning) Individuals in my nest are kino Associative learning (learning) Individuals I interact with all the time are kino Phenotype matching (learning & genes) Individuals that resemble those I interact with are kino Recognition alleles (genes) Individuals that have my alleles are kinHow do bacteria acquire resistance?- Bacteria has advantages over us due to their large population size, quick mutations- Transfer of plasmids between each other allows for resistance development without reproducing- Mutations- Lateral transfer of plasmids- Viral transfer of resistance gene- Scavenging of resistance geneLecture 20 (April 7)What symptoms are an adaptive response to illness?- Body tries to get rid of the pathogens quickly using means of coughing, sneezing, diarrhea à allows the pathogens to be transmitted elsewhere; high reservoirs of transmittance- Low/moderate fever is body’s adaptive response to get rid of the pathogensWhat are some examples of diseases maintain by overdominance?- Sickle cell anemia- Cystic fibrosisLecture 21 (April 9)What does the branch length in a phenetic tree represent?- Branch order and branch length are important - Branch length tell us how similar two taxa are- Branch length reflects degree of nucleotide differenceWhat is the difference between homology and homoplasy?- Homology: based on traits that are identical in two or more species because they are descended from a common ancestoro Informativeo Cladistics are based on the concept of homology- Homoplasy – shared traits between taxa that have difference common ancestorso Uninformative – only confuses cladisticso Causes by similar environments, convergence, or parallel evolutionLecture 22 (April 14)Compare and contrast phonetics versus cladistics.- Phenetics:o Dendogram or phenogramo Distance: Euclidean or genetico Always unrootedo Does not make inferences about ancestry- Cladistics:o Phylogeny or cladogramo Evolutionary steps or mutational changeso Unrooted unless you have the true ancestoro Makes inferences about ancestryWhy use DNA for molecular phylogenetics?- Access to many characters- Character states are unambiguous- Some genes evolve very rapidly- Molecular “clock” can be used to date divergences between taxaLecture 23 (April 16)What are some advantages and disadvantages to the biological species concept?o Advantages Intuitive – conceptually makes sense that two different breeds couldn’t breed with each other Complete lack of gene flow – no gray areas Two main processes where species become isolated from each other and speciation occurs over time = genetic drift and natural selection Adaptation to different habitats will cause differences in allelic distributions because the favored allele will become more common over timeo Disadvantages  - Allopatric – organisms can’t physically meet If they are not in the same place at the same time, they can’t interbreed with each other Fossil – can’t tell if they are the same or different species because we do not know if they interbred Hybridizing – two different parents so which species does the hybrid belong to? Asexual – parthenogenic à females produced eggs that are clones of justthemselves, no DNA from the males  Are females then a species of their own? Biological species concept does not take into account the evolutionary processWhat is the morphospecies concept?- Looking at morphological traits and trying to come up with some measurement based on the differences of the features to distinguish two different species- Often used for fossil speciesLecture 24 (April 21)What are some potential outcomes of hybrids?o Hybrid fitness is lower than parentals Hybrids go extinct Parental species divergeo Hybrid fitness is equal to parentals Hybrids are maintained in relatively wide zoneo Hybrid fitness is higher than parentals New hybrid species may formWhat was hypothesized to be the adaptive means by which the Crocodylidae clade evolved?- Vicariance