PSB4731 Final Exam ReviewCh. 2 Sex & Evolutiona. What are 3 advantages of sexual reproduction?a. Limit harmful mutations—random distribution of mutations; those with most harmful ones tend not to reproduce i. Asexual reproduction—all offspring get all mutationsb. Generate beneficial gene combinations i. Adaptation to changing environment ii. Adaptation to all aspects of constant environment 1. Jack Spratt hypothesis--iii. Can separate beneficial mutations from harmful ones c. Dilution of own inheritance 2. What are 2 advantages of asexual reproduction?a. Quicker, easier, >> more offspring/individual 3. Explain the following regarding gametes: only the average is selected against.b. Survival of the fittest 4. What are 3 means of sex determination? a. Sex determination : the biological mechanism that determines whether an organism will develop as male or female a. Temperature i. Reptiles, amphibians, fish b. Social factorsi. Some fish: presence of reproductive male >> others are female or nonreproductive males 1. His death >> largest among remaining group >> reproductive male c. Chromosomes i. Sex chromosomes 1. Mammals: XX (F) vs. XY (M)2. Birds: ZZ (M) vs. ZW (F)a. Sry: sex determining region of the Y chromosome b. Sry >> testes >> T >> masculinization of brain & external genitals 5. Which cells in the body are diploid and which are haploid?a. Diploid cells contain several pairs of homologous chromosomes. (Mitosis)b. After cell division (Meiosis 1), each daughter cell is haploid—it contains half the number of parental chromosomes, each of which consists of two sister chromatids 1PSB4731 Final Exam Reviewa. After Meiosis 2—resulting gametes are haploid, and each chromosome consists of only a single chromatid c. Gametes a. Haploid : half usual complement of chromosomes (after meiosis)b. Diploid : full complement of chromosomes 6. Describe the lineup of replicated chromosomes in the metaphase stage of meiosis vs. mitosis.d. Mitosis a. Metaphase—Nuclear membrane breaks down and mitotic spindle forms e. Meiosisa. Metaphase—Genetic exchange takes place between homologous chromosomes 7. Describe the X and Y chromosomes. Which gene confers maleness?f. X : sex chromosome that is present as two copies in females and one copy in males g. Y : present only in males, confers maleness. 8. How can an XX individual develop as a phenotypic male? h. XX male with SRY translocation i. XY female with SRY missing 9. What is a hermaphrodite? Do hermaphrodites fertilize themselves?j. Hermaphrodites: produce sperm and ova at the same time but DO NOT fertilize themselves 10. What is the supposed rationale for male peacocks to have such huge tails, and for male bowerbirds to build such fancy, but non-functional bowers?a. The peacocks tail feather display is used by females to judge his health and the quality of his genes b. The male satin bowerbird is not as eye-catching as a peacock, but makes up for it by building a bower and decorating its entrances with blue-colored objects, such as shells, berries, or bottle tops. If a female approvesof his work, she will mate with him within the avenue of the bower11. Describe the reproduction strategy of male and female seahorses. Which sex supplies the most nutrients to the developing young?a. Sex Role reversal: sea horses (hippocampus) a. Males get pregnant & give birth b. Females reproduce ova and deposit them in a deep cavity in the male, where he fertilizes them 2PSB4731 Final Exam Reviewc. Pouch opening then closes for ~10 days, then opens and babies pop out d. However, FEMALE makes the greatest investment: nutrients come from the egg yolk 12. What are 2 potential advantages to female promiscuity?a. Promiscuity : pursuit of sex outside of an established relationship b. Potential Advantages: a. Obtain resources from multiple males b. Increase total number of offspring c. Obtain better quality sperm d. Safeguard offspring from new dominant male 13. Describe the process of paternity testing.a. DNA samples from the mother, the offspring, and two possible fathers are broken into fragments with an enzyme b. The fragments are then separated into bands, according to size, by gel electrophoresisc. Every band of the offspring’s DNA must match a band in at least one ofits parents’ DNA14. Describe the theory of kin selection. What is a rationale for its existence?a. Kin selection : theory that it can be advantageous, in evolutionary terms to support the reproductive success of close relatives. a. It has to be considered that all copies of that individual’s genes that persist into future generations, whether in direct descendants or in the descendants of siblings or other relativeswho share some of the individual’s genes 15. Describe sexual activity among Bonobos.b. Female bonobos are receptive during most of their ovarian cycles and also during nursing c. Front to front copulation is rare among mammals d. Bonobos have male-female, female-female, and male-male sexual encounters e. They frequently engage in bouts of sex before dividing up a new food source Ch. 3 Women’s Bodies 1. What part of the male genitals is homologous to the female outer labia? 3PSB4731 Final Exam Reviewa. Scrotum 2. What part of the male genitals is homologous to the female inner labia?b. Shaft of penis 3. What are the corpora cavernosa and what is their function? a. Fill with blood to become hard and erect (2) 4. How does the vagina maintain an acidic pH? What is a benefit of that?b. Vagina inhabited by large numbers of “friendly” bacteria called lactobacilli—which converts sugars to lactic acid. Helps prevent the growth of harmful bacteria 5. What is the G-spot? What part of the male anatomy may it be homologous to?c. G-spot (Grafenberg) : controversial erogenous zone on front (anterior)wall of vagina, 1-2” in from entrance a. Increased erotic sensitivity on or deep within the front wall of the vagina d. Homologous to the male prostate 6. What is endometriosis? Uterine fibroids?e. Endometriosis : bits of endometrium in abdominal cavity; treated withoral contraceptives, surgery f. Fibroids : noncancerous tumors of smooth muscle a. Painful, sometimes >> bleeding 7. Where does fertilization occur? g. In the oviducts—either of two bilateral tubes that lead from the uterus toward the ovaries; the usual site of fertilization. Also called fallopian tube. 8. How is the ovum moved along