STUDY QUESTIONS FOR QUIZ 1 PSB 4731 1 What are 3 advantages of sexual reproduction Limits harmful mutations generates beneficial gene combinations Adaptation to changing environment 2 What are 2 advantages of asexual reproduction Quicker Easier More offspring 3 Explain the statement regarding gametes that only the average is selected against In Disruptive Selection a form of natural selection the average values are selected against so that the distribution of the trait becomes bimodal http en wikipedia org wiki Disruptive selection 4 What are 3 means of sex determination Temperature social aspects sex chromosomes 5 Which cells in the body are diploid and which are haploid Gametes sex cells are haploid and all other body cells are diploid 6 Describe the lineup of replicated chromosomes in the metaphase stage of meiosis vs mitosis In metaphase of meiosis 1 pairs of homologous chromosomes line up together In mitosis and M2 chromosomes line up as single individuals 7 Describe the X and Y chromosomes Which gene confers maleness Females have two X chromosomes while males have one X and one Y Y chromosome typically contains the SRY gene which confers maleness 8 How can an XX individual develop as a phenotypic male If they have part of the Y chromosome with the SRY gene that has crossed over to 9 What is a hermaphrodite Do hermaphrodites fertilize themselves Both produce sperm and ova at the same time But they do not fertilize the X chromosome 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 Used by females to judge the quality and health of the males genes 11 Describe the reproduction strategy of male and female seahorses Which sex supplies the most nutrients to the developing young Males get pregnant and give birth Females produce ova and deposit them in a deep cavity in the male where he fertilizes them Pouch opening then closes for 10 days then opens and babies pop out Females make the greatest investment nutrients come from the egg yolk 12 What are 2 potential advantages to female promiscuity Obtain better quality sperm increase total number of offspring safeguard offspring from new dominant male obtain sources from multiple males 13 Describe the process of paternity testing DNA samples from the mother offspring and two offspring are broken down into fragments by an enzyme The fragments are separated into bands according to size by gel electrophoresis Every band of the offsprings DNA must match up with a band of at least either parent 14 Describe the theory of kin selection What is a rationale for its existence Females contribute the major resoures but they are able to select a mate that will protect them and take care of their kids 15 Describe sexual activity among Bonobos Female bonobos are receptive during most of their ovarian cycles and also during nursing Bonobos have male female female female and male male sexual encounters They frequently engage in bouts of sex before dividing up a new food source 16 What part of the male genitals is homologous to the female outer labia 17 What part of the male genitals is homologous to the female inner labia The scrotum Spongy urethra 18 What are the corpora cavernosa and what is their function Part of the clitoris Fills with blood and becomes hard and erect 19 Where is the corpus spongiosum and why is it spongy It is located in the glans of the clitoris It is spongy so that blood can fill it 20 How does the vagina maintain an acidic pH What is a benefit of that Maintains acidic pH due to friendly bacteria that produce lactic acid It inhibits growth of bad bacteria 21 Which part of the clitoris becomes firm during erection and which part remains soft The corpora cavernosa becomes hard as it fills with blood The corpus spongiosum remains soft 22 What is the G spot What part of the male anatomy may it be homologous to Grafenberg spot most controversial erogenous feature of the vagina Only a small minority of women have such a spot If they do it is spot of heightened sensitivity on anterior wall of vagina about 3 5 cm from vaginal entrance Deep pressure can cause desire to urinate or be sexually arousing trigger orgasm It is homologous to the male prostate 23 What is endometriosis Uterine fibroids bits of endometrium layer of the walls of the uterus It is the source of menstruation in abdominal cavity treated with oral contraceptives surgery Uterine fibroids are noncancerous tumors of smooth muscle in the uterus 24 Where does fertilization occur Fallopian tubes 25 How is the ovum moved along toward the uterus after ovulation Cilia in the fallopian tubes move the ovum 26 What are granulosa cells and what are their 2 main functions produce estrogen 27 What are thecal cells and what is their main function Cells in the ovaries They produce testosterone 28 What are 3 factors that affect the risk of breast cancer Cells within the ovaries They nourish oocytes prevent 1st meiotic division Genes age Early menarche or late menopause no children alcohol or obesity 29 What are 3 physical signs of sexual arousal in women Erection of clitoris Vasocongestion of labia minora and vaginal walls Lubrication 30 What hormone neurotransmitter is important for promoting smooth muscle contractions and lack of exercise of vagina pleasurable feelings of orgasm Oxytocin 31 What are 2 sources of fluid that may be ejaculated by some women at orgasm Urine and female equivalent of prostatic fluid 32 What are proceptive behaviors What are 2 proceptive behaviors of female rats Proceptive behaviors are courting behaviors EX Approach the male then hop and dart away may wiggle her ears 33 What brain area is especially important for female receptive behavior Ventromedial nucleus of hypothalamus VMH 34 What is lordosis and why is it important for rodent sexual behavior Receptive mating posture arching of the back in response to stimulation from the male Lordosis makes successful copulation possible 35 What is the major effect of the forebrain module on female rat sexual behavior It is inhibitory Inhibits lordosis 36 What is one way in which the hypothalamus influences lordosis in female rats Responds to steroid hormones produces proteins and peptides which are sent to the midbrain Is important for lordosis 37 Describe the pacing of copulation by female rodents Female rats approach and dart away from males allow an intromission and then retire to a burrow or hiding place