AP Biology March 31, 2011 BR: Explain how the number of choices an organism has may affect its mating behaviors Obj: Students will familiarize themselves with the structure/function of animal reprodcutive systems. HW: Ch 45 GR

AP Biology

Animal Reproduction & Development

AP Biology Fertilization  fertilization  cleavage  gastrulation  neurulation  organogenesis

AP Biology Fertilization  Joining of sperm & egg  sperm head (nucleus) enters egg

AP Biology Cleavage  Repeated mitotic divisions of zygote  1st step to becoming multicellular  unequal divisions establishes body plan  different cells receive different portions of egg cytoplasm & therefore different regulatory signals

AP Biology Cleavage  zygote  morula  blastula  establishes future development zygote blastula morula gastrulation

AP Biology  Establish 3 cell layers  ectoderm  outer body tissues  skin, nails, teeth  nerves, eyes, lining of mouth  mesoderm  middle tissues  blood & lymph, bone & notochord, muscle  excretory & reproductive systems  endoderm  inner lining  digestive system  lining of respiratory, excretory & reproductive systems Gastrulation ectoderm mesoderm endoderm protostome vs. deuterostome gastrulation in primitive chordates

AP Biology Neurulation  Formation of notochord & neural tube  develop into nervous system Notochord Neural tube develops into vertebral column develops into CNS (brain & spinal cord)

AP Biology Organogenesis Umbilical blood vessels Chorion Amnion Yolk sac Allantois Fetal blood vessels Maternal blood vessels Bird embryo Mammalian embryo Placenta

AP Biology Placenta  Materials exchange across membranes

AP Biology Learning Check  In the first 7 weeks of gestation, all fetuses look the same. What causes the differentiation of male/female sex organs?

AP Biology Sex Differentiation  Which parts of the female anatomy go through changes in size/position to become parts of the male anatomy?  What evidence do we have of the shared origin of the male & female sex organs?

AP Biology Starter Parts

AP Biology Gamete Production  Considering all that is shared in the origin of genital anatomy, how is gamete production similar and different in the gonads?

AP Biology Spermatogenesis Puberty until death!

AP Biology Oogenesis Meiosis 1 completed during egg maturation Meiosis 2 completed triggered by fertilization ovulation  Unequal meiotic divisions  unequal distribution of cytoplasm  1 egg  2 polar bodies What is the advantage of this development system? Put all your egg in one basket!

AP Biology Reproductive hormones  Testosterone  from testes  functions  sperm production  2° sexual characteristics  Estrogen  from ovaries  functions  egg production  prepare uterus for fertilized egg  2° sexual characteristics LH & FSH testes or ovaries

AP Biology Sex hormone control in males Hypothalamus Pituitary Testes Body cells GnRH FSH & LH testosterone

AP Biology The female pattern  Estrous cycles/estrus (many mammals)  Menstrual cycle (humans & many other primates):  Ovarian/Menstrual cycles~  Follicular phase ~ follicle growth  Ovulation ~ oocyte release  Luteal phase~ hormone release  Menopause ~ cessation of ovarian and menstrual cycles.

AP Biology LH FSH estrogen progesterone lining of uterus egg developmentovulation = egg release corpus luteum days Menstrual cycle Hypothalamus Pituitary Ovaries Body cells GnRH FSH & LH estrogen

AP Biology Egg maturation in ovary  Corpus luteum  produces progesterone to maintain uterine lining

AP Biology Learning Check  Its been said that the menstrual cycle is regulated by “cause and effect.” Explain what is meant by this, addressing hormones and physical/structural changes that occur during menstruation.

AP Biology Menstruation & Ovulation  What factors can impact a woman’s menstruation?  When is a woman most fertile?  How long can sperm reside in a woman’s body “searching” for an egg?

AP Biology Human fetal development 7 weeks4 weeks

AP Biology Human fetal development 10 weeks

AP Biology Human fetal development 12 weeks20 weeks

AP Biology Human fetal development  The fetus just spends much of the 2 nd & 3 rd trimesters just growing …and doing various flip-turns & kicks inside amniotic fluid Week 20

AP Biology Human fetal development  24 weeks (6 months; 2nd trimester) fetus is covered with fine, downy hair called lanugo. Its skin is protected by a waxy material called vernix

AP Biology Human fetal development  30 weeks (7.5 months) umbilical cord

AP Biology Getting crowded in there!!  32 weeks (8 months) The fetus sleeps 90-95% of the day & sometimes experiences REM sleep, an indication of dreaming

AP Biology Birth positive feedback

AP Biology Intestine Placenta Umbilical cord Wall of uterus Vagina Cervix Birth (36 weeks) Bladder

AP Biology Parturition  OXYTOCIN~ stimulates uterine contractions  1 st stage:  Opening up and thinning of the cervix.  Ending in complete dilation.  2 nd stage:  Expulsion of the baby as a result of strong uterine contractions.  3 rd stage:  Expulsion of the placenta.  Lactation ~ prolactin & oxytocin

AP Biology The end of the journey! And you think 9 months of AP Bio is hard !