Some of the most important animal behaviors involve mating. Mating is the pairing of an adult male and female to produce young. Adults that are most successful at attracting a mate are most likely to have offspring. Traits that help animals attract a mate and have offspring increase their fitness.
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2. Review • Asexual Reproduction – One parent – No reproductive organs – No genetic variation – Mitosis and Cytokinesis – Binary Fission, Budding, Spores, Regeneration, Vegetative Propagation
3. Review • Sexual Reproduction – Two parents – Sex cells – Meiosis – Genetic variation • Survival of species
4. Sexual Reproduction in Lower Organisms • Conjugation – Conjugation bridge – Exchange or transfer of genetic material – No male/female – Bacteria, paramecia, spirogyra
5. Spirogyra Zygote develops tough coat and now called a Zygospore Zygospore hatches when conditions
6. Sexual Reproduction in Animals • Have Male and Female • Have sex organs (Gonads) – Ovaries-Ova or eggs (Haploid) – Testes-Sperm (Haploid)
7. Sexual Reproduction in Animals • Hermaphrodites – Ovaries and testes in same animal – In slow or sessile organisms (worm ,hydra snail) – Self fertilization rare
8. How are gametes made? • Gametogenesis – Oogenesis – Spermatogenesis
9. Spermatogenesis & Oogenesis 2n n n n
10. Sperm vs. Egg Sperm Egg Small Larger Many Few Mobile (1-4mm/min) Nonmobile Complex shape Round May have Yolk
11. Digestive Enzymes Energy to swim
12. Fertilization • Sperm swim to egg • Sperm releases enzymes to make hole in egg • Sperm injects nucleus into egg • Fertilization membrane form around egg • No future fertilization • Joining of sperm nucleus and egg nucleus • Form diploid zygote
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14. Where can fertilization happen? 1. Outside female (External Fertilization) 2. Inside Female (Internal Fertilization)
15. External Fertilization • Female releases eggs in water • Male releases sperm in water • Problems? • Sperm find eggs • Many gametes made! • Spawning behavior or Amplexus
16. Seasonal spawning of Salmon
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18. Internal Fertilization • Safer • Terrestrial animals and some aquatic • Need moist female repro. tract • Fewer eggs needed • Short life span of gametes (24hrs) • Need specialized organs • Timed release of gametes (Hormonal)
19. Adult with no fertilization? • Parthenogenesis – Egg develops without sperm – Insects – Unfertilized eggs of queen bee=male drone – Fertilized eggs of queen bee=female workers or queens
20. What happens after fertilization? • Development • Embryology=Study of embryo development
21. Stages of Development 1. Cleavage – Mitotic cell divisions – 2 cells, 4, 8,…..morula=solid ball of cells – No growth in cell size (cells get smaller)
22. Development • Cleavage – Blastula stage=Ball hollows out and has fluid in core (Blastocoel) Cells with yolk
23. Development 2. Gastrulation – Growth in cell size – Embryo changes shape (cells migrate)
24. Development • Gastrula: Development of 3 Primary Germ Layers Mesoderm
25. Development • Ectoderm: – Nervous sys, lining of mouth, nostrils and anus – Epidermis, hair, nails • Mesoderm: – Bone, muscles, blood vessels, repro and excretory system, dermis • Endoderm: – Lining of digestive sys, respiratory sys, liver, pancreas, glands, bladder
26. Development 3. Differentiation – Embryonic cells become specialized – Embryonic Induction=“organizers” influence cells to take on a certain role in life – Where cell is located will determine what it will become
27. • Ex. Nerve cord development
28. External vs. Internal Development • External: – Water • Embryo feeds on yolk • Wastes and Oxygen exchange via diffusion • Little to no care, dangerous • Ex. Many fish
29. External vs. Internal Development • External: – Land • Embryo feeds on yolk in a SHELLED egg • Pores in shell for gas exchange • Ex. Reptiles (Leathery Shell)-leave eggs • Ex. Birds (Hard Shell)-protect eggs
30. Extraembryonic membranes of Bird Eggs • Yolk sac=Nutrients • Amnion=shock absorption • Allantois=metabolic waste storage and gas exchange • Chorion=under shell, Embryo gas exchange
31. External vs. Internal Development • Internal – Some organisms: nutrients mostly from yolk and babies born self-sufficient – Others: development in womb (Uterus) – High protection – Little yolk, nutrients from mom – Born undeveloped – Mammals continue to feed via mammary glands
32. Placental vs. Nonplacental Mammals • Placental – Have placenta=site of nutrient and waste exchange between mom and baby – Baby side and mom side with space between – No blood-blood contact
33. Placental vs. Nonplacental Mammals • Nonplacental: – **Egg-laying mammals (External Development) Monotremes • Ex. Spiny anteater and duckbill platypus • Eggs with yolk develop outside • Babies feed on mammary gland milk
34. Placental vs. Nonplacental Mammals • Nonplacental – Pouched mammals (Marsupials) – Some internal development – Poorly developed babies born and remain in a pouch feeding on milk – Ex. Opossum, Kangaroo Link
35. Human Male Reproductive System
36. Human Male Reproductive System
37. Parts • Testes: – Semineferous tubules – Sperm production – Testosterone production – In scrotum sac • Epididymis – Sperm storage and maturation site
38. Parts • Vas deferens – Sperm ducts • Urethra – Exit route for sperm through penis • Glands: – Seminal vesicles=thick, nutrient-rich fluid – Cowper’s Gland (Bulbourethral glands)= preejaulation lubricant – Prostate Gland=milky, alkaline fluid (Semen is sperm and fluids)
39. Human Female Reproductive System
40. Human Female Reproductive System
41. Parts • Ovaries – matures eggs located in follicle sacs – Make estrogen – Usually one egg matures/month – Mature egg ovulated – Egg enters oviducts
42. Parts • Oviduct – Site of fertilization • Uterus – Site of embryo development • Cervix – Doorway into Uterus • Vagina – Birth canal and sperm receiving area
43. Human Sexuality • Fertilization – Hundreds of millions of sperm ejaculated into vagina – Fertilization in oviduct • (In vitro vs. in vivo fertilization)
44. Fraternal vs. Identical Twins “Identical” Twins may have some genetic differences. Can have difference in quantities of a gene (Am. J. Human Genetics) • Cleavage as zygote moves towards the uterus • Implantation and Gastrulation – Ectopic pregnancy
45. Human extraembryonic membranes • Chorion=surrounds other membranes – Chorionic villi – Villi+uterine wall=placenta • Placenta=Nutrient exchange, no blood-blood contact • Amnion=Surrounds fetus – Amniotic Fluid-shock • Yolk Sac and Allantois develop into umbilical cord
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47. Birth • Gestation Time= Time in womb – 9 months for humans – 20 days for mouse – 21 months for elephant • Labor – uterine contractions – Cervix enlargement – Amnion breaks – Baby’s head out first • Afterbirth – Placenta comes out
48. Terms • Embryo= zygote from fertilization till 8 weeks • Fetus= 8 weeks-birth
49. Menstrual Cycle Starts at Puberty (10-14 years old) Stops at (45-50 years old)
50. Stages 1. Follicle Stage • FSH from Pituitary matures one follicle • Follicle secretes Estrogen • Estrogen enhances Uterine Lining • High Estrogen levels inhibit Pit. From secreting FSH • Pit. Starts to secrete LH • Days 1-13
51. Stages 2. Ovulation – High levels of LH cause egg to pop out of follicle – Day 14 3. Corpus Luteum Stage – Ruptured follicle (ie. “corpus luteum”) releases Progesterone – Progesterone maintains uterine lining (Hormone of Pregnancy) – Progesterone inhibits FSH release
52. Stages 4. Menstruation – If no fertilization: • LH levels drop • Corpus luteum breaks down • Progesterone levels drop • Estrogen levels drop • Uterine lining shed • FSH no longer inhibited • Start maturing a new follicle
53. Estrous Cycle • Only humans and other primates have menstrual cycle • Other have Estrous Cycle – Periodic changes in female sex organs – Periodic desire to mate – Seasonally fertility (In Heat)
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