1. Ch. 46 Warm-Up
What is the advantage of sex vs. asex(ual) reproduction?
List at least 3 different modes of asexual reproduction.
What are the 2 types of human gametes? Where is each produced?
Define and give an example of parthenogenesis.

2. Chapter 46 Animal Reproduction

3. Egg (Ovum) + Sperm  Zygote
Types of Reproduction
Asexual
Sexual
Clone
Advantage: FAST, if env. is stable
Fission: parent separates into 2+ individuals of same size
Budding: outgrowths from parent (eg. cnidarians, tunicates)
Fragmentation: breaking of body into pieces, form into adults by regeneration (eg. sea stars, sponges, cnidarians)
Parthenogenesis: female produces eggs that develop w/o fertilization (eg. male bees – haploid)
Genetic diversity
Advantage: ability to change pop. when env. changes
Fusion of haploid gametes
Egg (Ovum) + Sperm  Zygote

4. Sexual Reproduction – Frogs (External fertilization)
Fission - Sea Anemone
Sexual Reproduction – Frogs
(External fertilization)

5. Reproductive Cycles and Patterns
Ovulation: release of mature eggs
Young produced when survival is most likely
Hormonal changes influenced by day length, season temp, rainfall or lunar cycles
Hermaphroditism: both M/F systems
Sessile/burrowing animals - barnacles, parasites (tapeworms), earthworms
Sex reversal: sex change during its lifetime
Bluehead wrasse (reef fish)

6. Sex reversal in a sequential hermaphrodite
Sex reversal in a sequential hermaphrodite. Wrasses (reef fish) born female, but oldest, largest individuals complete their lives as males.
Parthenogenesis in female Blacktip Shark: egg fuses with a polar body

7. Fertilization = sperm + egg
External Fertilization
Internal Fertilization
Egg shed by female, fert. by male in water
Environmental cues / courtship behavior
Large # gametes  low survival
Eg. fish, amphibians
Sperm deposited in female reprod. tract
Cooperative behavior
Dry environment
Fewer gametes, fewer zygotes  greater survival
External Devel.
Tough eggshell
Eg. reptiles, birds, platypus
Internal Devel.
High parental care
Eg. placentals, sharks, some reptiles

8. Human Reproductive System
MALE
FEMALE
Function
Produce & deliver sperm
produce eggs
development of baby
Main reproductive organs
Testes
(singular: testis)
Ovaries
Reproductive cells (Gametes)
Spermatogenesis  SPERM
Oogenesis  EGGS
Main hormone
Testosterone
Estrogens
Role of FSH (follicle-stimulating hormone)
Sperm formation
Egg development (in follicle)
Role of LH (luteinizing hormone)
Produce testosterone
Release of egg (ovulation)

9. Female Anatomy Ovaries – produce eggs, sex hormones
Follicles – contain oocyte (egg); release 1/month; produce estrogens
Ovulation – release of egg from follicle
Remaining follicle  corpus luteum (↑hormones)
egg  oviduct (fallopian tube)  uterus (baby)  cervix  vagina
Mammary glands – secrete milk through nipples in breast

10. Female Reproductive System

11. Male Anatomy Testes (inside scrotum) – produce sperm, sex hormones
Seminiferous tubules – make sperm
seminiferous tubules  epididymis  vas deferens  urethra (penis)
semen = alkaline fluid w/nutrients, enzymes
million sperm/ejaculation

12. Male Reproductive System

13. Meiosis Spermatogenesis Oogenesis Sperm production
Stem cells  spermatids in seminiferous tubules
Mature & add tail in epidymis
4 motile sperm
Ova production
Before birth: oogonia  meiosis - STOP at Prophase I (primary oocytes)
Puberty: each month, egg in follicle  Meiosis I (secondary oocytes)  fertilization  Meiosis II
1 ovum + 3 polar bodies

17. Menstrual cycle – humans & other primates
Prepare and release egg for fertilization
Prepare uterus to receive a fertilized egg
Estrous cycle – other mammals; no menstruation

18. Four Phases of Menstrual Cycle:
Follicular Phase : low estrogen, FSH = egg develops in ovary
Ovulation (Day 14): LH = egg released into Fallopian tube
Luteal Phase :
progesterone, estrogen = lining of uterus thickens to prepare for pregnancy
Egg travels down Fallopian tube, waits for fertilization
Menstruation (no fertilization) :
P/E = lining of uterus breaks down
Blood and unfertilized egg discharged

19. Human female reproductive cycle

20. Human embryonic development
Conception: in oviduct
Implantation: in uterus
Hormones:
Human Chorionic Gonadotropin (hCG): maintain estrogens in early pregnancy; pregnancy test
Human gestation (pregnancy) = 40 weeks
Rodents (21 days); Dogs (60 days); Cows (270 days); Elephants (600 days)
Egg lodged in oviduct = ectopic (tubal) pregnancy

21. Formation of Zygote Cleavage starts Cleavage continues Ovary
Fertilization occurs
The blastocyst implants
Uterus
Ovulation
Endometrium
From ovulation to implantation

22. Early Postfertilization Events
Endo-
metrium
Inner cell mass
Cavity
Trophoblast
Blastocyst
Implantation of blastocyst

23. Placental Circulation

24. Human Fetal Development

26. The Three Stages of Labor

27. How does “the Pill” work?
“the Pill” is an oral contraceptive
Contains estrogen and progesterone
First available in 1960
Main effect: Prevent ovulation
Other effects:
Thickens cervical mucus – slows down sperm
Thins uterus lining – prevent implantation of fertilized egg
Usage: active pill for 21 days, inactive pills for 7 days (“period”)
Other medical uses:
Medication for mild/moderate acne
Decrease painful menstruation
Treat polycystic ovary syndrome (PCOS)
Correct irregular menstrual cycle
Reduce risk of ovarian and endometrial cancers

28. Mechanisms of some contraceptive methods