1. How can each of these earthworms be both male and female?
Figure 46.1 How can each of these earthworms be both male and female?

2. Asexual reproduction of a sea anemone
Figure elegantissima)

3. The “reproductive handicap” of sex: Sexual females have half as many daughters as asexual females.
Asexual reproduction
Sexual reproduction
Female
Generation 1
Female
Generation 2
Male
Generation 3
Figure
Generation 4

4. External fertilization
Figure
Eggs

5. Parental care
in an invertebrate
Figure 46.6

6. Most insects have separate sexes with complex reproductive systems.
In many insects, the female has a spermatheca in which sperm is stored during copulation.
Accessory gland
Ovary
Ejaculatory duct
Testis
Oviduct
Spermatheca
Penis
Vas deferens
Vagina
Seminal vesicle
Accessory gland
Figure 46.7 Insect reproductive anatomy
(a) Male honeybee (drone)
(b) Female honeybee (queen)

7. Ovary Testis Reproductive anatomy of a hermaphrodite (Digestive tract)
Genital pore
Male organs:
Female organs:
Uterus Yolk gland 4
Seminal vesicle 3
Yolk duct 3
Sperm duct (vas deferens) 2
Oviduct 1
Ovary
Figure 46.8 Reproductive anatomy of a hermaphrodite 2
Vas efferens
Seminal receptacle 1
Testis
(Excretory pore)

8. Reproductive anatomy of the human female
Oviduct
Ovary
Uterus
(Urinary bladder)
(Rectum)
(Pubic bone)
Cervix
Urethra
Vagina
Shaft
Glans
Clitoris
Prepuce
Labia minora
Labia majora
Vaginal opening
Oviduct
Ovaries
Figure 46.10
Follicles
Corpus luteum
Uterine wall
Uterus
Endometrium
Cervix
Vagina

9. Reproductive anatomy of the human male
Seminal vesicle (behind bladder)
(Urinary bladder)
Prostate gland
Bulbourethral gland
Urethra
Erectile tissue of penis
Scrotum
Vas deferens
Epididymis
Testis
(Urinary bladder)
(Urinary duct)
Figure 46.11
Seminal vesicle
(Rectum)
(Pubic bone)
Vas deferens
Erectile tissue
Ejaculatory duct
Prostate gland
Urethra
Bulbourethral gland
Penis
Glans
Vas deferens
Epididymis Testis Scrotum
Prepuce

10. Spermatogenesis Figure 46.12 Human gametogenesis
Epididymis
Seminiferous tubule
Testis
Cross section of seminiferous tubule
Primordial germ cell in embryo
Mitotic divisions
Sertoli cell nucleus
Spermatogonial stem cell 2n
Mitotic divisions
Spermatogonium 2n
Mitotic divisions
Primary spermatocyte 2n
Meiosis I
Figure Human gametogenesis
For the Cell Biology Video Motion of Isolated Flagellum, go to Animation and Video Files.
For the Cell Biology Video Flagellum Movement in Swimming Sperm, go to Animation and Video Files.
Lumen of seminiferous tubule
Secondary spermatocyte n n
Meiosis II
Neck
Spermatids (at two stages of differentiation)
Early spermatid n n n n
Tail
Midpiece
Head
Plasma membrane
Differentiation (Sertoli cells provide nutrients)
Mitochondria
Sperm n n n n
Nucleus
Acrosome

11. Mature sperm Figure 46.12 Human gametogenesis Neck Tail Midpiece Head
Plasma membrane
Mitochondria
Nucleus
Acrosome
Figure Human gametogenesis

12. Oogenesis Figure 46.12 Human gametogenesis 2n 2n n n n n Ovary
Primary oocyte within follicle
In embryo
Growing follicle
Primordial germ cell
Mitotic divisions 2n
Oogonium
Mitotic divisions
Primary oocyte (present at birth), arrested in prophase of meiosis I 2n
Mature follicle
Ruptured follicle
Completion of meiosis I and onset of meiosis II
First polar body
Figure Human gametogenesis n n
Secondary oocyte, arrested at metaphase of meiosis II
Ovulated secondary oocyte
Ovulation, sperm entry
Completion of meiosis II
Second polar body
Corpus luteum n n
Fertilized egg
Degenerating corpus luteum

13. Testis Hormonal control in the Male – – – Hypothalamus GnRH
Anterior pituitary
FSH LH
Negative feedback
Negative feedback
Sertoli cells
Leydig cells
Figure 46.13
Inhibin
Spermatogenesis
Testosterone
Testis

14. Degenerating corpus luteum
The reproductive cycle of the human female
(a)
Control by hypothalamus
Inhibited by combination of estradiol and progesterone
Hypothalamus –
Stimulated by high levels of estradiol 1
GnRH +
Anterior pituitary
Inhibited by low levels of estradiol – 2
FSH LH
(b)
Pituitary gonadotropins in blood 6 LH
FSH
FSH and LH stimulate follicle to grow
LH surge triggers ovulation 3
(c)
Ovarian cycle 7 8
Growing follicle
Maturing follicle
Corpus luteum
Degenerating corpus luteum
Follicular phase
Ovulation
Luteal phase
Estradiol secreted by growing follicle in increasing amounts
Progesterone and estradiol secreted by corpus luteum 4
(d)
Ovarian hormones in blood
Peak causes LH surge 5
Figure 46.14 10
Estradiol
Progesterone 9
Estradiol level very low
Progesterone and estra- diol promote thickening of endometrium
(e)
Uterine (menstrual) cycle
Endometrium
Menstrual flow phase Proliferative phase
Secretory phase
Days | | | | | | | | 5 10 14 15 20 25 28

15. (a) From ovulation to implantation3
Cleavage
Cleavage continues 4
Ovary 2
Fertilization
Uterus
The blastocyst implants 5 1
Ovulation
(a) From ovulation to implantation
Endometrium
Figure Formation of the zygote and early post-fertilization events
Endo- metrium
Inner cell mass
Cavity
Trophoblast
Blastocyst
(b) Implantation of blastocyst

16. Placental circulation
Maternal arteries
Maternal veins
Placenta
Maternal portion of placenta
Umbilical cord
Chorionic villus, containing fetal capillaries
Fetal portion of placenta (chorion)
Maternal blood pools
Figure 46.16
Uterus
Umbilical arteries
Fetal arteriole
Fetal venule
Umbilical cord
Umbilical vein

17. Human fetal development
Figure 46.17
(a) 5 weeks
(b) 14 weeks
(c) 20 weeks

18. from fetus and mother’s posterior pituitary
Labor
Estradiol
Oxytocin +
from ovaries
from fetus and mother’s posterior pituitary
Induces oxytocin receptors on uterus
Positive feedback
Stimulates uterus to contract
Stimulates placenta to make +
Figure A model for the induction of labor
Prostaglandins
Stimulate more contractions of uterus

19. The three stages of labor
Placenta
Umbilical cord
Uterus
Cervix
Dilation of the cervix 1
Expulsion: delivery of the infant
Figure 2
Uterus
Placenta (detaching)
Umbilical cord
Delivery of the placenta 3

20. Mechanisms of several contraceptive methods
Male
Female
Method
Event
Event
Method
Production of sperm
Production of primary oocytes
Vasectomy
Combination birth control pill (or injection, patch, or vaginal ring)
Sperm transport down male duct system
Oocyte development and ovulation
Abstinence
Abstinence
Condom
Female condom
Coitus interruptus (very high failure rate)
Sperm deposited in vagina
Capture of the oocyte by the oviduct
Tubal ligation
Spermicides; diaphragm; cervical cap; progestin alone (as minipill, implant, or injection)
Sperm movement through female reproductive tract
Transport of oocyte in oviduct
Figure 46.20
Meeting of sperm and oocyte in oviduct
Morning-after pill; intrauterine device (IUD)
Union of sperm and egg
Implantation of blastocyst in endometrium

21. Gametogenesis Spermatogenesis Oogenesis n n n n n n n n n n n n n n
Primary spermatocyte
Primary oocyte 2n 2n n
Polar body
Secondary spermatocytes
Secondary oocyte n n n n n n n
Spermatids n n n n
Sperm n
Polar body
Fertilized egg n

22. You should now be able to:
Distinguish between asexual and sexual reproduction.
Explain how hermaphroditism may be advantageous to animals that have difficulty encountering a member of the opposite sex.
Describe various ways in which animals may protect developing embryos.
Using diagrams, identify and state the function of each component of the male and female reproductive systems.

23. Describe oogenesis and spermatogenesis; describe three major differences between them.
Explain how the uterine and ovarian cycles are synchronized and describe the functions of the hormones involved.
List the various methods of contraception, how each works.
Describe techniques that allow us to learn about the health and genetics of a fetus.