1. Animal Reproduction & Development

2. Sexual & asexual reproduction
offspring all have same genes (clones)
Little to no variation
Fragmentation and budding
Sexual
gametes (sperm & egg)  fertilization
mixing of genes  variation
Budding- small part that breaks off, hydra and yeast
fragmentation breaking of parent into smaller pieces regeneration must occur then. Annelids, sea stars some fungus and plants does not mean that they do not reproduce sexually too, this is just a means for “emergency”
4/14/2017

3. Parthenogenesis Egg development without a male contribution
Wasps, honeybees, aphids, komodo dragons, some fish, frogs and lizards
Usually produces males
4/14/2017

4. Mechanisms of sexual reproduction
Fertilization(union of sperm and egg)
external
internal
Timing
Compatible copulatory organs
All species produce more offspring than the environment can handle
Survival???
Pheromones
chemical signals that influence the behavior of others (mate attractants)
4/14/2017

5. Reproductive hormones
LH & FSH
Testosterone
from testes
functions
sperm production
2° sexual characteristics
Estrogen
from ovaries
egg production
prepare uterus for fertilized egg
testes or ovaries
4/14/2017

6. Sex hormone control in males
Hypothalamus
GnRH
Pituitary
FSH & LH
Gonadotropin releasing hormone
Testes
testosterone
Body cells
4/14/2017

7. Male reproductive system
Testicle (seminiferous tubules)
Male reproductive system
sperm
spermatocytes
Testes & epididymis
sperm production & maturation
Sperm production
over 100 million produced per day!
~2.5 million released per drop!
Glands
seminal vesicles, prostate, bulbourethal
produce seminal fluid = nutrient-rich (sugars)

8. Spermatogenesis Produce semen by age 7 Produce sperm by puberty (11-14
Epididymis
Testis
Germ cell
(diploid)
Coiled
seminiferous
tubules 1°
spermatocyte
(diploid)
MEIOSIS I 2°
spermatocytes
(haploid)
MEIOSIS II
Vas deferens
Spermatids
(haploid)
Spermatozoa
Cross-section of
seminiferous tubule
4/14/2017

9. Female reproductive system
4/14/2017

10. Female reproductive system
Ovaries
produces eggs & hormones
Uterus
nurtures fetus; lining builds up each month
Fallopian tubes
tubes for eggs to travel from ovaries to uterus
Cervix
opening to uterus, dilates 10cm (4 inches) for birthing baby
Vagina
birth canal for birthing baby
Ovaries in a protective capsule with many follicles
4/14/2017

11. Menstrual cycle Hypothalamus Pituitary Ovaries Body cells GnRHLH
FSH
Hypothalamus
egg development
ovulation = egg release
GnRH
corpus luteum
Pituitary
FSH & LH
estrogen
About 450 cycles occur in a womans lifetime and then menopause
progesterone
Ovaries
lining of uterus
estrogen
Body cells
4/14/2017
days 7 14 21 28

12. Female hormones cells that used to take care of developing egg
FSH & LH
release from pituitary
stimulates egg development (follicle) & hormone release
peak release = release of egg (ovulation)
Estrogen
released from ovary cells around developing egg
stimulates growth of lining of uterus
lowered levels = menstruation
Progesterone
released from “corpus luteum” in ovaries
cells that used to take care of developing egg
stimulates blood supply to lining of uterus
4/14/2017

13. Egg maturation in ovary
Corpus luteum
produces progesterone to maintain uterine lining
4/14/2017

14. Oogenesis Unequal meiotic divisions unequal distribution of cytoplasm
release
Oogenesis
Unequal meiotic divisions
unequal distribution of cytoplasm
1 egg
2 polar bodies
Cell stored in ovaries
Meiosis 1 completed
during egg maturation
Cell matures in follicle on ovary
ovulation
Meiosis 2 completed
triggered by fertilization

15. Fertilization fertilization Cleavage Morula Blastocyst Implantation
gastrulation
neurulation
Organogenesis
Fetus

16. Fertilization Joining of sperm & egg sperm head (nucleus) enters egg
Acrosome (enzyme filled vesicle)

18. 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

19. Cleavage zygote  morula  blastula establishes future development
gastrulation
morula
blastula

20. Gastrulation Establish 3 cell layers ectoderm mesoderm endoderm
gastrulation in primitive chordates
Gastrulation
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
ectoderm
mesoderm
endoderm

21. Neurulation Formation of notochord & neural tube
develop into nervous system
develops into CNS (brain & spinal cord)
Neural tube
Notochord
develops into vertebral column

22. Organogenesis
Organ development and differentiation from germ layers

23. Placenta
Materials exchange across membranes

24. Human fetal development
4 weeks
7 weeks

25. Human fetal development
10 weeks

26. Human fetal development
12 weeks
20 weeks

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

28. 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

29. Human fetal development
30 weeks (7.5 months)
umbilical cord

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

31. Fetal slide notes

32. Apoptosis Programmed cell death Sculpts body parts
Genetically programmed elimination of tissues & cells that were used for only short periods in embryo or adult
human embryos develop with webs between toes & fingers, but they are not born that way!

33. positive feedback
Birth

34. Birth (36 weeks) Intestine Placenta Umbilical cord Wall of uterus
Bladder
Cervix
Vagina