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Animal Reproduction & Development

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Presentation on theme: "Animal Reproduction & Development"— Presentation transcript:

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 spermatocyte (diploid) MEIOSIS I spermatocytes (haploid) MEIOSIS II Vas deferens Spermatids (haploid) Spermatozoa Cross-section of seminiferous tubule 4/14/2017

9 Female reproductive system

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 GnRH
LH 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

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