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2007-2008 Animal Reproduction & Development Sexual & asexual reproduction 5/3/2015 Asexual  offspring all have same genes (clones)  Little to no variation.

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Presentation on theme: "2007-2008 Animal Reproduction & Development Sexual & asexual reproduction 5/3/2015 Asexual  offspring all have same genes (clones)  Little to no variation."— Presentation transcript:

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2 Animal Reproduction & Development

3 Sexual & asexual reproduction 5/3/2015 Asexual  offspring all have same genes (clones)  Little to no variation  Fragmentation and budding Sexual  gametes (sperm & egg)  fertilization  mixing of genes  variation

4 Parthenogenesis 5/3/2015  Egg development without a male contribution  Wasps, honeybees, aphids, komodo dragons, some fish, frogs and lizards  Usually produces males

5 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) 5/3/2015

6 Reproductive hormones 5/3/2015  Testosterone  from testes  functions sperm production 2° sexual characteristics  Estrogen  from ovaries  functions egg production prepare uterus for fertilized egg 2° sexual characteristics LH & FSH testes or ovaries

7 Sex hormone control in males 5/3/2015 Hypothalamus Pituitary Testes Body cells GnRH FSH & LH testosterone

8  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) Male reproductive system Testicle (seminiferous tubules) sperm spermatocytes

9 Spermatogenesis 5/3/2015 Epididymis Testis Coiled seminiferous tubules Vas deferens Cross-section of seminiferous tubule Spermatozoa Spermatids (haploid) 2° spermatocytes (haploid) 1° spermatocyte (diploid) Germ cell (diploid) MEIOSIS II MEIOSIS I Produce semen by age 7 Produce sperm by puberty (11-14

10 Female reproductiv e system 5/3/2015

11 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 5/3/2015

12 Menstrual cycle LH FSH estrogen progesterone lining of uterus egg developmentovulation = egg release corpus luteum days Hypothalamus Pituitary Ovaries Body cells GnRH FSH & LH estrogen 5/3/2015

13 Female hormones  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  lowered levels = menstruation 5/3/2015

14 Egg maturation in ovary 5/3/2015  Corpus luteum  produces progesterone to maintain uterine lining

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

16 Fertilization  fertilization  Cleavage  Morula  Blastocyst  Implantation  gastrulation  neurulation  Organogenesis  Fetus

17 Fertilization  Joining of sperm & egg  sperm head (nucleus) enters egg  Acrosome (enzyme filled vesicle)

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19 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

20 Cleavage  zygote  morula  blastula  establishes future development zygote blastula morula gastrulation

21 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 gastrulation in primitive chordates

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

23 Organogenesis  Organ development and differentiation from germ layers

24 Placenta  Materials exchange across membranes

25 Human fetal development 7 weeks4 weeks

26 Human fetal development 10 weeks

27 Human fetal development 12 weeks20 weeks

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

29 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

30 Human fetal development  30 weeks (7.5 months) umbilical cord

31 Getting crowded in there!!  32 weeks (8 months) The fetus sleeps % of the day & sometimes experiences REM sleep, an indication of dreaming

32 Fetal slide notes

33 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!

34 Birth positive feedback

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


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