AP Biology
March 31, 2011BR: Explain how the number of choices an
organism has may affect its mating behaviors
Obj: Students will familiarize themselves with the structure/function of animal reprodcutive systems.
HW: Ch 45 GR
AP Biology
AP Biology 2007-2008
Animal Reproduction&
Development
AP Biology
Fertilization
fertilization cleavage gastrulation neurulation organogenesis
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Fertilization Joining of sperm & egg
sperm head (nucleus) enters egg
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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
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Cleavage zygote morula blastula
establishes future development
zygote
blastulamorula
gastrulation
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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
Gastrulation
ectoderm
mesoderm
endoderm
protostome vs. deuterostome
gastrulation inprimitive chordates
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Neurulation Formation of notochord & neural tube
develop into nervous system
Notochord
Neural tube
develops intovertebral column
develops into CNS (brain & spinal cord)
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OrganogenesisUmbilical blood vessels
Chorion
Amnion
Yolksac
AllantoisFetal blood vessels
Maternal blood vessels
Bird embryo
Mammalian embryo
Placenta
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Placenta Materials exchange across membranes
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Learning Check In the first 7 weeks of gestation, all
fetuses look the same. What causes the differentiation of male/female sex organs?
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Sex Differentiation Which parts of the female anatomy go
through changes in size/position to become parts of the male anatomy?
What evidence do we have of the shared origin of the male & female sex organs?
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Starter Parts
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Gamete Production Considering all that is shared in the origin
of genital anatomy, how is gamete production similar and different in the gonads?
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Spermatogenesis
• Puberty until death!
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Oogenesis
Meiosis 1 completedduring egg maturation
Meiosis 2 completedtriggered by fertilization
ovulation
Unequal meiotic divisions unequal distribution
of cytoplasm 1 egg 2 polar bodies
What is theadvantage of
this development system?
Put all your eggin one basket!
AP Biology 2005-2006
Reproductive hormones 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
testesor
ovaries
AP Biology 2005-2006
Sex hormone control in males
Hypothalamus
Pituitary
Testes
Body cells
GnRH
FSH & LH
testosterone
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The female pattern Estrous cycles/estrus
(many mammals) Menstrual cycle (humans &
many other primates): Ovarian/Menstrual cycles~
Follicular phase ~ follicle growth
Ovulation ~ oocyte release Luteal phase~ hormone
release
Menopause ~ cessation of ovarian and menstrual cycles.
AP Biology 2005-2006
LH
FSH
estrogen
progesterone
lining of uterus
egg development ovulation = egg release
corpus luteum
0 7 14 21 28days
Menstrual cycle
Hypothalamus
Pituitary
Ovaries
Body cells
GnRH
FSH & LH
estrogen
AP Biology 2005-2006
Egg maturation in ovary Corpus luteum
produces progesterone to maintain uterine lining
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Learning Check Its been said that the menstrual cycle is
regulated by “cause and effect.” Explain what is meant by this, addressing hormones and physical/structural changes that occur during menstruation.
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Menstruation & Ovulation What factors can impact a woman’s
menstruation? When is a woman most fertile? How long can sperm reside in a
woman’s body “searching” for an egg?
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Human fetal development
7 weeks4 weeks
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Human fetal development10 weeks
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Human fetal development
12 weeks 20 weeks
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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
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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
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Human fetal development 30 weeks (7.5 months)
umbilical cord
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Getting crowded in there!! 32 weeks (8 months)
The fetus sleeps 90-95% of the day & sometimes experiences REM sleep, an indication of dreaming
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Birthpositive feedback
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Intestine
Placenta
Umbilicalcord
Wall ofuterus
VaginaCervix
Birth (36 weeks)
Bladder
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Parturition
OXYTOCIN~ stimulates uterine contractions
1st stage: Opening up and thinning of
the cervix. Ending in complete dilation.
2nd stage: Expulsion of the baby as a
result of strong uterinecontractions.
3rd stage: Expulsion of the placenta.
Lactation ~ prolactin & oxytocin
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The end of the journey!
And you think 9 months of
AP Bio is hard!