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

AP Biology

Fertilization Joining of sperm & egg

sperm head (nucleus) enters egg

AP Biology

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

AP Biology

Cleavage zygote morula blastula

establishes future development

zygote

blastulamorula

gastrulation

AP Biology

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

AP Biology

Neurulation Formation of notochord & neural tube

develop into nervous system

Notochord

Neural tube

develops intovertebral column

develops into CNS (brain & spinal cord)

AP Biology

OrganogenesisUmbilical blood vessels

Chorion

Amnion

Yolksac

AllantoisFetal blood vessels

Maternal blood vessels

Bird embryo

Mammalian embryo

Placenta

AP Biology

Placenta Materials exchange across membranes

AP Biology

Learning Check In the first 7 weeks of gestation, all

fetuses look the same. What causes the differentiation of male/female sex organs?

AP Biology

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?

AP Biology

Starter Parts

AP Biology

Gamete Production Considering all that is shared in the origin

of genital anatomy, how is gamete production similar and different in the gonads?

AP Biology

Spermatogenesis

• Puberty until death!

AP Biology

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

AP Biology

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

AP Biology

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.

AP Biology

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?

AP Biology

Human fetal development

7 weeks4 weeks

AP Biology

Human fetal development10 weeks

AP Biology

Human fetal development

12 weeks 20 weeks

AP Biology

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

AP Biology

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

AP Biology

Human fetal development 30 weeks (7.5 months)

umbilical cord

AP Biology

Getting crowded in there!! 32 weeks (8 months)

The fetus sleeps 90-95% of the day & sometimes experiences REM sleep, an indication of dreaming

AP Biology

Birthpositive feedback

AP Biology

Intestine

Placenta

Umbilicalcord

Wall ofuterus

VaginaCervix

Birth (36 weeks)

Bladder

AP Biology

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

AP Biology

The end of the journey!

And you think 9 months of

AP Bio is hard!