 1.
A cell contains two homologous sets of chromosomes.
 a. The cell that contains these homologous sets of chromosomes must be diploid.
 b. Each homologous pair of chromosomes was formed by
DNA replication of a single chromosome.
 c. Barring mutation, the two chromosomes in a homologous pair must be identical.
 d. One member of each homologous pair is from the maternal family line; the other member is from the paternal family line.
AP Biology 2005-2006

1.
Two sister chromatids are joined at the centromere prior to meiosis. a.
These chromatids make up a diploid chromosome. b.
The cell that contains these sister chromatids must be diploid. c.
The two sister chromatids were formed by DNA replication of a single chromatid.
AP Biology 2005-2006

AP Biology 2005-2006


Asexual
 offspring all have same genes (clones)
 no variation unless there is mutation

Sexual
 gametes (sperm & egg)
 fertilization
 mixing of genes
 variation
AP Biology 2005-2006


Development of an unfertilized egg
 honey bees
 drones = males produced through parthenogenesis
 haploid
 workers & queens = females produced from fertilized eggs
 diploid
AP Biology queen worker drone
2005-2006


Having functional reproductive system of both sexes earthworms mating
AP Biology flat worm
2005-2006


Joining of egg & sperm
 external
 usually aquatic animals
 internal
 usually land animals
AP Biology 2005-2006


External
 development in eggs
 fish & amphibians in water
 soft eggs= exchange across membrane
 birds & reptiles on land
 hard-shell amniotic eggs
 structures for exchange of food, O
2
& waste
 sharks & some snakes
 live births from eggs

Internal
 placenta
 exchange food & waste
 live birth
AP Biology 2005-2006


What is the adaptive value of each type of sexual reproduction
 number of eggs?
 level of parental of care
 habitat?
AP Biology 2005-2006


Testosterone
 from testes
 functions
 sperm production
 2 ° sexual characteristics

Estrogen
 from ovaries
 functions
 egg production

 prepare uterus for fertilized egg
2 ° sexual characteristics
AP Biology
LH &
FSH testes or ovaries
2005-2006

Hypothalamus
GnRH
Pituitary
FSH
&
LH
Testes testosterone
2005-2006


Testicles
 produces sperm & hormones

Scrotum
 sac that holds testicles outside of body

Epididymis
 where sperm mature

Vas deferens
 tubes for sperm to travel from testes to penis

Prostate, seminal vesicles,
Cowper’s (bulbourethal) glands
AP Biology

 nutrient rich fluid to feed
& protect sperm buffer to counteract acids in vagina
2005-2006

seminiferous tubule sperm spermatocytes

Testes & epididymis
 sperm production & maturation

Glands
 seminal vesicles, prostate, bulbourethal
 produce seminal fluid =
AP Biology

Testis Epididymis
Coiled seminiferous tubules
Vas deferens
Germ cell
(diploid)
1
° spermatocyte
(diploid)
2 ° spermatocytes
(haploid)
Spermatids
(haploid)
MEIOSIS I
MEIOSIS II
Spermatozoa
Cross-section of seminiferous tubule
AP Biology 2005-2006


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
AP Biology 2005-2006

Hypothalamus
GnRH egg development
Pituitary
FSH
&
LH estrogen
Ovaries estrogen
LH
FSH ovulation = egg release corpus luteum progesterone lining of uterus days 0 7 14 21


Corpus luteum
 produces progesterone to maintain uterine lining
AP Biology 2005-2006


FSH & LH
 release from pituitary

 stimulates egg development & 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
AP Biology
 lowered levels = menstruation
2005-2006


What is the advantage of this development system?
Meiosis 1 completed during egg maturation
Meiosis 2 completed triggered by fertilization
AP Biology ovulation
2005-2006

AP Biology 2005-2006


Joining of sperm & egg
 sperm head enters egg
AP Biology 2005-2006


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 2005-2006

 zygote
 morula
 blastula
 establishes future development
AP Biology 2005-2006


Establish 3 cell layers
 ectoderm
 outer layers
 skin, nails, teeth, nerves
 mesoderm
 blood, bone & muscle
 endoderm
 inner lining
 digestive system
AP Biology ectoderm mesoderm endoderm
2005-2006


1st organ to form is notochord & nerve chord
 develop into nervous system
Neural groove
Neural tube
Notochord
AP Biology 2005-2006


Materials exchange across membranes
AP Biology 2005-2006


32 weeks (8 months)
The fetus sleeps 90-95% of the day & sometimes experiences
REM sleep, an indication of dreaming
AP Biology 2005-2006

AP Biology
Hormone induction positive feedback
2005-2006

Intestine
Placenta
Umbilical cord
Wall of uterus
Bladder
Cervix
2005-2006

AP Biology 2005-2006


Contraception and Abortion

Contraception , the deliberate prevention of pregnancy, can be achieved in a number of ways

Contraceptive methods fall into three categories:

Preventing release of eggs and sperm

Keeping sperm and egg apart

Preventing implantation of an embryo
AP Biology 2005-2006

1.
Distinguish between asexual and sexual reproduction
2.
Explain how hermaphroditism may be advantageous to animals that have difficulty encountering a member of the opposite sex
3.
Describe various ways in which animals may protect developing embryos
4.
Using diagrams, identify and state the function of each component of the male and female reproductive systems
AP Biology 2005-2006

5.
Describe oogenesis and spermatogenesis; describe three major differences between them
6.
Explain how the uterine and ovarian cycles are synchronized and describe the functions of the hormones involved
7.
List the various methods of contraception, how each works, and how effective each is
8.
Describe techniques that allow us to learn about the health and genetics of a fetus
AP Biology 2005-2006

AP Biology 2005-2006