Reproduction

1
Reproduction
Asexual-
Fission-
Separation of the original parent into 2 or more
http//www.dnai.org/text/mediashowcase/index2.html
?id590
Budding-
New individual splits off from a larger original
http//etic.univ-reunion.fr/hydroids/animaux_sarsi
a_reproduction.htm
Fragmentation-
Breaking of body into several pieces
Advantages of asexual Reproduction
Very efficient- lots in a short period of time
Perpetuates a successful genotype
Disadvantages
Loss of variation!!!
You know!!!
2
Sexual Reproduction
Bring on the variation!
External Fertilization-
Eggs are shed by Female, then fertilized by the
male.
AQUATIC
Occurs almost exclusively in a(n) _______________
habitat.
Internal Fertilization-
Sperm is deposited in or near the female
reproductive tract, fertilization then
occurs within the female body.
Invertebrate vs Vertebrate
Invertebrate-
Range from very complex to very simple systems
without any distinct gonads.
Examples
Insects have a spermatheca
Earthworms are hermaphroditic, but still
copulate.
3
Sexual Reproduction inVertebrates

• Some have a common opening for

digestive,
excretory,
and reproductive products
Called a cloaca
http//www.vpi.com/images/118

• There is a complex interplay of hormones and
• organ responses which regulate reproduction

Estrous cycles occur in non-primate mammals
If pregnancy does not occur, endometrium gets
reabsorbed
Involves pronounced behavioral changes and tends
to
follow seasonal and climatic cues.
(cats in heat)
Egg Sperm production in Humans is quite complex
http//health.howstuffworks.com/adam-roundup.htm
Menstrual cycles occur in humans and most
primates.
4

• The Human Male
• Testes male gonads
• Seminiferous tubules sperm formation
• Leydig cells hormone production
• Scrotum outside body temp.
• Epididymis sperm storage
• Vas deferens sperm propulsion
• Seminal vesicles provides 60 of semen fluid.
  Contains amino acids, fructose, and
  prostaglandins.
• Prostate gland anticoagulant nutrients,
  alkaline
• Bulbourethral glands also contains acid
  neutralizers
• Penis/urethra semen delivery

5

• The Human Female
• Ovaries female gonads
• Follicle egg capsule
• Corpus luteum hormone secretion
• Oviduct fertilization
• Uterus/endometrium womb/lining
• Cervix/vagina sperm receptacle

6
Spermatogenesis

• Puberty until death!
• Seminiferous tubules location
• Primordial germ cell (2N) differentiate into.
• Spermatogonium (2N) sperm precursor
• Repeated mitosis into.
• Primary spermatocyte (2N)
• 1st meiotic division
• Secondary spermatocyte (1N)
• 2nd meiotic division
• Spermatids (1N)Sertoli cells.
• Sperm cells (1N)

7
Oogenesis
Well.anyone hungry for pizza??? (go to
transparency)
http//health.howstuffworks.com/adam-roundup.htm
8
The Menstrual / Ovarian CycleHold on tight!
Menstruation (endometrium sheds)
GnRH from Hypothalamus
Corpus Luteum atrophies (if egg not fertilized)
Low LH
Low Estrogen/Progesterone
Signals pituitary to Secrete small amounts of
FSH and LH
Stops
Inhibits FSH LH production in the pituitary
(stops more eggs)
Estrogen also causes The endometrium to Thicken.
Signals to Ovary to stimulate growth of a
follicle.
Corpus Luteum secretes Progesterone
More estrogen.
More.
MORE.!!
Remains of follicle called A Corpus Luteum
Follicle secretes Estrogen
which causes increased LH FSH production
LH surge from Pituitary.
As follicle grows more more Estrogen gets
produced
OVULATION!!
NOTE IF egg is fertilized, embryo secretes HCG
(Human Chorionic Gonadotropin) which Maintains
progesterone/estrogen secretions From corpus
luteum so endometrium is still maintained.
Egg