Sexual

1
Sexual Reproduction
2
Overview Sexual reproduction allows for greater
genetic diversity in the hopes that at least some
offspring will survive in a changing environment.
3
Girlie Parts Jobs

• Ovaries Produce release mature eggs.
• Fallopian Tubes carries egg to uterus,
  fertilization occurs here.
• Uterus Site of embryo development.
• Vagina Birth canal and site of sperm deposit.

4
Female Naughty Bits
1.
2a.

2b.

3.
Oroviduct

4.

5.
5
Same Bits, different view!
See why pregnant women always have to pee?
6
Boy Parts Jobs

• Testes Produce Sperm
• Scrotum Outer pocket of skin to keep testes
  cooler for ideal conditions for sperm
  development.
• Epididymis A collection area for sperm.
• Vas Deferens Carries sperm to the urethra (and
  picks up other secretions from the seminal
  vesicles to create semen).
• Semen a mix of sperm and nutrient containing
  fluid.

7
Male Naughty Bits

Vas deferens
6.
7.
Seminal Vesicle
Penis
5.
4.
Urethra
1.
Testes
3.
Scrotum
2.
Epididymis
8

• External Fertilization
• Sperm released into environment (usually water).
• Eggs released into (watery) environment.
• Fertilization occurs in environment.
• of sperm released?
• of eggs released?
• Why?

• Internal Fertilization
• Sperm released inside female body (vagina).
• Eggs released into fallopian tubes.
• Fertilization occurs in oviduct (aka?).
• of sperm released?
• of eggs released?
• Why?

TONS!
TONS!
One (or few)
TONS!
9
Internal Fertilization
? occurs in the upper portion of the
oviduct
?a fertilized egg is called
zygote
? cell division of a zygote by begins in the
. 6-10 days later, the embryo implants in the
cleavage
mitosis
In vitro test tube fertilization
oviduct
uterus
Fraternal 2 eggs and 2 sperm
Identical 1 egg 1 sperm
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Internal V. External Development
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External Development
Shell
Air Sac
Chorion
Amnion
Embryo
Yolk (good for dipping your toast!)
Allantois (for gas exchange)
Albumin (egg white)
Both of these are filled with blood vessels
running to and from the embryo.
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Internal Development
8.
Fallopian Tube (aka?)
Placenta
1.
Oops! Same as ?
Umbilical Cord
2.
7.
Uterine Wall
6.
Fetus
Amniotic Sac
3.
Amniotic Fluid
4.
Cervix
5.
13
Embryonic Development

1. Cleavage repeating mitosis forms a hollow
ball of cells, no increase in size, just in cell
number!
2. Blastula A hollow ball of cells
approximately the same size as the zygote
(fertilized egg)
3. Gastrulation One side of the blastula
indents.
4. Differentiation see next slide!
14
Differentiation
Ectoderm The outer part of the gastrula becomes
the nervous system and epidermis of the skin.
Mesoderm The middle of the gastrula becomes the
muscles, skeleton, circulatory system, excretory
system and reproductive system.
Endoderm The inner layer becomes the lining of
the digestive tract, respiratory tract and the
liver and pancreas.
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Whats What?
16
Gestation time fetus develops in the uterus (40
weeks for humans)

6 weeks
12 weeks
18 weeks
24 weeks
36 weeks
28 weeks
17
birth video
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Other really weird organisms!
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And now you know about the birds and the bees