Reproduction and Development

1
Reproduction and Development

• Chapters 44 and 45

2
I. Chapter 44 Overview

• Asexual vs. Sexual
• Costs of Sexual Reproduction
• Timing Factors
• Find potential mate
• Chemical signals and body color/pattern
• Males lots of energy on courtship rituals
• Fertilization costs
• External lots of sperm to increase chances
• Internal elaborate repro organs to transfer
  sperm
• Energy to nourish offspring
• Egg includes food source (yolk)
• Human no yolk, must get energy from mother

3
C. Stages of Embryonic Development
4
II. Historical Views

• A. Preformation - idea that the sperm or egg
  contained a preformed individual
• B. Epigenesis - idea that individual emerges
  gradually from a relatively formless egg
• 1. Differentiation of cells
• 2. Morphogenesis - tissue and organ
  development follow a pattern

5

• III. Human Reproduction and Development
• Male
• 1. Anatomy

6
2. Sperm Formation (spermatogenesis)
7
(No Transcript)
8
(No Transcript)
9
B. Female 1. Anatomy
10
2. Oogenesis (egg formation)
11
3. Menstrual Cycle
12
Hormonal changes
Ovarian and Uterine changes
13
(No Transcript)
14
C. Fertilization
15

• A. Contact and recognition
• 1. Acrosome releases enzymes to eat through
  eggs jelly coat
• 2. Acrosome-vitelline membrane contact is made
  (bindin on sperm head docks with receptor
  proteins on vitelline membrane (species ID)
• B. Sperm Entry
• 1. Enzymes on acrosome dissolve opening in
  vitelline membrane
• 2. Egg microvilli surround head of sperm
  (fertilization cone)
• 3. Plasma membranes fuse
• 4. Two mechanisms kick in to prevent
  polyspermy
• a. Na ions pore through now open Na gates
  causing an electrical charge across membrane
  (fast block)
• b. Raising and hardening of vitelline membrane
  forms fertilization membrane (slow block

16
Fertilization in Sea Urchins
17

• C. Activation of egg
• 1. Cause is sperm entry (Ca injec-tions and
  platinum needles can do the same thing)
• 2. Results in great increase in cell
  respiration and protein synthesis (stored mRNA)
• D. Haploid nuclei join

18
Fertilization in Mammals