1. Fertilization and Development

2. Sexual Reproduction The joining of gametes (sperm and egg)
The nuclei of sperm and egg fuse
This is called fertilization
Forms a zygote

3. Conjugation
Sexual reproduction in simple organisms where EXCHANGE of genetic material takes place.
Ex: Paramecium, spirogyra, and some bacteria

4. In Humans Male gamete (sperm) made in the male gonads (testes)
Female gamete (egg) made in the female gonads (ovaries)

5. Hermaphrodites The Earthworm
Contains both male and female reproductive organs.
Cannot self fertilize
Will mate with another earthworm

6. What is fertilization
The joining of male gamete (sperm) with female gamete (egg). The nucleus of these gametes fuse and forms a zygote
Sperm (23) egg(23) = Zygote (46)
(n) (n) = (2n)
haploid haploid = diploid
Fertilization

7. Types of fertilization
External Fertilization- Sperm and egg are released into the environment to fuse
Internal Fertilization- The fusion of egg and sperm occurs inside the body

8. The embryo
The developing embryo requires food, a stable environment and shelter

9. External Development
On Land- Occurs in birds, reptiles, and few mammals (platypus)
A hard shell is required
In water- Occurs in fish and amphibians.
Fertilized zygote develops in an egg, feeding on the yolk.

10. Internal Development
Fertilization and development of embryo occurs within the mother
With placenta- the embryo receives nutrients through the placenta
Without placenta- An egg is used to give nutrients to embryo (tropical fish and opossums)

11. Reproduction in Vertebrates
Fertilization
Development
# of Eggs
Parent Care (Yes or No)
Fish
Amphibians
Reptiles
Birds
Mammals
Chart

12. Embryonic development
Fertilized embryo travels down oviduct
Attaches to uterine walls (5-10 days)
Embryo starts to divide (mitosis)- 1 becomes 2, becomes 4, and so on until you make a ball of cells called morula.
Further mitotic divisions produces a blastula (filled with fluid).
5. The next stage is called gastrula (a ball with 3 germ layers)

14. The 3 Germ Layers- differentiate
Ectoderm- Develops into skin, nervous system, eyes, hair, and teeth
Mesoderm- develops into muscles, skeleton, circulatory system, kidney, and gonads
Endoderm-develops into digestive and respiratory systems, and liver