1. Reproduction in Animals

2. Brainstorm Do all animals reproduce similarly?No
Why might different animals have different forms of reproduction?
Different organs
Different habitat (ie. Land, water)
Different climate (tropics, rain forest, dessert)
Are there any advantages/ disadvantages to reproducing at different times of the year?
WHEN? and WHERE?

3. WHEN?
Mating occurs when the environmental conditions are good to raise the young.
Among most birds, mating occurs in the Spring
the young are born several weeks later
They reach maturity before the onset of winter
Q: Why is this important in cold climates?
Birds need to have reached maturity before they can migrate south for the winter

4. WHEN? Among most mammals, mating occurs in the fall
the embryos develop in the winter
the young are born in the spring
Q: Why is this important in cold climates?
- The newborn might not be able to survive the cold of the winter

5. Fertilization
Fertilization: union of sperm and ovum

6. Reproduction in water animals
Fertilization is external in animals that live in the water
The female fish will lay eggs in the water.
the male fish will deposit a liquid that contains sperm over the eggs
The sperm swims to and fertilizes the egg
The fertilized egg will divide over and over again; this is the developing embryo (young fish)
Reproduction Movie

7. Land Animals
Q: What problem might land animals encounter during reproduction?
A: Dehydration
Q: What adaptations have evolved in these animals to combat this?
A: Internal fertilization
Q: How are the reproductive systems of land animals different than those of water animals?
A: 1) both males and females have special organs for the internal transfer and union of sperm and ova (egg)
2) an internal womb is required for the development of the young

8. What are the different forms of Reproduction?
Animals can be:
Oviparous: the young hatch from eggs
risk?: eggs are vulnerable to predators
ex. Reptiles and birds
2) Ovoviviparous: the female retains the egg until shortly before hatching or the eggs may hatch within the female’s body
ex: some snakes and lizards
3) Viviparous: the young develop in the mother’s body
ex: mammals

9. Mammals Mammals are classified into 3 groups:
1) Monotremes: egg laying
ex: duck-bill platypus
2) Marsupials: their young are born in an immature state and complete their development in their mother’s pouch
ex: kangaroos, koalas
3) Placentals: the young develop in the mother’s body and are nourished by the placenta
ex: baboons, humans

10. Eureka Textbook Questions
READ pages A
B 250 – 256;
Do Questions from 1 – 6 on Handout.
Hand in before you go.