2Brainstorm Do all animals reproduce similarly? NoWhy might different animals have different forms of reproduction?Different organsDifferent 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?
3WHEN?Mating occurs when the environmental conditions are good to raise the young.Among most birds, mating occurs in the Springthe young are born several weeks laterThey reach maturity before the onset of winterQ: Why is this important in cold climates?Birds need to have reached maturity before they can migrate south for the winter
4WHEN? Among most mammals, mating occurs in the fall the embryos develop in the winterthe young are born in the springQ: Why is this important in cold climates?- The newborn might not be able to survive the cold of the winter
5FertilizationFertilization: union of sperm and ovum
6Reproduction in water animals Fertilization is external in animals that live in the waterThe female fish will lay eggs in the water.the male fish will deposit a liquid that contains sperm over the eggsThe sperm swims to and fertilizes the eggThe fertilized egg will divide over and over again; this is the developing embryo (young fish)Reproduction Movie
7Land AnimalsQ: What problem might land animals encounter during reproduction?A: DehydrationQ: What adaptations have evolved in these animals to combat this?A: Internal fertilizationQ: 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
8What are the different forms of Reproduction? Animals can be:Oviparous: the young hatch from eggsrisk?: eggs are vulnerable to predatorsex. Reptiles and birds2) Ovoviviparous: the female retains the egg until shortly before hatching or the eggs may hatch within the female’s bodyex: some snakes and lizards3) Viviparous: the young develop in the mother’s bodyex: mammals
9Mammals Mammals are classified into 3 groups: 1) Monotremes: egg layingex: duck-bill platypus2) Marsupials: their young are born in an immature state and complete their development in their mother’s pouchex: kangaroos, koalas3) Placentals: the young develop in the mother’s body and are nourished by the placentaex: baboons, humans
10Eureka Textbook Questions READ pages AB 250 – 256;Do Questions from 1 – 6 on Handout.Hand in before you go.