1. Sex Cells Egg: big size, immobile, there are only a few. Insidethe egg there are nutrients for the embryo. Sperm cell: small size, mobiles, thereare many and are produced at all times.

2. Fertilization External fertilization: expel sex cells into the water.How do they avoid the risk of not finding the other sex cell? 3. Internal fertilization: sperm cells are expelled insidethe female body.What is the advantage? 4. This type of fertilization requires courtship andintercourse. 5. Disney Nature Minuto 24. 6. Monogamy Polygyny PolyandryAn individual has onepartner during theirlifetime or at any one time.A male has more than onefemale.A female has more thanone male. 7. Sexual Dimorphism Males and females of the same species are different. 8. It doesnt occur in every species... 9. Animals exhibitdifferentstrategies andsocialinteractions.. 10. Ovuliparous They release sex cells into the water and the embryodevelops there. 11. Oviparous The embryos development occurs inside an egg,outside of the females body. 12. Some of them incubatethe eggs. 13. Others simply bury them! 14. Ovoviviparous They keep the eggs inside their body. 15. Viviparous The embryos development occurs inside the femalesbody (pregnancy). 16. Marsupials: the offspring are born very inmature andthey are kept inside a bag in the moms body(marsupio) where the mammal glands are. There theycomplete their development. 17. Placental: the development occurs inside the uterus.The mother has a connection with the baby throughthe placenta. 18. Development Direct development: they only change in size, but thecharacteristics are pretty similar between an adult anda baby. 19. Indirect development (metamorphosis): adults arevery different from youngsters. 20. Reproductive Strategies r strategy: have a large number of offspring but theydont take care of them. 21. K strategy: have few offspring but they look afterthem until they reach the reproductive age (theybecome adults). 22. Some of them prefferto get a nanny!