Sexual reproduction in animals: Despite the many differences seen in animals, the process that allows them to reproduce sexually is the same: - meiosis produces gametes - male sperm combine with female egg - a zygote is produced and then develops into an embryo, which is a fertilized egg during early development - the embryo develops through mitosis and cell division into a mature offspring * draw figure 2.7 on page 52, answer 3 questions For sexual reproduction to be successful, there are two requirements: 1. both male and female gametes must arrive in the same place at the same time for fertilization 2. the zygote must receive adequate food, moisture, warmth, and protection to develop Mating: the process by which two members of a population come together to combine their gametes for fertilization. - for some animals, there is only one mating season each year ………but why? - it is usually timed so that the offspring will be born when environmental conditions are favorable for growth - there are two main patterns of fertilization for animals: 1. external fertilization: the sperm and egg meet outside the bodies of both parents (usually seen in water-dwelling animals like fish & frogs) * figure 2.12 p.55 * figure 2.14 p 56 2. internal fertilization: the sperm travels from the male’s body into the females body to meet the egg (usually seen in land animals like humans, reptiles & birds) - what do we have in common with deer? - we are mammals, which both retain the embryo inside the female for further development and protection - other animals, such as birds and reptiles lay eggs, which they sit on to keep warm and to protect it Hermaphrodite: an animal that has both male and female reproductive organs. - many worms, including earthworms are hermaphrodites.