Sexual reproduction in animals:

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
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
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.