Fertilization in animals occurs when the male sperm
joins with the female egg. Sperm is produced in organs called
testes. Female eggs are produced in organs called ovaries.
Animal fertilization can occur either externally or
internally. Spawning is an example of external fertilization.
During spawning, male fish and female fish come very close together in the
water. The female release eggs into the water. The male
releases his sperm. The sperm swim to the eggs and fertilize
them. Fertilization occurs outside the body.
Birds and also mammals reproduce by internal fertilization.
The female releases an egg from the ovary. It travels down a tube
that leads from the ovary. When the male and female mate, the male
releases sperm inside the female. The sperm travels to the tube
where the egg is and fertilizes it. If fertilization does not occur,
the egg leaves the female's body.
The fertilized egg is called a zygote. The zygote
begins to divide and grow and becomes an embryo. In most mammals the
embryo develops inside the mother's body in an organ called the
uterus. While in the uterus the developing embryo gets its food and
water from the mother. As the embryo grows it is called a
fetus. When the fetus has developed enough to live on its own, birth
EGG - ZYGOTE - EMBRYO
- FETUS - NEWBORN
the questions about reproduction in animals.
Fertilization in animals occurs when the
joins with the female
When sperm and egg join
outside the bodies of parents the process is called
Spawning is an example of
When sperm and egg join
inside the body of the female the process is called
Birds, cows and horses
The fertilized egg is
develops inside the mother's body in an organ called the uterus.
has developed enough to live on its own, birth occurs.
Put the stages of an embryo in the correct
order. Use the numbers 1, 2, 3, 4, 5.
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