Sexual and Asexual Reproduction
Sexual reproduction happens in both plants and animals.
Plants
Animals
When a pollen grain lands on a compatible
stigma, a pollen tube grows. The pollen tube
carries the nucleus of the pollen grain from
the surface of the flower to the ovule where
the egg cell is contained. Inside the ovule, the
pollen nucleus and egg cell join in a process
called fertilisation. A seed will now start to
develop from the fertilised egg cell.
A sperm cell travels through the female
reproductive system. If ovulation has occurred,
an egg will travel from the ovary towards the
uterus through the oviduct (fallopian tube).
The sperm meets the egg inside the oviduct
which is where fertilisation happens. The
fertilised egg will travel to the uterus where it
will develop into a baby.
pollen
pollen nucleus
travelling to egg cell
egg cell
egg cell
sperm cell
The gametes are the cells involved in sexual reproduction.
1. Complete the sentences to name the cells involved in sexual reproduction.
a. The gametes in plants are the
and the
b. The gametes in animals are the
and the
.
.
Gametes are formed by meiosis. In sexual reproduction, gametes from two parents combine
during fertilisation. This results in the mixing of genetic information from two different parents.
This introduces variation to the offspring which makes it more likely that some individuals will
have a survival advantage if there are changes to their environment.
Asexual reproduction only involves one parent which saves time and energy as they do not need
to find a mate. No gametes are involved so there is no mixing of genetic information. Asexual
reproduction only involves mitosis, and therefore produces genetically identical offspring (clones).
It is faster, and therefore many identical offspring can be produced when the conditions are
favourable.
2. Write down three differences between sexual and asexual reproduction.
1. 2. 3. 1 of 2
Sexual and Asexual Reproduction
3. Explain when it is useful to have variation in the offspring.
4. Give two advantages of asexual reproduction.
1. 2. Sea anemones can reproduce both sexually and asexually. They can make a large colony of clones
by budding off from an existing organism. They can also release sperm and egg cells into the
water where fertilisation occurs. Fertilisation results in larvae that swim around until they find a
suitable place to settle, before undergoing metamorphosis to form a new sea anemone.
5. What are the advantages of the sea anemone reproducing both sexually and asexually?
2 of 2