reproduction in vertebrates,

2. Courtship

3. Courtship behaviour
is displayed by many
mammals, birds and
some fish

4. Occurs before
mating and helps
males and
females
recognise each
other

5. Courtship prevents
immature animals
from breeding

6. It also allows the
females animal to
make a choice as to
which males she
wishes to breed with.

8. -secretion of chemicals
(pheromones) to attract a mating
partner
-change in appearance of males
to attract the females e.g.
peacock displaying his feathers to
attract a peahen
- making sounds: male frogs
make a loud croaking sound to
attract female frogs

9. Courtship behaviour is of
survival values it is only
the strong, fittest males
that mate with the
females and in so doing,
passes on their genes to
the next generation.

11. Occurs when a sperm fuses
with an egg to form a
zygote
Fertilization may take place
outside a female (external)
or it may take place inside a
female’s body (internal)

12. External fertilisation Internal fertilisation
Fertilisation occurs outside
the body, usually in water
The female lays her eggs in
the eggs in the water and the
male releases sperm over the
eggs
Aquatic animals they rely on
external fertilization produce
large numbers of gametes to
increase the chances of
successful fertilisation
Sperm are realised into the
females body and the sperm
swim towards the egg where
fertilization occurs
Internal fertilization allows
terrestrial animals to
reproduce since the eggs and
the sperm cannot survive the
terrestrial environment
Animals that rely on
fertilisation are some fish
species, birds and all
mammals

13. THERE ARE THREE WAYS AN EMBRYOS MAY
DEVELOP

14. Ovipary refers to the
development of a fertilized egg
that has been laid. The
development of this egg occurs
outside the body and the young
hatchling from the egg e.g.
Birds and reptiles

15. Refers to the development of
fertilised egg that is retained in the
mother’s body. The developing
young obtain nutrients from the yolk
of the egg. The young hatch within
the mother’s body and are then
born.
-occurs in some insects, some fish
and some reptiles.

16. Refers to the development of an
embryo within the females
body. Nutrients and oxygen are
obtained from the others blood
via the placenta. Most mammals
are viviparous and the young
are born alive.

18. The amniotic egg allows the
embryos of vertebrates to
develop in a liquid. The egg is
protected by a shell and has
four membrane, namely, the
amnion, yolk sac, allantois
and chorion

20. Birds produce chicks that
display precocial development
or altricial development

21. Precocial development Altricial development
This type of chick
development is mainly
found in birds that make
their nest on the ground.
The eggs have a lot of
energy. The hatchlings are
easy pray for roving
predators. The young chicks
are able to move
immediately after hatching
and leave the nest two days
later
This is typical of birds that build
nests high up on the trees. The
eggs have little energy. The young
chicks are poorly developed when
they hatch, and their eyes are
closed; they are helpless and
totally dependent on their parents
for food and protection