Reproductive strategies involve adaptations that improve chances of fertilization or offspring survival. There are two main types: asexual reproduction requiring one parent produces clones, while sexual reproduction between two parents creates genetic variation. Asexual reproduction is simple but limits variation, while sexual reproduction requires more energy but allows adaptation to changing environments.

2. Reproductive strategies are
structural, functional and behavioural
adaptations that improve the chances of
fertilization and/or increase the survival rate of

4. Asexual Reproduction
 Requires only one parent
 Offspring have 100% the
same chromosomes as
the parent.
 In other words, the
offspring are exact
“clones” of the parent.
 Mitosis

5. Types of Asexual Reproduction
 There are several different types of asexual
reproduction they are:
 Binary Fission
 Budding
 Fragmentation
 Regeneration
 Parthenogenesis

6. Binary Fission
 Binary Fission Occurs in:
 Bacteria
 Protists
Binary fission is a form
of asexual reproduction
where every organelle
is copied and the
organism divides in two.
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7. Budding
Hydra
 Budding is a means of asexual reproduction whereby a
new individual develops from an outgrowth of a
parent, splits off, and lives independently.

8. Fragmentation
 Fragmentation is a means of asexual reproduction
whereby a single parent breaks into parts that
regenerate into whole new individuals.
Starfish Planarians
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9. Regeneration
 Regeneration occurs when a body part has broken off
and the organism grows a new one.
http://www.youtube.com/watch?v=f7cXeWxxfD4
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11. Parthenogenesis
 This type of reproduction involves the development of
an egg that has not been fertilized into an individual.
 Animals like most kinds of wasps, bees, and ants that
have no sex chromosomes reproduce by this process.
Some reptiles and fish are also capable of reproducing
in this manner.

13. Sexual Reproduction
 Requires two parents that
each share ½ of the
genetic information.
 Offspring share the
characteristics of each
parent.
 Meiosis to create sex
cells

14. Sexual Reproduction
 All the members of the Animal
Kingdom
 Fish
 Mammals
 Amphibians
 Birds
 Reptiles
 Insects
 Crustaceans

15. Sexual Reproduction in plants
 Plant Kingdom
 Flowers are the reproductive organs of plants.
Male flower Female flower
 Some flowers have both male and female reproductive
organs on the same flower.

16. Sexual Reproduction
 Happens 2 ways
 Internally (inside)
 The egg is fertilized by sperm inside the female
 Mammals, birds, reptiles, insects, spiders
 Externally (outside)
 The egg is fertilized by sperm outside the female
 The female lays the eggs and then the male fertilizes
them.
 Fish and some amphibians
 Plants and fungi (pollen and spores)
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17. Summary
Asexual Reproduction Sexual Reproduction
No genetic differences Random gamete formation
and combination allows
genetic variation
Simple and easy – no need Must find a suitable partner
to find a mate – time and effort
Little energy expended More energy required
Good strategy when Good strategy when
environmental conditions environmental conditions
are favourable are variable

19. External versus Internal fertilisation
Male gametes are small, fragile and prone to
dehydration. Aquatic organisms are able to disperse
their gametes in the water around them. Terrestrial
organisms require alternative methods to ensure
viable sperm is able to fertilize the egg.

20. Broadcast Spawning: Reef fish that gather
together and release their eggs and sperm
simultaneously into the water – these eggs are
termed ‘pelagic’, or free-floating. (eg.
Boxfish, abalone and coral)

21. Demersal Spawning:
Fish that lay eggs together
in a type of ‘nest’ (a hollow
in the sand or a crevice in
rocks) which are then
fertilised by the males are
demersal spawners. They
produce larger and fewer
eggs than broadcast
spawners, because energy
is needed to guard and
clean the eggs. (eg.
Anenome fish)

22. ONE mating partner vs. MANY mating partners

23. Monogamy
More than 90% of bird species are monogamous, that is, they form pairs
for one or more breeding seasons. Eg. Eagles, albatross and brolgas.
These species are more likely to have altricial development (require
significant parental care).

24. Polygamy
Polygyny (one Polyandry (one
male, many females) female, many
males)

25. Promiscuous – males and females in a social group
engage in multiple and indiscriminate mating.

27. Fast versus slow
 Fast reproductive strategies are known as R-strategies
 Slow Reproductive strategies are called the K-strategy

28. R-selection (Quick and many Eg. Mice and
rabbits)

29. K-selection (slow and few
Eg. Elephants, whales, humans)

30. Slow (K) vs Fast (r)
 Large body size • Small body size
 Long life span • Short life span
 Take a long time to • Sexually mature very
sexually mature quickly (weeks to
months)

31. Slow (K) vs Fast (r)
 Typically carry 1-2 • Carry/hatch many young
young • Must care for themselves
 Protect and nurture at an early age
their young • Low Survivorship of
 High survivorship (type young (many die) – type
1) of species over time. 3

33. Eggs or live born young?
 Oviparity – eggs released by the mother so embryos
develop outside mother’s body with nutrients for the
embryo coming from the egg yolk
 Viviparity – embryos develop within the mother’s
body and are born as miniature copies of the adult.
Nutrition of the developing embryo within the mother
occurs in different ways.

34. Oviparity
 Oviparous animals lay hard-
shelled eggs that act as a
‘pond’ for the developing
embryo.
 The yolk of the egg acts as a
source of nutrients.
 The size of the newly
hatched young is
determined by the yolk
supply in the egg – the
larger the yolk, the larger
the young.

35. Vivaparity – Live birth
 Placental mammals (Eg.
humans, cats, dogs, sheep and cows).
 Viviparity increases the chance of
survival by protecting the young within
a female’s body rather than leaving
them exposed to predators

36. Additional Examples

37. Monotremes (Echidna and Platypus)
Primitive mammals that lay soft-shelled eggs.