Asexual reproduction requires only one parent and produces offspring that are exact genetic copies. This process is faster than sexual reproduction but does not allow for variation and evolution. Common asexual reproduction methods include binary fission, budding, fragmentation, and spore production.
Sexual reproduction requires two parents and the fusion of egg and sperm to produce offspring with unique combinations of genetic material. This process creates genetic variation and drives evolution by allowing populations to adapt to changing environments. Common sexual reproduction methods include pollination, external fertilization in water, and internal fertilization in mammals and other land animals.
3. Asexual Reproduction:
• Organisms that reproduce asexually cannot
develop much variety, because they are
“copying” the original organism exactly.
• This does not allow for evolution of the
species. Each organism is the exact same as
its parent.
• This process take a relatively short period of
time. And can produce 1-100s of offspring.
4. Methods of asexual reproduction:
Binary fission
Budding
Fragmentation
Parthenogenesis
6. • When conditions are good, such as plenty
of water, food, right temperatures, etc.,
binary fission is a very effective way of
producing many, many offspring.
• For example, the cell of a Paramecium
can divide, grow, and divide again in the
space of 8 hours.
7. Budding- an offspring grows out
of the body of the parent.
Hydra Budding
offspring
Cactus Budding
8. Budding cont.
Green plants are quite sophisticated in
their methods of asexual reproduction.
Offspring may be produced by runners,
bulbs, rhizomes or tubers.
9. Regeneration
In this form, the body of the parent breaks
into distinct pieces, each of which can
produce an offspring.
Pieces of coral broken off in storms
can grow into new colonies.
A new starfish can grow from
one detached arm.
10. Fragmentation
In this form, the organism fragments into
smaller pieces and each piece forms a new
organism identical to its parent.
A flat worm will break into distinct pieces and
each will regrow another smaller organism.
12. Sporulation
In this form, the
parent organism
produces tiny spores
that it releases. They
will then create an
exact copy of the
original organism
without fertilization.
The mushroom is releasing
unfertilized spores
14. Asexual Reproduction:
Advantages of Asexual Reproduction
• uses less energy (it is not necessary to find a
partner)
• offspring is usually well adapted to its
environment because of the success of its
parent
15. Asexual Reproduction:
Disadvantages of Asexual Reproduction
• the species does not adapt at all or adapts
very slowly when circumstances change
• an asexual species runs the risk of
suddenly disappearing because of a
catastrophe that affects all organisms
27. What is sexual reproduction?
• Requiring 2 parents
– male and female (egg & sperm)
• The egg and sperm join (zygote) to form an
entirely new organism
• Offspring are different from the parent
organism.
• This process creates a variety of genetic
make-up which is the driving force behind
evolution.
28. Sexual Reproduction
• Sexual reproduction produces a greater
chance of variation within a species than
asexual reproduction would.
• This variation improves the chances that a
species will adapt to his environment and
survive.
31. Sexual Reproduction Adv.
• increases the genetic variability in
organisms of the same species and even
within the offspring of one couple
• in the long run, allows the best adaptations
to be widespread within a species,
especially in changing circumstances
32. Sexual Reproduction Adv.
• the variability of organisms within a
species guarantees that a higher
proportion will survive in perilous
circumstances
33. Sexual Reproduction Dis.
• finding a reproductive partner and
producing gametes demands the output of
a lot of energy
• not only do you need two gametes for
fertilization, one has to be male, the other
Female
• genetic “errors” happen more frequently
because meiosis is more complex than
mitosis and diploid organisms have more
chromosomes to double
34. Methods of sexual reproduction:
Pollination
External Fertilization
Internal Fertilization
35. Pollen is produced in
the male organs of the
flowers - anthers.
Pollination occurs
when pollen is
transferred from the
anthers to the female
organs by wind or by
animals. If the female
stigma is receptive to a
pollen grain, the pollen
produces a pollen tube,
which grows through
the female tissue to the
egg, where
fertilization takes
place by the sperm
nucleus.
Sexual Reproduction
in Flowering Plants
36. External Fertilization
• External fertilization usually requires a
medium such as water, which the sperms
can use to swim towards the egg cell.
External fertilization usually occur in fish
and amphibians.
• The females lay the eggs in the water and
the male squirts the sperm
in the same area.
37. Internal Fertilization
• Fertilization occurs within the female.
• Internal fertilization occurs in mammals,
insects, birds, reptiles.
– Mammals (gorillas, lions, elephants, rats,
zebras, and dolphins have live births)
– Insects, birds, reptiles lay eggs
38. Sexual vs. Asexual Reproduction
• Asexual reproduction results in offspring
that are genetically identical to the parent
organism.
• Sexual reproduction results in offspring that
are genetically different from the parent
organisms.