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Chapter 10:
Asexual
Reproduction
- Advantages
- Growth can occur very rapidly;
- Hence can rebuild their numbers rapidly
- Can produce twice as fast the rate of
sexually reproducing organisms
- Hence can rebuild their numbers rapidly
- Every member of a population can give birth too
offspring; in sexual R. only females can give
birth
- Can quickly exploit the resources of space and
energy in this new habitat if a new habitat
becomes available for colonisation.
- Organisms with a successful genetic makeup
(genotype) can spread quickly
- Parental genotype is passed on unaltered because it does
NOT involve the process of genetic shuffling
- Parental genotype is passed on unaltered because it does
NOT involve the process of genetic shuffling
- Growth can occur very rapidly;
- Disadvantages
- Does not create any
genetic variability
- Likewise if a disease breaks out, it
could affect all members
- If one member of the
population is susceptible, all
will be susceptible
- Genetic uniformity reduces the change of a population
adapting to new environmental conditions
- Likewise if a disease breaks out, it
could affect all members
- Rapid population growth may lead to competition for resources such as food, shelter and nesting
sites
- Does not create any
genetic variability
- Key Concepts
- The daughter cells are
CLONES, hence no genetic
variability
- Does nor involve GAMETES
- In prokaryotes: involves binary fission.
In eukaryotes: involves mitosis
- The daughter cells are
CLONES, hence no genetic
variability
- Technology: Asexual Reproduction
- Issues concerning cloning
- Somatic cell cloning is very unreliable; with fewer than 1 percent of cloned
embryos surviving beyond birth. Of the clones that do survive beyond birth,
many have abnormalities that result i an early death
- Somatic cell cloning is very unreliable; with fewer than 1 percent of cloned
embryos surviving beyond birth. Of the clones that do survive beyond birth,
many have abnormalities that result i an early death
- Issues concerning cloning
- Definition: A form of reproduction in which one parent produces
offspring that are genetically identical to each other and of the
parent
- Examples of asexual respoduction
- Prokaryotes
- Binary Fission
- Binary Fission
- Eukaryotes
- Binary Fission (splitting)
- Examples: Flatworms,
amoeba, anemones
- Occurs in unicellular organisms
only, because the structure of
multicellular is too complex, being
built of different tissues and organs
- They split in two like bacteria,
however, involve the process of
mitosis
- Examples: Flatworms,
amoeba, anemones
- Budding
- Clone of parent is produced. Bud grows out of parent and detaches for form a new organism
- Examples: Sea sponges, jelly fish
- Clone of parent is produced. Bud grows out of parent and detaches for form a new organism
- Spitting/Fregmentation
- The body of the parent organism splits into two or mre
pieces. Each piece regenerates the missing pieces
- Examples: Flat worms,sponges
- The body of the parent organism splits into two or mre
pieces. Each piece regenerates the missing pieces
- Spore Formation
- Examples: Mushrooms, algae, mold, toad stools
- Offsprings are NOT clones of parents. Spores which are haploid are released
from a structure called sporangia. Spores disperse and grow to become new
organism
- Examples: Mushrooms, algae, mold, toad stools
- Vegetative Reproduction
- Where organ parts of a plant can give rise to new
off springs that are genetic of the parent
- Examples: All types of plants that contain
bulbs, stems, runners, rhyzomes
- Where organ parts of a plant can give rise to new
off springs that are genetic of the parent
- Parthenogenisis
- Offspirngs are produced from unfertilised eggsby mitosis and
develop into offspring identical to female parent
- Examples: Many invertibrate animals but also whiptail lizards and some shark species
- Offspirngs are produced from unfertilised eggsby mitosis and
develop into offspring identical to female parent
- Binary Fission (splitting)
- Prokaryotes
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