chapter 9A: asexual reproduction

asexual reproduction

• form of reproduction involving a single parent that results in offspring genetically identical to the parent

forms of asexual reproduction

• binary fission

• budding

• fragmentation

• vegetative propagation

features of asexual reproduction

• genetically identical offspring

• no gamete fusion

• rapid reproduction

  • useful in stable environments

    • note = decrease in genetic diversity → decrease in adaptability → risk of extinction

binary fission

a form of reproduction for prokaryotes

• e.g. bacteria

steps for binary fission

1. circular chromosome (1) replicates and the copies attach to the cell membrane. plasmids also replicate.

1. the cell begins to grow.

2. the cell continues to grow, elongating further.

3. the cell membrane + wall pinches inwards (septum) to divide the cell into two. (cytokenesis)

4. two daughter cells are produced, each genetically identical to each other and the original cell

importance of binary fission

• critical in bacterial reproduction

• drives evolution through mutations in DNA replication

• used in biotechnology for producing insulin, enzymes, etc.

budding

• asexual reproduction where a new organism develops as an outgrowth from the parent due to localised mitotic cell division

  • has identical DNA

organisms that bud

• yeast

• sponges

• jellyfish

• coral

• worms

steps (summarised)

bud forms → breaks away → entirely separate

• bud forms due to increased cell growth

fragmentation

• asexual reproduction where an organisms breaks into fragments

  • regenerates into a complete, genetically identical organism

  • may be intentional / unintentional

organisms that undergo fragmentation

• worms, sea stars, as well as some plants

vegetative propagation

• asexual reproduction in which new plants grow from the vegetative parts of a parent plant without seeds