9.1 Aesexual reproduction Flashcards
What is asexual reproduction?
The production of offspring from only 1 parent, where the offspring is identical to the parent.
In what organisms does asexual reproduction occur?
It occurs in bacteria, fungi, and some types of plants and animals.
Name the 6 ways of reproducing asexually:
- Fission
- Budding
- Fragmentation
- Spore formation
- Vegetative reproduction
- Parthenogenesis
What is fission?
How unicellular organisms divide.
eg. Bacteria
Name the 3 ways fission can occur:
- Longitudinal fission
- Transverse fission
- Strobiliation
What is the process of longitudinal fission?
Division along the longest axis
What is the process of transverse fission?
The cell splits along the shortest axis
What is the process of strobilation (similar to transverse fission)?
The cell splits along the shortest axis but occurs in multicellular organisms.
What is budding?
It is similar to fission except the division of the cytoplasm is uneven.
What is fragmentation?
Is similar to fission but occurs in multicellular organisms
What is spore formation?
(Is common in fungi and can be both asexual and sexual.)
If it is asexual, spores are produced by mitosis, which are then released into the air and grow into a new fungus where they land.
What is vegetative reproduction?
Where a new plant grows an offshoot of the original plant, if separated from the parent plant. Different plants have the new plant growing from different tissues.
Name the 4 ways plants can reproduce:
- Rhizomes
- Stolons
- Tubers
- Bulbs and corms
What are rhizomes?
Underground stems that branch and put up new shoots.
What are stolons (similar to rhizomes)
Aboveground stems that branch and put up new shoots.
What are tubers?
Swollen underground stems with buds ‘eyes’ that can grow into new plants.
What are bulbs and corms?
Lateral buds that produce new plants.
What is parthenogenesis?
The development of an egg in the absence of fertilisation.
Name 5 advantages of asexual reproduction:
- Efficient
- Don’t need to waste energy to find mates
- Populations can rapidly increase when conditions are good
- No need to have a sexual partner
- Offspring are identical to the parent which is a benefit in a stable environment
What are 2 disadvantages of asexual reproduction?
- Rapid population growth can overuse resources
- Lack of genetic variation means that there is little/no pherotypic (physical) variation, so if the environment changes, all individuals are equally susceptible.
What is cloning?
Cloning is the process of producing genetically identical organisms from one parent.
What are the 3 types of cloning?
- Cuttings and grafts
- Tissue culture
- Embryo splitting
What are cuttings and grafts?
- Cuttings are a piece of plant
eg. A stem that is used to grow a new plant - Grafts are a plant stem that is placed onto the root of another
What is tissue culture?
A process to make large numbers of plants rapidly grow.
Explain the process of tissue culture:
- Pieces of plants are washed, sterilized and placed on special growth mediums in pretri dishes.
- Shoots quickly grow from the pieces and can be removed and further cultured or potted up.
What is tissue culture used for?
It is often used for endangered plants or research
What are cuttings and grafts useful for?
- Disease resistance in roots
- Cold tolerance
- Early fruiting
What are the 2 processes of embryo cloning?
- Embryo splitting
- Nuclear transfer
Explain the process of embryo splitting:
At or before the 16 cell stage of an embryo, it can be split and developed into two (or more) individuals.
Explain the process of nuclear transfer:
- Unfertilised eggs can be taken and its nucleus replaced with the nucleus from an adult somatic cell
- It can then be placed into a surrogate (substitute) mother to develop into a new individual.
Give an example of a nuclear transfer in the past:
Dolly the sheep (1996)
Name 3 issues surrounding embryo cloning:
- High failure rater: 0.1-3% success
- Health effects
- Premature aging
What is a zygote?
A fertilised egg
