Asexual reproduction Flashcards
asexual reproduction
- offspring genetically identical to parent and each other
- requires only one parent
- mainly used by unicellular organisms
advantages
- quick reproduction without partner, good for immobile organisms
- good for harsh environments where little benefit for variation
- less energy required to produce offspring, good during food shortages
- small mating population/no need to find mate
disadvantages
- little to no variation, susceptible to sudden environmental selection pressures
alternation of generations
mechanism that involves alternating between sexual and asexual reproduction
- sexual gamete-bearing generation alternating with asexual spore-bearing generation
fungi can…
reproduce both sexually and asexually
isogamous
gametes are similar, not classified as female or male
- undergoes isogamy, has a ‘charge’; positive and negative come together to reproduce
- fungi sexual reproduction
spores
single-celled reproductive unit of non-flowering plants
- asexual, distributed through wind, water, other agents
- does not require another gamete
- used by fungi
vegetative propagation
some adults plants produce vegetative organs from which new plants can arise; genetically identical to parent
perennating organs
underground roots/stems to sustain the plant in a dormant state
- allows survival in adverse conditions
- can be used by gardeners(cutting) as sexual reproduction
runners
long, thin modified stems that grow along surface of soil, produces nodes to continue runner
- new plants at new nodes
- each node grows leaves + roots
rhizomes
underground modified stems, new shoots grow at each node
suckers
roots of some plants can be modified to be suckers, gives rise to new plants
- sends shoots up from outer roots to grow into separate plants if parent shrub dies
apomixis
uses special generative tissues, with no need for fertilizations or production of seeds
- generative tissues: can be gametes or somatic
- includes parthenogenesis
budding
organism makes small bud, which separates from parent and grows into new individual
- when conditions favorable: bud will grow and detach, and grow into reproductive adult
- genetically identical offspring
what organisms use budding
molds/fungi + mushrooms + bacteria
mold
type of fungi that uses budding as reproductive mechanism
- only buds under favorable conditions
- mold can be both diploid and haploid, and both can reproduce asexually
- sexual reproduction if lack of ingredients
- diploid form harsh for environment conditions, produces spores that germinate under favorable conditions
binary fission
