Chapter 16 - Reproduction Flashcards
Define asexual reproduction.
The process resulting in the production of genetically identical offspring from one parent.
What are some examples of asexual reproduction?
Budding (yeast), spore germination (fungi), binary fission (bacteria).
What are the advantages of asexual reproduction?
- One parent required.
- Colonises area rapidly.
- Develops from bud to plant rapidly.
- No external agents required.
What are the disadvantages of sexual reproduction?
- No genetic variation.
- A disease may affect all in one population.
- Less adaptable to environmental changes.
- Overcrowding, competition.
Define sexual reproduction.
The process involving the fusion of the nuclei of two gametes to form a zygote and production of offspring that are genetically different from each other.
The nuclei of gametes are ________ while the nucleus of a zygote is _______.
Nuclei of gametes are haploid (23) while the zygote is diploid (46).
What are the advantages of sexual reproduction?
- More genetic variation.
- Ability to environmental changes.
- A disease is less likely to affect all in one population.
What are the disadvantages of sexual reproduction?
- Time & energy required to find a mate.
- Change due to mutation.
- More than one parent required.
- Very few offsprings produced at a time.
What is the name of the male reproductive part of a flower and what does it include?
Stamen:
- Anther
- Filament
What is the name of the female reproductive part of a flower and what does it include?
Carpel:
- Stigma
- Style
- Ovary
What is the function of the sepal?
Protects flower while it is still a bud.
What’s the function of the petals?
Attracts insects for pollination.
What’s the function of the stigma?
Sticky surface catches pollen.
What’s the function of the anther?
Produces pollen which contains the male nucleus.
What’s the function of the ovaries?
Produces female gametes (contained in ovule).
Define pollination.
The transfer of pollen grains from the anther to the stigma.
What are the characteristics of wind-pollinated flowers?
Petals: small, dull coloured, no nectar guides
Stigmas: Large, feathery
Stamen: Long, slender filaments and anthers are usually outside
Pollen grains: small, dry, light, have smooth surfaces and feathery
What are some examples of wind-pollinated flowers?
Grass, papaya
What are the characteristics of insect pollinated flowers?
Petals: Bright coloured, Large
Stigma: Small, sticky
Stamen: Short, anthers usually inside
Pollen grains: Heavy, sticky, large, have rough surfaces
What are some examples of insect pollinated flowers?
Tomato, orchid
Define pollination.
The transfer of pollen grains from the anther to the stigma.
Define self-pollination.
The transfer of pollen grains from the anther of a flowert to the stigma of the same flower or a different flower on the same plant.
Define cross-pollination.
The transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species.
What are the advantages of self-pollination?
- Less dependency on external agents.
- Generally needs to produce less pollen grains to ensure pollination.
- Less threat of extinction.
What are some disadvantages of self pollination?
- Less genetic variation.
- Weaker offspring
- Less adaptable to changes in environment.
What are some advantages of cross-pollination?
- Offspring may have desirable qualities from both parents.
- Greater genetic variability.
- Increased chance of survival of species during change in environment.
What are some disadvantages of cross-pollination?
- Greater threat of extinction.
- More pollen grains are generally produced.
- Uncertainty whether pollen grains can reach the stigma.
