Biology π | Plant Reproduction | 16.1 Flashcards
Define reproduction.
The process where more of the same species is created for longevity.
What is asexual reproduction?
A process of reproduction resulting in the production of genetically identical offspring from one parent.
What is the major difference between asexual and sexual reproduction?
- Sexual reproduction requires two parents / asexual reproduction requires one
- In sexual reproduction, offspring are unique / in asexual reproduction they are identical
Where does mitosis take place?
- In most unicellular organisms
- In animal cells, for growth - body / somatic cells
What are the advantages of asexual reproduction?
- Produces more offspring
- Asexual reproduction takes less time
- Only one parent is involved, no search for mates
- Takes less energy
- Inheriting of features from a parents (good adapted)
- High turnover rate for crops
What are the disadvantages of asexual reproduction?
- Natural selection is not possible
- No genetic variation - same DNA passed down
- A disease may affect all in a population
- Species may only be suited to one habitat
How does asexual reproduction work in a runner?
Food is conducted from the parent to the daughter plant, via tiny horizontal plantlets that when they reach the ground, grow roots and develop into full plants.
How does asexual reproduction work in a bulb?
They are underground food storage organs with fleshy leaves that store food and grow and develop into new plants.
How does asexual reproduction work in a tuber?
They have underground food stores. Groups of cells in the tuber use this food to produce the energy needed for cell division. These cells then grow and develop into new plants.
What is sexual reproduction?
The process of reproduction involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other
Define fertilisation.
The fusion of nuclei of gametes.
What are the advantages of sexual reproduction?
- Variation in offspring helps in evolution
- Organism is protected because of genetic variation
What are the disadvantages of sexual reproduction?
- Requires two organisms, need for a mate
- Requires more energy and respiration
- More time is needed to develop the offspring
What is the difference between diploid and haploid?
A diploid has two pairs of chromosomes, a haploid has only one.
How do bacteria asexually reproduce?
Via binary fission / mitosis, where each bacteria divides into two
How do fungi asexually reproduce?
- Yeast uses binary fission
- Other fungi use spores
The nuclei of gametes are _ and the nuclei of a zygote is _
Gametes are haploid, zygotes are diploid
What are the advantages of sexual reproduction?
- Variation in offspring helps in evolution
- Organism is protected because of genetic variation
What are the disadvantages of sexual reproduction?
- Takes more time and energy
- Good characteristics can be lost
- Requires finding a mate: requires two organisms
Define carpel
The female part of a flower
Define stamen
The male part of a flower
Which organs are found in the carpel?
- Stigma
- Style
- Ovary
- Ovule
Which organs are found in the stamen?
Anther and filament
What is the sepalβs function?
Protecting the flower bud
What is the petalβs function?
Attracting insects through nice colors
What does the anther contain?
Pollen sacs with pollen grains
What is the function of a stigma?
To be a platform for a pollen grain to land on
What is an ovary in plants?
A hollow chamber where ovules grow from walls
Define pollination
Transfer of pollen grains from the male part of the plant to the female part of the plant
What are the agents of pollination?
Insects, birds, mammals, water and wind
What are petals like in wind pollinated plants?
- Small or absent
- Not colorful
- Scentless
- No nectaries
What are petals like in insect pollinated plants?
- Large, as a landing platform
- Colorful
- Scented
- Have nectaries
What are pollen grains like in wind pollinated plants?
- Small, in large quantities
- Dry and dusty
- Smooth coated
- Light, easily carried by wind
What are pollen grains like in insect pollinated plants?
- Larger, heavier
- Sticky
- Rough coated
- In smaller quantities
What is the anther like in wind pollinated plants?
- Held outside flower in the wind
- Relatively large
What is the anther like in insect pollinated plants?
- Protected within flower, where insects touch them
- Relatively small
What are stigmas like in wind pollinated plants?
- Large surface area
- Outside flower
What are stigmas like in insect pollinated plants?
- Smaller surface area
- Inside flower
Define self pollination
The transfer of pollen grains from the anther of a flower 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
Why can self-pollination be disadvantageous?
It reduces genetic variety of the offspring as all the gametes come from the same parent.
If environmental conditions change, offspring are less likely to have adaptations that suit the new conditions well.
Why can cross-pollination be disadvantageous?
Cross-pollination relies completely on the presence of pollinators and this can be a problem if those pollinators are missing.
This doesnβt apply to wind-pollinated plants
When does fertilisation occur in a plant?
When a pollen nucleus fuses with a nucleus in an ovule
How does a pollen nucleus get to an ovule?
A pollen grain lands on stigma and creates a tunnel down the style, through the micropyle, to the ovules.
Define Germination
The start of growth of a seed
What factors are needed for germination?
- Water
- Oxygen
- Temperature
Why is water needed for germination?
Allows the seed to swell up so the testa splits, and allows enzymes to start working
Why is oxygen needed for germination?
It allows energy release from chemical reactions (respiration)
Why is warmth needed for germination?
It has to be a suitable temperature for enzymes to work
How might you prevent oxygen reaching a seed in a germination experiment?
By placing the seed in water and then having a layer of oil above
