Reproduction in flowering plants Flashcards
(40 cards)
Define reproduction:
Reproduction is the biological process by which a new individual is produced from an already existing individual.
What is essential for the survival and evolution of a species?
Genes being transferred to the next generation are essential for the survival and evolution of a species.
What’s the difference between Asexual & sexual reproduction in plants?
- Asexual reproduction:
-one parent
-offspring has same genetic material
-no gametes
-“clones”
-mitosis - Sexual reproduction:
-two parents
-mix of genetic material
-gametes
-meiosis
-fertilization -> zygote
List the different types of Asexual reproduction:
-
Binary Fission
-a single parent cell divides into two daughter cells. -
Spore Formation
-reproduces using spores -
Regeneration
-organism’s body breaks up into one or several parts. -
Budding
-parent cell produces bud, breaks away and forms new individual. - Fragmentation
- Vegetative Reproduction
- Grafting
What are the pros of asexual reproduction?
-Lots of offspring in favourable conditions
-No energy, no gametes
-Offspring same as parent -> well suited to environment.
-No need to find a mate or pollinator.
What are the cons of asexual reproduction?
-No genetic variation, adaptation is difficult.
-Shared weak characteristics -> decreased survival.
-Can lead to overpopulation.
What are the pros of sexual reproduction?
-Genetic variation -> more adaptable
-Basis of evolution.
-“Reshuffling” of genes, lower chances of inheriting harmful genes.
What are the cons of sexual reproduction?
-Process is slower.
-Fewer offspring.
-High energy cost (flowers)
-Negative mutations can appear.
-Need agents (wind/insects)
What are flowers?
- Organs of sexual reproduction.
-Contain reproductive organs and attract pollinators.
What happens during pollination?
-The anther matures, splits open, and discharges the pollen.
-The pollen is carried to stigma by various agents.
What are some agents of pollination?
Biotic:
-insects
-birds
-mammals
Abiotic:
-water
-wind
What are two different types of pollen transfer?
-Self-pollination.
-Cross-pollination.
What are two different types of self-pollination?
-Type 1 = within the same flower.
-Type 2 = occurs between two flowers of the same plant.
Why would plants avoid self-pollination?
It doesn’t create much genetic variation in offspring.
Is self-pollination considered cloning/asexual reproduction?
No, self-pollination results in offspring with different gametes to parent cells.
-Cloning has identical DNA to parent cell.
How do plants avoid self-pollination?
Some plants have both male & female organs, so have developed strategies to avoid self-pollination.
- Timing -> male & female parts mature at different times.
- Morphological -> structure of male & female organs prevent it.
- Biochemical -> chemicals on surface of pollen & stigma that prevents pollen tube germination.
What is germination?
Germination is when seeds absorb water.
Define cross-pollination:
Pollen is transferred from the anther of a flower of one plant to the stigma of a flower of another plant -> same species.
What does cross-pollination allow for?
cross-pollination allows for genetic variation.
What’s the difference between pollination & fertilization?
Pollination is the pollen transfer from anther from one flower to the stigma of another.
VS
Fertilization is the joining of a sperm and egg in the ovule to form a zygote -> occurs after pollination
What is double fertilization?
When two sperm are released from pollen tube into the ovule.
- One sperm fertilizes the ovum -> zygote
-Another sperm fuses with the two nuclei in the ovule
-> food source for ovule.
-Zygote develops -> dormant phase.
What does a fertilized ovule become?
The fertilized ovule becomes the seed, which encloses and protects the embryo and endosperm.
What is the testa?
The testa aka the seed coat
- It is hardened tissue around the ovule.
What does the embryo become?
the embryo becomes a cotyledon, which stores nutrients and water.
