Lesson 3: Plant reproduction Flashcards
What are the reproductive parts of flowering plants?
Flowers are the reproductive parts of whole flowering plants.
What are the four main layers of a flower and their brief functions?
Petals (attract pollinators), sepals (protect bud), stamens (male), pistils (female).
What are the parts of the stamen and their functions?
Filament (stalk) and anther (produces pollen grains).
What are the components of a pollen grain and their functions/structure?
Generative cell (makes sperm), tube cell (forms pollen tube), exine (tough outer layer), intine (inner cellulose layer).
What are the parts of a pistil and their functions?
Stigma (pollen lands), style (connects stigma to ovary), ovary (contains ovules).
What is pollination and methods?
Transfer of pollen from stamen to pistil, can be via wind, insects, animals, or water.
What happens during fertilization in plants?
One sperm fuses with the egg (zygote), another fuses with central cell to form endosperm.
Name adaptations of insect-pollinated flowers.
Nectar production, scent, bright colors, sticky/heavy pollen, pollinator specificity.
What are features of wind-pollinated flowers?
Light pollen and feathery stigma for effective dispersal.
What are the advantages of cross-pollination?
Increased genetic diversity and evolutionary success.
What are some mechanisms promoting cross-pollination?
Dioecious plants, temporal and physical separation, and self-incompatibility.
What happens after fertilization?
Flower parts dry, ovule becomes seed, ovary becomes fruit, seed is dispersed.
What are methods of seed dispersal?
Wind, water, animals, and explosions.
What is temporal separation?
Male and female parts mature at different times.
What is self-incompatibility?
Pollen fails to germinate if it shares the same allele as the stigma.
What is physical separation?
Differences in stamen and style length reduce contact between pollen and stigma in the same flower.
What’s the difference between monoecious, dioecious, and bisexual plants?
Monoecious: Male and female flowers are separate but on the same plant (e.g. corn).
Dioecious: Male and female flowers are on different plants (e.g. holly).
Bisexual (hermaphroditic): Each flower has both male (stamens) and female (pistils) parts.
Fertilisation stages for plants.
A pollen tube grows from the pollen grain down the style to the ovary after pollination.
Two male nuclei travel down the pollen tube; one fuses with an egg to form a diploid zygote, and the other forms the endosperm.
