Ch 38 Pollination and Reproduction Flashcards
Angiosperms
Flowering seed plants
Flower
A specialized shoot modified for sexual reproduction
Pollination
The transfer of pollen from an anther to a stigma
How can angiosperms be pollinated?
Via wind, water, or animals
How much pollen do wind-pollinated species release?
Large amounts
How are most gymnosperms pollinated?
By wind
What percentage of angiosperms are wind pollinated?
20%
How are most angiosperms pollinated?
By animals
Coevolution
The evolution of interacting species in responses to changes in each other
Man flowering plants coevolve with what?
Specific pollinators
What do the shape and size of a flower often correspond with?
The pollen transporting parts of their animal pollinators
Double fertilization
Results from the discharge of two sperm from the pollen tube into the embryo sac
During double fertilization, what occurs to each sperm?
One sperm fertilizes the egg
One sperm combine with the polar nuclei
What gives rise to the endosperm?
When a sperm combines with the polar nuclei during double fertilization
Endosperm (3n)
Triploid
Food-storing
What occurs in a plant after double fertilization?
Each ovule grows into a seed
What does the ovary develop into?
A fruit
Fruit
Encloses the seed(s)
Dormancy
A state where the seed’s water content is reduced to about 5% to 15%
What is the benefit of seed dormancy?
It increases the chances that germination will occur at a time and place most advantageous to the seedling
Germination depends on what?
The uptake of water
Radicle
Embryonic root
What is the first part of the plant to emerge from the seed?
The radicle
Does self-fertilization produce genetic variation in offspring?
Yes, but not as much as mating with another individual
What is possessed by many angiosperms?
Mechanisms to prevent self-fetilzation
Dioecious
Have stiminate (male) and carpellate (female) flowers on separate plants
Adventitious shoots
Originate from the parent plant’s root system and become separate shoot system
Asexual reproduction
Apomixis
The asexual production of seeds (no pollination)
Asexual reproduction
Benefit of asexual reproduction
It results in rapid production of genetically identical offspring
Cons of asexual reproduciton
Offspring are vulnerable to local extinction if there is environmental change
What is a common form of asexual reproduction in agriculture?
Cuttings
Callus
A mass of dividing undifferentiated cells that form where a stem is cut and produces adventitious roots
