Chapter 38 Flashcards
Angiosperms and reproduction
Can reproduce sexually and asexually
Plant life cycles
Alternate between sporophyte and gametophyte generations
Angiosperm life cycle
Three Fs
flowers, double fertilization, and fruits
Complete flowers
Contain all four floral organs
Inflorescences
Clusters of flowers
Pollination
the transfer of pollen from an anther to a stigma
Pollen tube
Produced after landing on receptive stigma
grows deep into ovary and disperses 2 sperm cells
Fertilization
the fusion of gametes
What do the 2 sperm do?
- One fertilizes the egg
2. The other gives rise to the endosperm
Endosperm
stores food
3n
What does double fertilization guarantee?
Endosperm only develops in ovules containing fertilized eggs
After fertilization…
each ovule develops into a seed
the ovary develops into a fruit
Ways to transfer pollen
wind, water, animals
Coevolution
the joint evolution of interacting species in response to selection imposed by each other
many flowering plants have coevolved with specific pollinators
First mitotic division
Splits the zygote into a basal cell and a terminal cell
Basal cell
Produces a multicellular suspensor
Anchors the embryo to the parent plant
Terminal cell
Gives rise to most of the embryo
Seed coat
Protects the embryo and its food supply
Advantages of seed dormancy
Increases the chances that germination will occur at a time and place most advantageous for the seedling
Imbibition
the uptake of water due to low water potential of the dry seed
triggers germination
What emerges first?
the radicle
embryonic root
Fragmentation
the separation of a parent plant into parts that develop into whole plants
asexual reproduction
Apomixis
the asexual production of seeds from a diploid cell
Vegetative reproduction
another name for asexual reproduction