Seed Plant Characteristics
What are the two alternating generations in the plant life cycle?
Gametophyte (haploid) and sporophyte (diploid)
What structure develops from a microspore?
Pollen grain
What are the three main components of an ovule?
Integuments, megasporangium, and megaspore
What does “gymnosperm” literally mean?
Naked seed
Are gymnosperms homosporous or heterosporous?
Heterosporous
What adaptation allowed plants to reproduce without water?
Seeds and pollen
What does the pollen grain contain?
The male gametophyte
What is the ploidy (N/2N) of the seed coat, embryo, and food source in gymnosperms?
Seed coat = 2N, Embryo = 2N, Food = N
Which group has one extant species?
Ginkgophyta
How long after pollination does fertilization occur in most conifers? (Immediately/over a long period?)
What are the five key characteristics of seed plants? (name 3)
Reduced gametophyte, heterospory, pollen, ovules, seeds
How do gymnosperms typically disperse pollen?
Wind
What does an ovule become after fertilization?
Seed
Name two examples of gymnosperm reproductive structures.
Pollen cones (male) and ovulate cones (female)
Why are conifers well adapted to cold, dry habitats?
Needle-like leaves and snow-shedding shape reduce water loss
In seed plants, which generation is dominant?
Sporophyte
What two nuclei are found in pollen, and what do they do?
Tube nucleus (forms pollen tube) and generative nucleus (forms two sperm)
What are two ecological advantages of seeds over spores?
Protection from harsh conditions and ability to remain dormant
Angiosperms: What is the difference between a seed and a fruit?
A seed is a mature ovule; a fruit is a mature ovary containing one or more seeds.
What is a serotinous cone?
A cone that opens and releases seeds after fire
Why are gametophytes so reduced in seed plants?
So they can be protected and nourished by the sporophyte- prevents desiccation and damage
What’s the difference between pollination and fertilization?
Pollination is when pollen lands on an ovule-bearing structure
Fertilization is when sperm and egg unite
Why are gymnosperm seeds sometimes called “naked”?
They aren’t enclosed in an ovary, no fruit surrounds them
How do flowers increase reproductive success in angiosperms?
They attract specific pollinators, increasing the likelihood that pollen reaches a compatible flower of the same species
How did seeds change plant evolution and ecosystems?
They allowed plants to spread into dry habitats, survive harsh conditions, and outcompete spore-bearing plants