Unit3-3 Flashcards
(18 cards)
What are seed plants?
Seed plants are vascular plants that reproduce via seeds, which protect and nourish the embryo. They include gymnosperms (like conifers) and angiosperms (flowering plants).
What are the key features of seed plants?
Key features include seeds for reproductive success, a vascular system, and specialized structures like cones in gymnosperms and flowers in angiosperms.
What is the evolutionary significance of seed plants?
Seed plants have become dominant on land due to their ability to survive harsh conditions, protect embryos, and disperse seeds effectively, offering advantages over spore-producing plants.
How do seed plants reproduce?
Seed plants reproduce sexually through the production of seeds. The male gametophyte (pollen) fertilizes the female gametophyte, leading to the formation of seeds.
What is the role of the seed coat?
The seed coat protects the embryo from environmental stresses, such as desiccation and damage. It is derived from the integument, a tissue layer surrounding the ovule.
What are the two types of gametophytes in seed plants?
The male gametophyte is the pollen grain, while the female gametophyte develops within the ovule and produces the egg.
What are the five phyla of seed plants?
The five phyla are:
- Coniferophyta (conifers)
- Cycadophyta (cycads)
- Gnetophyta (gnetophytes)
- Ginkgophyta (Ginkgo)
- Anthophyta (angiosperms)
What are conifers?
Conifers are gymnosperms like pines, spruces, and firs. They have needle-like leaves, produce cones, and are adapted to cold, dry environments.
How do conifers reproduce?
Conifers reproduce via cones, with male cones producing pollen and female cones containing ovules. Pollen reaches the ovule through a pollen tube, and fertilization occurs.
What are cycads?
Cycads are tropical and subtropical gymnosperms that resemble palm trees. They have flagellated sperm and produce large cones.
What are gnetophytes?
Gnetophytes are a diverse group of gymnosperms that include species like Ephedra and Welwitschia, which have vessel elements in their vascular tissue, making them unique among gymnosperms.
What is Ginkgo?
Ginkgo is a unique gymnosperm with fan-shaped leaves and flagellated sperm. It is dioecious, with male and female reproductive organs on separate trees.
What are angiosperms?
Angiosperms are flowering plants that produce seeds enclosed within a fruit. They have unique features like flowers, insect pollination, and broad leaves with thick veins.
What is the role of flowers in angiosperms?
Flowers are the reproductive structures of angiosperms, containing both male (stamens) and female (carpels) gametophytes. They facilitate pollination and fertilization.
How do fruits develop in angiosperms?
Fruits develop from the ovary of a flower after fertilization. The ovary wall thickens to form the pericarp, which surrounds and protects the seed.
What is seed dispersal?
Seed dispersal is the process by which seeds are transported away from the parent plant. This can occur via wind, water, or animals, facilitating the colonization of new areas.
How do seeds survive harsh conditions?
Seeds can remain dormant for extended periods, protecting the embryo and conserving resources. They require specific conditions, such as water and oxygen, to begin germination.
What is germination?
Germination is the process by which a seed begins to grow into a new plant, triggered by the right environmental conditions like moisture, temperature, and oxygen.
