Labs 1-3 Flashcards
1
Q
What two means of dispersal have plants evolved?
A
Plants have evolved two means of dispersal: spores or seeds
2
Q
How do the seedless plants disperse?
A
- They disperse as spores
- The seedless plants include the bryophytes (liverworts, hornworts, mosses), the lycophytes (club mosses, quillworts Selagineslla), Psilotum, horsetails, and ferns
3
Q
What are spores?
A
Spores are thick-walled single cells that are typically wind dispersed
4
Q
How do the seed plants disperse?
A
- they disperse as seeds
- each seed includes an embryonic plant supplied with stored food
- the seeds are dispersed by various means, depending on the design of the seed
5
Q
What is in a seed?
A
- each seed includes an embryonic plant supplied with stored food
- the seeds are dispersed by various means, depending on the design of the seed
6
Q
Gymnosperms
A
- the naked-seeded plants that include the conifers, ginkgo, cycads, and several others
- “gymnos” =naked
- “sperma” =seed
- the seed is naked because the ovule from which it developed was naked (not enclosed in tissue)
7
Q
Angiosperms
A
- the flowering plants
- seed is enclosed because the ovule from which it developed was enclosed within the ovary of the flower’s pistil
- (Greek: angeion = container; the seeds are contained, enclosed within a fruit, although at maturity the fruit may split open to release the seeds)
8
Q
Ovules
A
- produced by all seed plants
- develop into seeds after fertilization
- the structure contained within the ovary that gives rise to the female gametophyte and, when fertilized and mature, a seed
- embedded within the tissue of each ovule is an egg cell; the egg cell is located near a tiny opening in the ovule called the micropyle (Greek: mikros = small; pyle = gate)
- Pine: ovules on the scales of young female cone
- Flower: ovules within the ovary
9
Q
What do all seed plants produce?
A
Ovules and pollen
10
Q
Pollen
A
- Pine: produced by separate male cones
- Flower: produced by anthers
- pollen grains contain sperm cells, after a sperm fertilizes the egg cel in an ovule, the ovule matures into a seed
- (Latin: pollen= fine flour)
11
Q
What are the parts of a seed?
A
- Seed coat
- embryo
- nutritive tissue
12
Q
Seed coat
A
- a protective covering that developed from the outer layers of the ovule and is thus material from the mother plant
- the seed coat may have structural modifications to assist in seed dispersal; for example, many pines produce “winged” seeds, the wing being a dry extension of the seed coat that aids in gliding through the air
13
Q
Embryo
A
- the offspring plant that developed from the fertilized egg
- attached to the embryo are one or more fleshy, nutrient-rich structures called cotyledons
14
Q
Cotyledons
A
- fleshy, nutrient-rich structures
- attached to the embryo are one or more of these
- gymnosperms tend to have several cotyledons per embryo
15
Q
What two groups are angiosperms divided into?
A
- Monocotyledons or monocots (one cotyledon per embryo)
- and dicotyledons or dicots (two cotyledons per embryo)
