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22 Cards in this Set
- Front
- Back
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What are the most recent group to appear in the evolution of the tracheophytes?
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The seed plants which include:
- Gymnosperms (pines and cycads) - Angiosperms (flowering plants) |
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The seed plants are HETEROSPOROUS, meaning…
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Have separate FEMALE megasporangia and MALE microsporangia
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Tell me about microsporangia…
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- Develop into MALE gametophytes called pollen grains
- The micro-gametophytes are wind-distributed |
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What may a seed contain?
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Tissues from three generations
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What does Gymnosperm mean and which phyla are included in this group?
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Gymnosperm = “naked seed”
- Phylum Cycadophyta (palm-like) - Phylum Ginkgophyta (fan-shaped leaves) - Phylum Gnetophyta (2 split leaves) - Phylum Pinophyta (conifers) |
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Tell me about Gymnosperms and secondary growth…
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- All gymnosperms exhibit secondary growth
- Wood = secondary xylem |
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Tell me about the phylum Pinophyta…
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- aka. Conifers or cone-bearers
- Include: Fir, Cedar, Spruce, and Pine |
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What is a cone?
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A modified stem bearing a tight cluster of scales specialized for reproduction
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What does Angiosperm mean and how many plants does the phylum Angiospermae consist of?
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- Angiosperm means “enclosed seed”
- Consists of over 257,000 species of flowering plants |
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How do the angiosperms represent the extreme of an evolutionary trend in the tracheophytes?
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The sporophyte generation becomes larger and more independent of the gametophyte, while the gametophyte becomes smaller and more dependent on the sporophyte
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What traits characterize the angiosperms?
(7) |
- Double fertilization
- Produce triploid endosperm - Their ovules and seeds are enclosed in a carpel - Have flowers - Produce fruit - Their xylem contains vessel elements and fibers - Their phloem contains companion cells |
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How does double fertilization work? (4 steps)
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- Two male gametes participate in fertilization events within the megagametophyte
- One sperm combines with the egg to produce a diploid zygote - The other sperm combines with two other haploid nuclei of the female gametophyte to form a triploid nucleus - This gives rise to the endosperm, triploid tissue that nourishes the embryonic sporophyte during its early development |
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What is a carpel?
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A modified leaf that encloses the ovules and seeds of the angiosperms
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What is a stamen?
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A modified leaf composed of a filament that bears an anther containing the pollen-producing microsporangia
(MALE) |
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What is a pistil?
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- A modified leaf composed of one carpel or two or more fused carpels
- It has a swollen base called the ovary that contains the megasporangia (FEMALE) |
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When referring to a pistil, what is the style and what is the stigma?
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Style = the apical stalk of the pistil
Stigma = the terminal surface that receives pollen grains |
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What is the difference between perfect and imperfect flowers?
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- Perfect flowers have both microsporangia and megasporangia
- Imperfect flowers have either functional megasporangia or microsporangia, but not both |
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What is the difference between monoecious and dioecious species?
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- Monoecious = both male and female parts on one plant
- Dioecious = plant is either male or female |
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What is a flower?
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The reproductive organ of an angiosperm
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Angiosperms are heterosporous. Tell me about their ovules and embryos…
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- Ovules are contained within carpels, rather than being exposed on the scales as in gymnosperms
- Ovule develops into a seed containing the products of double fertilization, a diploid zygote and a triploid endosperm - Embryo consists of an embryonic axis and one or two cotyledons, or seed leaves. The cotyledons may digest the endosperm, and later expand and become photosynthetic |
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What happens to the ovary of a flowering plant after fertilization?
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Develops into a fruit
- Simple (ex. cherry) - Aggregate (ex. raspberry) - Multiple (ex. pineapple) - Accessory (ex. strawberry) |
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What is the difference between monocots and eudicots?
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Monocots = have a single embryonic cotyledon (ex. grasses, cattails, lilies, orchids, and palms)
Eudicots = have two cotyledons (ex. most herbs, vine trees, and shrubs) |
