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 Posted: Sat Dec 01, 2007 4:27 pm
List and be able to distinguish between the groups of the nontracheophytes and seedless tracheophytes:
Nontracheophytes - no developed vascular system, Consist of the liverworts, hornworts, and mosses. They lack leaves, stems, and roots.
Seedless Tracheophytes - Vascular system (tracheids), Have branching, independent sporophyte.
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Posted: Sat Dec 01, 2007 5:11 pm
Describe the general structure of the sporophyte and gametophyte stages of nontracheophytes and seedless tracheophytes. Which stage is dominant for each group (diploid or haploid)?
Nontracheophytes: Gametophyte stage is dominant (Haploid)
Seedless Tracheophytes: Sporophyte stage is dominant. (Diploid)
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Posted: Sat Dec 01, 2007 7:26 pm
How do the sporophyte and gametophyte relate to each other in each major plant group? What trend is observed? Why does this trend occur—what’s the point?
The Sporophyte produces the spores that produce the gametophyte which produces the gametes the unite to form the sporophyte. Gah, I can't think of any trend D:
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Posted: Sat Dec 01, 2007 7:40 pm
Why do most nontraceophytes grow close to the ground?
Because they lack the support structure to grow higher, and they need to grow in moisture-filled environments.
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Posted: Sat Dec 01, 2007 7:52 pm
What are the advantages (pros) and disadvantages (cons) to life on land?
Pros:
Increased Light
Increased Gas
Much Less Competition
Cons:
Increased Gravity
Decreased Water
Temp Variation
Reproduction Air vs. Water
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Posted: Sat Dec 01, 2007 8:51 pm
What adaptations have allowed plants to diversify on land? How do these adaptations relate to the pros and cons of life on land?
To Manage and Prevent Water Loss:
The cuticle-waxy coating on leaves
Stomata- Guard Cells and Pores
Collection of Water:
Roots via Osmosis facilitated by aquaporins
Collection of Minerals:
Roots via membrane transport proteins
Managing Gravity:
Tracheids - Lignin in Cell Walls
Managing Temperature:
-Transpiration, CAM, heat shock proteins, and reflection in hot climates.
-Dormant, anti-freeze proteins, increase unsaturated fatty acids in membranes in cool/cold climates.
Managing Reproduction:
Land plants are embryophytes - multicellular embryophytes are retained within the tissue of the maternal parent.
Spores: airborne, resistant to drying, encased in sporopollenin
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Posted: Sat Dec 01, 2007 9:09 pm
Distinguish between heterosporous and homosporous life cycles.
Homosporous - one spore
Gametophyte -> Either Archegonium (Eggs) or Antheridium (Sperm)
Heterosporous - more than one spore
Sporophyte -> Either (Megasporangium -> Spore Mother -> Megaspore -> Megagametophyte -> Eggs) or (Microsporangium -> Spore (Father) -> Microspore -> Microgametophyte -> Sperm)
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Posted: Sat Dec 01, 2007 10:51 pm
What is a seed? How many generations contribute to its tissues? Describe each tissue in detail including its origin and function.
A seed is the protecting envelope of a developing embryo. 3 generations contribute to its tissues.
1. Seed coat called integument from diploid sporophyte parent.
2. Nutrient content is derived from haploid gametophyte retained in megasporangium.
3. Developing Sporophyte embryo after fertilization.
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Posted: Sun Dec 02, 2007 3:26 pm
In general, what characteristics place an organism within the kingdom fungi vs. plantae (i.e. if you were trying to identify an organism, what characteristics would convince you that it was a fungus or plant)?
Fungi - Have cell wall made of chitin, have a mass of hyphae called mycelium.
Hyphae has 2 different cell structures: septate and coenocytic. They are heterotrophic.
Plants - Have a cell wall made of cellulose. Have chloroplasts, and have pigements, usually chlorophyll mainly. Are Autotrophic.
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Posted: Sun Dec 02, 2007 5:40 pm
What structures are used to determine fungal phylogeny? Describe them in detail for each group.
1. Chytridiomycota - Aquatic, gametes have flagella
2. Zygomycota - Zygosporangium, no regularly occurring septa, usually no fleshy fruiting body.
3. Ascomycota - Ascus, perforated septa
4. Basidiomycota - Basidium, perforated septa
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Posted: Sun Dec 02, 2007 5:43 pm
What is the major difference between the fungal and plant cell walls?
Fungual cell wells - chitin
Plant cell walls - cellulose
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Posted: Sun Dec 02, 2007 6:01 pm
Describe the bodies of both single-celled and multicelled fungi. Understand structure and function of each part.
Multicellular fungi - Have Hyphae (septate or coenocytic). Body is mycelium. Pores in septa allow organelles, sometimes even nuclei, to move in a controlled way between cells. Certain modified hyphae called rhizoids, anchor chytrids and some other fungi to substratum. Some mycelium reorganizes into fruiting structures (mushroom). Some hyphae produce haustoria, branching projections that push into living cells.
Unicellular fungi - yeasts
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Posted: Sun Dec 02, 2007 6:15 pm
Why are Fungi uniquely suited for absorptive nutrition?
Because they have the structures that absorb nutrients, and many can grow on artificial media.
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Posted: Sun Dec 02, 2007 6:29 pm
What is a dikaryon? Heterokaryon? Describe this process. Is the hypha haploid or diploid? Distinguish between the four main groups of fungi.
A Dirkaryon is a cell with two nuclei. Heterokaryon is a cell with many nuclei. A cell is dikaryon before fertilization happens, and then it becomes diploid. The hypha can be haploid and then dikaryotic. Chytrids have no dikaryon stage. Basidiomycotes have 2 dikaryon stages.
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Posted: Sun Dec 02, 2007 6:39 pm
Why do Fungi develop a dikaryote stage—what’s the point?
They develop a dikaryote stage so they can choose when they want to reproduce.
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