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All the cells in a _______ are diploid; all the cells in a _______ are haploid.
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The sporophyte generation begins with a ______ and ends with a ______; the gametophyte genation begins with a _____ and ends with a _______.
- zygote; spore
- spore; gamete
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Fertilization triggers the transition from ______ to ______ generation; meiosis triggers the transition from _______ to ______ generation.
- gametophyte; sporophyte
- sporophyte; gametophyte
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mitosis
- primary function: growth, repair & development
- two "daughter" nuclei produced
- daughter nucleus have the same number of chromosomes as parent nucleus
- daughter nuclei is genetically identical to original cell
- daughter nuclei are genetically identical to each other
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Meiosis
- Primary function: makes spores in plants; gametes in animals
- Four "daughter" nuclei produced
- Half the number of chromosome found in the parent nucleus are in each daughter nucleus
- Daughter nuclei are not genentically identical to original cell and are not genetically identical to each other
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Haploid
Having half the number of chromosomes found in the diploid spore mother cell.
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Meiosis in animals
Only occurs in the gonads -- the diploid ovary and testes that produce haploid eggs and sperm
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Both meiosis and mitosis are usually followed by ______.
cytokinesis
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Cytokinesis
the division of the cytoplasm
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Zygote
the offspring that is produced when a haploid egg and sperm fuse.
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Major evolutionary trends
- reduction in the size of the gametophyte
- complex vascular systems
- heterospory
- the seed
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heterospory
Primitive vascular plants produce only one type of spore in one kind of sporangium
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peat
water-soaked, slightly rotted plant debris
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petrified
impregnated with minerals from teh swamp waters
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coal balls
petrified lumps of fossil peat
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Which half of the life cycle is dominant, the gametophyte or the sporophyte?
The sporophyte, except for in moss, gametophyte is dominant in moss
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How do the sperm in non-flowering plants get to the egg?
The flagella helps it swim
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In non-flowering plants, what is the primary mode of dispersal?
By spores, "naked seeds (inside cones)
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The green portion of the moss is the ______.
gametophyte
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why do mosses usually grow only in moist, shady habitats?
They need water/moisture for sperm to travel to femal gametangia.
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Which generation is independent (capable of photosynthesis) in mosses and which one is "dependent" on the other for nutrition?
gametophyte is independent and provides nutrition for dependent sporophyte generation
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why don't all the gametophytes have a sporophyte growing from their tops? Are those without sporophytes the "male" gametophytes?
some gamtetophytes are males and others are female and the sporophyte can only grow from the female
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what is the primary mode of dispersal in mosses?
water
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how do the gametophytes produce haploid gametes without meiosis?
exponlixis: a sexual reproduction, deregulation of meiosis resulting in mitotic cell division
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fronds
large, leathery leaves normally found on ferns
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Sporophytes on mosses
brownish, hair-like structures growing out of the top of some of the gametophytes
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Mosses are ______ that lack _______: they have no true stems.
bryophytes; vascular tissues
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rhizome
underground, creeping stem that roots grow off of
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sori
clusters of (spore producing) sporangia, found on the underside of the fronds
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sporangia
part of the sporophyte, along with the fronds, the roots, and the rhizomes
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in what sense can ferns be considered "intermediate" between bryophytes and higher plants?
- like bryophytes, ferns produce sexually by making spores rather than seeds
- like higher plants, ferns have stems with vascular tissue
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what is the primary method of dispersal in ferns?
wind an water, especially wind
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how is water transported in ferns?
ferns are vascular plants with vascular tissue that allow active water transport
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why are ferns most common in moist habitats?
they need water to reproduce
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"naked" seeds
not protected inside a fruit
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conifers
cone-bearing plants
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angiosperms
plants with flowers in which sexual reproduction occurs, in which seeds are formed, and from which fruits develop
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peduncle
stalk of a solitary flower
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receptacle
bears sepals and petals
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sepals (collectively: calyx)
usually green; protects bud
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petals (collectively: corolla)
often pigmented to attract pollinators
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stamens
filament:
anther:
- male flower organ
- stalk supporting anther
- produces pollen
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carpel
stigma:
style:
ovary:
- female organ
- often "sticky" to receive pollen
- stalk supporting stigma
- enlarged base that ripens into fruit; contains one or more "ovules" (potential seeds)
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how are microspores formed?
Each microspore mother cell divides by meiosis to produce four haploid microspores
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are microspores haploid or diploid?
microspore mother cells are diploid, microspores are haploid
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The ovary and egg formation
- 1. diploid megaspore mother cell undergoes meiosis and produces 4 haploid megaspores
- 2. three haploid megaspores die, one haploid megaspore left
- 3. single haploid megaspore undergoes mitosis producing 2 identical haploid nuclei
- 4. 2 identical nuclei undergo mitosis and form 4 identical haploid nuclei
- 5. 4 identical haploid nuclei undergo mitosis and form 8 identical haploid nuclei in mature ovule
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what is the difference between pollination and fertilization?
in pollination, pollen is transferred in plants enabling sexual reproduction. in fertilization, fusion of gametes produce a new organism
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