BI111 Study Guide - Vascular Plant, Gametophyte, Sporophyte

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Published on 20 Apr 2013
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WLU
Department
Biology
Course
BI111
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Chapter 24 13-03-03 1:59 PM
alternation of generations: the regular alternation of mode of
reproduction in the life cycle of an organism, such as the alternation
between diploid (sporophyte) and haploid (gametophyte) phases in plants.
Sporophyte: an individual of the diploid generation produced through
fertilization in organisms that undergo alternations of generations; it
produces haploid spores.
Gametophyte: an individual of the haploid generation produced when a
spore germinates and grows directly by mitotic divisions in organisms that
under go alternation of generations.
Poikilohydric: having little control over internal water content. P 550
Xylem: the plant vascular tissue that distributes water and nutrients.
Phloem: the food conducting tissue of a vascular plant.
Ovule: in plants, the structure in a carpel in which female gametophyte
develops and fertilization takes place.
Seed: the structure that forms when an ovule matures after a pollen grain
reaches it and a sperm fertilizes the egg
Coevolution: the evolution of genetically based, reciprocal adaptations in
two or more species that interact closely in the same ecological setting
List the defining characteristics of land plants, and how these
characteristics are different from those found in other eukaryotic
groups
They are eukaryotes
Almost all are photoautotrophs
Multicellular
Have cell walls
All are sessile (stationary)
No terrestrial animals are sessile, but some aquatic ones are
Has a very different life cycle than animals (alternation of generations)
Explain the basic pattern of the plant life cycle, and the steps
involved (see Fig 24.1)
1. meiosis produces spores (plant produces haploid seed)
2. spores germinate, it divides by mitosis to produce multicellular haploid
gametophyte (baby haploid plant)
3. gametophytes give rise to haploid gametes (baby plant makes ovule and
sperm)
4. fertilization of gametes occurs
5. a zygote is produced and develops the plant into a “sporophyte” and the
zygote produces seeds.
7. produces spores through meiosis.
Explain the evidence in support of the hypothesis that land plants
and charophytes share a common ancestor
the first “believed” ancestor of the modern plant is algae: these algae were
charyophytes…
Both groups have cellulose cell walls
They store energy as starch
And light absorbing pigments include both chlorophyll a and b
List the variety of opportunities and challenges faced by the aquatic
plant ancestors as they attempted to colonize land.
Challenge:
how to survive in dry conditions… did not have water proof cuticle or tissues
strong enough for growing upright.> they were limited to moist
environments and had to stay close to the ground.. they were poikilohydric.
Evolved to vascular plants which were able to control their water an avoid
drying out (cuticle, stomata, pores)
The tissues of the plant were not strong enough to grow upright.
Growing up-right is more beneficial in capturing light… became a competition
for light
Plants developed specialized water conducting cells .. transport water
through the plant body
Changes in earths atmosphere … changed certain biochemical pathways in
plants…they were able to synthesize lignin(the molecules that absorb UV)
List and explain (in broad terms) the adaptive nature of derived
traits that facilitated the success of plants on land
Cuticle>> protection against water loss and pathenogens
Stomata>> regulation of water loss and gas exchange
Vascular xylem and phloem>> internal tubes that transport water and
nutrients
Lignin>>mechanical support for vertical growth
Apical meristem>> branching root system
Roots, stems, leaves>> enhanced uptake, transport of nutrients and
enhanced photosysnthesis
Diploid phase dominant>> genetic diversity
Heterospory>> genetic variation
Nonmotile sperm>>protection of gametes within parent body
Seed>> protection of embryo.
Bryophytes: nonvascular plants. Gametophyte dominant, free water
required for fertilization, cuticle and stomata present in some
Seedless vascular plants: sporophyte dominant, free water required for
fertilization, cuticle and stomata present
Gymnosperms: vascular plants with ‘naked’ seeds. Sporophyte dominant,
fertilization by pollination, cuticle and stomata
Angiosperms: plants with flowers and seeds protected inside fruits.
Sporophyte dominant, fertilization by pollination, cuticle and stomata
present. Major groups: monocots, eudicots.

Document Summary

13-03-03 1:59 pm alternation of generations: the regular alternation of mode of reproduction in the life cycle of an organism, such as the alternation between diploid (sporophyte) and haploid (gametophyte) phases in plants. Sporophyte: an individual of the diploid generation produced through fertilization in organisms that undergo alternations of generations; it produces haploid spores. Gametophyte: an individual of the haploid generation produced when a spore germinates and grows directly by mitotic divisions in organisms that under go alternation of generations. Poikilohydric: having little control over internal water content. Xylem: the plant vascular tissue that distributes water and nutrients. Phloem: the food conducting tissue of a vascular plant. Ovule: in plants, the structure in a carpel in which female gametophyte develops and fertilization takes place. Seed: the structure that forms when an ovule matures after a pollen grain reaches it and a sperm fertilizes the egg.