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microspores or megaspores |
What are the products of meiosis in the life cycle of a seed plant? |
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mature ovary |
A fruit is most commonly a |
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within an ovule contained within an ovary of a flower |
Where in an angiosperm would you find a megasporangium? |
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human population growth |
What is the greatest threat to plant diversity? |
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angiosperms |
Human survival literally depends on the produce of |
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one embryo involving one sperm cell and an endosperm involving a second sperm cell. |
Angiosperm double fertilization is so-called because it features the formation of |
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modified sporophylls |
Carpels and stamens are |
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flowers |
Angiosperms are different from all other plants because only they have |
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presence or absence of a protective covering over the ovule |
The major difference between angiosperms and gymnosperms comes from the |
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4 → 2 → 3 → 1 |
Within a gymnosperm megasporangium, what is the correct sequence in which the following should appear during development, assuming that fertilization occurs? 1. sporophyte embryo 2. female gametophyte 3. egg cell 4. megaspore |
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have pollen |
Gymnosperms differ from both extinct and extant (living) ferns because they |
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protection for the embryo |
The seed coat’s most important function is to provide |
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seed |
consists of embryo and food supply surrounded by protective coat |
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all seed plants |
____ include reduced gametophytes, heterospory, ovules, and pollen |
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integument |
envelopes and protects megasporangium layer of sporophyte tissue |
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ovule |
a structure in the ovary of a seed plant that contains an embryo sac and that develops into a seed after fertilization megasporangium+megaspore+integuments |
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pollen grain |
In seed plants, a structure consisting of the male gametophyte enclosed within a pollen wall. |
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pollination |
the transfer of pollen from male reproductive structures to female reproductive structures in plants |
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gymnosperms vs. angiosperms |
gymno: reporduction takes place in cones- two types of cones…pollen- male pollen grains seed cones- female angio: flowering plants, flowers are reproductive organs, specialized leaves |
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progymnosperms |
a group of Devonian plants that were heterosporous but lacked seeds; Gymnosperms probably descended from this |
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conifers |
cone-bearing plants |
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Anthophyta |
all angiosperms are in Phylum |
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flower |
the reproductive structure of an angiosperm sepals petals stamens carpels |
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sepals |
green, leaflike part of the plower that covers and protects the flower bud before it opens |
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petals |
modified leaves which are usually bright in color to attract pollinators. |
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stamens |
The pollen-producing male reproductive organ of a flower, consisting of an anther and filament. |
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carpels |
The female reproductive organ of a flower, consisting of the stigma, style, and ovary. |
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fruit |
wall of tissue surrounding an angiosperm seed |
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cross pollination |
a reproductive process in which pollen from one plant is transferred to the stigma of another plant |
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micropyle |
in the ovules of seed plants, the opening in the integuments through which the pollen tube usually enters |
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cotyledon |
a seed leaf that stores food |
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monocots |
angiosperms that have only one seed leaf |
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dicots |
angiosperms that have two seed leaves |
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megasporangia |
where megaspores are produced from meiosis of megaspore mother cells |
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microsporangia |
where the microspores are produced from meiosis of microspore mother cells |
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pollen |
eliminates the need for a film of water and can be dispersed great distances by air or animals |
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evolutionary advantage of seeds |
They may remain dormant for days to years, until conditions are favorable for germination Seeds have a supply of stored food They may be transported long distances by wind or animals |
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Gymnosperms |
were better suited than nonvascular plants to drier conditions |
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Gymnosperm 4 phyla |
Cycadophyta (cycads) Gingkophyta (one living species: Ginkgo biloba) Gnetophyta (three genera: Gnetum, Ephedra, Welwitschia) Coniferophyta (conifers, such as pine, fir, and redwood) |
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Three key features of the gymnosperm life cycle |
Dominance of the sporophyte generation Development of seeds from fertilized ovules The transfer of sperm to ovules by pollen |
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two key adaptions of angiosperms |
Flowers Fruits |
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triploid endosperm |
after one sperm unites with the egg, the other two unite with polar nuclei, provides nutrtion to the embryo |
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Animals |
influence the evolution of plants and vice versa |
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bilateral |
Clades with ______ symmetrical flowers have more species than those with radially symmetrical flowers |
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