Phylum Bryophyta

Review Last Class
­ Characteristics of plants
­ Vascular vs. Non­vascular plants
Jan 10­4:58 PM
Bryophytes (Phylum Bryophyta)
­ Non­vascular land plants which are often small and low growing (short). Examples: moss, liverwort, hornwort. (figure 6.6 page 170)
­ Reproduce through alternation of generations. (figure 6.7, page 170)
­ The dominant life stage for these non­vascular plants is the gametophyte.
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Alternation of Generations
­ as mentioned in the previous section the life cycle of plants consists of two generations which alternate between a haploid and a diploid stage
­
the diploid phase is the sporophyte generation and the haploid phase is the gametophyte generation
­ mosses live the majority of their life in the gametophyte generation ­ an example of this is the moss life cycle of page 170 and the fern life cycle on page 173
Jan 10­10:52 PM
Characteristics of Bryophytes
(1) Lack specialized tissue that transports water. These plants require moist environments or they will dry out.
(2) Have no true roots, stems or leaves and are most often anchored to the ground by structures called Rhizoids.
(3) Require water for sexual reproduction. Sperm must swim through water in order to reach the egg.
(4) Live most of their life in gametophyte generation
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Tracheophytes
­ true terrestrial plants
­ examples include ferns, herbs, trees, and flowering plants.
­ vascular plants with vascular tissue.
­ in seedless tracheophytes reproduction occurs through alternation of generation (the sporophyte generation is dominant).
­ some tracheophytes are spore producing plants such as ferns and club mosses, thus using alternation of generation. ­ most are seed producing and use a form of alternation of generation.
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Fern Life Cycle ﴾Spore Producing﴿ pg. 173 ﴾text﴿
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Fern Life Cycle ﴾Spore Producing﴿ pg. 173 ﴾text﴿
Fern Life Cycle ﴾within phylum Tracheophyta﴿
VIDEO
Jan 10­4:59 PM
Characteristics of Tracheophytes
(1) They are vascular plants having specialized conducting tissue: xylem (water) and phloem (food).
(2) Means of reproduction
­ spores (require water)
­ seeds
(3) Dominant phase is the sporophyte generation.
(4) Water is not essential for reproduction in most cases. Plants thus have greater adaptability and less dependence on a wet environment.
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Classification of Tracheophytes
­ Tracheophytes can be classed into three main groups
1. Ferns and fern allies
2. Gymnosperms:
cone bearing plants
3. Angiosperms: seed bearing plants
(these are the most successful types of plants)
­ see handout for more information
Jan 6­10:35 AM
Diversity & Success of the Angiosperm
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­
see handout provided
see fig. 6.13 on page 176.
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Readings
Text pages 164 ­ 181
Questions
Page 181: #'s 1,3,4,6,7,8
Jan 10­9:56 PM
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