CH 29: Bryophytes Flashcards
What challenges did plants face when making their move to land?
- Dessication
- Temperature/environment changes
- Reproduction without water
- Structural support without water
- Trasnporting nutrients
What are Streptophytes?
Transition between protists and land plants
- group of green algae and land plants
- Have plasmodesmata: communicates between cells
What traits do Streptophytes share with land plants?
- Plasmodesmata
- Sexual reproduction using egg and smaller sperm
- Cytokinesis
- Chlorophyll a/b
- Store carbs as starch
- Cell walls made of cellulose
What are embryophytes?
land plants
What are the distinctive features of land plants?
1) Bodies composed of 3-D tissues
- avoid water loss
2) Apical Meristems grow new tissues
3) Structural support from thick, robust body
4) Specialized tissues and organs
5) Distinct reproductive features
What are the plant phyla of bryophytes?
Bryophytes
1) Marchantiophyta - liverworts
2) Bryophyta - mosses
3) Anthocerophyta - hornworts
What group of land plants are models of the earliest terrestrial plants? What are their general characteristics?
Bryophytes (liverworts, hornworts, mosses)
- Simple structure
- Lack true roots, stems, leaves
- Rhizoids: rootlike structures
What kind of life cycle do bryophytes have?
Sporic life cycle with alternation of generations
- Diploid, spore-producing sporophyte generation
- Haploid, gamete-producing gametophyte generation
What are the distinguishing features of Bryophytes?
- Gametophyte dominant generation
- Sporophytes dependent on gametophyte
- Non-vascular
What are the reproductive adaptations of Bryophytes?
Diploid sporophyte generation allows a single plant to disperse widely
- Meiosis produces genetically variable haploid spores
- Each spore can grow into gametophyte
What are the characteristics of Bryophyte Gametophytes?
- Produce Haploid gametes
- Produced by mitosis
- Gametangia protects developing gametes from drying out and microbial attack (archegonia/antheridia)
- Sperm swim to egg
- Diploid zygote formed and grows in sporophyte
What are the characteristics of Bryophyte Sporophytes?
- Matrotrophy: zygotes are sheltered and fed within gametophyte tissue
- Embryophytes: Having matrotrophic embryos
- Spores produced in sporangia
Why are Bryophytes thought to be the oldest land plants?
The Gametophyte generation is the dominant generation. As land plants evolved they shifted from Gametophyte gen. dominant to Sporophyte gen. dominant.
Marchantophyta characteristics?
- No Stomata (Use diffusion/osmosis)
- Thick Waxy cuticle
- Single-celled rhizoids
- 4-valved capsules
- Sperm movement using water
- Also reproduce asexually with gemmae cups
Anthocerophyta characteristics?
- Tall narrow sporophytes which continue to grow throughout plant life (unlike other bryophytes)
- Blue/green color from cyanobacteria
- True stomata
- Monoecious
- Spores move via water
