Chapter 29: How Plants Colonized Land Flashcards
What is the closest relative to land plants?
Green algae (charophytes)
Name 6 basic characteristics of plants
- Multicellular eukaryotes
- Photoautotrophs
- Organelles extensive in number and diversity - chloroplast - chlorophyll
- Reproduce asexually/sexually
- Cell walls made of cellulose
- Undergo alternation of generations
What are 4 similarities land plants possess with charophytes and no other plants?
- They have rose-shaped complexes for cellulose synthesis in their plasma membrane
- Peroxisome enzymes
- Structure of flagellated sperm
- Formation of a phragmoplast Phragmoplast = area of plant cell that collects building materials for a new cell wall
What are 5 adjustments photosynthetic organisms had to do to transition from aquatic to terrestrial environments?
- A waxy cuticle was introduced to coat the leaves to prevent water loss
- Stomata (pores on the leaf surface) were introduced to open and close for gas exchange for photosynthesis
- Vascular tissue was introduced to help the plants defy gravity and grow upwards (sprawling growth)
- Vascular tissue also allows plants to transport water throughout the plant and provides structural support
- Elaborate reproductive structures (such as pollen, seeds, and flowers) were introduced to protect the gametes
What are 4 characteristics that land plants have and charophytes do not?
- Alternation of generations - includes multicellular, dependent embryos
- Walled spores produced in sporangia
- Multicellular gametangia
- Apical meristems
What is alternation of generations?
- when an organism has two distinct life stages; diploid sporophyte generation and haploid gametophyte generation
- Haploid spores (from meiosis) develop through mitosis
- Gametophyte does mitosis to make gametes
- Gamete from another plant comes along and fertilizes the other gamete
- Zygote does mitosis and matures into a sporophyte (diploid)
- Zygote undergoes meiosis to produce spores
Land plants are known as ______________.
Embryophytes
Explain how walled spores produced in sporangia is are unique in comparison to spores in charophytes.
- Within the sporangia of a land plant’s sporophyte, sporocytes (diploid spore mother cells) undergo meiosis and generate haploid spores with sporopellenin-enriched walls.
(These walls are resistant to harsh environments) - charophytes lack multicellular sporangia and their spores lack sporopellenin
Explain the multicellular gametangia of land plants.
- Land plants produce gametes within the gametangia (multicellular organs)
- The female’s gametangia are called archegonia (holds an egg)
- The male’s gametangia are called antheridia (produces sperm)
The male gametangia release sperm into the environment and need water to swim to archegonia’s egg and fertilize it
What are apical meristems?
Areas in plants where mitosis occurs and growth occurs (happens at the root and shoot of a plant)
- this increases their exposure to environmental resources
Shoot apical meristems also produce ___________ in most plants.
leaves
What differentiates the gametangia in land plants vs the gametangia in other organisms?
The gametangia in land plants are multicellular; the gametangia in other organisms are not.
What is the function of vascular tissue?
Transport water and nutrients throughout the plant body
What are the 3 large categories of plants and what are the phyla within them?
- Seedless Nonvascular plants
- Bryophyta
- Hepatophyta
- Anthocerophyta - Seedless Vascular plants
- Lycophyta
- Monilophyta - Seed plants
> Gymnosperms
- Ginkgophyta
- Cycadophyta
- Gnetophyta
- Coniferophyta
> Angiosperms
- Anthophyta
What are characteristics of the phylum bryophyta (mosses)?
- Rhizoids = roots
- Archegonia/Antheridia
- Sporophytes
( ) - capsule
| } sporophyte
| - seta
|
[] - gametophyte
Explain the life cycle of a moss (bryophytes)
^ the seedless nonvascular plants
- Haploid spores develop threadlike protonemata
- Protonemata produces buds, which divide by mitosis to grow into a gametophyte (male and female)
- Sperm from the antheridia swim to the archegonia and fertilize the egg
- The diploid zygote develops into a sporophyte embryo (nutritionally dependent on gametophyte)
- Sporophytes undergo meiosis, producing haploid spores, which are released when the sporophyte matures
Explain the life cycle of a fern (lycophyta and monilophyta)
^ the seedless vascular plants
- Sporangia release haploid spores and a young gametophyte starts to develop
- Gametophyte develops archegonia and antheridia
- Sperm swim to eggs inside the archegonia and fertilize them
- The diploid zygote develops into a sporophyte that branched off of the gametophyte
- The mature sporophyte develop sori (clusters of sporangia) on one side of the leaves where spores develop through meiosis, ready to be released again
Label the different structures
Moss
- Capsule
- Seta
- Sporophyte
- Gametophyte
Liverwort
- Antheridia
- Archegonia
- Thallus
- Gemmae cups with gemmae
Hornwort
- Sporophyte
- Horn-like structure
- Gametophyte
