Colonisation of Land Flashcards
5 requirements for land plant
- Multicellular
- Eukaryotic
- Autotrophic
- Cell wall characterized by cellulose
- Chloroplast with chlorophyll a and b
4 shared feature between charophytes and land plants
- Biochemistry
- Cytokinesis
- Sperm ultrastructure
- Cell wall composition
What does close relationship between two groups suggest
Land plants most likely evolved from green algae
Charophyte-like algae are ancestors of land plants
What are ancestral traits
Evolutionary origin of plants from ancestral algae
- Traits we see land plants have today that ancestors displayed as well
What are derived traits
Adaption to plants to a terrestrial environment
- trais organisms have now but ancestors did not have
4 problems faced by land plants
- Desiccation
- Support
- Reproduction & development
- Coping w/environmental fluctuations
What are embryophyteds
- Land plants with multicellular embryo that develops within the mother plant
What are gametophytes
- Multicellular adult with haploid cells that produce gametes by mitosis
What are sporophytes
- Multicellular adult with diploid cells that produce spores by meiosis
- It is a diploid cuhs has 2 copies of each chromosome in each cell
Describe 3 derived traits of plants
- Alternation of generation & multicellular embryo develops within mother plant
- Walled spores (with sporopollenin) produced in multicellular sporangia)
- Gametes produced in multicellular gametangia
- Growth of shoots and roots (apical meristem)
List 4 other adaptions to life on land
- Waterproof cuticle to prevent water loss
- Stoma :
Allow exchange of co2 and o2
Prevent moisture loss - Vascular tissues:
Xylem; h2o and minerals up fem roots
Phloem; distribute sugars etc - Secondary compounds:
Protect against herbivores, UV, pathogens
What key adaption do bryophytes not have that is present in seedless land plants
No vascular system (i.e. no xylem or phloem) so there is a constraint to take up co2.
Name 2 constraints and their result for bryophytes that have no vascular system
- Constrain #1 height:
No vascular system, no true roots, no true leaves
Water & nutrients transported by diffusion - Constraint #2 moist environment
Flagellated sperm must swim to egg thru film o water
So must live in moist areas
How many species of moss found in BC?
1000
What does seedless vascular plants key adaption and 3 pros
Vascular tissue
- Allows for efficient transport of water, nutrients, sugars
- Provides structural support
- Reduces height constrant
Why would taller plants be better competitors
Better access to sunlight
Name a consequence of vascular system and a constraint of seedless vascular plants
Consequence: Increased vegetation
- Increase photosynthetic activity caused a decreased in atmospheric co2
Constraint: Moist environment
- Flagellated sperm must swim to egg thru film of water
Name two key adaptions of gymnosperms aka conifers and ginkgoes
Key adaption: Seed
- New sporophyte embryo protected in seed
- Allows for interruption of lifecycle
Key adaption: Pollen
- Male gametophyte protected by spore coat
- Sperm travels in pollen
- Travel by wind: no need for h2o
What are 2 key adaptions of angiosperms aka flowering plants
Key adaption: Flower
- Vector pollination increases reproductive success -> more economical & effective even @ low population density
- Co-evolution of plants & pollinators
Key adaption: Fruit
- Dispersal of seeds by animal movement
4 characteristics of fungus
- Multicellular
- Eukaryotic
- Heterotrophic
- Absorptive nutrition
How do fungal hyphae and plant root function together
Fungal hyphae absorb h2o and minerals better than plant
Plant exchanges sugars and h2o for nutrients
Fungus called Mycorrhizae
