Practical 3 Flashcards
Terrestrial plants are thought to have evolved
from __________________.
algae called Charophytes
To survive on land a plant must…
- Avoid drying out (desiccation)
- Uptake nutrients from the soil
- Have structures to support their body support
- Be able to reproduce
- Possess differentiated cells (be multicellular)
In the lifecycle of plants, what does ‘dominant generation’ mean?
The generation that occupy the largest portion of the plant lifecycle.
What does ‘alternation of generations’ mean?
The fluctuation between diploid and haploid stages that occurs in plants.
(Spores form haploid plant structures (gametophytes) give rise to haploid gametes.)
Define:
Homosporous
Production of only one type of spore.
Define:
Heterosporous
Production of two spore types: microspores (male) and megaspores (females). Occurs in vascular plants
Define:
Gametophyte
A haploud cell (n) that produces the sporophytes after the zygote forms.
Define:
Sporophyte
A diploid cell (2n) that produces spores from which the gametophyte forms.
Define:
Cuticle
A waxy or fatty non-cellular layer on the oyter walls of plant epidermmal tissue.
Algae
A large group of different organisms from different phylogenetic groups
Definie these algae features
Holdfast
Stipe
Blade
Holdfast - root-like structure that attaches algae to the substrate
Stipe - a stem-like structure
Blade - leaf-like structure
Why is a stipe not considered as a true stem?
It does not provide structure or transport nutrients.
Why is a blade not considered as a true leaf?
They don’t have veins or any vascular tissue.
Define:
Bryophyta
A group of plants that includes liverworts, hornworts and mosses growing predominantly in moist environments.
Gametophytes of mosses typically consist of _________.
small leaf-like structures
How do Bryophytes avoid drying out on land?
- Waxy cuticle
- Stomata
- Live in moist environments
How do Bryophytes support themselves on land?
They don’t require strong tissues due to their small size.
How do Lycophytes avoid drying out on land?
- Vascular tissue
* Waxy cuticle
How do Lycophytes support themselves on land?
Tracheids are strengthened with lignin (25% of the cell wall).
How do ferns avoid drying out on land?
- Cuticle
- Xylem
- Phloem
How do ferns support themselves on land?
Lignified xylem
Define:
Xylem
Vascular tissue in plants which conduct water and dissolved nutrients upwards from the root and also helps to form the woody element in the stem.
Evolution of algae:
Algae»_space; Bryophyte»_space; Lycophyte»_space; Pterophyte»_space; Gymnosperm»_space; Angiosperm
