Evolution of Land Plants & Structures of Plant Bodies Flashcards
(90 cards)
What does “alternation of generations” refer to?
1. Fertilization of gametes into zygote
2. Zygote divides by mitosis into sporophyte
3. Sporophyte produces spores by meiosis
4. Spores divide by mitosis into gametophyte
5. Gametophyte produces gametes by mitosis–> RESTART.
Therefore there are 2 phases: Haploid gametophytes and diploid sporophytes.
How do gametophytes produce gametes?
By mitosis
What does it mean for gametes to be iso-gametes? What is the opposite?
If the sperm and egg are similar in morphology. If they are different, they are hetero-gametes.
What is it called when spores are similar in morphology? What is it called when different?
homosporous; heterosporous.
At what point in the “alternation of generation” process is there germination?
When the spores develop before dividing by mitosis into gametophytes.
What is the purpose of the waxy cuticle?
To promote water conservation by preventing water loss.
What is a stomate?
A pore in leaves used for controlled gas exchange (including water vapor)
What type of plant did stomates first appear in?
Mosses.
What are bryophytes and what is an example of one?
A plant that doesn’t have any vascular tissue. Ex. Moss
What is the difference between lower pteridophytes and advanced pteridophytes?
Lower are microphylls whereas advanced are megaphylls.
What is the difference between microphylls and megaphylls?
The leaves of microphylls are small with one central vein whereas the leaves of megaphylls are large with a complex vascular system.
What plant first had microphylls?
club-mosses
What plant first had megaphylls?
ferns
In plants, what is the technical name for the structure that contains the sperm?
Antheridium
In plants, what is the technical name for the structure that contains the egg?
Archegonium
What type of reproduction does Chlamydomonas, the green algae we saw in the lab, undergo?
Sexual AND asexual modes. (asexual reproduction refers to the multiplication of the haploid gametophytic phase)
Is it necessary for both gametes and spores to be similar or different?
No. Some plants can be heterogametes (different) and homosporous (same) Ex. the coleochaete.
What does matrotrophic mean? Give two important examples of matrotrophism.
It means “parasitic on its mother”. In bryophytes, the sporophyte is matrotrophic on the gametophyte. In gymnio & angiosperms, it’s the opposite: the gametophyte is matrotrophic on the sporophyte!
What plant has the largest motile sperm? How many flagella does it have?
Horsetail, it is bi-flagellated
What are sporangia?
Spore-making structures inside the little bumps on the underside of fern megaphylls.
What is the difference between gymnosperm and angiosperm?
In gymnosperm, the seeds lie naked and unprotected on the outside of the structure whereas in angiosperm the seeds are enclosed in the ovary (the fruit)
In bryophytes and pteridophytes, the sperm is motile. What about in gymnosperms and angiosperms?
In gymno- & angiosperms, the sperm is NOT motile.
What is the advantage of having a dominant sporophyte?
The sporophytes are HAPLOID which means better protection against genetic mutations.
What is the difference between taproots and fibrous roots?
Taproot systems have one main thick root with long thin branches.
Fibrous roots on the other hand have many branches of similar thickness (like a bush of roots underground)