Embryophytes Flashcards
What are the characteristics of stoneworts?
Mitotic phragmoplast
Plasmodesmata
What are the characteristics of the embryophytes?
Sexual process is vulnerable to terrestrial conditions
Land plants have an egg protected by archegonium
Antheridium
Retention of zygote and young embryo
Mitotic phragmoplast
Plasmodesmata
Plasm
Describe plasmodesmata
Fine strands of cytoplasm that extend through pores in the cell wall connecting the cytoplasm of each cell with it’s neighbours. This allows communication.
What is the importance of plasmodesmata in the evolution of land fauna?
It allows communication between the gametophyte and the sporophyte
What is the adaptive significance of sporophyte phase?
Increased number of spore mother cells, leads to more meiosis and more spores.
More meiosis, means more recombination potential and increases the ecological amplitude.
More spores, means more dispersal events and more gametophytes
How do mosses disperse their spores?
They have peristome teeth which flex as humidity changes. One cell layer absorbs water easily and the other does not. As water is lost, one surface shrinks causing the peristome teeth to contract, until they snap back into shape releasing the spore.
What is phragmosplastic mitosis?
In green plants the microtubules are not replaced, instead the cell wall disintegrates.
What is phycoplastic mitosis?
The microtubules replaced by set that run parallel to plane of division.
What are the characteristics of streptophyta?
Photo-respiratory enzymes in perioxisomes
Asymmetrical, bi-flagellated gametes
How do the liverworts disperse their spores?
Sporangium splits when dry which exposes the spores and elaters
. Elaters flick the spores into the air.
How do hornworts disperse their spores?
Spore dispersal via stomata
What are the 2 sub groups of the viridiplantae?
Chlorophyta
Streptophyta
What are the 2 sub-groups of streptophyta?
Stonewort
Embryophytes
What are the 4 subgroups of the embryophytes?
Liver worts
Hornworts
Mosses
Vascular Plants
