Dr Peddie Flashcards
What was a problem for early land plants regarding nutrients?
Nutrients are in the soil rather than in water around them.
What was a problem for early land plants regarding light?
They experienced more damaging light, which previously would’ve reflected off the water.
What was a problem for early land plants regarding sperm?
They had motile, swimming sperm which on land had no medium.
What was a advantage for early land plants regarding light?
There is no filter on useful light and greater levels are available.
What was an advantage for early land plants regarding higher oxygen concentrations?
That meant also higher carbon dioxide concentrations.
What could early land plants escape from?
Competition and herbivores.
What are rhizoids?
Specialised organs that anchor plants to the ground to ensure they remain in the optimal wet habitat.
What is the function of waxy cuticles?
To aid in retention of water.
What are charophytes?
The likely ancestor of all land plants.
Name the asexual, diploid generation of plant life cycles.
Sporophyte generation
Name the sexual, haploid generation of plant life cycles.
Gametophyte generation
Early land plants and present day Bryophytes have which phase as the dominant one?
Gametophyte phase
What is the evidence that liverworts are the most ancient land plant group?
They are the only land plants that lack stomata and have less efficient pores.
What are archegonia?
The female organs in liverworts from which sporophytes grow.
In which group does the sporophyte outgrow and often outlive the gametophyte?
Bryophytes
In what way do their sporophytes characterise vascular plants?
They are independent for most/all of their lifetimes, allowing for gradual increase in size and complexity.
What are sori?
Spores produced on the back of leaflets which ?
Well developed vascular systems, xylem which forms wood and phloem which are part of bark are all characteristics of which group?
Gymnosperms
What is heterospory?
Where microspores, produced by microsporangia, grow into male gametophytes and megaspores, produced by megasporangia, grow into female gametophytes.
In early progymnosperms, what was dispersed instead of spores?
Gametophytes
How did male gametophytes become specialised for flight?
Development of pollen grain: Size reduction, sculpting for air resistance and, sometimes, development of wings.
How did female gametophytes become specialised for male gametophytes to take flight?
Development of ovule: Size and complexity reduction, total decency on mother and enclosing structures.
Give 2 advantages of the development of seeds.
1) Allows production of plants in adverse conditions.
2) Provide a head start in competition.
Give 2 disadvantages of the development of seeds.
1) Require more investment.
2) Harder to disperse due to increased size.
What was a problem for early land plants regarding temperature?
There was much more temperature variation on land.
What was a problem for early land plants regarding oxygen concentration?
Higher O2 concentration meant potential oxidative stress.
What was a problem for early land plants regarding sex cells and propagules?
Desiccation
What did plants evolve to solve the problems of sex cell desiccation?
Sporopollenin
What is calyptra?
A covering that protects spores, which are normally liberated by wind.
What is an indusium?
An umbrella that dries up to release spores.
Where are sporangia on ferns?
Leaf undersides
What are 2 things provided by a mother gymnosperm when an embryo leaves?
Integument for protection and nucleus for food.
