Topic 1 Study Questions

Question 1

Terrestrial environments can have as much as 1,000 times more
autotrophic (plant) biomass than marine environments. However,
terrestrial and marine ecosystems contribute almost equally to the annual
photosynthesis on Earth. Explain this apparent discrepancy.

Answer 1

Marine photosynthesis occurs in organisms that have chlorophyll in all/most of their tissues. Less biomass needed for photosynthetic output

Question 2

Can algae be found in non-aquatic environments? Where exactly?

Answer 2

Algae often exist in extreme dry/arid environments as well as in snow where they are often the only primary producers

They can also be found as part of the assemblages of lichen

Question 3

In regards to algal nutrition, what is autotrophy and mixotrophy?

Answer 3

Autotrophy is the energy mode by which they produce all their own food from use of an inorganic energy source

Algae that are mixotrophic use both autotrophy to supply themselves with food, but also absorb nutrients through their cells

Question 4

Describe the different morphological types in algae.

Answer 4

Unicells
Colonies
Filaments: daughter cells remain attached after division
Coenocytic: one continuous multinucleate cell
Parenchytmous: 3-D thallus
Pseudoparenchyma: appears to be parenchyma, but is actually aggregated filaments

Question 5

What is a coenobium?

Answer 5

Colony assemblies with constant number of cells

Question 6

What is the difference between a filament and a linear colony?

Answer 6

In filamentous algae the cells share cell walls

Colonies can be linear but each cell will have its own cell wall

Question 7

What is the tallus of pseudoparenchymatous algae made of?

Answer 7

Aggregated filaments or amorphous aggregations of cells

Question 8

Briefly describe the different types of asexual reproduction in algae

Answer 8

Cellular bisection: Longitudinal or transverse cell division

Zoospores: flagellated cells, that can produce new individuals

Aplanspore: non-flagellated (genetics to make them)

Monospore/Autospore: non-motile, resemble parents

Fragmentation: Splitting of filaments that continue to grow into new individuals

Autocolony: Produce miniature versions of coenobia

Akinete: specialized resting cells

Question 9

What are the different types of sexual reproduction based on the form and
the behaviour of gametes?

Answer 9

Zygotic: Meiosis takes place on zygote.
Only diploid cell is the zygote.
Vegetative state (non-reproductive) and gametes are haploid

Gametic: Meiosis produces haploid gametes.
Diploid zygote undergoes mitotic divisions to produce the diploid vegetative state

Sporic: Meiosis generates haploid spores.
Haploid body: gametophyte.
Haploid gametes are produced by the mitosis of gametophytes.
The diploid zygote divides mitotically to produce a diploid sporophyte.
2 or 3 multicellular phases

Question 10

What type of life cycle includes alternation of generations?

Answer 10

This is sporic meiosis

Question 11

Using a diagram, describe a monoecious heterothallic alga.

Question 12

Draw labeled diagrams of the sexual zygotic, gametic and sporic life
cycles.