lecture 1 (introduction to algae)

Question 1

terrestrial environments have much more plant biomass than marine. but terrestrial and marine ecosystems contribute almost equally to the annual photosynthesis on Earth. Explain this apparent discrepancy.

Answer 1

this is because a lot of the terrestrial biomass does not photosynthesize (eg. roots, trunks). Marine photosynthesizers have no non-photosynthetic tissues

Question 2

can algae be found in non-aquatic environments? where exactly?

Answer 2

yes, lichens (symbiosis with fungi), in snow, embedded within rocks, polar bear hairs, sloth hairs, cryptobiotic/microbiotic crusts in desert and grassland soils

Question 3

what is autotrophy

Answer 3

synthesis of high energy organic compounds from low energy inorganic compounds (Primary producers)

Question 4

what is mixotrophy

Answer 4

autotrophic and heterotrophic (obtain organic carbon from external environment)

Question 5

describe different morphological types in algae (6)

Answer 5

unicells, colonies, filaments, coenocytes, parenchymatous, pseudoparenchymatous

Question 6

what is a coenobium

Answer 6

an assemblage of a constant number of cells (a type of colony)

Question 7

importance of algae

Answer 7

base of food web, form large blooms/aggregations, influence atmospheric chemistry/biogechemistry of nutrient cycling, form oil/siliceous/limestone deposits, source of biofuels

Question 8

difference between a filament and a linear colony

Answer 8

filament: branched or unbranched, daughter cells remain attached after division, share cell walls
linear colony: does not share cell walls

Question 9

three ways to distinguish species

Answer 9

biological species -> can it interbreed
morphological species ->shared structural characteristics
phylogenetic species -> biochemical/molecular characteristics

Question 10

first alga

Answer 10

cyanobacteria, 3.5 billion yrs ago

Question 11

what is the thallus of pseudoparenchymatous algae made of? (how does it differ from parenchymatous)

Answer 11

composed of aggregated filaments
parenchymatous have 3D thallus

Question 12

describe the types of asexual reproduction in algae (7)

Answer 12

cellular bisection -> longitudinal or transverse division
zoospores -> flagellated cells produced in vegetative or specialized cells, containing components to form new individual
aplanospore-> nonmotile (has genetic ability to develop flagella)
autospore/monospore -> non-motile, lack capacity to generate flagella, miniature of parent cell
fragmentation-> random, controlled breaks in filaments/non-coenobic colonies
autocolony -> produces miniature version of coenobia
akinete -> specialized resting cell in cyano

Question 13

what are the different types of sexual reproduction based on form/behaviour of gametes?

Answer 13

zygotic -> meiosis occurs on zygote (the only diploid cell), all vegetative and gametes are haploid
gametic -> meiosis produces haploid gametes(only haploid stage), diploid zygote and diploid vegetative state
sporic (AOG) -> meiosis generates haploid spores that produce a haploid gametophyte, producing haploid gametes. these form a diploid zygote and diploid sporophyte (2-3 multicellular phases, can be isomorphic or heteromorphic)

Question 14

use a diagram to describe a monoecious heterothallic alga

Answer 14

monoecious = same individual produces female and male gametes
heterothallic = gametes of genetically different organisms needed for successful mating (self-sterile)

Question 15

draw diagram of zygotic life cycle

Answer 15

all haploid, diploid zygote. meiosis on zygote

Question 16

draw diagram of gametic life cycle

Answer 16

meiosis on vegetative state to form haploid gametes. otherwise diploid (like us)

Question 17

draw diagram of sporic life cycle

Answer 17

haploid gametophyte and gametes, fuse to make diploid zygote and diploid sporophyte, meiosis produces haploid spores that become gametophytes

Question 18

which life cycle includes alternation of generations

Answer 18

sporic

Question 19

haplobiontic

Answer 19

one type of free-living individual

Question 20

diplobiontic

Answer 20

two free-living stages

Question 21

haplontic

Answer 21

single predominant haploid phase

Question 22

diplontic

Answer 22

single predominant diploid stage

Question 23

diplohaplontic

Answer 23

two phases (haploid and diploid)