midterm 1 Flashcards
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.
land plants store carbon differently
carbon is stored for longer time in land plants due to longer lifespan and slower growth rates
terrestrial carbon storage is seen in standing biomass
marine organisms have short lifespans and fast turnover
- high growth rates and fast reproduction rates along with the fast consumption by herbivores allows for fast turnover
TAKEHOME:
fast turnover and efficiency of marine photosythesizers allow for them to contribute this much to global photosynthesis
Can algae be found in non-aquatic environments? Where exactly?
yes,
- snow algae
- lichens
- deserts and grasslands (cryptobiotic or microbiotic crusts)
- within rock surfaces
- unusual places like sloth hairs, polar bear hollow hairs, flamingo feathers
Regarding algal nutrition, what is autotrophy and mixotrophy?
AUTOTROPHY
- change particles from low inorganic compounds to high energy organic compounds
– photoautotrophs = where light it energy source
– primary producers = first producers of organic carbon in food chain
MIXOTROPHY
= heterotrophic AND autotrophic
–> Heterotrophic = phagotrophic
- ingest particles
osmotrophic
- take up dissolved organic compounds
Describe the different morphological types in algae.
- Unicellular
- solitary cells
- motile or nonmotile
- Colonies
- assemblage of variable number of individual cells
- assemblage of constant number of cells: coenobium
- motile or nonmotile
- Filaments
- unbranched or branched
- uniseriate or multiseriate
- Coenocytic or siphonaceous forms
- less common
- one large multinucleate cell without cross walls
- Parenchymatous forms
- three-dimensional thallus (algal body) - form cell division in 3D
- Pseudoparenchymatous forms
- superficially resemble parenchyma
- composed of aggregated filaments or amorphous aggregations of cells
- parenchymatous and pseudoparenchymatous algae: wide range of shapes and sizes
what is a coenobium ?
a colony with a constant number of cells
what is the difference between a filament and a linear colony ?
filament = share same cell wall
linear colony = cells have separate cell walls
what is the tallus of pseudoparenchymatous algae made of ?
aggregated filaments or amorphous aggregation of cells
Briefly describe the different types of asexual reproduction in algae.
- Cellular Bisection
longitudinal or transverse cell division
- unicellular algae = cell division produces population growth
- multicellular algae = cell division produces growth of the individual
- Spores
- ZOOSPORES
= flagellated cells
= produced in vegetative cells or in specialized cells
= contains components needed to form new individual - APLANOSPORES
= nonmotile
(but have genetic capacity to develop flagella) - AUTOSPORES (green algae) or MONOSPORE (red algae)
= nonmotile spores
= lack capacity to develop flagella
= miniature versions of parental cells
- Fragmentation
- random or controlled breaks in filaments or non-coenobic colonies
- each piece continues to grow
- Autocolony
- produce miniature versions of coenobia - Akinete
- specialized resting cell
- (cyanobacteria)
what are the different types of sexual reproduction based on the form and behaviour of gametes ?
isogamy
- two structurally identical gametes fuse (+ and -)
anisogamy
- two different (size and behaviour) gametes fuse
oogamy
- motile or nonmotile cell (male) fuses with large immobile large egg cell
Using a diagram, describe a monoecious heterothallic alga.
monoecious algae:
- same individual produce male and female gametes
dioecious algae:
- male and female gametes produced by different individuals
homothallic algae:
- gametes of genetically-similar individuals fuse and produce viable offspring (self-fertile)
heterothallic algae:
- gametes of genetically-different individuals needed for successful mating (self-sterile)
Draw labeled diagrams of the sexual zygotic, gametic and sporic life cycles.
which type of lifecycle includes alternation of generations ?
sporic
