final Flashcards

Question

adaptation of conifers to fires

Answer 1

- survive low intensity fires - killed bu high intensity fires - restistance correlated with -increased bark thickness - high open branching habit - lack of lichens

Answer 2

remain in the cone for up to 25 years - resin bonds sealing cone scales melt at 60 C (in fire) - seeds resist high temps - released onto bare ground

Answer 3

the third and perhaps most important agent of seed release is fire. hot air produced by locally intense fire and convected high into the canopy can dry cones, resulting in release of enormous quantities of seed over small areas. this increased seed fall coincides both spatially and temporally with fire related seedbed conditions favorable for seed germination and seedling survival. first year giant sequoia seedlings established on treated-bulldozed or burned or both area, were 30 to 150 times more numbers than those on undisturbed forest floor survival of sequoia seedlings for a 7 to 9 year period was 27% on areas subjected to a hot burn as opposed to 3.5% on other treated substrates

Answer 4

biomass/productivity - 120-300 t ha-1 seasonally very varied nutrient cycling - major nutrients input from litter , quality of nutrient supply dependent on time of fall decomposers - earthworms, nematodes, bacteria, fungi

Answer 5

biomass/productivity - 10 - 160 t ha-1 site variable nutrient cycling - infertile soils, nutrient limited, limited by rate of cycling, soil acid evergreen, require less nutrients, lichen fall increasesN decomposers - predominantly fungi

Answer 6

arctic, antarctic, sub-antarctic islands, and alpine tundra - regions just below ice caps of the arctic, extending across N america, to europe, and siberia - alaska and canada - high latitude land masses (other places in the world) --> polar and alpine tundras are continuous

Answer 7

- species diversity is low, <900 species flowering plants - gradients of decreasing diversity with increasing stress - species may be: widely distributed (circumpolar), disjunct (bipolar), and endemic (restricted to a mountain range)

Answer 8

low temperature exerts the dominant effect POLAR REGIONS - ave temp <10 C for the warmest month - above freezing < 2 months per year - summers: high radiant energy input - winters: negative radiant energy balance - precipitation < 250 mm y-1, mostly snow - permafrost limits the contribution of snowmelt

Answer 9

low temperature exerts the dominant effect ALPINE REGIONS - similar to polar regions at high latitude - close the equator, diurnal (daily) temperature fluctuations become more important - mountain rain shadow and fog affect the amount of available moisture - snow insulates thus temperature is highest nearest the ground - microclimate is important for growth of plants - environmental gradients of topography, snow and wind influence plant distribution

Answer 10

cold and frost --> gleization, acid peats --> rock shattering + rock sorting permafrost vs. active layer --> thawed in summer in polar and daytime in alpine low nutrients: acid, slow breakdown, leaching and lateral flow over permafrost

Answer 11

very little therophytes, mostly chameaphytes and hemicryptophytes - growth forms show distributions within tundra biomes

Answer 12

- low growth form: chameaphytes and hemicryptophytes, close to ground (cushion plants) increase heat uptake from ground - grasses insulated by dead leaves - rosettes insulated by living leaves - leaves are pubescent (hairy) - red coloration (anthocyanin- sugars) to increase leaf temperature

Answer 13

- few annuals, summer too short for reproduction - semi-evergreen - vegetative reproduction - vivipary; the germination of seeds while still attached to the fruit, whether or not the fruit is still attached to the plant - initiate growth and flowering early before snowmelt: grow under snow (greenhouse effect) and flower through snow (cyanide resistant respiration) - flower over several seasons - high floral temperature (pollination and seed set) : heliotropism (the direcitional growth of a plant in response to sunlight) and furry flowers sexual and clonal reproduction in flowers

Answer 14

thermogenetic plants have the ability to raise their temperature above that of the surrounding air --> heat is generated in the mitochondria as a secondary process of cellular respiration - seen in skunk cabbage - thermogenesis in plants is associated with cyanide resistant respiration aka alternative oxidation pathways (mitochondria produces heat, not ATP)

Answer 15

- giant rosette plants: convergent evolution --> giant rosette, cushion plants, sclerophyllous shrubs - night bud (nyctinastic leaves) - do not shed dead leaves - leaves have airspaces which increase insulation - pubescent (hairy) - thick roots resist frost heaving - andean-alpine : supercool - afro-alpine : extracellular ice formation

Answer 16

- very low : probably less than deserts, many limitations especially cold 10 - 400

Answer 17

- slow: breakdown and weathering limited - nematodes, bacteria and fungi - animal manuring is a significant input

Answer 18

- very fragile biome --> carry capacity is easily exceeded (the number of living organisms and crops that a region can support without environmental degradation) - global warming is a big threat --> more carbon out than in, more thawed

Answer 19

- tropical and subtropical - sea surface temperature >24 C all year - influenced by ocean currents

Answer 20

- temperature and high latitude - sea surface temperature <30 C for most of year - predominantly N hemisphere

Answer 21

- coastal - occur where fine sediments accumulate - occur where wave action is minimal (usually associated with estuaries, also behind sand bars) - influenced by tidal action - freshwater input

Answer 22

- dominant plants are woody trees (phanerophytes) - old world diversity high (over 40 species) - new world diversity low (8 species) - important groups are Rhizophore and Avicenna - unrelated species show convergent evolution - plants reproduce sexually - plants viviparous, allows for seedlings establishment on mud flats despite tidal action - colonization of new areas occurs through 'propagule' distribution by ocean currents

Answer 23

- dominant plants are grasses and low-growing succulent species (hemicryptophytes and chamaephytes) - grasses and succulents represent two different strategies for dealing with similar environmental stresses - diversity greater in temperate than high latitude areas - grasses are the most common species at high latitude - important groups include Puccinellia, Care, Juncus, Spartina, Distinchlis, Salicornia, Suaeda - in high latitudes plants reproduce vegetatively only, colonization of new areas occurs through ice-rafting of rhizomes

Answer 24

plants show zonation in response to gradients established through tidal action - gradients include: anoxia, greater inundation, finer particles, wetter soil substrate salinity, higher near the sea edge, lower near fresh water inflow, higher where evaporation between tidal extremes concentrates the salt lights, highest on extending and back edge of mangrove swamps, low within the forest extreme high tide= salt grass mean high tide = pickle weed mean seal level = cordgrass mudflat

Answer 25

- anoxia = an absence of oxygen, caused by too much water/fooding, eliminates and replaces oxygen in the soil - rhizomes --> near surface, more chance of getting O2, stores starch to provide carbon which aids with the stress - pneumatophores --> an aerial root specialized for gaseous exchange - aerenchyma --> open channels for oxygen in roots, also helps with ethanol leaving the plants

Answer 26

- salt exclusion at the root level - succulence --> dilution - semi-deciduous habit --> - salt excretion through salt glands --> quantitatively reduces salt stress, reduced imbalance of some ions (NA vs K) - accumulation of solutes --> overcoming water stress associated with salt stress , maintains transpiration

Answer 27

- high, similar to tropical forests - not nutrient limited - rapid degradation detritus, crabs (increase nutrients exchange through excretion

Answer 28

- loss of development: direct and indirect effects - sea level rise - land clearing for coastal development - erosion from agriculture and grazing

Answer 29

- fast moving current ORIGIN (headwater) - rainfall, snowmelt, ground water, lake outflow - four groups based on the ratio of discharge volume and drainage area - tropical rainforest - warm temperte or subtropical -moderately dry - desert rivers

Answer 30

- standing body of water ORIGIN - tectonic , volcanic, glacial - other: man made, solution lakes, beaver lakes, etc

Answer 31

- still water in lakes becomes thermally stratified - gives rise to thermal lake types -these occur at different altitudes and latitudes - affects water mixing and lake - dimictic: mix twice a year in spring and fall - monomictic: warm mix in winter, cold mix in summer - amictic: never mix always frozen - polymictic: mix everyday/weeks, shallow -oligomictic: rarely circulate - meromictic: so deep, have permanent thermoclines with seasonal thermoclines superimposed

Answer 32

- closely related to atmospheric temperatures - daily rhythms: afternoon maximum for small, clear streams - cooler at headwaters - turbulence reduces stratification

Answer 33

- absorption of radiant energy gives rise to thermal stratification - lakes divided into photic versus aphotic zones based on sufficient light for photosynthesis - light quality is affected by depth and lake nutrient type -green light predominates with increasing depth

Answer 34

- O2 and CO2 important bc of photsynthesis - levels of O2 and CO2 are also influenced by photosynthesis - ratios of O2 and CO2 are different from the atmosphere - solubility of O2 decreases with increases temp - less oxygen dissolves into water at higher elevations bc of reduced atmospheric pressure

Answer 35

- temperature is the most important determination of O2 and CO2 concentrations - oligotrophic lakes are near saturation for O2 and CO2 - for eutrophication lakes, O2 concentrations are greater in the epilimnion because of photsynthesis; O2 in the hypolimnion is depleted during periods of stagnation, replenished by mixing - CO2 seldom limting in the long term, 30 times greater solubility than O2 - CO2 can show dial variations - CO2 buffers pH

Answer 36

- O2 and CO2 levels in natural rivers are near saturation, especially below fast flowing areas such as rapids - groundwater seeping into streams carries variable amounts of CO2 depending on the nature of the underlying rock - some species require such high O2, it only occurs near waterfalls - O2 levels fluctuate in response to 'organic' pollution, natural and man made - damming of rivers removed natural re-aeration - giant spillways result in supersaturation; e.g. columbia river where gas bubble disease kills salmon during migration

Answer 37

- nutrient concentrations in lakes reflect mineral composition of incoming rivers and land use practice -soft water contains few dissolved solutes: igneous rock - hard water contains dissolved solutes: sedimentary rock - N and P most limiting, but increased where sewage, fertilizers,

Answer 38

life forms depend on position within the lake or river LAKES - littoral: shallow water anchorage and light to the bottom - pelagic: floating deep open water - limnetic: light for photosynthesis - profundal: light limited submerged vegetation -> floating vegetation --> emergent vegetation --> riparian bushes --> riparian trees --> forest canopy trees RIVERS - differences in distribution along the length

Answer 39

- reduced structural tissue, little lignin - no cambium - xylem cavities - leaves narrow and elongated - SA: mV high for increased uptake - heterophylly - rhizomes/stolons

Answer 40

- restricted to sheltered sites - rhizomes anchor - long flexible petioles, allow for wave action - aerenchyma, floating - stiffened veins - stomata on upper surface, raised - hydrophobic leaf surface

Answer 41

- more variable - flotation mechanism, e.g., water repellent hairs, his trap air bubbles, have gas bladders - WEEDS

Answer 42

- angiosperms are secondarily aquatic, i.e. returned to water - have cuticles, stomata, and features associated with the terrestrial environment

Answer 43

adaptations to low O2 conditions (anoxia) - aerenchyma allows diffusion of toxic in products of respiration to the surface - rhizomes store carbohydrates

Answer 44

-CAM photosynthesis associated with low daytime CO2 - most species C3 and shaded adapted - some C4

Answer 45

-plants and phytoplankton contribute to primary productivity - primary productivity is very low - lower than most terrestrial ecosystems, higher than the ocean - limited by nutrients, also sometimes light - seasonal effects through temperature, nutrients, oxygen depletion

Answer 46

POLLUTION - low nutrients and nutrient limitations make lakes and rivers susceptible to eutrophication (excessive richness of nutrients due to runoff from the land that causes a dense growth of plant life and death of animal life from lack of oxygen) RESERVOIR CONSTRUCTION - removal and channel modification