Biomes and Ecosystems Flashcards
Broad categories of living systems
defined mainly by climate
Biomes
what do biomes vary in
biodiversity, productivity, structure
vegetation zones defined by altitude
Vertical zonation
what are communities shaped by
temperature ranges, availability of moisture (precipitation)
biome with abundant rainfall; warm and hot temperatures all year
tropical rainforests
soil in tropical rainforests
thin, acidic, nutrient-poor
90% of nutrients in organisms
Distinct wet and dry seasons
drought-deciduous trees/shrubs
More agriculturally productive than moist forests
highly endangered
tropical seasonal rainforests
trees that lose leaves and cease growing with low water availability
drought-deciduous trees
grassland with sparse tree cover
savanna
rainy season- less abundant/dependable
dry season- risk of fires
plant adaptations- deep, persistent roots
threat- grazing from livestock
Tropical savannas & grasslands
extreme hot and extreme cold temperatures
low and sporadic precipitation
plant adaptations are drought-deciduous
animal adaptations- nocturnal; concentrated excrement
deserts
biome with enough rain to support grass; not enough for a forest
deep, persistent roots (like plants in the savana)
produces thick, organic-rich soils
main threats: agriculture, overgrazing
temperate grasslands
broad-leaf forests
trees lose leaves in winter
dense canopy in summer; diverse understory in spring
Greatest threat: rapid deforestation
deciduous forests
evergreen forests
often occur with limited moisture
in pacific coast: known as temperate rainforests (cool, rainy, fog)
pines, spruce, fir, etc.
coniferous forests
dominated by conifers w some deciduous trees (low species diversity due to allelopathy)
extreme cold, short summer (limit growth rate of trees)
boreal forests
below freezing temperatures most of the year
high latitudes or mountaintops
low productivity (short growing season, frost any month of year)
low diversity
not directly threatened (indirectly affected by climate change and air pollution)
tundra
tundra- extensive nights (winter) and 24h sunshine (summer)
important for migratory birds
arctic tundra
tundra- on or near mountaintops; conditions/vegetation similar to arctic tundra
plants: deep pigmentation, leathery leaves (protect against UV)
alpine tundra
depend on tiny, free-floating phytoplankton
ocean/upwelling currents transport nutrients
vertical stratification due to temperature and light decreasing w depth
marine environments
described by depth and proximity to the shore
relatively low productivity but have thriving communities
open ocean
features that support communities in the open ocean
-sea mounts (undersea mountain chains and islands)
-ocean currents
-free floating mats of brown algae
communities based on microbes that capture chemical energy (taken from sulfur compounds released from vents)
magma under oceanic crust provide heat to vents
deep-sea thermal vents
vary w depth, light, temp
high productivity and diversity
-nutrients washing from land
-shallow, clear, warm waters supporting photosynthesis
littoral and intertidal communities
very high productivity/biodiversity
occurs where water are shallow/clear (enough for sunlight)
coral reefs
shelters algae and other species
found in coral reefs
calcium-rich coral skeletons
colonial animals symbiotic w photosynthetic algae
found in coral reefs
coral polyps
occur in shallow, warm, sandy coastlines
support rich communities of grazers
seagrass beds
depressions in rocky shoreline
subjected to violent wave action
specialized animals/plants
tidal pools
what does violent wave action prevent?
plant growth and sediment accumulation
bays where rivers empty into the sea; freshwater mixes w salt water
estuaries
shallow wetlands regularly or occasionally flooded w seawater; occurs in estuaries
salt marshes
lentic environments
distinct vertical zones
freshwater lakes
vertical zone- emergent plants create functional links between layers
littoral zone
vertical zone- lowest oxygen due to little mixing; lowest light
benthic zone
shallow ecosystems; saturated/submerged part of the year
described by vegetation; adapted in saturated conditions
support rich biodiversity; essential for breeding and migratory birds
reduce flooding; replenish groundwater supplies; filters runoff
wetlands
wetlands w trees
shallow water; full sunlight penetration (high productivity)
swamp
wetlands w/o trees
shallow water; full sunlight penetration (high productivity)
marsh
water-saturated; deep layers of peat
nutrient poor (low productivity)
bog
lotic environments
precip > evap
surplus water drains from land
constantly changing conditions/inhabitants
streams and rivers
water runs rapidly over rocks
(well mixed and oxygenated)
riffles
in streams and rivers- stretches of slowly moving current (collect silt/organic matter)
pools
headwaters (source) to mouth of a drainage
watershed
