Earth's Biomes and Spatial Diversity Flashcards
climate
long term average weather
solar radiation angle and surface temperature
sun hits the equator directly - hotter
at the poles, light hits less directly and is spread further - cooler
earth tilts 23.5 degrees - seasonal variation (more sun/closer in summer). variation is most impactful at poles
topography
- mountains
physical features of the earth
mountains can be glaciated to reflect heat
ocean currents and wind and heat movement
move heat to poles - equator is less hot than expected and the poles are warmer
wind and ocean current mechanisms
- hot air rises from equator and spreads towards poles, cooling as it goes. eventually it is dense enough to return to the surface where it heats and moves towards the equators
- series of cells (heating and cooling cycles)
- when warm air moves up, cool air replaces it (wind)
Coriolis effect
because of the earth’s counterclockwise rotation about its axis, winds and oceanic currents in the Northern Hemisphere deflect to the right and those in the south deflect to the left
earth’s rotation and winds and water
earth rotates clockwise - equator moves furthest and fastest in a spin
- wind push oceans to form currents in surface water
- water carries more heat than air and moves to the poles
- cold water sinks and moves to equator
rainfall
- warm air carries more water vapour than cold air
- rising air cools = rain
- descending air warms, taking more moisture = arid climate
rain shadows
the area on the lee side of mountains, where air masses descend, warming and taking up water vapour; these lands are arid
- takes moisture into mountains where the air cools and it rains
biomes and distributions
distributions of biomes reflect regional climates
evapotranspiration
the sum of evaporation directly from soils and water bodies plus the amount transpired by plants
potential evapotranspiration
the amount of evapotranspiration that temperature, humidity and wind would cause if water supply wasn’t limiting; the demand on water in an ecosystem
potential evapotranspiration ratio
the ratio of water demand to supply - what vegetation can be supported?
plant evolution
evolve to conditions and may look similar but be unrelated
tundra
coldest, short days - grasses, moss, rabbits, wolves
alpine
lacks permanent ice below soil (tundra), cold, windy, small plants
taiga
cool, moist forests, rainy summers, conifers, mosses, shrubs, moose
temperate coniferous forest
lots of rain, enormous conifers, warm
deciduous forests
moderate climate, nutrient rich soil from leaf fall, lots of insects, lizards etc.
temperate grassland
lack of precipitation (few trees), bison, horses, prairie dogs, foxes, eagles
desert
deep-rooted plants, low nutrient soils, high salinity, not much primary production, small animals
chaparral
30-75mm rain a year, herbs that die and reseed, shrubs, small trees, olives, eucalypts
savanna
tall, perennial grasslands, warm, dry, seasonal rain, scattered trees, grazers, predators
tropical rainforest
more than 250mm rain, warm, fast decay, small mammals, insects
plants in aquatic biomes
buoyancy means plants don’t need structural support like those on land
nutrients in aquatic biomes
dissolves in water
nutrients and oxygen supply impact biomes
nutrients run off continents into oceans; cyanobacteria fix nitrogen
nutrients from bottom upwell - 1% of earth supports 20% of fish
fresh water
2.5%
glaciers, permafrost, groundwater
oceans
71% of earth surface
photic zone
top 200cm
deep sea organisms
detritus and chemotropic bacteria and archaea support deep sea
algae
occupy continental shelves and are grazed upon
viruses
lyse phytoplankton and algae, releasing organic molecules that support bacteria and other consumers
deep sea oxygen
less wind so less oxygen
lakes
20% of freshwater, varying nutrients, plants and algae in shallows, cyanobacteria, zooplankton, fish, birds
rivers
well oxygenated, plants and algae on edge, phytoplankton, fish, turtles, insects
intertidal
neritic (shallow water), close to shore, rock pools, muscles, dry out daily
coral reefs
most diverse, tropical/subtropical, little water movement, algae live in corals, low nutrients
pelagic realm
not close to seashore or seafloor
final oceanic region
deep sea
physical factors of biodiversity’s unequal distribution
climate, topographical regions, barriers to movement
biotic factors of biodiversity’s unequal distribution
depend on another species for survival
evolution factors of biodiversity’s unequal distribution
large diversity of animals, plants etc. arrive at a place by chance and adapt to that environment
cradle
high speciation rates - tropics are a cradle for diversity
museum
low extinction rates in the tropics
destination
high immigration rates
