Chapter 2

How many biomes are there and how do they vary?

- 9 diff biomes and they vary by their temp and precipitation

Below photic zone and deep pelagic zone

- E by falling detritus - temp drops and pressure increases - DEM predators live there

Tropical rainforest: plant life?

- Plants exploit L in diff ways b/c it is a selection pressure - must grow tall/adjust to low levels of L - emergents = rise above canopy -lianas (vines) +epiphytes = use tress for support - understory trees = grow in shade; shade tolerant (exploit little L on floor)

Precipitation and temp?

- act together to influence the water loss/availability in plants - has physiological effects on plant growth form

Tundra

- also looks like grasslands, temperate deciduous and boreal forest -diff b/w boreal and tundra: tundra precip peaks in august (also temp is lower) - long, severe winters - growing season lengths and temps decrease

Why are biomes characterized by plants not animals?

- always in place -occupy space for long time -good indicators of physical env't -reflect climate conditions and disturbances

how have humans impacted oceans? Everything goes somewhere maxim

- b/c of vast oceans ; everything goes there -coastal areas highly impacted - we impact every part of the ocean, even if we have never been there

Tropical seasonal forests and savanna: Intercontinental convergence zone?

- band of rain at the equator - shifts in ICZ cause really wet (forest) or really dry (savannah) seasons

Benthic organisms

- bottom dwellers (water just above hyporheic zone) - like deep sea -many invertebrates - feed on detritus (dead organic matter) and some predators -some live in hyporheic zone

Temperate grassland: plant life

- called terrestrial ocean - grasses grow more roots than stems and leaves - helps cope w/ dry conditions - :. accumulation of organic matter - high soil fertility - converted to agriculture

convergence?

- evolution of similar growth forms amongst distantly related species in response to similar selection pressures - found on diff continents but converge to look the same due to similar env'ts/pressures

Desert

- extremely dry - high temp (esp. during summer); very low precipitation - sparse vegetation and animal pops - low water availability (high evaporation)

Tropical seasonal forests and savanna?

- extremes of year = high precipation - summer mnths = low precipiation precipitation = seasonal - uniform warm/hot temp year round

Streams and rivers are lotic?

- flowing water systems

Tundra: probs

- human activity will increase eventually - climate change and global warming

water availability and soil temp

- influence nutrient supply in the soil

boreal forest AKA taiga

- kinda looks like grasslands and temperate deciduous - but it has wider temp range - long cold severe winter -extreme winter temps

How have human activities influenced distribution of biomes?

- land use change - conversion of land to agriculture, logging , urban dev't - potential and actual distributions very different - most biomes don't resemble what they used to be (seen in plant growth forms)

Biomes

- large scale biological communities shaped by env't (esp climate) - categorized by dominant plant forms (animals come and go, but plants are forever)

Tropical seasonal forests and savanna: probs for savannah vs forest and both

- maintained as savanna by forest fires, animals and flooding - influences growth forms - dominated by shrubs/grasses - trees intolerant of long periods of too much water (seasonal flooding)= Orinoco River floodplain - herbivores influence balance b/w trees and grass - can be maintained as forest by lack of herbivores from area - less than half of biome remains b/c human poo growth and agriculture

Temperate vs tropical climates?

- more seasonal temp variation than tropical ; tropical its warm all the time

Littoral zone

- near shore - where photic zone reaches bottom -macrophytes occur in this zone (plants rooted in substrate)

Boreal forest: human probs

- not been affected by humans (but will increase eventually) - climate warming = lots of CO2 from decomposition; accelerates green house effect

Temperate evergreen forest: plant life

- nutrient poor = evergreen - little old growth forest remains b/c logging - suppression of fires = increased density of forest :. more intense fires (unstoppable)

pelagic zone

- open water beyond continental shelves -dominated by plankton - supports highest densities of organism

Boreal forest: plant life

- permafrost (soil that is frozen all year) - prevents drainage = saturated soils - trees = conifers (pines, spruces,etc)

temperate shrublands and woodlands: plant life

- plants green in the fall and winter and fall off during (opp season effect) -b) evergreens (active during cool, wet periods) - lower nutrient requirements b./c nutrient poor soil - don't have to make new leaves every year - sclerophyllous leaves (leatheryy; herbivores can't eat it)

salt marshes

- shallow coastal wetlands domanted by grasses and rushes -transitional zone and hatcheries for animals - vulnerable to humans

Temperate deciduous forest : probs

- shifts on species composition due to: - nutrient depletion (agriculture) - invasive species (chestnut blight) - dominant forest species wiped out

Tropical seasonal forests and savanna: plant life

- short deciduous trees - dry season they fall off - then more grass and shrubs - fewer trees than in rainforest - can be maintained as either forest/savanna

temperate evergreen forest

- spans wide range of env'tal conditions - includes temperate rainforest - opposite trend of temperate deciduous and grasslands - cold summer mnths = low precip -warm winter mnths = high precip

Desert: plant life

- succulent stems (store water) - lots of grasses - convergence seen in western (cacti) and eastern hemisphere (euphorbs) - face same selective pressures

On mountains what happens w/ elevation?

- temp and precip change and this results in zones similar to biomes

Tropical rainforests

- uniformly wet and uniformly warm year round- stays constant - high precipitation and high temp -high biomass and diversity - broad leaved evergreens and deciduous trees

Desert: Probs

- used for agriculture and livestock grazing (depends on irrigation) -this fails b/c of soil salinization (salty soil) - long term droughts and unsustainable grazing = desertification - loss of plant cover and soil erosion = famine

Temperate deciduous forest : agriculture

- very good for agriculture b/c fertile soils - little old growth forest left b/c logging - agriculture shifted to tropics; so it has had time to grow back

Temperate grasslands (the best)

- warm, moist summers and cold, dry winters - high precipitation to support forests but grasses dominate b/c of fires and herbivores - like tropical seasonal forest (inverse precip)

temperate deciduous forest

- wet enough for trees to flourish - deciduous leaves - fertile soils, nutrients and enough water to support tree growth (Canada and glacial tilt) - follows same trends as temperate grasslands (but grasslands have more precip)

estuaries

- where river flows into ocean -fresh meets salt water

Tropical rainforest: problem?

-disappearing due to logging and conversion to agriculture -half the biome has been altered - may not recover; soil is old and nutrient poor (will take long) - esp. if you take out trees (majority of nutrient supply) - have become fragemented over time due to logging, etc

phytoplankton

-photosynthetic - restricted to upper layers (where there is L) = photic zone

temperate shrublands and woodlands

-precipitation and summer growing season work in opp direction - warm summers = low precip. -cold mnths = high precip - high species diversity - Cali and mediterranean

hyporheic zone?

-rocky portion of the stream- the sea bed and the rock sides - substratum below and adjacent to stream

zooplankton

Non photosynthethic protists and tiny animals

9 diff biomes?

a) tundra b) boreal forest c) desert c) temperate deciduous forest d) temperate evergreen forest e) temperate grassland f) temperate shrubland g) tropical seasonal forest and savanna h) tropical rainforest

4 types of terrestrial growth forms -all have adapted to diff biomes

a)deciduous - moist ; seasonally warm/cool on fertile soils - warm, seasonally wet/dry b) cacti and shrubs AKA succulent - dry; seasonally hot/cool -c) needle/ evergreen trees - moist; seasonally warm/cool - env't cool/cold on infertile soil d) grasses/sedges - moist, seasonally warm/cool. w/ fire e) evergreen broad leaved -wet,warm year round f)forbs - seasonally cool/cold g) sclerophyllous shrubs - seasonally dry/moist and warm/cool -leathery

Plants have taken many forms in response to selection pressure: what are these selection pressures?

aridity (lack of water), extreme temp, too much sun, grazing and crowding

Boreal forest: prob

cold, wet soils; limit decomposition, plants grow faster than they decompose = spongy soil = soil has lots of organic matter - peat bog formation (from soil saturation) - summer droughts = forest fire can be set (burns trees and soil b/c of organic matter)

terrestrial biomes characterized by:

growth forms of dominant plants - like leaf deciduousness/ succulence

mangrove forests

mudflats dominated by salt tolerant trees

Predators vs invertebrates: where do they live?

predators = main channels invertebrates = benthic/hyperheic zone

Lakes are lentic?

still water - occurs where there are depressions in landscape and they fill w/ water

Photic zone

support PTS organisms

Tundra:plant life

trees cease to be dominant vegetation - tree line marks boreal to tundra transition - sedges, grasses, forms, shrubs

What is a biosphere?

zone of life on earth