Ecology: Chapter 9

Biomes

biome

one of several categories into which ecosystems can be grouped based on climate and dominant plant growth forms

growth form

the physical structure of a plant

example of a growth form

moss grows flat, dense, and tightly packed against the ground

convergent evolution

phenomenon in which 2 spcies that descended from unrelated ancestors have similar adpatations because they evolved under similar selective forces

example of convergent evolution

a shark, fish, and a dolphin, mammal, both have streamlined bodies and dorsal fins

terrestrial biome

biome that fits in a triangular climate space with corners that represent warm moist, warm dry or cool dry climates

list the 9 terrestrial biomes

1) tropical rainforest

2) tundra

3) subtropical desserts

4) tropical seaosnal forest/savanna

5) temperature grassland/cold dessert

6) woodland/shrubland

7) boreal forests

8) temperate rainforest

9) temperate seasonal forest

what kind of weather doe steh tropical rainforest exhibit?

warm and rainy

why is the tropical rainforest so biologically rich?

plant growth is not limited by water or low temperatures leading to more productive species and organic matter decomposes quickly so vegetation rapidly takes up nutrients

since vegetation rapdily takes up nutrients what does that mean for the soil in tropical rainforest?

little organic matter and retain nutrients poorly

where are tropical rainforest located?

central america, congo basin, indonesia, malaysia, and australia

what kind of weather does the tundra exhibit?

coldest biome

why does tundra have low biological richness?

plant growth is limited by temperature

permafrost

permanently frozen soil

what are the soils like in the tundra and why?

soils are acidic and nutrient poor because decomposition is slow and rotting plants pile up and release acid that doesn’t drain away

what happens during the summer in the tundra?

upper soils thaw during a brief growing season

where do tundras exist?

polar regions and alaska, canada, greenland, and siberia

whats the weather like in subtropical deserts?

hot temperatures, scarce rainfall, long growing seasons, and sparse vegetation

wht kind of hadley cells are associated with subtropical deserts?

dry, descending air of hadley cells

what kind of plants are common, C3, C4, or CAM in subtropical deserts?

CAM plants

what is the soil like in subtropical deserts?

shallow and contains little organic matter

where do subtropical deserts exist?

Sahara, middle east, US/Mexico, chile, and australia

what is the weather like in the tropical seasonal forest/savanna?

warm temps with pronounced wet and dry seasons

in tropical seasonal forest/savanna when is wet and dry seasons?

summer is wet seasons and the winter is dry seasons

why does the tropical seasonal forest/savanna have wet and dry seasons?

the movement of the intertropical convergence zone in the summer drags rain belt over biome and in winter the sun pulls rainbelt away

what kinds of plants are tropical seasonal forest/savanna dominated by C3, C4, or CAM plants?

C4 grasses and trees

what do fires and large herbivores in savannas do for plant life?

keep tree density low keeping the landscape open

how can the exact same weather in the dry season result in either a wide open savanna or a tropical seasonal forest?

in savannas C4 grass grows and creates a hot and dry climate which allows frequent fires to ignite and keep tree cover sparse. in the same manner tropical seasonal forest with no C4 grasses and canopy trees that block out sun keep climate cool and moist so no fires catch allowing multiple trees to thrive.

where do savannas and tropical seasonal forest exist?

africa, south america, southeast asia, and northern australia

what is the weather like in temperate grassland and cold desert?

hot dry summers and dry winters

what kind of plants dominate temperate grassland and cold desert?

grass, non-woody flowering plants, drought adapted shrubs

what are the 3 reasons cold deserts and temperate grassland are grouped together?

1) both have hot summers and cold winters

2) neither landscape supports trees

3) as rainfall drops the land can change from tall grass to cold desert

how does fire play a role in grasslands vs. cold deserts?

frequent fires from C4 grasses block trees form taking over while cold deserts with little rainfall have little vegetation so fires can’t spread

where do grasslands and cold deserts exist?

great plains in america, eurasia, and argentina

what kind of weather is the woodland/shrublands?

hot dry summers and mild wet winters

what are the plants like in woodlands/shrublands?

small tough leaves that resist desiccation from drought

comapre shrublands vs. savanna in terms of rainy season, C4 grasses, cire type, fire interval, and woody plants

1)savannas 2)shrublands

• rainy season: warmest season

  • coolest season

• C4 grasses: yes

  • no

• fire type: mild+grass fueled

  • severe+shrub fuel

• fire interval: 1-5 years

  • 30+ years

• woody plants: thin leaves+ decidiois

  • everygreen+ sclerophyllous

whats the weather like in boreal forest?

long, brutal winters and short mild summers

what type of plants dominate boreal forests?

evergreen needle-leaved trees

what is the soil like in boreal forests and why (hint: similar to tundra)?

acidic and nutrient poor because litter decomposes slolwy and accumulates

what is species diveristy like in boreal forest?

low

where do boreal forests exist?

alaska, canada, siberia, scandinavia

what is the weather like in temperate rainforest?

mild temperatures and abundant precipitation

what gives for mild temperature in temperate rainforests?

nearby ocean currents

what plants dominate temperate rainforests?

evergreen forests

where do temperate rainforest exist?

coastal redwood and douglas fir in california

what weather do temperate season forest have?

moderate temperature and precipitation conditions

how does teh ocean influence temperate season forest?

conditions fluctuate because these forest are not near warm ocean currents

what type of plants dominate temperate season forest?

deciduous trees like maple and oak

what doe sit mean for temperate season forest that precipitation exceeds transpiration?

creates a water surplus that keeps soil moist, and supports understory

climate diagram

maps temperature and precipitation to easily visual when water deficit occurs

what does it mean for plants when the temperature line is above the precipitation line?

plant growth is limited by water

hardiness zone map

geographic guide that divides areas into zones based on their average lowest winter temperature

what do hardiness zone maps bring to the table that climate diagrams don’t?

tracks absolute minimums to capture single coldest annual spike which then helps predict plant survival since averages, from climate diagrams, hide fatal overnight freezes

how are aquatic biomes charcterized?

flow of water, depth, and salinity

lotic ecosystem

aquatic ecosystem with active flowing water

true or false: rivers and streams are lotic ecosystems

true

whats the riparian zone in rivers and streams?

terrestrial vegetation alongside rivers and streams that is infleunced by seasonal flooding and elevated water tables

describe conditions of upstream portions of rivers and streams and how that affects productivity?

often shaded and nutrient poor which limits productivity

where do upstream portions get nutrients?

allochotnous organic matter which is input from outside stream

describe conditions of downstream portions of rivers and streams and how that affects productivity?

much sunnier and nutrient rich and thus highly productive

where do downstream portions get nutrients?

autochthonous organic matter produced by algae and aquatic plants

what aquatic biome characterized by non flowing fresh water with some area of water thats too deep for plants to rise above water surface?

ponds and lakes

littoral zone in ponds/lakes (littoral→ lit→ sunlight→ vegetation)

the shallow area around edge containing rooted vegetation

limnetic zone in ponds/lakes

open water beyond littoral zone where dominant photosynthetic orgabisms are floating algae

benthic zone in ponds/lakes (benthic→ beneath→ bottom)

area with sediments at the bottom which is a habitat for burrowing organisms

stratification

the condition of lake/pond when the warmer, less dense surface water floats on the cooler, denser water below

describe the 3 layers of stratification

1) empliminion: surface layer of water

2) thermocline: middle depth of water that exhibits rapid decline in temperature

3) hypolimnion: deep layer of wate rin lake

in what layer of lake stratification does the most production occur?

epilimnion

what season is water stratified?

summer

whats the fall and spring overturn in lake/ponds?

the vertical mixing of lake water that occurs in early spring assisted by winds that drive surface currents

whats the name of the aquatic biome containing standing fresh water for at least part of the year?

freshwater wetlands

what kind of vegetation is present in freshwater wetlands?

shallow enough for emergent vegetation

whats the difference between swamps vs. marshes vs. bogs?

swamps are wetlands that contain emergent trees, marshes are wetlands that contain emergent non woody vegetation, and bogs have acidic water with dead plant material

salt marshes/esturaries

saltwater biome that contains non woody emergent vegetation

why are estuaries highly biologically productive?

contain abundant nutrients and sediments carried downstream by rivers

where do mangrove swamps occur?

along tropical and subtropical coast and esturaries

what function do mangrive trees serve?

prevent erosion of shoreline from incoming waves and provide habitats

intertidal zones

the narrow band of coastline between levels of hight tide and low tide

what does the coming and going f teh tide do in the intertidal zone?

fluctuating temperatures and salinity

coral reefs

found in warm shalow water above 20C year round with teh greatest species diveristy

how do corals and algae work together?

they exhibit a symbiotic relationship where corals produce CO2 and provide shelter/nutrients for algae while algae produces sugar to feed coral

when does coral bleaching occur?

when algae gets expelled from coral tissue

what 4 zones is the open ocean split into?

1) netritic zone

2) oceanic zone

3) photic zone

4) aphotic zone

netritic zone (netritic→ nemo→ high productivity)

beyond range of the lowest tidal level which extends to the end of continental shelf and is region of high productivity

oceanic zone

beyond netritic zone where nutrients are sparse and production is limited

photic zone

area of netritic and oceanic zones that contain sufficient light for photosynthetic algae

aphotic zone

area of netritic and oceanic zones where water is so depe that sunlight can’t penetrate leading to low productivity and chemosynthesis