Unit 4: Sustaining Ecosystems

what is an ecosystem

the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment

how are organisms in ecosystems classed as

producers

consumers

decomposers

what is a producer

an organism that uses sunlight energy to produce food

what is a consumer

an organism that gets its energy by eating other organisms

what is a decomposer

an organism that gets its energy by breaking down dead material

how do decomposers cycle nutrients

after decay, the nutrients return to the soil

these are then used by plants

what is interdependence

when each species in a community depends on other species

if one species is removed it can affect the whole community

what can species rely on other species for

food, shelter, pollination, seed dispersal etc

what are the six major ecosystems

hot desert

polar

temperate forests

tropical rainforests

grassland

coral reef

where are hot deserts found

between 15° and 35° north and south of the equator

what is the climate of hot deserts

little rainfall, less than 250 mm per year

may rain once every two to three years

extreme temperatures, very hot in the day to cold at night

what is the flora of hot deserts

lack of rainfall so sparse plant growth

but cacti and thornbushes grow

what are the adaptations of flora in hot deserts

long roots to reach deep water supplies

roots spread out to catch as much water as possible

fleshy stems and thick, waxy skin to cope with dry climate

what is the fauna of hot deserts

lizards, snakes, insects, and scorpions

mammals are small

what are the adaptations of fauna in hot deserts

birds leave during the hottest weather

many nocturnal animals so they can stay in burrows / shade

animals lose very little water

where are polar ecosystems found

around the north and south poles

what is the climate of polar ecosystems

temperatures often less than 10°C

\-40°C to -90°C in winter

low precipitation, no more than 500 mm a year

cold summers and even colder winters

what is the flora of polar ecosystems

very few plants, some lichens and mosses on rocks

few grasses and flowering plants on the warmer coasts

small, short trees and shrubs in warmer sheltered areas

what are the adaptations of flora in polar ecosystems

plants grow slowly and not very tall

what is the fauna of polar ecosystems

relatively few different species of animals

polar bears, penguins, whales, seals, and walruses

what are the adaptations of fauna in polar ecosystems

migration to warmer areas

hibernate during winter

layers of blubber / fur act as insulation

where are temperate forests found

mainly in the mid-latitudes

between tropics and polar regions (60°N/S)

what is the climate of temperate forests

four distinct seasons with warm summers and cool winters

high rainfall all year round, up to 1500 mm per year

what is the flora of temperate forests

deciduous trees (oak), shurbs (brambles), undergrowth (ferns)

forest-floor plants, such as bluebells

coniferous forests, such as pine and larch

what are the adaptations of flora in temperate forests

deciduous trees drop leaves in autumn

forest-floor plants flower in spring before trees grow leaves

coniferous trees are evergreen to make use of sunlight

what is the fauna of temperate forests

foxes, squirrels, woodpeckers

beetles, moths, mosquitoes

trout and salmon

where are tropical rainforests found

found at the equator

at the intertropical convergence zone (ITCZ)

what is the climate of tropical rainforests

same all year round, no definite seasons

hot all year as they are around the equator

high rainfall, around 2000 mm per year

rains every day, ususally in afternoon

what is the flora of tropical rainforests

evergreen trees and dense vegetation cover

four layers: emergent, canopy, under-canopy, forest floor

what are the adaptations of flora in tropical rainforests

evergreen to take advantage of continual growing season

little light reaches forest floor so trees are tall

have shallow buttress roots to support trunks

large leaves to absorb as much light as possible

what is the fauna in tropical rainforests

have more animal species than any other ecosystem

gorillas, jaguras, anacondas, tree frogs, sloths

many insects and birds

what are the adaptations of fauna in tropical rainforests

camouflaged to hide from predators

nocturnal animals (sloths) since it’s cooler at night, saving energy

what are the two types of grassland

tropical savannah grasslands

temperate grasslands

where are tropical savannah grasslands found

found between the tropics

what is the climate of tropical savannah grasslands

low rainfall, 800-900 mm per year

distinct wet and dry seasons

hot before wet season (35°C), and cold just after it (15°C)

what is the flora of tropical savannah grasslands

mostly grass, scrub, and small plants

few trees, such as acacia

what are the adaptations of flora in tropical savannah grasslands

long roots to reach deep water

small, waxy leaves reduce water loss

what is the fauna in tropical savannah grasslands

lots of insects, such as grasshoppers, beetles, and termites

lions, elephants, giraffes, zebras, and antelope

where are temperature grasslands found

found at mid-latitudes

what is the flora of temperate grasslands

grasses and small plants

very few trees

what are the adaptations of flora in temperate grasslands

grasses often have roots that spread out wide

absorb as much water as possible

what is the fauna of temperate grasslands

fewer animal species than savannah

bison, mole rats, and wild horses

what are the adaptations of fauna in grasslands

grazing animals travel long distances in search of food and water so they are camoflauged

mole rats dig burrows to escape climate

where are coral reefs found

between 30° north and south of equator

a few miles off the coast

what is the climate of coral reefs

often in warm areas with lots of sunlight

grow best in shallow, clear, salty water

what is the flora of coral reefs

form underwater so few plants grow there

tiny algae live inside the tissue of corals

algae and coral are interdependent

what is the fauna of coral reefs

coral is an animal, like a sea anemone

25% of all marine species live in coral reefs

fish, molluscs, sea snakes, turtles, and shrimps

what are the adaptations of fauna in coral reefs

some coral species have a hard outer coating for protection

fish have flat, streamlined bdies so they can swim and hide in small gaps in the coral

what are the 5 stages of the water cycle

water evaporates after being heated by the sun

transpiration from plants releases water vapour

water vapour is moved by winds

water vapour condenses to form clouds then falls as rain

water flows from one place to another and is stored on land

water eventually ends up in the river / sea, so cycle repeats

why are evaporation rates high in tropical rainforests

the sun is usually overhead so it is always hot

why is rainfall high in tropical rainforests

high evaporation rates means there’s lots of water vapour

why is lots of water stored by plants in tropical rainforests

vegetation is very dense so water is intercepted

what are the stages of the nutrient cycle in tropical rainforests

trees are evergreen so dead leaves and other material fall all year round

warm moist climate means fungi and bacteria decompose quickly, releasing nutrients into the soil

rainwater soaks into the soil and the nutrients are dissolved in the water

dense vegetation and rapid plant growth means nutrient rich water is rapdily taken up by plant roots

what are the characteristics of tropical rainforest soils

very deep. bedrock can be up to 30 m below surface

only have a very thin fertile layer

generally nutrient poor

why are tropical rainforest soils deep

hot wet climate means chemical weathering is rapid

why is there a thick leaf layer

the trees drop their leaves all year round

so there is a constant supply of dead leaves and twigs falling onto the soil suface

how does the humus layer form

the thick leaf layer is quickly broken down

and the humus gets mixed with the soil

why is the humus layer thin

the high density, fast growing plants quickly absorb the nutrients

why is the soil nutrient poor

nutrients are leached (washed downwards) by heavy rainfall

they go through the soil to the bedrock

where in the soil do trees grow their roots

they have roots close to the surface where the nutrients are

there are lots of roots in humus layer

what products are sourced from tropical rainforests

rubber, coffee, chocolate, medicines

how do hardwoods from tropical rainforests benefit humans

mahogancy is used for high-end furniture and buildings

logging of hardwoods contributes to a country’s economy

how do tropical rainforests provide jobs

if vegetation is cleared, farming and mining can take place

this increases income in rainforest areas

how do tropical rainforests benefit the environment

highest diversity of animal and plant species on planet

0\.7 billion tonnes of CO2 absorbed each year

how do rainforests use water to benefit the world

rainfall intercepted by dense vegetation

reduces risk of flooding as less water enters rivers

regulate global water cycle by storing water and releasing it into the atmposhere slowly, reducing drought and flooding

what are the negative impacts of logging

soil becomes less stable so heavy rain washes away soil

eroded soil enters rivers, affecting fish

interrupts water cycle, flooding and drought / wildfires

logging requires the building of new roads in rainforests

what are the negative impacts of agriculture

land often cleared using slash-and-burn, producing CO2

less trees so nutrients are washed away reducing soil fertility

artficial fertilisers are washed into streams harming wildlife

what are the negative impacts of mineral extraction (rainforest)

needs heavy machinery and removal of trees

toxic chemicals are used to extract and purify metals

they are washed into streams and rivers, killing wildlife and polluting drinking water

what are the negative impacts of tourism (rainforest)

tourists may scare wildlife and damage vegetation

vegetation must be cleared to build infrastructure

tourists will leave litter

what is the arctic defined as?

the region north of the Artic Circle, around 66°N

what is the climate of the arctic?

average summer temperatures are less than 10°C

winter temperatures are about -20°C to -40°C

precipitation is less than 500 mm per year

what is the climate of the antarctic?

colder than the arctic

summer: -20°C to -5°C winter: drops to -90°C

50 mm precipitation inland and 200 mm at the coast

what are the features of the arctic land

mountainous regions

areas permanently covered in snow and ice

treeless tundra with soil that thaws in the summer

what are the features of the antarctic land

land mass that is 99% ice sheet

few mountains poke up out of the ice

what are the features of the arctic sea

majority is made up of ocean

lots of drifting pack ice and icebergs

sea ice extends further in winter

what are the features of the antarctic sea

freezes in the winter

this nearly doubles the size of the continent

what is the flora of the arctic

low growing shrubs, licken, moss

some flowering plants, eg: arctic poppies

what is the flora of the antarctic

much less vegetation

mainly moss and lichen

sea has phytoplankton

what is the fauna of the arctic

whales, seals, fish

wolves, polar bears, reindeers, caribou

lots of birds

what is the fauna of the antarctic

whales, seals

penguins, seabirds

mostly rely on the sea

what are the negative impacts of tourism (polar)

increases shipping and air travel leading to pollution

litter damages habitats and harm wildlife

introduction of non-native species alter food webs

what are the negative impacts of fishing

threatens many species, eg Patagonian Toothfish

this affects other species in the food chain

other species may be affected by fishing practices

what are the negative impacts of scientific research

scientists dump rubbish and broken equipment into the sea

research stations and ships produce chemical pollution

sewage pollution produced from stations

what are the negative impacts of mineral extraction (polar)

drilling for oil and gas is risky due to oil spills

pipelines must be built which can melt permafrost

causes lots of pollution which damages ecosystems

what are the negative impacts of whaling

many species of whale are close to extinction

eg: Blue, Fin, and Minke

whales are very slow breeders so long population recovery