The living world

ecosystem

ecosystems are living communities of plants and creatures that, although diverse, share common characteristics

biotic

living (plants, animals, fungi, etc.)

abiotic

not alive but affects the ecosystem (rocks, the sun, relief, dead leaves, etc.)

producer

producers convert energy from the environment (mainly sunlight) into glucose. the most obvious producers are plants, which use photosynthesis

consumer

consumers get energy from the glucose produced by producers. a pond snail is an example because it eats plants. you can also get secondary, tertiary, etc. consumers

decomposer

decomposers break down plant and animal material and return the nutrients to the soil. bacteria and fungi are good examples of decomposers.

an example of a small scale UK ecosystem

Epping Forest:

• in southeastern England, northeast of London

• all producers, consumers and decomposers are interdependent

• interdependence demonstrated through nutrient cycling:

• e.g. visitors pick berries and flowers, which helps to spread the seeds which stick to their clothing

• variety of species with owls and sparrowhawks at the top of the food web, and deciduous trees and shrubs at the bottom

how can nutrients be transferred? (7 ways)

1. input dissolved in rainfall (into litter)

2. loss in runoff

3. fallout as tissues die

4. release as litter decomposes (into soil)

5. loss by leaching

6. input weathered from rock (into soil)

7. uptake by plants (into biomass)

the 4 layers of a tropical rainforest

1. emergents

2. canopy

3. under canopy

4. forest floor/shrub layer

features of the emergents layer

• giant trees above dense canopy

• trees have huge mushroom shaped crowns

• lots of sunlight

• low humidity

• strong winds

features of the canopy

• broad, irregular and dense trees

• lianas/vines and other plants

• 90% of forest organisms live here (attain nutrients from air and water)

• ample sunlight with occasional shade

• not exposed to much wind

• high temperature and rainfall

features of under canopy

• young trees and leafy herbaceous plants (tolerate low light)

• dark

• little sunlight: only 2-15% of the sunlight that falls on the canopy reaches this layer

features of forest floor/shrubs layer

• less than 2% of the sunlight

• only plants adapted to low light

• thin layer of fallen leaves etc

• only a thin layer of decaying organic matter (humus)

what is rainforest soil like?

mostly very infertile as it receives little sunlight and water, but the top layer (the humus) is very fertile due to decomposition.

how are plants adapted to the rainforest? (8)

• buttress roots

• stilt roots

• red leaves (protection from sunlight for saplings while internal organs are developing)

• lianas

• leaf angling (plant avoids shading its own leaves)

• drip tips

• epiphytes (these live on the surface of other plants to make the most of sunlight in the canopy)

• thin and smooth bark

what are some causes of deforestation?

• energy e.g. access to dams

• logging

• mineral extraction

• population pressure

• commercial farming (for plantations, cattle)

• subsistence farming (used by tribal communities, leaves carbon/nutrients in soil)

what are some impacts of deforestation?

• rainforests could completely disappear within 100 years

• forestry and agriculture produce 24% of greenhouse gases

• increase in climate change and global warming

• destruction of habitats

• biodiversity lost

why should we protect rainforests?

• climate change- trees remove CO2

• trees prevent flooding

• protect indigenous people

• preserve plants with medicinal properties

• they help generate rain

• lots of everyday resources e.g. paper, timber, fuel

• protect animals’ habitat and diverse ecosystem

• provide 28% of the world’s oxygen

how can rainforests be managed more sustainably?

cut down fewer trees and don't burn the excess, but leave it for homes for small animals

plant adaptations in cold environments (8)

1. grow close to the ground

2. small leaves- conserves water

3. shallow root systems- grows in active layer and avoids permafrost

4. grow in close proximity to one another

5. stems, bus and leaves and covered in small hairs

6. can photosynthesise in extremely cold weather

7. develop and produce seeds quickly

8. ability to survive on bare rock (lichen)

opportunities for development in Svalbard

• tourism

• coal mining- employs over 300 people, coal is exported

• starting point for arctic explorers

• fishing (Barents Sea is one of the richest fishing grounds in the world)

• mineral extraction

• energy production

challenges for development in Svalbard

construction, services, extreme temperatures, accessibility

why is construction difficult in Svalbard?

• thawing of permafrost could cause buildings to collpse

• very difficult to build houses due to high risk of sinking in summer

• most roads are dirt or gravel and raised above the ground surface

• houses are constructed to have steep roofs and triple glazing

why are services a challenge in Svalbard?

• must be kept above ground to prevent thawing of permafrost

• utilities (like sewage, gas) can’t be kept underground as they would freeze

• utilisers are built above ground out of wood to keep pipes insulated

why is accessibility a challenge in Svalbard?

• few roads, most use snowmobiles

• roads built on gravel pads to prevent heat transfer

• can only be reached by plane or ship

• most transport systems are just around Longyearbyen

• runways at airports are painted white to reflect heat and prevent heat transfer to permafrost (prevents sinking)

threats to Svalbard

coal mining: increased temperature, environmental impact

tourism: extended summer due to climate change, more cruises, risk of accidents increases

off road vehicles: soil erosion, nutrient leaching, water runoff

what are the threats posed to Svalbard by climate change?

• less ice, loss of habitat for polar bears and seals

• melting raises sea levels and affect weather patterns

• thawing ground can cause avalanches

• coal mines don’t close due to economic profit despite environmental impacts

why do cold environments need to be protected?

• habitats for many

• indigenous people live there

• important outdoor laboratories for scientific research

• beauty attracts tourists, economic benefit

• opportunities for forestry and fishing

• they are fragile

how are cold environments being protected?

• Worldwide Fund for Nature (WWF) Arctic programme works to protect biodiversity, launched in 1992

• the 1959 Antarctic treaty prevents exploitation of Antarctica

• NOAA monitor marine habitats