Ecosystems and Biodiversity

Question 1

Abiotic factors affecting ecology:

Answer 1

climate- the temperature and amount of rainfall are very important for determining what species can survive in the ecosystem

soil - the soil type is important as this provides nutrients that will support different plants

water - the amount of water available in an ecosystem will determine what plants and animals can be supported

Question 2

What is an ecosystem?

Answer 2

The living organisms in a particular area, together with the non-living components of the environment.

Question 3

What are local factors that affect the distribution of large-scale ecosystems?

Answer 3

Rock and Soil type-leads to different vegetation
Altitude differences-Lower the temperature , for every 100m gain in height, temperature drops by 1c

Question 4

Where are Tropical rainforest located?

Answer 4

Directly either side of the equator

Question 5

Where are deserts likely to be found?

Answer 5

Close to both tropics

Question 6

Where is tundra likely to be found?

Answer 6

Close to the arctic circle

Question 7

What is a biome?

Answer 7

A distinct geographical region with specific climate and specific fauna and flora

Question 8

Why does TRF not have seasons?

Answer 8

The equator is not affected by tilt

Question 9

What is the biosphere?

Answer 9

The part of the world made up of living organisms.

Question 10

What 3 factors affect the climate of a biome?

Answer 10

Latitude, air pressure and winds

Question 11

What are the 4 main terrestrial ecosystems of the Uk and their characteristic?

Answer 11

Moorlands are found in upland areas, mainly in Scotland, where estimates suggest they make up between 38% and 50% of the total land area. The Cairngorms and the Southern Uplands are an example of this kind of area. They have low growing grasse and peatbogs and historically used for grouse hunting.

Heathlands have been highly fragmented and only small, isolated areas exist in Breckland, Surrey, Hampshire and Dorset and the Lizard Peninsula in Cornwall. They can be dry and sandy or marshy with distinctive species.

Only 13% of the land area of the UK is made up of woodland. Woodland makes up 10% of land in England, 15% in Wales, 19% in Scotland and 9% in Northern Ireland. A large proportion of these are less than 100 years old and very few could be considered ‘ancient’ woodlands. In England they are mainly made up of broadleaf
deciduous while in scotland it is coniferous.

Wetland: Rare but to mostly the eastern side of the country. They are rare due to the fact that have been drained to make farmland in the UK. Characteristics include low nutrients, waterlogged soil with distinctive plants and animals.

Question 12

What is the inter tropical convergence zone?

Answer 12

The Intertropical Convergence Zone is a band of low pressure around the Earth which generally lies near to the equator.

Question 13

How are Marine ecosystems important to the UK?

Answer 13

Tourism-An estimated 250m visit the UK’s coast annually generating income for the local economy and providing employment
Energy-Wind energy helps the UK reduce reliance on fossil fuels and meet carbon targets. In fact the London Array is the world’s largest offshore wind farm.
Fishing-Marine ecosystems provide jobs in commercial fishing and in fish processing industry

Question 14

How is marine ecosystems being degraded?

Answer 14

-development of coastline leads to habitat loss
-Overfishing of fish species like cod in the North Sea can impact the food chain and damage the wider ecosystems
-Eutrophication where fertilisers and other chemicals used by farmers reach into the sea and pollute

Question 15

What is a gersmehl model?

Answer 15

A model that shows hoe nutrients are transferred across an ecosystem
3 main stores of nutrients-Soil Biomass and Litter

Question 16

What is the stratification of the TRF from lowest to highest?

Answer 16

ground level
shrub layer
under canopy
canopy
emergents

Question 17

Describe the gersmehl model of A TRF?

Answer 17

Biomass is the largest store of nutrients
nutrients are recycled quickly due to rapid decomposition of dead matter due to warm wet conditions
Weathering is high due to warm moist conditions but nutrients usually get leached out
Leaching is high as heavy rainfall so many nutrients lost
Uptake is high due to the amount of species
Fallout is low due to there being no season so leaves dont drop

Question 18

Plant adaptations in the TRF?

Answer 18

Buttress roots for anchorage
Drip tips on leaves which stop algae forming on water on leaves blocking light for photosynthesis

Question 19

Animal adaptations in the TRF?

Answer 19

Monkeys have prehensile tails for climbing
Many animals like chameleons have camouflage to evade predation

Question 20

TRF goods and services

Answer 20

Goods are tangible items:
Services are intangible activities or benefits:

Goods:
Food for locals
Hardwood Timber like rosewood
Plant compounds used for drugs(over 7000)
oxygen

Services:
Home for some tribes
Carbon store
Tourism
Maintaining Biodiversity

Question 21

Effects of Climate change on TRF

Answer 21

Structure of TRF:
-Drier process slow down decomposition (Litter store higher)
-Animals have to hibernate or live on stored food
-Some trees swell trunks to store water
Function of TRF:
-More surface runoff as less vegetation for infiltration
-Drier forests emit more CO2 than soak up and the risk of Forest fires adds immense amounts of CO2
Biodiversity:
-Plant species that couldnt tolerate die or get outcompeted
-Spread of Pests and Diseases that can tolerate these conditions
-Migration
Extinction of species

Question 22

Causes of deforestation in TRF:

Answer 22

Farming
Logging - tropical rainforests are cut down so that valuable trees like mahogany can be accessed and sold for timber to make furniture. Other trees are cut down for making paper products.
Mining
Roads - the construction of access roads for farmers, loggers and miners results in large parts of the tropical rainforest being destroyed.
Hydroelectric power(HEP) -

Question 23

What is Slash and burn agriculture?

Answer 23

Where forest is cleared and crops planted and when nutrients exhausted another forest is cleared.

Question 24

Impacts of deforestation in TRF:

Answer 24

Soil erosion
Once the land is cleared of rainforest vegetation the soil is left bare. When it rains, the nutrients in the soil are washed away. The
nutrient cycle stops because there are no plants or trees shedding leaves to replace the nutrients in the soil. The soil is no longer able to support plant life because it is not fertile. The roots of plants and trees no longer hold the soil together so it is easily eroded.

Loss of biodiversity
Many different species of plants and animals die because of deforestation. As plants and animals are closely connected through the food web, deforestation this reduces the
biodiversity, or variety of species found in the tropical rainforest.

Climate change
The trees and plants of the Amazon Basin absorb carbon dioxide during the process of
photosynthesis. If there are fewer trees and plants, due to deforestation, then less carbon dioxide is removed from the atmosphere. In this way deforestation contributes to
global warming and therefore climate change.

Economic development
The creation of mines, farms and roads - which caused deforestation - has also led to economic development. The money created from these enterprises allows a country to generate foreign income, which can then be used to pay off debts or be invested in further development projects.

Question 25

Describe the gersmehl model of Deciduous Woodland(DW)

Answer 25

Biomass and soil stores are larger than the litter store but are same size

Deep tree roots break up the bedrock, and weathered rock adds those nutrients to the soil

Leaching is less significant in the soil store and soil fertility is higher due to mixing by earthworms

Litter is

The rates of nutrient cycling is moderate

Question 26

Stratification of DW

Answer 26

Herb-Subcanopy-Canopy

Question 27

Characteristics of DW?

Answer 27

-Trees that shed leaves in autumn to cope with lower light which means lower photosynthesis so trees lay dormant in the winter
-Deep roots for breaking up rock and access groundwater and minerals
-Well developed humus at the top of the soil
-Herb layer plants flower early as there is light before the canopy blocks it when leaves grow back

Question 28

Why do DWs have low biodiversity

Answer 28

-Lower food production in the winter
-smaller size ecosystem than TRF
-Higher latitudes- lower temperature and little light means low photosynthesis for plants

Question 29

Animal and Plant adaptations in DWs:

Answer 29

Animals:
Squirrels burying acorns to use in spring
Hedgehogs hibernate through the winter
Plants:
Trees drop leaves to conserve water by reducing transpiration through leaves
Trees spread their branches wide for greater acces to sunlight

Question 30

Goods and Services of DW:

Answer 30

Goods:
-Timber
-Wild food
-Wood pellets for fuel
Services:
-Carbon store
-Rare plant and animal species
-Tourism and recreation

Question 31

Threats to DW:

Answer 31

-Replanting with Conifers for timber industry as conifers grow faster and easier to manage
-Pesticide Damage
-Deforestation for farmland, roadbuilding and land for new homes

Question 32

Assess the view that climate is the most important reason why tropical rainforests
have higher biodiversity than deciduous woodlands.

Answer 32

Deciduous woodlands have only moderate biodiversity compared with
tropical rainforests.
* The tropical rainforest biome is the most productive on Earth because it
has optimum conditions for plant growth which, in turn, supports very
high animal biodiversity.
* These conditions include high levels of insolation; high monthly
temperatures (with very little seasonal variation) and high levels of
precipitation.
* These conditions mean that photosynthesis is rapid.
* These abiotic conditions also drive the rapid cycling of nutrients owing to
rapid decomposition of dead organic matter.
* In the deciduous woodlands the conditions are less favourable for growth
with cold winters (with limited sunlight) being the main limiting factor.
* Nutrient cycling is also less rapid as the rate of decomposition is slower.
* The tropical rainforest biome has also been in existence for millions of
years and has had a long time to develop its biodiversity.
* The area covered by the tropical rainforest biome is huge which has
helped the development of a higher biodiversity.

Naturally, climate is a very significant factor in explaining the difference
in the levels of biodiversity.
* It plays a key role in controlling the distribution of each biome and their
biodiversity.
* The high levels of sunlight, temperature and precipitation (with very
limited seasonal variation) are the key factors in the tropical rainforest
biome- in comparison with the deciduous woodlands.
* In the past human impact was a huge factor affecting biodiversity in
deciduous woodlands with the large-scale clearance for agriculture from
Roman times onwards.

Question 33

Assess the importance of the impact of human activity on deciduous woodland
ecosystems.

Answer 33

 A wide range of human activity is having a negative impact on
the biodiversity, structure and function of deciduous woodland
ecosystems:
- Deforestation
- People walking through woodlands, riding horses etc
- Climate change (increased temperatures, drought, more
storms)
- Introduction of alien species and diseases (e.g. ash die back)
 While many of these impacts are negative there are some
attempts to reduce their impact and even have a more positive
impact:
- Conservation
- Afforestation
 While human factors are having an increasing impact, physical
factors are also important.
 They are fundamental in determining the distribution and
function of this ecosystem.
 They can also lead to changes in the ecosystem – for example,
droughts occur naturally which can have an impact.
 Natural processes also interact with human impacts in relation to
climate change, for example.

 Naturally, climate is a very significant factor.
 This plays a key role in controlling the distribution of deciduous
woodlands and, as a result, the nature and functioning of the
nutrient cycle.
 Other physical factors that play a role include altitude and soils.
 These are, in turn, related to climate.
 However, the impact of human activity is increasing at a variety
of scales.
 The enhanced greenhouse effect is leading to global warming
(and other changes in climate) which may be affecting the
distribution of deciduous woodland – and the functioning of the
nutrient cycle.
 At a more localised level, deforestation may be having a negative
impact although there have been more recent moves towards
conservation of existing areas and also afforestation.