Ecosystems

Question 1

What are biotic organisms?

Answer 1

Animals
Micro-organisms
Plants

Question 2

What are abiotic features?

Answer 2

Soil
Climate
Relief and geology

Question 3

What are Autotrophs?

Answer 3

Organisms that are capable of converting sunlight energy into food energy by photosynthesis.

Question 4

What are Heteroptrophs?

Answer 4

Organisms that must feed on other organisms

Question 5

What is a Detrivore?

Answer 5

an animal which feeds on dead organic material, especially plant detritus.

Question 6

What 2 main processes do ecosystems rely on?

Answer 6

• The flow of energy

- The recycling of materials

Question 7

What % of energy makes it from one level of a food chain to the next?

Answer 7

10%

Question 8

What are the ways in which energy is lost within the food chain?

Answer 8

Respiration, Egestion, Heat loss, Decay of dead organisms, Movement

Question 9

What is succession?

Answer 9

The succession of vegetation as it adapts to environmental changes.

Question 10

What is climatic climax?

Answer 10

This is achieved when the largest, most dominant species that the environment will allow are established and the vegetation is in a state of equilibrium with its environment.

Question 11

What is a sere?

Answer 11

A sere is a stage in this sequence of colonisation by which the vegetation develops over a period of time.

Question 12

What is a prisere?

Answer 12

A prisere is the complete sequence of events beginning with the first plants to occupy the area and finishing with the climatic climax vegetation.

Question 13

What is Plagioclimax?

Answer 13

Plagioclimax is when human activity has permanently stopped and altered the natural vegetation.

Question 14

What does psammosere succession need in order to fully develop?

Answer 14

• A plentiful supply of sand
  Strong winds to transport sand particles through saltation
• An obstacle to trap the sand e.g. a plant, seaweed or driftwood.
• Plants are therefore central to the formation, growth and character of sand dunes

Question 15

What happens during the pioneer stage of psammosere succession? (Embryo and fore dunes)

Answer 15

• Seeds are blown in by the wind or washed in by the sea.
• The rooting conditions are poor due to drought, strong winds, salty sea-water immersion and alkaline conditions created by sea shells.
• The wind moves sand in the dunes and this allows rainwater to soak through rapidly.

Question 16

What happens during the ‘building stage’ of psammosere succession? (Yellow dunes)

Answer 16

Plants trap sand and grow with it, binding the sand together with their roots

The humus created by decaying pioneer plants creates more fertile growing conditions, and the soil becomes less alkaline as pioneer plants grow and trap rainwater

Less hardy plants can now grow and start to shade out the pioneers

As plants colonise the dunes, the sand disappears and the dunes change colour as a result of the increase in the humus content - from yellow to grey

Question 17

What happens during the climax stage of psammosere succession? (Dune Heath)

Answer 17

Taller plants (such as trees) and more complex plant species (like moorland heathers) can now grow

Plants from earlier stages die out because of competition for light and water

When the water table reaches, or nearly reaches the surface, dune slacks can occur. Plants which are specially adapted to be water-tolerant grow here

Question 18

Temperate Deciduous Woodland case study - Hayley Wood. List some general information about the area.

Answer 18

Owned and managed by the Cambridgeshire Wildlife Trust it occupies 150 hectares. Records show that it has been used and managed for over 700 years.

Soils are rich in humus due to a thick leaf litter that accumulates in Autumn when the leaves fall.

Broadleaved, deciduous woodland. Dominant species include oak, ash, elm, maple and willow.

Oak trees can support over 250 species of insect. Animal species include carnivores such as the fox, tawny owl and weasel and herbivores such as rabbits, field mice, squirrels and birds.

Grasses, brambles, ferns and wild flowers such as bluebells cover the floor in the spring.

Question 19

Tropical Biome Case Study : The Amazon

List some general information/facts/figures

Answer 19

Occupies an area more than 6 million km²
70% in Brazil - The largest tract rainforest
Area: 5.5million km² - Estimated home to 30% of species: Great diversity of plant species estimated 40,000 varieties & 2.5million species of insect
25% of drugs come from the Amazon
20% of Oxygen produced by Amazon rainforest
Location: 60% Brazil, 13% Peru (smaller proportions in Ecuador, Venezuela, Colombia, Suriname, Guyana, French Guiana.)

Question 20

What are the climatic conditions of the Amazon?

Answer 20

High average annual rainfall (>2000mm) with no dry season
Water losses from Amazon Basin result from river flow & export of atmospheric vapour to other regions. This loss is made good by an inward flux of moisture from the Atlantic Ocean.
High average annual temperatures between 25⁰C - 30⁰C - response to intense insolation throughout the year. Significant cloud cover ensures that maximum temps do not reach the extremes of subtropical desert climates.

Question 21

What types of vegetation can be found in the rain forests?

Answer 21

Ground vegetation
Shrub layer
Under Canopy
Canopy
Emergent Trees

Question 22

Characteristics of vegetation in the rain forest?

Answer 22

Lianas grow quickly towards the canopy to reach sunlight.
Drip tip leaves allow water to easily be shed
Leaves of canopy vegetation are large to catch any light that manages to penetrate the dense canopy layer.
Epiphytes set their roots into the trunk or branches of other plants enabling them to reach maximum sunlight.
Trees grow tall and straight to reach the canopy where maximum sunlight can be absorbed.
Large buttress roots support trees which can grow to 90m and have shallow roots systems in the ground due to the latosol. (Dominant - Kapok tree)

Question 23

Causes of deforestation in the Amazon?

Answer 23

Small farmers practicing slash and burn: once cleared land quickly becomes infertile.
Transmigration schemes encouraging land colonisation in the Amazon by the Brazilian government.
Schemes to improve access to the Amazon e.g. the building of the Trans-Amazonian Highway
HEP schemes: The Tucurui dam completed in 1984 creating Lago Tucurui which flooded 2250 km² of forest.
Mining: increases in gold and mineral mining leave areas cleared and greater volumes of suspended sediments and mercury in rivers.
Cattle ranching accounts of over 60% of deforestation in the Amazon. The beef has become an important export for Brazil; 80% of its beef is farmed in the Amazon.
Soybean production is increasing facilitated by the opening up of the rainforest. Brazil is now the 2nd largest producer of soybean after the USA.

Question 24

Impacts of human activity in the Amazon

Answer 24

Deforestation has contributed 10% of CO² to the atmosphere that would have been absorbed by the vegetation.
The burning of the forest adds further to greenhouse gas emissions
A reduction in the amount of oxygen produced.
The loss of plant, animal and insect species; many species are yet to be classified.
Only 1% of plant varieties have been tested by scientists in medical exploration; cures for AIDS and cancers could be found.
Increase in soil erosion and soil infertility.
Increase in levels of mercury in the water through mining
The loss of plant, animal and insect species; many species are yet to be classified.
Only 1% of plant varieties have been tested by scientists in medical exploration; cures for AIDS and cancers could be found.
Increase in soil erosion and soil infertility.
Increase in levels of mercury in the water through mining
There are over 200 indigenous tribes left in the rainforest. The traditional livelihood of these groups are being threatened by loss of land, conflict and new diseases.

Question 25

Strategies to manage the rainforest?

Answer 25

Since 1998, the Brazilian government has established many forest conservation areas. Amazon Regional Protected Areas now cover an area twenty times the size of Belgium. By 2015 44% of the Brazilian Amazon comprised of national parks, wildlife reserves & indigenous reserves where farming is banned. Several reforestation projects, sponsored by local authorities, non-governmental organisations (NGO’s) & businesses are underway, but so far progress has been slow, eg, in Rondonia in the Western Amazon. This sustainable forestry scheme aims to develop a 1000km² commercial timber plantation on governments-owned, deforested land. The plan is 20million fast-growing, tropical hardwood seedlings, planted on 4000 smallholdings, to mature over a 25yr period. Brazil is committed to restoring 120,000km² of rainforest by 2030.

Question 26

What is an urban niche?

Answer 26

An urban niche is a small scale area within an urban location where conditions are favourable for certain species to thrive. These may often be alien (or invasive) rather than native species.

Question 27

Characteristics of urban environments?

Answer 27

• Higher temperatures than in rural areas due to the urban heat island.
• less available water supply.
• high amounts of disturbance.
• high levels of air, water and noise pollution

Question 28

Describe the economic and environmental costs of the UK’s top 2 invasive species (Japanese Knotweed and buddleia)

Answer 28

The economic & environmental costs:

No 1 Japanese Knotweed
The plant absorbs pollution emissions which is why it was first planted. It grows at a rapid rate. Today it is recorded as the most aggressive weed within the UK, A rhizome root system can stem 20ft across and 9ft down. It cost £9million to clear the 2012 Stratford Olympic site.

No 2 Buddleia
1 plant creates 1000 offspring, colonises upon ballast as it is similar to alpine slopes (China), network Rail spends £3/4 million annually clearing Buddleia, small pellets applied to the stem of plant kills rhizome root system and prevents run-off (labour intensive).

Question 29

Describe the colonisation of a wasteland

Answer 29

The first pioneer colonisers on a gravel surface tend to be mosses. The mosses retain water and trap debris which accelerates soil formation allowing other plant colonisers

Invasive species (Ragwort & Buddleia), grasses and annual flowering plants. Initially these are small species but as conditions become favourable larger species such as thistle colonise and dominate the area and the pioneer plants can no longer thrive.

Woody plants such as brambles will colonise later and subsequently trees could invade the site if left without human disturbance for long enough.

St Werburghs, Bristol. (Case Study)

Question 30

Why are conditions favourable for plants along routeways? (Railways and motorways)

Answer 30

Routeways through and between urban areas have developed their own unique ecosystems, affected by:
- Construction techniques that lead to unique substrate conditions (e.g. the steep incline of a motorway verge or the balast of a railway line)
- Drainage systems
- Neglect and minimal human management
- Constant linear traffic movements, enhancing seed dispersion
- Addition of salt (e.g. high pH Ragwort, Buddleia)
Pollution