Ecosystems Flashcards
What are biotic organisms?
Animals
Micro-organisms
Plants
What are abiotic features?
Soil
Climate
Relief and geology
What are Autotrophs?
Organisms that are capable of converting sunlight energy into food energy by photosynthesis.
What are Heteroptrophs?
Organisms that must feed on other organisms
What is a Detrivore?
an animal which feeds on dead organic material, especially plant detritus.
What 2 main processes do ecosystems rely on?
- The flow of energy
- The recycling of materials
What % of energy makes it from one level of a food chain to the next?
10%
What are the ways in which energy is lost within the food chain?
Respiration, Egestion, Heat loss, Decay of dead organisms, Movement
What is succession?
The succession of vegetation as it adapts to environmental changes.
What is climatic climax?
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.
What is a sere?
A sere is a stage in this sequence of colonisation by which the vegetation develops over a period of time.
What is a prisere?
A prisere is the complete sequence of events beginning with the first plants to occupy the area and finishing with the climatic climax vegetation.
What is Plagioclimax?
Plagioclimax is when human activity has permanently stopped and altered the natural vegetation.
What does psammosere succession need in order to fully develop?
- 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
What happens during the pioneer stage of psammosere succession? (Embryo and fore dunes)
- 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.
What happens during the ‘building stage’ of psammosere succession? (Yellow dunes)
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
What happens during the climax stage of psammosere succession? (Dune Heath)
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
Temperate Deciduous Woodland case study - Hayley Wood. List some general information about the area.
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.
Tropical Biome Case Study : The Amazon
List some general information/facts/figures
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.)
What are the climatic conditions of the Amazon?
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.
What types of vegetation can be found in the rain forests?
Ground vegetation Shrub layer Under Canopy Canopy Emergent Trees
Characteristics of vegetation in the rain forest?
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)
Causes of deforestation in the Amazon?
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.
Impacts of human activity in the Amazon
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.
