Flashcards in Topic 7 And 8 Revision List Deck (17):
7.1 How are major biomes (tropical, temperate/ boreal, temperate grasslands, deserts and tundra). Are influenced by climate.
Tropical- warm, wet all year round meaning very biodiverse.
Desert- hot dry and cold at night. Few organisms can survive.
Tundra- Cold, icy, dark- only well adapted organisms survive.
Temperate- mild, wet. Less species than tropical but more than boreal. Rich soil.
Boreal- cold, dry. Most evergreen, few animals; less food, nutrient poor soil.
Tropical Grasslands- low rainfall, lots of sunshine, scrubs and small plants, many insects, and mammals, nutrient is washed in rain season.
Temperate grasslands- hot summer cold winter, lower rainfall. Few trees, fewer animals than tropical, nutrient rich soil.
b. Local factors (altitude, rock and soil type, drainage) can alter the biome distribution locally and how the biotic (flora, fauna) and abiotic (soils, rock, water, atmosphere) components of biomes interact.
Altitude- cold temperature so limited plants; poor soil.
Rock type- some are easily weathered to for soil, could be impermeable or have good nutrients.
Soil type- more nutrient rich support more plants. Acid plants only support acid tolerant plants, clay soils are less permeable.
Drainage- poor drainage leads to water logging. Only well adapted or marine plants may grow.
Biotic- living. Plants (flora) animals (fauna).
Amount of water affects type of plant.
Type and density of plants can effect the soil.
Trees can do biological weathering, tree roots breaking up roots.
How the biosphere provides resources for indigenous and local people (food, medicine, building materials and fuel resources) but is also increasingly exploited commercially for energy, water and mineral resources.
Food- mist indigenous people get food from plants/ animals. (Fish, fruit, nuts). Others grow vegetables.
Medicine- plants have created over 7000 drugs.
Building materials- trees from taiga woods are used for furniture. Sap can be used as glue. Reeds and straw used for roofs.
Fuel- indigenous people need dried dung for cooking food.
Exploit energy- increasing demand means large areas cleared for crops for biofuels, coal mines or power stations. Drilling oil damages trees.
Water- lakes are exploited making areas mire arid damaging ecosystem.
Minerals- mines cause deforestation and pollution of chemicals in streams.
How the biosphere regulates the composition of the atmosphere, maintains soil health and regulates water within the hydrological cycle, providing globally important services.
Plants take in CO2 and give out oxygen. Animals do the opposite.
Plants and animals spread nutrients through the soil helping structure and fertility. Roots stop wind and rain from braking soil apart. Vegetation intercepts rainfall which prevents leaching.
Water is taken up by plants meaning less reaches the river which prevents flooding and soil erosion. Plants release water to the atmosphere helping to regulate the water cycle and reduce drought.
The global and regional trends increasing demand for food, energy and water resources (population growth, rising affluence, urbanisation and industrialisation) and theories on the relationships between population and resources (Malthus and Boserup).
The globes population is increasing meaning the demand for resources is becoming greater.
Wealthier people have more disposable income increasing their resource consumption. Mire electrical/ water appliances raise requirements.
Urbanisation means there are mire areas which are more resource intensive, eg neon signs, fountains. Food and water needs to be transported further and waste needs to be disposed of.
Industrialisation- manufacturing goods needs a lot of energy. (Washing/ components). Processed goods increased, eg palm oil.
Malthus- when the population became too much for resources, people will be killed in catastrophes until it is balanced.
Boserup- however big the population, the world will always produce enough resources. They will find new ways (technology)
How biotic and abiotic characteristics are interdependent (climate, soil, water, plants, animals and humans), how plants (stratified layers, buttress roots, drip tips) and animals are adapted to the climate.
Biotic features need energy from the sun (abiotic) to survive. warm climate means plants grow faster which protects the forest floor. Animals eat plants and humans eat animals.
Each layer is stratified. Shrub layer, plants have large broad dark leaves. Undercanopy- younger trees can survive where there are breaks in the trees. Main canopy- only have leaves at the top so they can survive. Emergents are at the top with straight trunks and have the most sunlight. Buttress roots support the trunk. Drip tip leaves allow water to drop of so mould doesn't form. Some animals have strong limbs for climbing, can glide between trees, camouflage, nocturnal (cooler at night for sloths it saves energy), sharp sense of smell and hearing, can swim river channels.
Why tropical rainforests have a very high rate of nutrient cycling which, in turn, supports high levels of biodiversity and complex food webs.
Trees are evergreen so dead leaves fall all year round, warm moist climate means bacteria and fungi decompose quickly. Dense vegetation and rapid growth means nutrients are taken up quickly by plants. There has been a lot of time for plants and animals to adapt, the layered structure supports different species, stable environment means animals don't have to cope with change.
Food webs are complex because there are many different species and some animals can be both primary and secondary eg fruit bats who est bananas and mice.
How biotic and abiotic characteristics are interdependent (climate, soil, water, plants, animals and humans), how taiga plants (cone-shaped, needles, simple structure) and animals (migratory) are adapted to the climate.
Cone shaped trees allow snow to fall off branches more easily so they can photosynthesise. Needles meaning water loss is reduced from winds. They have a simple structures because only specific trees can survive the climate. Migratory mammals move long distances through the forest in order to find food. Well insulated, hibernate, camouflage.
Why the taiga has lower productivity, with less active nutrient cycling and much lower levels of biodiversity.
Nutrient cycle is slow because low temperatures mean that needles decompose slowly as the conditions are too harsh for many decomposers. Plants also grow slowly in the cold so nutrient transfer is slow.
Not biodiverse because species have less time to adapt, simple structure means not many habitats, growing season is only a few months, many under represented animals like amphibians.
Causes of deforestation: commercial hardwood logging, subsistence and commercial agriculture, local demand for fuel wood and how demand for biofuels, mineral resources and electricity (HEP) contribute to deforestation.
Hardwood logging- trees are cut down so they can be made into furniture and fir buildings. Fossil fuels- trees are cleared so fossil fuels can be extracted . Local demand for fuel is increasing so more fuels are being mined. Tiaga forest have rich minerals (iron gold copper) underneath the surface so many trees are cut down so these can be mined. HEP can cause flooding which destroys trees as well as trees needing to be cleared so the damn can be built.
Why climate change is an indirect threat to the health of tropical rainforests (ecosystem stress, drought).
Temperature is increasing and rainfall is decreasing which leads to drought. This puts stress on the ecosystem as the rainforest is adapted to moist conditions. Drought can also lead to forest fires which could kill many species and even leave some extinct.
Direct threats from logging for softwood, pulp and paper production and indirect threats resulting from the exploitation of minerals, fossil fuels and HEP potential.
Loggins soft wood leads to deforestation which could damage the nutrient cycle and therefore the ecosystem. Pulp paper involves mashing up fallen trees which releases harmful gases. Large areas have to be cleared so that the minerals under Tiaga forests can be mined. HEP can kead to flooding which destroys trees as well as trees needing to be cleared so the damn can be built.
How acid precipitation, forest fires, pests and diseases and forest fires contribute to a loss of biodiversity.
Acid precipitation can damage leaves and roots making it more difficult for the plants to cope with the cold. It can poison any animals who eat the plants or any species that live in water. Increase in forest fires destroy huge number of frees and change the distribution of species as some species are better at recolonising areas. Makes it hard for migratory animals as there is less space to find food. Pests can wipe out large numbers of trees as many pests are specific to one species and as there is a limited species in the rainforest pests can target one species and wipe out large amounts of trees.
Advantages and disadvantages of global actions (CITES, REDD) designed to protect tropical rainforest species and areas and why deforestation rates are rising in some areas but falling in others.
REDD- Advantages: delas with direct causes of deforestation. Protects habitats and biodiversity. Relatively cheap. Disadvantages- prevents activities (mining) which may negatively affect local communities)
CITIES- advantages-Tackled at a global level! Raises awareness of biodiversity threats through education.
Disadvantages- it protects species but mot their habitat, some rules are unclear (trade pf ivory), not all countries are members.
The challenge of achieving sustainable forest management and why alternative livelihoods (ecotourism, sustainable farming) might better protect the remaining tropical rainforest.
Poor countries need income immediately and sustainable forestry is more expensive also making it difficult for private companies to follow methods. Funded by unreliable NGOs. Replaced tees may not resemble natural forest, may not restore ecosystem. Even selective logging can damage large amounts of trees. Sustainable forest management provides fewer jobs. Ecotourism raises awareness for deforestation and employs local people so they don't have to log or farm. Agro forestry- trees planted at the same time so roots bind the soil and leaves protect it from heavy rain. Crop rotations crops are moved to fields to recover the soil. Green mature- plants which add nutrients to the soil are planted.
Challenges of creating and maintaining protected wilderness areas, national parks and sustainable forestry in the taiga.
Large remote areas are hard to police, there is economic pressure from governments to log and mine the areas for resources. There is pressure from companies and tourist to build roads and cut through these wilderness areas. National parks must conciser the needs of indigenous people (hunting). Access roads and pollution from tourists may damage the area. Some countries struggle to enforce sustainable forestry; illegal logging takes place. May be a lack of clear management, different groups may not agree with the rules (loggers indigenous people.)