The Living World Flashcards
What is an ecosystem
A natural system that is made up of plants, animals and the environment in which they live.
What is a food chain?
The direct links between different organisms that rely on each other as a source of food.
What is a food web?
The complex hierarchy of plants and animals that rely on each other as a source of food within an ecosystem.
What is nutrient cycling?
Nutrients are foods that are used by plants and animals as they grow. Nutrients are derived from rainwater and weathering of rocks.
In a typical nutrient cycle, there are three main nutrient stores and several flows for transferring nutrients between stores.
Natural change of an ecosystem
Extreme weather events, such as flooding and drought
Fire caused by lightning strikes
Climate changes and global warming
Spread of invasive species or introduction of an alien species
Human-induced changes on an ecosystem
Land use change, such as deforestation and hedgerow removal
Alteration to water and soils, such as land drainage or adding fertilisers
Hunting or trapping of animals or birds
Causes of deforestation- subsistence farming and commercial farmimg
Increasingly land is cleared to make way for commercial farming- crop plantations and cattle grazing.
In Brazil, cattle ranching accounts for 80% of deforestation. Also in Brazil, soybeans, palm oil and sugar cane are major crops.
Malaysia is the largest exporter of Palm oil in the world. Huge areas of rainforest have been converted since the 1970s. Tax incentives for plantation owners encourage further development.
Causes of deforestation-Logging
Trees such as mahogany and teak are highly valued for furniture and other uses.
Smaller trees are used for fuel, pulped or made into charcoal.
Malaysia is one of the worlds largest exporters of tropical wood. Much of it involves clear felling, causing total habitat destruction.
Around 80% of deforestation in Malaysia is for logging.
Causes of deforestation- road building
Roads bring new supplies and precise access to new mining areas, new settlements and energy projects.
In Brazil. The trans-Amazonian highway stretches for some 4,000 kilometres through the rain forest.
In Malaysia, logging companies use an extensive network of roads for heavy machinery and to transport wood.
Causes of deforestation- mineral extraction
Mineral extraction is a major cause of deforestation in many countries.
In Brazil, minerals such as gold,bauxite and copper are min e extensively, causing huge scars in the landscape and polluting rivers. The largest iron ore mine in the world is at carajas, which is worked by 3,000 people, 24 hours a day.
Borneo has rich reserves of tin,copper and gold. Coal is an important source of energy, with 99% of Malaysia’s supply in Borneo. Tin mining is common in Malaysia.
Causes of deforestation-energy development.
High rainfall creates ideal conditions for hydro-electric power, and there are several large dams and reservoirs.
In Brazil, the belo monte dam(currently under construction) will block the river xingu, in the Amazon, flooding more than 40,500 hectares of rainforest and displacing more than 15,000 people.
In Malaysia,there are several dams supplying hydro-electric power including the Bakun dam, completed in 2011. It’s the highest dam in Asia. Supplies energy for industries in peninsular Malaysia. Drilling for oil and gas has started in Borneo.
Causes of deforestation- settlement and population growth
Settlements had developed to service the developments in the Brazilian and Malaysian rainforests, such as farmimg and mineral extraction. This has led to an increase in population.
