| Population density | The number of people in a given area, usually in 1000km |
| Population distribution | Where populations of people either do or do not live |
| Lag phase | The period in population growth when an organism is adapting to its new environment and growth is slow |
| Log (exponential) phase | When the growth rate of a population increases rapidly over time |
| Carrying capacity | The maximum size of a population that an environment can support in terms of food, water and other resources |
| Birth rate | The total number of live births over time |
| Death rate | The total number of deaths over time |
| Factors affecting birth rate and death rate | lack of access to birth control, availability to medicine, farming communities in LEDC's need a bigger family for farm work |
| factors affecting migration | weather events, poverty, famine |
| ways to manage population size | family planning, improved health & education, national population policies |
| pronatalist | A national or regional policy that aims to encourage couples to have children |
| antinatalist | A national or regional policy that aims to discourage couples from having children |
| Ecosystem | All the living things (biotic components) together with all the non-living things (abiotic components) in an area |
| Population | All the organisms of one species living in a defined area |
| Community | A group of populations of different species that live together in an area and interact with each other |
| Habitat | The place within an ecosystem where an organism lives |
| Niche | The role of a species within the ecosystem |
| Biotic | Living components of the environment that may affect other living things |
| biotic components examples | producers, primary, secondary, tertiary consumers, decomposers |
| Abiotic | Non-living components of the environment that may affect other living things |
| abiotic components | temperature, humidity, water, oxygen, salinity, light, pH |
| Predation | when one organism eats another with usually the larger being the predator |
| Pollination | is the transfer of pollen from a male anther to the female stigma of a flower |
| Competition | for the resources available (light, food, space, mates) occurs between different species and within a population of a species |
| role of chlorophyll | absorb sunlight used for photosynthesis |
| word equation for photosynthesis | glucose + oxygen → carbon dioxide + water |
| causes of habitat loss | drainage of wetlands, intensive agriculture practices, deforestation |
| impacts of habitat loss | extinction, loss of diversity and genetic depletion |
| genetic depletion | The loss of species containing potentially useful genes |
| biodiversity | the variety of plant and animal life in the world or in a particular habitat, a high level of which is usually considered to be important and desirable |
| causes of deforestation | timber extraction and logging, subsistence and commercial farming, roads and settlements, rock, mineral extraction |
| role of forests within the water cycle | Forests add water to the atmosphere in the process of respiration. This leads to the formation of clouds. Eventually the clouds release the water back as precipitation |
| role of forests with carbon sinks and carbon stores | A vegetated area where the intake of carbon dioxide from the atmosphere in photosynthesis exceeds its output from respiration, so the net flow of carbon is from the atmosphere into plants. |
| ways of estimating biodiversity | pitfall traps, pooters, quadrats and transects |
| what is a quadrat | A frame of known area used to sample organisms that do not move, such as plants. It is used to measure abundance by recording: the number of an individual species |
| what is a pitfall trap | A pitfall trap consists of a jar sunk up to its rim in the soil. The top may or may not be covered, depending on the predicted likelihood of rainfall. |
| what is a pooter | A simple piece of equipment for getting the animals out of the net and into a specimen container |
| Strategies for conserving biodiversity and genetic resources | National parks, ecological reserves, extractive reserves, world biosphere reserves, seed banks, role of zoos, captive breeding, sustainable tourism, ecotourism |
| National parks | National parks are areas created by the government where wildlife is protected by certain laws. This makes a safe space for animals to have their habitats and to reproduce. |
| ecological reserves | National parks and ecological reserves differ only in size with ecological reserves being generally being smaller. |
| extractive reserves | Extraction reserves are things that attempt to find a balance between destroying the forest for short-term benefits and stopping all economic activity |
| seed banks | A seed bank is a place where seeds are stored to preserve genetic diversity for the future. |
| role of zoos and captive breeding | They are good at providing education about the illegal trading in animals and products |
| sustainable tourism | Sustainable tourism is very important because it brings in income which can be reinvested into a reserve, measures can be taken to protect the environment from tourists, some of these can be rules or laws set by government officials or owners of the land if there are any |
| ecotourism | A form of sustainable tourism, it is guided by environmental tourism. Some examples of ecotourism would be camping, hiking, and wildlife viewing. |
| percent of water that is saline | 97% |
| percent of fresh water and percent that is available for drinking | 3 percent of fresh water on earth and 1 percent of that is available for drinking, the other percent is locked up in glaciers, icecaps etc |
| precipitation | The process in which liquid water (as rain) or ice particles (as snow or hail) fall to Earth due to gravity |
| Surface run-off | The process by which water runs over the ground into rivers |
| interception | The process in which precipitation is stopped from reaching the ground surface by the presence of trees and other plans |
| infiltration | The process by which water seeps into the ground |
| groundwater flow | The process by which infiltrated water flows through rocks |
| through flow | The process by which infiltrated water flows through soil |
| transpiration | The movement of water up plants and its subsequent loss as water vapour from their leaves |
| evaporation | The process in which liquid water turns into vapor, the opposite of condensation |
| condensation | The process in which water vapour turns into liquid water, the opposite of evaporation |
| water cycle | water cycle |
| domestic use of water examples | Drinking, washing dishes, showering, cooking, flushing the toilet |
| industrial use of water examples | Cooling down equipment, manufacturing products |
| agriculture use of water examples | Crops, animals drinking water |
| aquifer | Water stored in porous rocks underneath the ground |
| well | A hole bored or dug into rock to reach the water stored there |
| Reservoir | An artificial lake where water can be stored |
| desalination | Removal of salt from sea water to make it potable |
| Physical water scarcity | A situation where there physically not enough water for human needs |
| Economic water scarcity | A situation in which there is enough water available, but the money does not exist to extract and/or treat enough of it for human needs |
| Sanitation systems | Ensure that dirty water does not mix with water intended for human use |
| Water-treatment processes | Ensure that the water supplied to people is safe to drink |
| environmental advantages for dams | Creation of habitat for wetland species, irrigation, flood control |
| environmental disadvantages for dams | Disrupting the life cycles of fish and ither aquatic organisms |
| economical advantages for dams | Provision of water, access by boat to otherwise inaccessible areas |
| economical disadvantages for dams | Flooding land |
| social advantages for dams | Tourism and leisure |
| social disadvantages for dams | Relocating people |
| Conditions required for citing a dam | high rainfall, low temperature, isolated to minimise affect on human life |
| bioaccumulation of toxic substances | substances such as heavy metals and some pesticides may build up to high levels in fish so when consumed by humans we are impacted |
| how industrial process impacts water | A wide range of chemicals are used in the industry, and many are solvents which when discharged into rivers and likes cause harm to humans and the environment |
| effects of acid rain on organisms in rivers and lakes | When water in a river or lake it acidified, the lower pH level makes it intolerable for organisms to live in. Egg-laying is often reduced due to this, and young fish are malformed. |
| nutrient enrichment leading to eutorphication | enrichment of water by mineral nutrients or organic matter that leads to a reduction in oxygen levels in the water and the death of fish and other animals |
| how bacteria impacts water pollution | Bacteria may enter sources of drinking water from sewage if sanitation is poor. If these bacteria are pathogens (disease causing), and the water in which they live is drunk untreated, diseases can be spread. |
| ways to improve water quality | improve sanitation, treatment of sewage, laws requiring industries to monitor the pollution they cause and keep it within set levels |
| Individual strategies to control malaria | avoid being outside when mosquitos are active, wearing clothing that covers most of the body, spraying the inside of accommodation with insecticide |
| government strategies to control malaria | spraying insecticide inside buildings, draining wetland areas, introducing fish that eat the larvae, pour oil on the surface of the water to stop the larvae from breathing and stops them from having larvae |
| how to prevent cholera | Good sanitation – sewage and water treatment processes in place, good hygiene and cooking of food, boiling and chlorination of contaminated water. |
| soil and list the 4 components | It is made up of a number of components, mineral particles, organic content, air, water |
| plant mineral ions | nitrate ions (NO3-), phosphate ions (PO43-), potassium ions (K+) |
| drainage of sandy vs clay soils | Free draining due to the large air spaces between the particles, vs. water does not drain away easily |
| Ease of cultivation of sandy vs clay soils | Easier to cultivate, this is because the particles do not stick together easily vs. hard to cultivate, it is sticky and wet after heavy rain. |
| water content of sandy vs clay soils | Has fewer particles, a smaller surface area vs. has far more particles, and therefore a far larger surface area. |
| air content of sandy vs clay soils | Have large air gaps allowing for good transmission with high levels of oxygen and therefore a healthy root system, vs. Have small air spaces that can limit the amount of oxygen reaching plant roots. |
| Arable farming | The production of plants for human consumption. For example, growing of rice, maize, wheat, and soybeans |
| Pastoral farming | The production of animals or animal-related |
| Mixed farming | Farming, those practises both rearing livestock and growing crops |
| Subsistence farming | The cultivation and production of food to meet the needs of the farmers and their families. There is very surplus food; if there is any, it is often exchanged for other things the family needs |
| Commercial farming | The cultivation of products with the main focus of selling them for cash. |
| how to increase agriculture yield | crop rotation, fertilisers, irrigation, insecticide, herbicide and fungicide |
| Moving a crop to a different piece of land each year means that | Diseases in the soil have nothing to infect, pests need to find a new site, so their numbers are reduced, soil in the new plot is more likely to have the nutrients the crop needs |
| What do fertilisers contain and why are they important? | They contain minerals such as nitrogen, potassium, and phosphorus. These are essential for plant growth. |
| Why is water (irrigation) important for plants? | A large percent of a plant is made up of water. Water is essential for cell activity and used in photosynthesis. Mineral nutrient uptake by the roots require water in the soil |
| why do weeds need to be controlled | might be poisonous either to livestock or to humans, can block drainage systems with excessive growth, compete with crops for water, light, and nutrients |
| What do fungi do to a crop? | Cause crop diseases, bacteria, or viruses. They are collectively known as pathogens. Of these three groups, fungal diseases of crops are most common. |
| Describe the advantages to using machines to till the soil, plant, and harvest crops. | Larger areas can be cultivated easily by one person rather than lot of people and intensive labour. This reduces the labour costs for the farmer and also means they are cropping from a large area. The power of the machine’s engine means work like ploughing can take place when there is more water in the soil (when it is heavier), extending the season when soils can be cultivated. |
| selective breeding | It is continuous and slow, combining the existing characteristics of parents and selecting the best offspring for future crosses. |
| Genetically modified organism | An organism whose genetic material has been altered by genetic engineering. |
| greenhouse | A building made of glass or similar transparent material that is used to manage the environment for plant growth. |
| hydroponics | Growing plants without soil, with the nutrients the plant needs to be dissolved in water |
| overuse of insecticides and herbicides | can cause the plant to become resistant, can kill beneficial insects such which can impact wider food webs, leaching of insecticides and herbicides into rivers and lakes |
| overuse of fertilizers | excess can be leached out of the soil and drain into waterways, can cause excessive growth where the plant can't support itself, can affect osmosis |
| mismanagement of irrigation | waterlogged plants prevent plant roots getting sufficient oxygen to respire, can become waterlogged and salts in soil can move through to the top and when it evaporated only the salts are left which can means osmosis isn't effective and water supplies may also become unsuitable for drinking |
| causes of soil erosion | removal of natural vegetation, over cultivation, overgrazing, wind erosion, water erosion |
| Impacts of soil erosion | loss of habitats, desertification, silting of rivers, displacement of people, malnutrition and famine |
| how does removal of natural vegetation by over cultivation impact soil erosion | soils that are cultivated regularly can lose soil structure when they are broken up into small amounts, meaning the smaller particles are more vulnerable to erosion |
| how does water erosion impact soil erosion | heavy rainfall, rainwater run off, gulley erosions |
| how does wind erosion impact soil erosion | removal of vegetation makes the soil far more prone to be blown around by the wind |
| impact of soil erosion on desertification | The poorer remaining subsoil cannot support the growth of plants and impacts on both the growing of crops and the growing of grass to feed livestock. |
| impact of soil erosion on silting of rivers | the build-up of sediment due to more topsoil being washed into the rivers and the flow of the rivers slow down as they get shallower |
| impact of soil erosion on the displacement of people | With the decline of agriculture due to desertification, local people may be forced to move to make a living or feed their families |
| impact of soil erosion on famine | the time delay between planting new crops after migrating and harvesting the food means that there is not a reliable source of food |
| impact of soil erosion on malnutrition | if famine is on a large scale, is can lead to large scale malnutrition |
| Methods to reduce soil erosion | terracing, contour ploughing, bunds, wind breaks, maintaining vegetation cover, addition of organic matter to improve soil structure, planting trees, mixed cropping, intercropping and crop rotation. |
| terracing | the artificial development of flat areas, for growing crops, in a sloping terrain (on a hillside). |
| how does terracing reduce soil erosion | each plough furrow holds water back and prevents large amounts of water running down the slope, so preventing the formation of larger gullies and the run-off of topsoil |
| how does contour ploughing reduce soil erosion | when the ridges and furrow from the ploughing run along the contours of the land (around the hillside) rather than up and down. Each plough furrow holds water back and prevents large amounts of water rushing down the slope and carrying topsoil with it. |
| bunds | artificial banks at the edges of growing spaces designed to hold back water |
| how do bunds reduce soil erosion | preventing soil erosion from run-off, protect the soil from wind erosion |
| how do wind breaks reduce soil erosion | Wind breaks, made from natural vegetation, allows some wind to pass through, but reduces the wind speed and therefore the amount of wind erosion. |
| how maintaining vegetation (crop) cover reduces soil erosion | The roots of plants bind the soil together as they anchor the plant into the ground. They also act as a natural windbreak and reduce wind speed over the field. |
| how does adding organic matter reduce soil erosion | more organic matter has a higher water content and making it heavier and therefore less susceptible to erosion, holding extra water and preventing the soil from drying out and being blown away by wind |
| how does tree planting reduce soil erosion | A row of trees can form a windbreak to protect other crops, tree leaves fall to the ground and will add to the organic matter content of the soil, providing a natural habitat |
| how does mixed cropping reduce soil erosion | Is the growing of more than one type of plant in the same area. Each plant may have different characteristics that reduce soil erosion, e.g., one has deep roots and the other shallow roots. A smaller, sturdier plant acts as a support for a taller crop. |
| how does intercropping reduce soil erosion | Rows of different crops are grown between the established rows of the main crop. The quicker growing plants can be harvested for profit while the slower main crop is maturing. |
| how does crop rotation impact soil erosion | helps reduce pests, improves the quality of the soil, and utilises the different nutrients more effectively. Different crops use the soil in different ways and therefore reduces soil damage. |
| Sustainable agriculture | maximising production yields in a way that does not damage the wider environment and maintains resources for future generations |
| strategies for sustainable agriculture | organic fertiliser, managed grazing, crop rotation, use of pest resistant and drought resistant varieties of crops, trickle drip irrigation, rainwater harvesting. |
| how organic fertilizers are sustainable | release their nutrients slowly reducing eutrophication, don't require to manufacture energy, improve soil structure |
| how managed grazing is sustainable | prevent overgrazing, different fields are fertilised by animal waste and not one field has too many nutrients, maintain good drainage as animal hooves don't reduce soil compaction |
| how crop rotation is sustainable | less likely to be an oversupply, fewer risks of pests and diseases, natural fertiliser for the soil if animals are included |
| how use of pest resistant and drought resistant varieties of crops is sustainable | reduced pesticide use, reduced need of irrigation, shorting cropping cycles allowing two or more crops a year |
| how trickle drip irrigation systems are sustainable | minimised the amount of water used, targeted delivery of water to the plants, only use the system when the plants need water |
| rainwater harvesting | the collection of rainwater for example from the roofs of buildings and storage in a tank or reservoir for later use |
| how rainwater harvesting is sustainable | make use of a readily available natural resource |
| resource potential of the ocean | food, chemicals and building materials, wave and tidal energy, tourism, transport, potential for safe drinking water |
| how the ocean can provide food | True fish, shellfish, finfish and other animals that live in the sea and can be eaten |
| how the ocean can provide chemicals and building materials | Salt, magnesium, gold (in estuaries), tin, titanium, diamonds |
| how the ocean can provide wave and tidal energy | The Islay LIMPET (land-installed marine powered energy transformer) on the west coast of Scotland, and the agucadoura wave farm off northern Portugal, sihwa lake tidal power station, penzhin bay in north east Russia (proposal) |
| how the ocean can provide tourism | The seaside, coral reefs in places such as around the Caribbean, the red sea, the Indian ocean, and the great barrier reef. Whale watching - california |
| how the ocean can provide transport | Pleasure cruises and bulk freight, merchant-carrying ships |
| how the ocean can provide potential for safe drinking water | It is possible to derive safe drinking water from salt water by desalination |
| effect of El Niño on the fisheries | fewer fish are caught and if fishing continues at its usual amount, over-fishing can occur, and the fishery can collapse, phytoplankton do not grow well, so there is less food for the fish. During El Niño, the reduction in fish-meal affects the fish farming industry of countries |
| effect of el nino on peru | The normal trade wind direction from east to west changes every 8 – 12 years allowing warm nutrient-poor water to flow from the west towards the coast of Peru. This stops the upwelling of the cold, nutrient-rich water that supports the anchovie fishing |
| where do warm currents come from | either from the tropics of flow either side of the equator |
| where do cold currents come from | north or South Pole |
