4246072
Description
Flashcards by muon neutrino, updated more than 1 year ago
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Created by muon neutrino
almost 9 years ago
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| Question | Answer |
| What does the term 'population' mean? | All the organisms of a particular species found in an ecosystem at any one time. |
| What does the term 'community' mean? | The populations of all species found in a particular ecosystem at any one time. |
| Name 4 things animals compete over and 4 things plants compete over in ecosystems. | Animals: Food, shelter, mates, nesting sites. Plants: carbon dioxide, mineral ions, light, water |
| What are trophic levels? | The different stages in a food chain. |
| In what ways is energy lost between the trophic levels? | Some parts of organism not eaten Some parts not digested and therefore not absorbed Some absorbed materials excreted Much energy lost in respiration as heat, carbon dioxide, water. |
| Sketch the carbon cycle, complete with the processes that move carbon from one state to another. | |
| In which major biological molecules is nitrogen present in? | Proteins, amino acids, most vitamins, DNA, RNA, and ATP. |
| Sketch the nitrogen cycle, complete with labels for all the processes that move nitrogen around. | |
| What is putrefaction? | One of the stages of decomposition by decomposers that produces ammonia from the nitrogen in compounds such as proteins, DNA, and vitamins. |
| What is nitrification? | The oxidation of ammonia into nitrite and then nitrate by nitrifying bacteria. |
| What two types of nitrogen fixing bacteria are there and what do they do? | Free-living NFB in soil convert nitrogen gas into ammonia used for making proteins. When they die, the ammonia is released back into the soil. NFB in root nodules make ammonia which is used by the plant, and death and decomposition of the plant release the ammonia back into the soil. |
| What do denitrifying bacteria do? | Use nitrates as an energy source and convert them into nitrogen gas. Undoes the combined work of nitrogen fixing bacteria and nitrifying bacteria. |
| What is transpiration? | Evaporation of water from plant leaves |
| Why do farmers need to use fertilisers? | When they sell crops or livestock, the nitrogen contained in their proteins is lost from the farm's ecosystem. The lost nitrogen can be replaced with a fertiliser. |
| What is the role of lightning in the nitrogen cycle? | Lightning converts nitrogen gas in the air to various nitrogen oxides. These dissolve in rainwater and are carried into the soil, where nitrifying bacteria convert then into nitrates, which are then taken up by plants. |
| Name one benefit and one problem with inorganic fertilisers. | Benefit: all the lost ions can be replaced (unlike organic fertilisers, which can only replace a portion of them). Problem: leads to eutrophication and can damage soil structure. |
| Name two ways in which pest numbers are controlled. | Pesticides and the use of a biological control. |
| Name two problems with the use of pesticides. | 1) Pesticide resistance 2) Some persist in the soil and can be accumulated along food chains. |
| Explain what monoculture is, what the problem with it is, and what process can counteract this problem. | Monoculture is when vast areas of land are used to grow a single crop. This encourages the spread of pests, as if one plant becomes infested, the pest can spread across millions of others. Crop rotation counteracts this because by growing different crops in different places every year, the pest for one particular crop does not flourish the next year. |
| Name 6 methods of biological control. | Introducing a natural predator Introducing a herbivore Introducing a parasite Introducing a pathogenic microorganism Introducing sterile males Using pheromones |
| What are the advantages of fish farming? | Water quality can be monitored Temperature and oxygenation of water controlled (sometimes) Diet of fish carefully controlled Fish protected against predators Pesticides used to kill parasites Selective breeding possible |
| What are the disadvantages of fish farming? | Potential for spread of disease is increased as animals are very close together. Antibiotics used to treat disease (always bad because antibiotic resistance). Organic material from the fish faeces and food pellets are pollutant. Pesticides sometimes highly toxic to non-harmful species. Most farmed species are carnivores, and fed with other fish. In 2001, 1.4 kg of wild fish was needed to produce 1 kg of farmed fish. |
| Define pollution | Releasing substances into the environment in amounts that cause harmful effect and which natural biological processes cannot easily remove. |
| What gases do we pollute the air with? | Carbon dioxide Carbon monoxide Sulfur dioxide Nitrous oxides Methane Chloroflourocarbons |
| Which pollutant gases cause acid rain? | Carbon dioxide Sulphur dioxide Nitrous oxides |
| Name 3 indicator species of organic water pollution. | bloodworm (heavy organic pollution) caddis-fly larva (some organic pollution) stone-fly nymph (clean water) |
| Explain how rapid eutrophication leads to anoxic conditions and the death of many of the species in the water. | |
| What is bioaccumulation? | The accumulation of pesticides in an organism that occurs when the organism consumes material with the pesticide faster than it can get rid of it. |
| What is DDT? | An extremely effective insecticide which prevented millions of malaria deaths by reducing the number of mosquitoes. However, it was passed along the food chain and accumulated in top carnivores in harmful ammounts, because the pesticide was so persistent and fat soluble. |
| What is biomagnification? | The increase in concentration of a harmful substance along a food chain. It occurs because each organism in the food chain eats many of the preceding organisms, magnifying the effects of bioaccumulation at each stage in the chain. |
| Define 'ecosystem' | A distinct, self-supporting system of organisms interacting with each other and with a physical environment. |
| How would you use a quadrat to sample from an area? | 1) Lay out two long tape measures on the area to form the sides of a square 2) Generate a pair of random numbers on a calculator-- use these as co-ordinates for where to place the quadrat 3) Count the number of whatever species you're interested in 4) Repeat several more times |
| What are the limitations of food webs? | --not all feeding relationships can be shown --don't give information about of many or what mass of organisms are involved --do not include the role of decomposers |
| Describe the relationship between a legume plant and nitrogen fixing bacteria. | NFB live in the root nodules of the legumes and fix nitrogen gas into ammonia, which is used by the plant to make amino acids. In return, the plant provides the bacteria with organic nutrients. |
| How can soil be made: i) more acidic? ii) more alkaline? | i) adding peat ii) adding lime |
| Why are plants sometimes grown in a hydroponic culture? | To provide exactly the right balance of mineral ions for the specific crop being grown. |
| By how much has the level of carbon dioxide in the atmosphere increased over the last 100 years? | 30% |
| What has caused the rise in CO2 levels over the past 100 years? | 1) burning fossil fuels 2) deforestation-- forests act as carbon sinks |
| What will be the likely effects of global warming? | --Polar ice caps melt --change in ocean currents --change in rainfall patterns --species extinction --larger pest problems |
| What is an indicator species for levels of sulphur dioxide pollution? | different lichens are tolerant of acid rain to varying degrees. Patterns of lichen growth can indicate levels of SO2. |
| What are the effects of acid rain on living organisms? | --death of conifers --acidification of soil --acidification of lakes |
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