524053
Description
Flashcards by paige-monaghan, updated more than 1 year ago
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Created by paige-monaghan
almost 11 years ago
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| Question | Answer |
| Define Population Growth. | It is a group of organisms of a single species interbreeding and occupying a particular area. |
| Why do they live in a population? | -Greater chance of mating. -Work together for protection from predators. -If disease; better adapted to changing environment |
| Lag phase: slow growth because of producing enzymes. Log phase: No limiting factor. Rapid population growth Stationary Phase: Population reaches its max. size. Factors limiting its population growth. Death Phase: Limiting factor causes bacteria to decline. Lack of nutrients/ build up of waste products | |
| What is environmental resistance and name some examples. | It is all the factors which may limit the growth of a population These include: -Food Availability -Parasitism -Predators -Disease -Weather -Competition -Accumulation of toxic waste |
| Define Carrying Capacity. | The most population number that can be held in a population before a decrease in a single species OVER A LONG PERIOD OF TIME |
| Define Immigration and Emigration | Immigration: Individuals joining a population permanently. Emigration: Individuals leaving a population permanently. |
| Name factors which can affect population size? | Density Dependent factors: Food, parasitism, accumulation of toxic waste, disease. Density Independent: (FFF) Frost, Fire, Floods |
| -Describe Population Fluctuations. -What happens below, on and over the set point? | -Population Fluctuations are regulated by the balance between the production rate and death rate. -Set point; is the number of most species that lie near an equilibrium -Population Increase S.P; Leads to a population decrease as more competition. Less resources. -Population Decrease S.P; Leads to a population increase as less competition. More resources |
| Comp What do plants and animals compete for? | Plants compete for: SUNLIGHT NUTRIENTS SPACE WATER Animals compete for: FOOD SHELTER SPACE REPRODUCTIVE PARTNER |
| Comp Describe intra specific competition? | It's a competition for resources between members of the same species It's also the best driving force behind natural selection |
| Comp Describe Inter-specific competition? | Competition for resources, i.e FOOD, SPACE, WATER, LIGHT between members of different species. In general, one will out compete the other. |
| Define Pest Control? | It is an ORGANISM which COMPETES with or ADVERSELY affects a POPULATION of organism that are of ECONOMIC importance. |
| Typical Nature of pests? | -Feed of crops and animals. -Compete with crop organisms for resources -Directly cause disease in crop organisms -Spoil food when it's being stored or transported. |
| Define Chemical Control and how it can be applied? | It involves the use of HERBICIDES, FUNGICIDES and INSECTICIDES to kill pests. It can be applied by; Spray, Powder, Smoked, Animal food |
| What is a pesticide? | It is a poisonous chemical weed to control organisms considered harmful to agriculture or organism involved in disease transmission. |
| What are the advantages of Chemical control? | -Application doesn't require a high level of skill -Very effective means of control -Pests are eradicated cheaply and quickly -Chemicals can be applied on a small scale such as a single field. |
| What are the disadvantages of Chemical control? | -Same pesticide could harm fish, birds and mammals by contamination of food. -Long term exposure to pesticide can cause harm to humans. Eg Farmers using sheep dips. -Pests become resistant to the pesticide. -Eradication may result in a resurgence of the pest. |
| How Biological control works? | -Beneficial organisms are deployed against the undesirable pest/target -Pests act as a food source for the introduced organism -Reduction in numbers of the pest as they are eaten, therefore their numbers are kept below economical damage threshold -However pests are not eradicated completely as this would leave no food source for introduced predator ad would die out. |
| Advantages of Biological Control? | -No environmental contamination. -Usually highly specific to one pest. -Can be used in glass house situations. -Provides long term control if population equilibrium is established. |
| Disadvantages of Biological Control? | -Very few successful examples of this strategy. -Biological Control agents are slow to build up in numbers. -Success involves a high level of skill and research -Detailed knowledge of life cycle of pesticide is required. |
| Describe carbon cycle? |
Image:
carbonCycle2.gif (image/gif)
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| Describe Nitrogen Cycle? |
Image:
NitrogenCycle (image/jpg)
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| How can humans improve the circulation of nitrogen? | -By fixing atmospheric nitrogen artificially using chemical processes that convert into fertilisers. -Large amounts of animal waste from stock rearing used as manure -Micro organisms can be used for making compost and silage -Sewage disposal boosts organic nitrogen supplies |
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