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The Kelso High School Biology Environment Name……………………..... Class……….. Keep this booklet safe – you will need it for revision. Environment Use this table as a checklist for your revision. = core = challenge Understood and learnt Level Need to do more work Need to get help - see my teacher. You need to be able to…… Give the definitions for ecosystem, habitat, population and community. Identify 2 abiotic and 2 biotic factors Give an example of a technique which could be used to measure an abiotic factor and describe its use. Identify a possible source of error of that technique and explain how it might be avoided. State the effect of one abiotic factor on the distribution of organisms. Explain how abiotic factor affect the distribution of organisms. Identify organisms using branching and paired statement keys. Construct branching and paired statement keys. Give an example of a technique which could be used for sampling organisms and describe its use. Identify a possible source of error of that technique and explain how it might be avoided. -1- Give the definitions for producer, consumer, herbivore, carnivore, omnivore, primary consumer, secondary consumer. Give an example of a food chain and a food web. State that the arrows in a food chain indicate the direction of energy flow. State 2 ways in which energy can be lost from a food chain. Explain the effects of removing one species on the remaining organisms in a food web. State that the growth of a population depends on the birth and death rate. Describe and explain the growth curve of a population under ideal conditions. State 3 factors which can limit the growth of a population. State that competition occurs when organisms have a need for the same resources. Describe some effects of competition. Date of ‘Environment’ End of Unit Assessment: …………………………………. Remember, in addition to testing your knowledge the assessment will include problem solving questions, eg graph drawing, calculations, etc. -2- Ecosystems Term Definition Example - a natural biological unit made up of living and non-living parts - tropical rain forest, freshwater loch, etc - place where an organism lives - pond, field, etc - all the organisms of one species that live together in an ecosystem - frogs in a pond, rabbits in a field - all the plants, animals and bacteria that live together in an ecosystem. All the frogs, fish, plants, bacteria etc that live in a pond. Ecosystem Habitat Population Community -3- Factors Affecting Ecosystems Many things can affect ecosystems. Living things which can affect ecosystems are called __abiotic________ factors. These include: ___Light intensity_______________________ ___soil pH_____________________________ ___soil moisture, etc_____________________ Non-living things which can affect ecosystems are called __biotic__________ factors. These include: ___food availability_______________________ ___number of predators___________________ ___diseases present_____________________ __competition __________________________ It is useful to measure abiotic factors and various pieces of equipment can be used to do this. To make sure that your measurements are reliable the equipment must be used properly. Abiotic Factor Light Intensity Soil moisture Equipment Used Sources of Error Ways in Which Error is Minimised Standing in front of the sensor - don’t stand in front of the sensor. - probe not left long enough to monitor the moisture level. - leave probe in soil for a few seconds - probe not wiped after each sample. - wipe probe after each reading Light meter Moisture Meter -4- Identifying Organisms If you are studying the populations and communities in ecosystems you need to be able to identify the plants and animals that are there. To do this you can use a key. There are two types of key: _____Branching key__________________________________ _____Paired statement key____________________________ A Branching Key: Leaves Prickles (HOLLY) No Prickles Jaggy Edge (ELM) Smooth Edge Lobes (OAK) No Lobes (BEECH) A Paired Statement Key: 1. Leave with prickles………………………HOLLY Leave without prickles…………………..Go to 2. 2. Jaggy edge………………………………..ELM Smooth edge……………………………..Go to 3. 3. Lobes……………………………………...OAK No lobes…………………………………...BEECH Use the keys to identify the following leaves: ___beech______ __________oak__________ ____elm_________ _____holly__________ -5- Sampling Organisms If you are studying plants and animals in an ecosystem you may need to find ways of capturing and counting them. There are many different ways to do this depending on the animal or plant you are studying. A pitfall trap is used to collect animals that live on the soil surface and amongst leaf litter. _____lid___________ ___pot_______ __alcohol_________ Avoiding Errors When Using a Pitfall Trap ____Several____________ pitfall traps should be set up to give reliable results. The opening of the trap should be disguised by a ___lid_________so that trapped animals are not seen and eaten by predators. A preservative liquid, eg ___alcohol______________ is put in the bottom of the trap to humanely kill and preserve the animals. -6- It is unlikely that you would be able to count all of the plants and animals in an ecosystem because this would take too long. Instead, small samples which represent the whole ecosystem are taken Plants are often sampled in this way using ____a quadrat______________. This is a square of a known area which is randomly placed on the site being studied. The plants inside the quadrat are identified and counted. From this information the estimate of the number of a certain plant can be calculated. __quadrat______ __area___ __plant______ Avoiding Errors When Using a Quadrat Make the results more _reliable_________ by using a bigger number of quadrats. Place the quadrats at ___random_________ over the area being studied, don’t choose where to place it. Make a rule to decide what to do with plants that fall partly in or out of the quadrat, eg more than half the plant in the quadrat counts, more than half out the quadrat doesn’t. Out In Out In In Out -7- Energy Flow Between Organisms There are several terms that can be used to describe the way organisms obtain their energy. Term Definition Example An organism that can produce its own Oak tree, food. Usually a green plant that dandelion Producer produces its own food using energy from the sun by the process of photosynthesis. Consumer Any organism that cannot produce its own food, instead they eat other organisms to get their energy. Sheep, fox, lion, giraffe Any animal that only eats plants to get their energy. Rabbit, deer, etc Any animal that eats other animals to get their energy Fox Tiger Herbivore (or primary consumer) Carnivore (or secondary consumer) Human being, fox, badger Omnivore An animal that eats both plants and animals to get their energy. The way in which energy passes from plants to animals and then to other animals can be shown by a food chain. There are two rules when you make your own food chains: All food chains start with a ___producer________________ You must show the __arrows______________ in a food chain. The arrows in a food chain go from food to feeder and represent the direction of energy flow. -8- As energy is passed along a food chain each of the organisms uses some of it for its own needs, eg moving, keeping warm, etc. This means that energy is lost at each link in the food chain and the only energy that can be passed to the next link in the food chain is that which is part of the body of the organism itself. Approximately ___90______% is used by the organism and not available to the next link in the food chain, so only about ___10_____% of the energy can be passed on. Most animals eat more than one kind of food and so in any ecosystem food chains connect to form a food web. All food webs are delicately balanced. The removal of one organism from the food web can have a serious effect on others. -9- Population Growth The size of most populations tends to stay roughly the same. The size of a population stays the same as long as the birth rate is the same as the death rate. 1. Little or no increase as the population starts to reproduce. 2. Rapid population increase. 3. No more increase as population numbers are checked by something. Time In most populations there is something which prevents a population explosion. Limiting factors are things that prevent a population from growing any larger. For example, 10 rabbits may live in a habitat that has enough water space to support 20 rabbits, but if there is only enough food for ten rabbits, the population will not grow any larger. In this example, food is the limiting factor. Food is not the only factor that may limit population growth. For example, there may be enough food to support a thousand birds in a certain area, but only suitable nesting sites for one hundred. - 10 - Competition If organisms use the same resources the competition will occur. Animals compete for: Plants compete for: __food______________ __sunlight___________ __water_____________ _space_____________ __mates____________ __water_____________ __nesting sites, etc___ __nutrients in the soil___ When competition occurs some organisms will be more successful than others. These organisms will be more likely to survive. - 11 -