2804787
| Pregunta | Respuesta |
| a) what are the groups used to classify animals called? | a) the groups are: kingdom,phylum, class,order,family,genus,speciese |
| a) what is the differance between an artificial system of classification and a natural system of classification? | a) an artificial system is based on one or two characteristics that make identification easier, for exalmple birds that always live by or on the sea are called sea birds, whilst a natural system is based on evolutionary relationships. Animals that are more closely relaated are more likely to be in the same group. |
| a) why is a natural system of identification considered better than an artificial one? | a) natural systems of classification are much more detailed and focus on the evolutionary relationships and origins of specific speciese whilst artificial systems focus on one or two characteristics and are less accurate. |
| a) how has sequencing the bases in DNA helped scientists? | a) DNA has enabed scientists to know much more about how closely related organisms are and re-classify some animals more accurately |
| a) what is a speciese | a) a speciese is a group of organisms that can inter-breed to produce fertile offspring |
| a) how are all organisms named? b) how does it work? | a) all organisms are named by the binomial system b) the binomial system works like this: - There are two parts to the organisms name, the first part is the genus and the second part is the speciese |
| a) explain two problems with classifying? | a) 1. living things are at different stages of evolution, and new ones are being discovered all the time 2. organisms that do not produce fertie offspring cannot be classified as a seciese so mules- which are infertile (they are hybrids like ligers) and bacteria which reproduce asexually cannot be classed as a speciese |
| a) why can 2 speciese of animals be grouped similarily but live in completely different habitats? | a) because they have the same recent common ancestor but have evolved to live in different habitats |
| a) what do pyramids of biomass show? b) why do pyramids of biomass give a better representation of the eco-system than pyramids of numbers? | a) pyramids of biomass show the dry mass of living material at each stage of the food chain b) pyramids of biomass give a better representation of the size of the producers and consumers and provide a more accurate image of how each speciese is sustained in the food chain. They are a better way of representing trophic levels. |
| a) why are pyramids of biomass difficult to construct? | a) 1. some organisms feed on organisms from many different trophic levels (this is also an issue for pyramids of numbers) 2. measeuring dry mass means removing all the water from an organism which would kill it. |
| As energy flows along a food chain some is used in growth a) can you suggest some other less useful energy transfers? | a) . heat from respiration .egestion .excretion |
| a) the material that is lost at each stage of the food chain is not wasted, explain why? | a) most of the waste is used up by decomposers that can then start a new food chain. |
| a) what is the carbon cycle? | a) the carbon cycle is the movement of carbon from the air into plants via photosynthesis, into animals via ingestion of plants and back into the air through respiration, decomposition, combustion of fossil fuels or acid rain on limestone (calcium carbonate, formed by the compresion of dead sea creatures) |
| a) why must carbon be recycled? | a) carbon must be recycled so that organisms can use it again |
| because each trophic level loses up to 90% of the available energy, an animal at the end of the food chain does not have much energy available to it a) what is the equasion for the efficiency of energy transfer whithin the food chain? | a) energy used for growth divided by energy input |
| a) what is the nitrogen cycle? | a) the nitrogen cycle is the movement of nitrogen from the air to the soil, through plants, into animals and returned to the soil by decomposer bacteria or fungi |
| a) how do bacteria and fungi break down dead animals and return nitrogen to the soil? | a) decomposer bacteria and fungi convert protiens and urea into ammonia then nitrifying bacteria convert the ammonia into nitrates and denitrifying bacteria convert nitrates into nitrogen gas. The gass is then absorbed into the soil by the large amounts of energy in lightening or the pressence of nitrogen- fixing bacteria in the soil/ root nodules. |
| a) what do decomposers need to break down dead material in the soil? b) how do the conditions in waterlogged soil affect decomposition? c) how do the conditions in acidic soil affect decomposition? | a) decomposers need oxygen and a suitable PH to break down dead matter. b) in waterlogged soil there is less oxygen so the process of decay will be slower. c) acidic conditions reduce the rate of decomposition |
| a) what do animals in the same HABBITAT compete for? b) what do animals in the same speciese compete for? | a) animals in the same HABBITAT compete for RESOURCES. b) animals in the same speciese compete for RESOURCES and MATES. |
| Animals with similar ecological niches are more likely to compete: a) what does an ECOLOGICAL NICHE describe? | a) an ecological niche describes the habitat and role of a particular speciese. |
| a) what is the differance between interpecific competition and intraspecific competition? | a) interspecific competition exists between organisms of different specieses whilst intraspecific competition exists between organisms of the same speciese and is likely to be more significant because they need exactly the same resources. |
| a) what is the differance between parasitism and mutualism? | a) parasitism is where an organism lives off another, causing it harm (parasites, on a host) whilst mutualism is where both organisms benefit from their relationship (cleaner fish eat the sharks parasites and get protection) |
| a) pea plants have nodules which contain nitrogen-fixing bacteria, explain how this is a mutualism relationship? | a) the nitrogen fixing bacteria converts nitrogen gass into nitates which the plant absorbs and replaces with sugars produced via photosynthesis |
| a) how are many animals adapted to cold conditions? (3) | a) 1. many animals are large to decrease the surface area to volume ratio and reduce heat loss 2. many animals have insulation which traps heat within within their boddies and reduces loss into the enviroment 3. penguins have counter current heat mechanisms which mean that the warm blood going to the flippers transfers heat into the cold blood returning to reduce heat loss from the feet |
| a) can you give an exalmple of a behavioural adaptation to living in cold conditions? b) can you give an exalmple of a biochemical adaptation to living in cold conditions? | a) some animals migrate to escape the coldest months b) some organisms have biochemical adaptations, such as anti-freeze protienes in their cells |
| a) how are many animals adapted to hot conditions? (2) | a) 1. many animals have have smaller boddies to increase surface area to volume ratio and create more heatloss into the enviroment. 2. many animals have very little hair on the undersides of their boddies to increase heat loss |
| a) can you give an exalmple of a behavioural adaptation to living in hot, dry conditions? b) can you give an exalmple of a biochemical adaptation to living in hot, dry conditions? (2) | a) many animals pant to create heat loss from the veigns in their tounges or lick their furr so that more heat is lost as moisture evapourates. b) camels can survive because they produce very concentrated urine and do not waste water. some bacteria can survive because they have enzymes which do not denature at 100 degrees celcius |
| a) what is meant by the term specialist? | a) specialist refers to an organism which is very well adapted to living in a specific habbitat but would struggle to live elsewhere (polar bears) |
| a) what is meant by the term generalist? | a) generalist refers to an organism which can live in several habbitats (rats) |
| a) how are cacti adapted to survive in desserts? | a) cacti leaves have been reduced to spines to minimise water loss. They also have deep roots so can find enough water and can store water in the stem for shortages. |
| a) can you explain the theory of natural selection using ideas of genes, variation, competition and reproduction? | a) within any speciese there is variation, organisms produce far more offspring than will survive so there is intraspecific competition for limited resources. Only those with successful genes, who are best adapted will survive to reproduce where they will pass on their characteristics to offspring. Unsuccesful genes will die out. |
| a) can you explain how natural selection can produce new specieses? | a) overtime populations of the same speciese that are isolated, geographically (birds on different islands) or behaviourally will mate inderpendantly and evolve differently. |
| a) explain why natural selection is difficult to study? | a) natural selection is difficult to study because it usually takes thousands of years to see the effect |
| a) give two reasons why darwin's theory of evolution was not accepted? b) why is darwin's theory of evolution accepted now? | a) people believed that God had created all the specieses just as they were and people did not believe darwin had enough evidence to back up his theory b) darwin's theory is accepted now because it explains a lot of observations and has been tested by a wide range of scientists |
| a) what is the differance between darwin's and lamarcks theory on natural selection? | a) darwin believed that changes occoured over thousands of years due to variation within a speciese and succesful characteristics being passed down to offspring because of survival of the fittest. lamarck believed that animals made consious efforts to change their boddies over their lives (girraffes stretching their necks) |
| a) what is exponential growth? b) why is the population growing? | a) exponential growth is where the population of a speciese (humans) is growing at an ever-increasing rate. b) the population is growing because the birth rate is greater than the death rate |
| a) what is a carbon footprint? | a) a carbon footprint is the total amount of greenhouse gas given off per personmor organisation within a certain time |
| a) suggest two ways that pollution can be measured? | a) pollution can be measured using direct methods or indicator organisms |
| a) how do direct methods work to measure pollution levels in an area? a) how do indicator organisms help scientists to estimate the pollution levels in an area? | a) direct methods use probes attatched to computers to measure the exact levels of oxygen in a pond or special chemicals to indicate levels of nitrogen pollution from fertalisers. b) each organism requires a certain condition to live, some need very clean fresh water to survive whilst others are more tollerable of pollution. The pressence or absence of certain specieses is used to estimate the levels of pollution. e.g. the pressence of an organism which can only live in clean water shows that there is very little pollution in the pond (otherwise it wouldnt be able to survive there). |
| a) what are the advantages and disadvantages of using indicator organisms to estimate pollution levels? | a) +Indicator organisms are cheaper, they do not rely on equiptment which can go wrong and give a good representation of pollution levels over a period of time - indicator organisms are less accurate at measuring pollution levels at a specific time |
| a) what is conservation? b) why do people think conservation is important? (4) | a) conservation is trying to preserve plants and animals and the habbitats they live in b) people think conservation is important becase it can: 1.) protect our food supply 2.) protect plants and animals which may be useful for future medicines 3.) prevent any damage to food chains- which can be unpredictable 4.) protect organisms and habbitats so people can visit and study them |
| a) when is a speciese 'at risk of extinction'? | a) a speciese is at risk of extinction when its numbers falls below critical. |
| a) what must be considered when trying to conserve a speciese? | a) 1.) you must consider the size of the population of the speciese, if it is below critical level it is unlikely that there will be enough genetic variation for the population to survive. 2.) you must consider the number of suitable habitats for the speciese to live in 3.) you must consider how much competition there is from other species |
| a) what are wales useful for? b) why are some wales kept in captivity? c) why do some people object to keeping wales in captivity? | a) wale body parts are used in many products and live wales provide income from tourism. b) some wales are kept in captivity for research, entertainment or captive breading c) some people object to keeping wales in captivity because they lose their freedom |
| a) why do some scientists believe it is neccesary to kill wales? b) why is killing wales for most research unneccesary? | a) some scientists think it is neccesary to kill wales to help find out more about how wales survive at extream depths. b) killing wales is actually unneccesary because you could study them live plus scientists are only be able to learn about wale communication and migration patterns when the wale is aive. |
| a)what does sustainable development mean? | a) sustainable development means taking enough resources from the enviroment to satisfy current needs while leaving enough for the future and preventing further damage. |
| a) what efforts have been made to try to ensure sustainable development? (3) | a) gouvernments set fishing quotas so that enough fish are left to breed and re-populate. woods are also being replanted to keep up the supply of trees and we are trying to find alternative energy sources to fossil fuels as they will eventually run out |
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