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  • Created by: dkoning00
  • Created on: 14-05-16 13:01
Why are living things classified?
To understand how organsims are related
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What are the two types of classification system and what are they based on?
Natural (evolutionary relation) and artificial (appereance and features)
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What are the seven levels of classification?
Kingdom, Phylum, Class, Order, Family, Genus and Species
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What is a Genus?
A group of closely related species
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What is a species?
A group of organisms that can be inbred to produce fertile offsring
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Why can classification systems change over time?
Discovery of new species and collection of DNA showing relations
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What do evolution trees show?
Relationships between species based on common ancestors
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Give three difficulties in classifying organisms into species and explain each
Asexual reproduction - no interbreeding so not technically a species. Hybrids - off-spring of two different species and usually infertile so not really a species. Continuous evolution - difficult to tell when a species has evolved into a new one
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What is a binomial name?
Two part Latin name
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What is each part? Give an example
First word, Genus. Second word, Species e.g. Homo (genus) Sapien (species)
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Why is the binomial system important?
So scientists all over the world can speak different languages but use the same name for an animal
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Why could two species with a recent common ancestor appear very different?
Adaptations due to different habitats
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In a food chain, how much energy is lost with every trophic level?
Roughly 90%
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Why are pyramids of numbers and biomass used?
To display the numbers/biomasses of each organism in a food chain
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Why might a pyramid of numbers and a pyramid of biomass for the same food chain be different shapes?
A pyramid of numbers could start with a single organism (e.g. a large tree) that feeds many organisms of the next trophic level making it narrow at the bottom
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Why is so much energy lost at each trophic level?
The organism respires, excretes, egests and reproduces - all of which requires energy that isn't passed on when it's eaten
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In a food chain, what do the arrows represent?
Transfer of energy
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How do you calculate the efficiency of energy transfer?
Energy available to the next level/Energy that was available to the previous level x 100
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Why must organisms compete with each other?
To gain resources like food and shelter in order to reproduce
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What are the two types of competition? Explain each
Intraspecific competition - competing for resources with organisms of the same species. Interspecific - competing for resources with organisms of another species
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Why does Intraspecific competition often have a bigger impact on organisms than Interspecific?
Because they are competing for exactly the same resources
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What is a species' niche?
How it fits into its ecosystem
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Why are the population numbers of prey and predator linked?
Because a population of any species is limited by the amount of food available
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Describe and explain what happens when the prey population in an area increases
The predator population increases as there is more food available so they can reproduce more effectively. As the predator numbers rise, they prey population begins to fall again causing predator numbers to drop due to lack of food
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Why are Predator-Prey population cycles always out of phase?
Because it takes time for the populations to respond to changes in the others e.g. increased prey doesn't increase predator numbers straight away - they need time to reproduce
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Define a Parasitic relationship and give an example
One organism lives off another without giving anything back and often harming the host e.g. a dog having fleas
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Define a mutualistic relationship and give an example
Both organisms benefit from the actions and resources of the other e.g. oxpeckers and buffalo
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What are adaptations?
The features that organisms have evolved to suit their environment better
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What are Specialists?
Organisms are higly-adapted to survive in one specific habitat
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What are Generalists?
Organisms that are adapted to live in a range of habitats with similar features
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When will Specialists out-compete Generalists? Why?
When the habitat's conditions are stable because they are better adapted to the specific conditions
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When will Generalists out-compete Specialists? Why?
When the habitat's conditions can change as they are better adapted to a range of conditions and are more likely to survive a change
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What are Extremophiles?
Organisms adapted to live in extreme conditions e.g. very high temperature or pressure
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How could an Extremophile be adapted to living in high temperatures?
By having enzymes with optimum temperatures that are much higher than other organisms' so they are not denatured
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How could another Extremophile be adapted to living in very low temperatures?
By having Antifreeze proteins that interfere with the formation of ice crystals thus stopping the cell from being damaged
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Why do organsisms need to keep their body temperatures at a certainn level?
To make sure their enzymes work effectively
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What are anatomical adaptations?
Features of the organisms body structure/function that help it to survive
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Give examples of an anatomical adaptation to reduce heat loss
Having a smaller surface area to volume ratio to reduce heat loss through the surface. Having a thick coat or layer of blubber.
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Give examples of anatomical adaptations to reduce heat gain
Being small and having large surface area to volume ratios; large, thin ears to increase surface area; storing fat in only one area of the body to reduce insulation
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What is a counter-current heat exchange system?
Transferring heat around the body to change the temperature of certain areas
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Why do penguins need to keep thier feet cold?
Penguins have to stand on ice for hours so if their feet are warm they will melt the ice which will then freeze again causing them to stick to it
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How is this achieved?
Bloods vessels carrying blood to and from the feet are close together so arteries pass heat to veins. This means that by the time blood reaches the feet it is cold, then it returns to the heart in veins and is warmed up going back up the legs
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What are Behavioural adaptations?
Organisms changing the way they act to deal with conditions
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Give three examples of behavioural adaptations to deal with cold temperature
Migration to warmer areas in winter; hibernation through winter; penguins huddling to share body heat
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Give three examples of behavioural adaptations to deal with hot temperatures
Finding shade; being active only at night; bathing in water
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Describe how desert plants are adapted to dry environments
Rounded shape gives small surface area to volume reducing water loss from surface; thick waxy cuticle layer to further reduce water loss; storing water in stems; shallow, extensive roots to absorb lots of water
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Describe how desert animals can be adapted to dry environments
Special kidneys allow for very concentrated urine with low water content; no sweat glands; burrow underground where the air contains more moisture
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What allows evolution to happen?
Genetic variation within a species
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Briefly describe Darwins theory of natural selection
Organisms that are better adapted to the environment are more likely to survive, reproduce and pass on their characteristics to the next generaton. Less well adapted organisms are more likely to die so over time the species evolves to be fitter
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Why wasn't Darwin's theory perfect and how has it been developed with new discoveries?
He couldn't explain the variation within a species or how it was passed on. The discovery of DNA and genetics confirmed his theory
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What is speciation?
When a species changes so much over time it becomes a new species
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At what point is speciation deemed to have happened?
When in the species becomes reproductively isolated - cannot interbreed with each other to produce fertile offspring
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How can geographical isolation cause speciation?
Two populations of one species become separated and cannot interact; each population continues to adapt to its surroundings by natural selection; eventually they will have adapted so much they are reproductively isolated
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Why didn't everyone initially agree with Darwin's theory?
It went against religious beliefs; he couldn't explain why new characteristics appeared and how they were passed on; there wasn't enough evidence to support him as few other scientists had studied it
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What was Lamarck's theory?
That acquired characteristics like big muscles from running a lot were passed from one organism to its off-spring
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Why was this eventually rejected?
Because acquired characteristics have no genetic basis so couldn't be passed on to the next generation
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Why is Darwin's theory now widely accepted?
Because many independent studies have been carried out and none have disproved it and it explains lots of observations of plants and animals that are suited to their environement
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In the carbon cycle, what is the only process which takes CO2 out of the atmosphere?
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What three processes put CO2 back into the atmosphere?
Respiration, decay and burning
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Why does recycling carbon in waterlogged areas take longer?
Because the bacteria and fungi that decompose organic material need oxygen which is limited in these areas so they have less energy and take longer
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What other factors can slow decomposers' functions?
pH levels slow decomposer reproduction or kill them
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How is carbon recycled in the sea?
Shells are made of carbonates which collect on the sea floor and eventually form limestone and other sedimentary rocks. These rocks are then melted and the CO2 is given out by volcanic eruptions. The ocean can also absorb CO2
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In what states does nitrogen appear in the nitrogen cycle?
Nitrogen gas in the air, nitrates in soil, plant and animal proteins and Ammonia
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What are the four kinds of bacteria involved and what do they do?
Decomposers turn proteins into nitrates in soil. Nitrifying bacteria turns Ammonia into nitrates in soil. Denitrifying bacteria turns nitrates into N2. Nitrogen fixing bacteria turns N2 into nitrates.
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How else is Nitrogen gas turned into Nitrates in the soil?
Lighting strikes
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Where can Nitrogen Fixing Bacteria be found?
In the root nodules of Legume (pea) plants and in the soil (in small amounts)
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What kind of relationship do plants have with the bacteria in the cycle?
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Why is an increasing human population putting strain on the environment?
More resources are being used up and more polution
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What is global warming?
Increased release of greenhouse gases such as CO2 trap heat in the atmosphere causing the temperature to rise
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What are its effects?
Ice caps melting, sea levels rising, weather systems becoming unpredictable, agricultural failures
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How is acid rain caused?
Impurities in fossil fuels release Sulfur dioxide and oxides of nitrogen when burned which creates acidic solutions when it comes into contact with clouds and falls as acidic rain
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What are its effects?
Water sources become more acidic, harming or killing the organisms that rely on it; damages limestone structures; releases CO2 when it degrades sedimentary rock
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How is Ozone depleted?
CFCs (Chlorofluorocarbons) used in aerosols and refrigerators break down ozone in the upper atmosphere
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What Does Ozone do to help us?
Filters out UV rays and reduces the amount that reach us
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What are the effects of Ozone depletion?
Higher risk of skin cancer; UV kills plankton affecting fish populations
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What kind of environmental issue is Ozone depletion? Why?
Historic because CFCs have been banned so they are no longer released meaning the process stops. Also the hole in the ozone layer has started to shrink as the O3 reproduces
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What are indicator species?
Species whose numbers and/or presence indicate how polluted an area is
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What does an abundance of Lichens indicate?
Very clean air
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Lichens are very sensitive to air pollution so if they are thriving, the air is clean
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What are Mayfly larvae used to monitor and how?
Water pollution as they cannot survive in polluted waters so the more Mayfly larvae, the cleaner the water
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What are Water lice, rat-tailed maggots and sludgeworms all indicators of?
Medium to high levels of water pollution
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How can pollution in an area be measured using indicator species?
By assessing whether or not certain indicator species are present (tells you if there is pollution or not) or by counting how many of each indicator species there are (tells you how much pollution there is)
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Give and advantage and a disadvantage of this method
It's simple, cheap and requires little/no training but not always accurate as there are other factors than pollution that affect a species' ability to thrive e.g. temperature
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How can pollution in an area be directly measured?
By using specialist equipment (e.g. instruments sensitive to sulfur dioxide give readings of air pollution)
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Give an advantage and a disadvantage of this method
It's accurate and reliable but expensive and requires specialist training
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List three factors that, if critically low, can cause a species to become endangered and explain each
Number of habitats - low number of habitats means not enough food and resources to support population. Number of individuals - difficult to find mates and reproduce. Genetic variation - little variation means smaller chance of being able to adapt
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In what four areas can you evaluate a conservation programme?
The amount of genetic variation; viability of the population (how easily it can reproduce); available habitats - both natural and artificial and interaction between species to simulate the wild
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How can conservation programmes benefit humans?
Protecting food supplies; reducing damage to food chains; providing future medicine; cultural aspects (one species may be important to a culture or nation e.g. America and the bald eagle)
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Define sustainable development
Providing for the needs of today's growing population without harming the environment
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Why is sustainable development so important?
To ensure we don't damage the world in such a way that it affects future generations of humans and animals
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Give examples of how sustainable development is being promoted
Fishing quotas prevent the over-fishing of certain species to maintain numbers. Laws force logging companies to plant new trees as they cut others down. Educating the masses on how important it is and how to help
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Why are some whales endangered?
Because they were hunted extensively for food, tourist attractions and cosmetics all over the world
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What laws have been introduced to stop the extinction of whales?
All countries except Norway agreed to ban whale hunting for all purposes apart from culling for scientific research
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Why does whaling still go on?
Because it is difficult to make sure countries are not hunting whales and there is no way of punishing those that do so illegal whaling still happens
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Why are many people against keeping whales captive?
They think it's cruel as they cannot live for themselves and often don't have big enough enclosures
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Other cards in this set

Card 2


What are the two types of classification system and what are they based on?


Natural (evolutionary relation) and artificial (appereance and features)

Card 3


What are the seven levels of classification?


Preview of the front of card 3

Card 4


What is a Genus?


Preview of the front of card 4

Card 5


What is a species?


Preview of the front of card 5
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I haven't read them all, but the ones I have read are really good. Nice work


Thank you :)

Bushra Patel

these are really good, thanks loads :)

Bravo 2-2 (Joshua.w)

Really useful. Thank you

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