GCSE Biology OCR Gateway Higher Tier- B2

What is an Artificial Classification system?
Based of a few simple characteristics to make identification easier
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What is an Natural Classification system?
Based on evolutionary relationships
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6 kingdoms that living things are divided in to?
Phylum, Class, Order, Family, Genus, Species.
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Whats is a genus?
A group of closely related species.
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What are species?
A group of organisms that can interbreed to produce fertile offsprings.
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Why is it sometimes difficult to classify organisms into distinct groups?
Many organisms share characteristics of multiple groups.
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What is Dna sequencing?
Allows us to see genetic differences between different groups. This also can show us that two groups we thought out to be closely related, may not be related at all, vice versa.
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What is Asexual reproduction?
An organism makes a copy of itself so there is no interbreeding, therefore it does not fit the species definition.
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What is a Hybrid?
Infertile. Result of breeding two animals from different species.
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What is evolution?
Organisms change or evolve over time so that the way they have been classified may change.
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What happens in the binomial system?
Every species is given a two-part Latin name. The first part refers to the genus that the organism belongs too and the second part refers to their species. Universal name in all languages
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Similar species?
They often look alike due to common recent ancestors e.g dolphin and whale however, this is not always the case as they may of evolved to live in different habitats e.g camels and llamas.
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What are biomass pyramids?
Need the dry mass which involves killing the organism. Always a pyramid.
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Why can constructing a biomass pyramid be difficult?
You have to kill the organism to work it out which people argue is unethical making it more difficult. This is easier to do with plants and trees. Also some organisms feed at more than one trophic level making it harder to get an accurate pyramid.
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What are pyramids of numbers?
Count the organisms in each trophic level. Not always pyramid shaped.
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Energy in the food chain? 1st.
1) Energy from the sun is the source for nearly ALL life on Earth.
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Energy in the food chain? 2nd.
2) Plants use a small percentage of light energy for photosynthesis, this energy works its way down the food chain as animals eat the plants and each other.
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Energy in the food chain? 3rd.
3) The energy lost at each stage is used for staying alive e.g respiration
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Energy in the food chain? 4th.
4) Most energy is eventually lost as heat which is especially true for mammals and birds who need to maintain a constant temperature.
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Energy in the food chain? 5th.
5) Material and energy are also lost from the food chain as waste products e.g urine.
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Energy in the food chain? 6th
6) Waste products and uneaten parts e.g bones can also become starting points for other food chains.
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Energy in the food chain? Overall.
So much energy is lost through the stages, demonstrated in pyramid of biomass, there's not enough to support organisms after 4 or 5 stages.
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Energy in the food chain? How to calculate efficiency?
Efficiency = Energy available to next level/Energy that was available to previous level x100
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What is Interspecific competition?
Competition between different species
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What is intraspecific competition?
Competition between the same species
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Population? Food available.
Population of species if limited by the amount of food available.
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Population? Prey.
If population of prey increases then population of predators will also increase.
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Why are predator prey cycles out of phase?
It takes a while for one population to respond to the changes of another population. E.g. takes time to reproduce.
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What is mutualism?
Relationship where both animals benefit
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What are adaptations?
Features that organisms have that make them better suited to their environment.
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What are specialists?
Organisms which adapted to survive in a specific habitat.
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What are generalists?
Organisms that are adapted to survive in different conditions.
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What is extromophile bacteria?
Have enzymes that work best at high optimum temperatures than enzymes in other organims. These enzymes are able to work in temperatures which would denature enzymes of other organisms.
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What are anti-freeze proteins?
Interfere with the formation of ice crystal in the cells, stopping the cells from being damaged by the ice.
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What is the counter current heat exchange systems?
The vessels pass close to eachother, allowing heat to transfer between them. Warm blood flowing in the arteries to the feet heat cold blood returning to the heart in the veins. This means the feet stay cold but stops cold blood from cooling the body.
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How do animals adapt when they are too hot?
Large surface area to volume ratio to lose heat
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What was Charles Darwin's 'Theory of Natural Selection'?
Some animals born with .... better adapted for ... more likely to survive and pass on their genes, gene pool changes, DNA so different they can't interbreed = new species
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Why wasn't Darwin's theory perfect?
Couldn't give a good explanation for why new characteristics appeared and exactly how individuals organisms passed on beneficial adaptations to their offspring.
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Why did some people choose not to believe Darwin's theory?
The theory went against common religious belief about how Life on Earth developed- not involving God. Also, there wasn't enough evidence to convince scientists.
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What are new adaptations because of & how do they arise?
New adaptations arise due to mutations within the DNA.
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What is speciation?
Overtime organisms may change so much -due to natural selection- that a completely new species is formed.
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What happens in geographic isolation?
A physical barrier e.g a river, separates a population of a species. Mutations create new features in the two organisms. Eventually they won't be able to breed together to produce fertile offspring as they are so different.
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Why does recycling of carbon and other nutrients take longer in water logged soils?
Bacteria and Fungi that decompose in organic material usually need oxygen to respire and produce energy. Waterlogged soil doesn't have as much oxygen so decomposers have less energy and work slower.
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Why does nutrient recycling take longer in highly acidic soils rather than neutral soils.
Due to extremes of pH slow down the reproduction of decomposers or kill them outright.
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What was Lamark's theory of evolution?
Acquired characteristics can be passed on.
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Why was Lamarcks theory discredited?
People began to understand acquired characteristics do not have a genetic basis.
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What 3 things are fossil fuels?
Coal, Oil and Natural Gas
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What is a greenhouse gas?
When fossil fuels are burned they release a lot of carbon dioxide -greenhouse gas. They trap heat in the atmosphere which causes global temperatures to rise.
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What does sulfur dioxide cause?
Acid rain, which kills trees and fish
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What do CFC's do?
Cause ozone layer depletion allowing more harmful UV rays to reach the Earth's surface which can cause skin cancer.
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Advantages of Living methods? -indicator species.
Relatively cheap, quick and easy way of saying whether an area is polluted or not. No specially trained workers or expensive equipment required.
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Disadvantages of Living methods? -indicator species.
Factors other than pollution e.g temperature can influence the survival of indicator species so not always reliable.
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Advantages of Non-Living methods?
Gives reliable, numerical data which is easy to compare and the exact pollutants can be identified.
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Disadvantages of Non-Living methods?
Often require more expensive equipment and trained workers.
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How does number of habitats lead to endangered species?
Hard for organisms to find food and shelter and other resources so there are not enough suitable habitats.
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How can genetic variation lead to endangered species?
This is the number of different alleles in a population. If genetic variation is low then a species is less likely to be able to adapt to changes in the environment or survive the appearance of a new disease.
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What are decomposers?
Convert proteins to ammonia.
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What is nitrogen-fixing bacteria?
Converts nitrogen gas into nitrates.
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What is denitrifying bacteria?
Converts nitrates to nitrogen gas.
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What is carbon footprint?
Amount of carbon dioxide given off in a certain time.
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What can carbon dioxide lead to?
Causes global warming which can cause a rise in sea level, resulting in habitat loss and extinction.
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What are the pollution indicator species?
Mayfly larvae = Good water quality. Sludge worms = Poor water quality. Poor air = Lots of different lichens. Clean air quality = No lichens.
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What is a sustainable resource?
Will not run out as it is being produced as fast as it is being used.
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How do animals adapt when they are too cold?
Small Surface area to volume ratio to conserve heat.
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What does nitrifying bacteria do?
Converts ammonia to nitrates.
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What do organisms compete for? - Animals, Plants and competition.
Animals -food, water,shelter,mates. Plants - light,water,minerals. Competition is greater in a smaller area.
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Properties of a hot + dry plant?
Long roots, thick cuticle, small surface area to collect water and reduce water loss.
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Advantages of conservation?
Tourism, jobs, plants for medical purposes.
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Disadvantages of conservation?
Might not breed well in captivity. Reduced gene pool. Less likely to survive when released.
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Other cards in this set

Card 2


What is an Natural Classification system?


Based on evolutionary relationships

Card 3


6 kingdoms that living things are divided in to?


Preview of the front of card 3

Card 4


Whats is a genus?


Preview of the front of card 4

Card 5


What are species?


Preview of the front of card 5
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