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B3 Science revision flashcards
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- 1B3- Life on EarthJessica Brown
- 2What is the definition of a species?It is similar organisms that can breed to produce offspring
- 3Why do species adapt to the Environment?So that they can survive and increase chance of reproducing
- 4How does a cactus adapt to the Environment?1) Thick outer layer to cut water loss
2) Leaves reduced to spines to cut water loss
3) They have a deep, wide root system to keep as much water as possible - 5How does a fish adapt to the Environment?1) Gills to take oxygen from water
2) A swim bladder to help maintain position in water
3) Streamlined shape and fins to swim - 6Why may a species become extinct? Give examplesIf it cant adapt to changes such as predators, diseases and competition
- 7What is the purpose of a food chain?They show the relationships between organisms
- 8What happens in a food chain when animals eat?Energy is passed up through the food chain
- 9Give an example of how animals depend on each other for survivalGrass- Rabbit- Fox
Grass- Rabbit- Stout
If rabbits became extinct then the fox and stout are at risk because competition for food has increased - 10What is the purpose of a food web?1) To show how all the food chains in a habitat are inter-related
2) It shows interdependance- showing how all the living organisms are dependant on eachother - 11How can Environmental changes alter a food web? Give an exampleIf there was less rain the food web would be altered because there would be less slugs and less lettuces
- 12What will happen if a food webs change is too great?They will die before they can reproduce
- 13Where do living things get energy from?The sun
- 14How is energy transferred?1) Through plants absorbing the Sun's energy through photosynthesis. The energy is stored in the chemicals e.g. starch that make up their cells
2) Moving to other organisms when plants/animals are eaten or they decompose
3) When decay organsisms feed off dead organsisms and animals waste products - 15What is an eco-system? Give an exampleAn area containing a self-sustained community of organisms and their surroundings (e.g. a pond or a wood)
- 16What must an eco-system contain? Give definitionsAutotrophs (self feeders)- plants that make their own food (also known as producers)
Heterotrophs- animals that cant make their own food- they get energy by consuming other organisms - 17What are the two types of heterotrophs?Herbivores- heterotrophs that eat plants (primary consumers)
Carnivores- heterotrophs that eat animals (secondary/ teritary consumers) - 18How are materials such as nitrogen recycled?Naturally
- 19Can energy be recycled? Give your reasonsNo because energy can only be changed, not created or destroyed
- 20Why is an input from the Sun always needed?Because energy is always lost over time
- 21What are the stages of energy transfer in a food chain?1) Light energy flows from the sun
2) Light energy flows from an autotroph which used it for photosynthesis (gets stored in the cells)
3) Herbivore eats the phototroph. Some energy is transferred from plant to herbivore cells
4) Carnivore eats the herbivore. Some energy is transferred from plant to carnivore cells
5) Dead organisms are fed on by decay organisms (decomposers) such as bacteria and detritivores - 22What is a detritivore? Give an exampleSomething that can re enter the food chain e.g woodlice
- 23What happens to the energy at each stage?1) Energy is lost through respiration or heat
2) Energy is excreted as waste products
3) Energy becomes trapped through materials such as fur - 24Why is there a limit to the length of a food chain?Because there becomes less energy at each stage of the food chain
- 25How did the first living things develop?By simple molecules that could copy and replicate themselves
- 26To this day, what is still unknown about the first molecules?1) If they were produced by conditions on Earth at the time
OR
2) If they arrived on Earth from an external source e.g. a comet - 27What did experiments on simple molecules lead too?These simple molecules developing
- 28How can the Nitrogen Cycle be recycled? Give examples where possible1) Animals getting nitrogen by eating protein in other plants/animals
2) Excess nitrogen is removed by excretion (e.g. urea in urine)
3) When plants/animals decompose, protein gets broken into nitrogen compounds (e.g. nitrates)
4) Nitrogen can be removed by nitrogen-fixing bacteria in the soil and in the root nodules of plants. Nitrogen is then converted into compounds (e.g. nitrates)
5) Nitrates are taken up by plant roots and converted into protein
6) Dentrification- where nitrates are broken into nitrogen through bacteria in the soil - 29How can the Carbon Cycle be recycled? Give examples where possible1) CO2 in the air is removed by plants in photosynthesis and gets into their cells
2) Animals eat protein (other plants and animals) and use the carbon in their cells
3) Combustion in forest fires and burning of fossil fuels e.g coal release CO2 into the air
4) Decomposer organisms break down dead material and waste, releasing CO2 into the atmosphere - 30What do all organisms share? Give examples where neccessary1) Traits e.g. cellular stucture and DNA
2) A common ancestor evolved from simple living things - 31What is the fossil record?It supports the common ancestor theory by stating that fossils can be formed from:
1) Organisms that don't easily decay
2) Animals/plants that cant decay due to a required factor such as moisture not being present
3) Soft parts of organisms that can be replaced by minerals as they decay - 32What is DNA Evidence?It supports the common ancestor theory by analysing both organisms DNA and comparing them to reveal differences.
It is used to fill gaps in the Fossil record - 33What is the theory behind DNA Evidence?1) The more shared genes the organisms have, the more similar they are.
2) Evolution by natural selection made life as it is today. (If the Earth was different, today would be as well) - 34What is Darwin's theory of the evolution of natural selection?1) Individuals show variation (differences)
2) There becomes competition for food and mates
3) Those who are better adapted are more likely to survive while others die out
4) Survivors pass on the genes to their offspring which improves evolved organsms - 35What is genetic variation caused by? Can it be passed on?Mutation
Yes - 36Can Environmental information be passed on?No
- 37What is selective breeding? What purpose is selective breeding used for?When certain animals are mated to produce outcomes
Human purposes - 38What is biodiversity?It is a variety of life that exists
- 39What would happen if there wasn't much variety?People will run out of crops/medicine
- 40Give an example of a bad way to sustain biodiversityBy having huge fields of a single crop as it doesn't supply a variety/base for various chains
- 41What ways can you reduce the amount of packaging? Give examples1) Recycling
2) Biodegradable packaging e.g. cardboard instead of oil-based plastics - 42Why do we need to reduce the amount of packaging?1) It saves energy and money
2) It is less transport (therefore less air pollution)
3) Because everything takes time to break down due to there not being enough oxygen for the decomposer organisms to function efficiently
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- GSCSE Science Fichas sobre B3 Science revision flashcards, creado por Jessica Brown el 14/03/2015.
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