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Description
Flashcards by Jessica Brown, updated more than 1 year ago
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Created by Jessica Brown
about 9 years ago
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| Question | Answer |
| B3- Life on Earth | Jessica Brown |
| What is the definition of a species? | It is similar organisms that can breed to produce offspring |
| Why do species adapt to the Environment? | So that they can survive and increase chance of reproducing |
| How 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 |
| How 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 |
| Why may a species become extinct? Give examples | If it cant adapt to changes such as predators, diseases and competition |
| What is the purpose of a food chain? | They show the relationships between organisms |
| What happens in a food chain when animals eat? | Energy is passed up through the food chain |
| Give an example of how animals depend on each other for survival | Grass- Rabbit- Fox Grass- Rabbit- Stout If rabbits became extinct then the fox and stout are at risk because competition for food has increased |
| What 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 |
| How can Environmental changes alter a food web? Give an example | If there was less rain the food web would be altered because there would be less slugs and less lettuces |
| What will happen if a food webs change is too great? | They will die before they can reproduce |
| Where do living things get energy from? | The sun |
| How 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 |
| What is an eco-system? Give an example | An area containing a self-sustained community of organisms and their surroundings (e.g. a pond or a wood) |
| What must an eco-system contain? Give definitions | Autotrophs (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 |
| What are the two types of heterotrophs? | Herbivores- heterotrophs that eat plants (primary consumers) Carnivores- heterotrophs that eat animals (secondary/ teritary consumers) |
| How are materials such as nitrogen recycled? | Naturally |
| Can energy be recycled? Give your reasons | No because energy can only be changed, not created or destroyed |
| Why is an input from the Sun always needed? | Because energy is always lost over time |
| What 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 |
| What is a detritivore? Give an example | Something that can re enter the food chain e.g woodlice |
| What 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 |
| Why is there a limit to the length of a food chain? | Because there becomes less energy at each stage of the food chain |
| How did the first living things develop? | By simple molecules that could copy and replicate themselves |
| To 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 |
| What did experiments on simple molecules lead too? | These simple molecules developing |
| How can the Nitrogen Cycle be recycled? Give examples where possible | 1) 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 |
| How can the Carbon Cycle be recycled? Give examples where possible | 1) 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 |
| What do all organisms share? Give examples where neccessary | 1) Traits e.g. cellular stucture and DNA 2) A common ancestor evolved from simple living things |
| What 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 |
| What 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 |
| What 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) |
| What 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 |
| What is genetic variation caused by? Can it be passed on? | Mutation Yes |
| Can Environmental information be passed on? | No |
| What is selective breeding? What purpose is selective breeding used for? | When certain animals are mated to produce outcomes Human purposes |
| What is biodiversity? | It is a variety of life that exists |
| What would happen if there wasn't much variety? | People will run out of crops/medicine |
| Give an example of a bad way to sustain biodiversity | By having huge fields of a single crop as it doesn't supply a variety/base for various chains |
| What ways can you reduce the amount of packaging? Give examples | 1) Recycling 2) Biodegradable packaging e.g. cardboard instead of oil-based plastics |
| Why 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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