B3

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  • Created by: Faith16
  • Created on: 31-03-16 11:14
What is a species?
A group of organisms that can breed together to produce fertile offspring
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How has a cactus adapted to its environment?
Have a rounded shape so they have a smaller surface area (reduce water loss), thick waxy layer and leaves that are spikes to reduce water loss, shallow but extensive roots so water can be absorbed quickly.
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How have fish adapted to their environment?
They have gills which extract oxygen from water so they can respire, tail fins with large surface area so they can swim fast, bodies are streamline- little resistance and they have a swim bladder.
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What is the variation in a species?
Where not everyone looks the same e.g. humans have different hair colour. Some of the variation is genetic.
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What is mutation?
When a genetic variation is caused by genes changing due radiation or chemicals or mistakes when copying genes. These can only be passed on if they are in the sex cells.
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What is natural selection?
Where certain variations cause a particular species to have a better change of survival causing them to have a better change to pass on their genes to their offspring. However the ones who don't have that variation will probably die.
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What is selective breeding?
When humans deliberately chose a feature they want to appear in the next generation e.g. farmer may chose to only breed cows that produce the most milk so in the future they get more money
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How can the process of evolution cause new species?
If a species get separated different mutations will occur for natural selection. So they species adapts differently depending on what the environment is like.
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What two things provide evidence of evolution?
Fossils and DNA (similarities and differences between species show how similar or not they are)
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What was Charles Darwin's theory?
Natural selection
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What was Lamarck's theory?
That if a characteristic was used a lot by an animal then it would become more developed so they acquired characteristics would be passed onto the animals offspring
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Why was Darwin's theory chosen over Lamarck's?
Because acquired characteristics don't have a genetic basis so they can't be passed on to offspring.
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What is biodiversity?
The number of different species on Earth, the range of different types of organisms and the genetic variation between organisms of the same species
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Why is biodiversity important?
As the more plants there are available the more resources we have for food crops and we also use plants in medicine so if it becomes extinct we will no longer have that unique chemical available.
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Why is the rate of extinction increasing?
As the worlds population increases so the rate of extinction due to humans directly hunting (Tasmanian wolf) and indirectly destroying habitats or introducing new species
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What is classification?
Groups of organisms order together due to their similarities in their characteristics
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What are the five group for classification?
Bacteria, fungi, algae, plants and animals.
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How is classification useful?
Shows evolutionary relationships
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What factors are essential to life?
Light (plants made food), food (animals) minerals (plants), oxygen (animals and plants) carbon dioxide (plants) and water
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What three changes in the environment can cause extinction?
Environmental conditions change (e.g. destruction of habitat), a new species is introduce which is a competitor, disease organism or predator and if an organism in a food web becomes extinct other species that were reliant on it can also die off.
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How is energy transferred in a food chain?
Energy comes from the sun to the plants which are eaten by animals or decaying organisms so energy is transferred
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How is energy lost in a food chain?
Through respiration, heat and as waste products e.g. urine, droppings and uneaten parts of organisms
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How do you calculate the efficiency of energy transfer?
Energy available to next stage/ energy that was available to the previous stage x 100
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Explain the carbon cycle.
There is only one arrow going down from the atmosphere which is photosynthesis which can be transferred to animals through eating. The arrows going up are animal respiration, plant respiration, CO2 released from decomposition, and combustion
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What is stored under ground in the carbon cycle?
Fossil fuels
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What are the four different types of microorganisms involved in the nitrogen cycle?
Decomposers (decompose proteins and urea turning them into ammonia) Nitrifying bacteria (turn ammonia in decaying matter into nitrates) Nitrogen-fixing bacteria (turn N2 into nitrogen compounds)
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Question 26 continued
and Denitrifying bateria (turn nitrates back into N2 gas)
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Explain the nitrogen cycle.
Page 36 revision guide
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Why do plants and animals need nitrogen?
So plants can use nitrates to make proteins which are then transferred to animals when they eat a plant or another animal
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What are the two main ways that nitrogen fixation takes place?
Lighting (strong energy making nitrogen react with oxygen) and Nitrogen-fixing bacteria in roots and soils
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What are non-living indicators that can measure environmental change?
Temperature, nitrate level and carbon dioxide level
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What are living indicators that can measure environmental change?
Lichen (different lichen grow in different levels of sulphur dioxide), mayfly nymphs (sensitive to amount of oxygen in water- if found water is clean) and phytoplankton (population increases when nitrates and phosphates increase- indicate pollution)
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What is sustainability?
Meeting the needs to todays population without harming the environment so that the future generations can still need their own needs
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Why is monoculture crop production not sustainable?
Because they are only growing one type of crop which does not help to maintain biodiversity
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Why is throwing away packaging material not sustainable?
Sources aren't being re-used for future generations, lots of energy has been made to make that material (e.g. burning fossil fuels) and landfill sites use up space and damage the environment
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How can we make packaging more sustainable?
Using renewable materials e.g. paper and card so trees can be replaced, using less energy e.g. recycling material, creating less pollution e.g. using biodegradable material and using less packaging material.
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Other cards in this set

Card 2

Front

How has a cactus adapted to its environment?

Back

Have a rounded shape so they have a smaller surface area (reduce water loss), thick waxy layer and leaves that are spikes to reduce water loss, shallow but extensive roots so water can be absorbed quickly.

Card 3

Front

How have fish adapted to their environment?

Back

Preview of the front of card 3

Card 4

Front

What is the variation in a species?

Back

Preview of the front of card 4

Card 5

Front

What is mutation?

Back

Preview of the front of card 5
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