What is variation?
Is the presence of variety - of differences between individuals
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What is genetic variation?
Is caused by differences between genes and the combinations of genes or alleles
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What are the two general causes of genetic variation?
Inherited/genetic or environmental factors
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What is inherited variation?
The genes we inherit from our parents - combination of inherited alleles (variation of gene) will not be the same as any other living thing due to the different combination
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What are environmental causes of vairation?
It affects the direction of growth (sun light, amount of growth)
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What is an adaptation?
A feature that enhances survival and long term reproductive success
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What are the three types of adaptation?
Behavioural, biological/physiological, amatomical
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What's a behavioural adaptation?
A change in behaviour that helps an organism survive in the conditions it lives in e.g. plants close stomata in low water availability
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What is a physiological/biochemical adaptation?
Ensures corrrect functioning of cell processes e.g. yeast can respire anearobically by producing the correct enzymes to respire
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What is a anatomical adaptation?
Structural adaptation that enhances the survival of an organism - bacteria have flagella to move
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What did Darwin observe?
Offspring genetically similar to parents, no 2 individuals are identical, large number of offspring, populations fairly stable in size
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How does speciation occur?
Through a reproductive barrier - some organisms unable to breed with others within a group, variation that provide benefits spread down generations through reproduction, changes occur in one part but do not spread to whol group = some diff
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What are reproductive barriers?
Geographical separation ALLOPATRIC speciation (adapting due to separation of surroundings) Can be within population, e.g. mating call no longer recognised SYMPATRIC speciation
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What are the 5 steps of evolution?
1 - variation, 2 - selection (of adv) 3 - these survive and reproduce 4- inheritance of advantageous characteristics 5 - adaptation occurs
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How does diversity increase with selection?
a population migrates to a new environment, the environmental change only affects some of the species to become better adapted, there is now a reproductive barrier preventing some species interbreeding, it cannot be passed on to the whole species
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How does diversity decrease?
The extinction of a species can decrease diversity through the removal of vegetation that destroys habitats and creates monoculture
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How has climate change decreased diversity?
A climate change may cause a inhabitable are to become uninhabitable (or visa versa) this may increase or decrease the range of biodiversity as some species may be forced to migrate causing a change in species distribution
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how does climate change and disease decrease biodiversity?
A wetter and warmer climate may suit fungal diseases, and insects that carry disease such as malaria as they can now spread into areas that were uninhabitable - some species may suffer decrease or extinction
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How do agricultural patternsaffect biodiversity?
Extreme weather may result in crop failure, or a new crop being able to grow that upsets the food chain, land that was previously unsuitable now becomes available which could increase biodiversity
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Why is biodiversity important?
Economic reasons (clothing, food, tourist) Ecological reasons (loss of habitat, habitat destruction affecting climate, disruption of food chain) Ethical reasons (organisms have a right to exist and we have a moral responsibility to conserve)
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What is in situ conservation?
Protecting species in their natural habitat - important for endangered species e.g. contr/prevent new species that threatenlocal biodiv. Protecting the habitat (water levels) Restoration and promotion of a species (protect food sources/nesting sites
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What is ex Situ conservation?
Removing part of the population from a threatened habitat to a new location (danger from poachers, breeding in captivityand releasing into wild, botanic gardens grow rare plants, seed banks of frozen seeds)
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Card 2


What is genetic variation?


Is caused by differences between genes and the combinations of genes or alleles

Card 3


What are the two general causes of genetic variation?


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Card 4


What is inherited variation?


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Card 5


What are environmental causes of vairation?


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