Inheritance, selection and speciation

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  • Created by: Sopha8
  • Created on: 26-05-15 20:02
What is an allele? how do they arise?
one or more versions of the same gene, arises due to mutations
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What is genotype and phenotype?
g= genetic consitution of an organism p=the expression of the genotype of an organism and its interactions with the environment
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State the hardy-weinberg principle
frequency of alleles wont change from one generation to the next providing there is no immigration, emigration, mutations or natural selection and that mating is random
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Give the 2 hardy-weinberg equations and what they are used for
to work out allele frequence- p+q=1. to work out genotype frequency- p + 2pq + q =1
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What are 2 types of natural selection and how do they affect allele frequencies?
stablising selection- characteristics in middle of range most likely to surive, occurs when environment not changing. directional selection=characterists at extreme ends of range most likely to survie due to changes in environment
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Define selection pressures
any reason for organisms with certain phenotypes to have either a survival advantage or disadvantage
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What is the equation for estimating a population size using the mark-release-recapture method?
total pop size= number caught in 1st sample X number caught in 2nd
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What 3 ways can farmers reduce the number of pests?
1. chemical pesticides 2. biological agents 3. fertilisers
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Explain the advantages and disadvantes of using chemical pesticides
herbicides- reduce competition, fungicides-less energy fighting infection & insecticides-more biomass good= act quicky and easy to apply bad= may affect other speices directly or indirectly, resistance, expensive
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Explain the advantages and disadvantes of using biological agents
method includes predators, parasites and pathogenic bacteria/viruses good=no resistance, species specific bad=become pest, longer process
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Explain the advantages and disadvantes of using fertilsiers
natual or artificial good= input more energy, make sure minerals not limiting factor bad=cause eutrophication, change soil balance so may reduce biodiversity, too much means wasted money
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Explain the advantages and disadvantes of using an intergrated system
good=reduce cost, can be more effective than one method on its own
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Describe methods for conserving species and habitats
1.manage succession to plagioclimax 2.seed banks (have to be regualry tested to see if they will grow) 3. captive breeding 4. relocation (may outcompete native speices) 5. protected areas
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Other cards in this set

Card 2

Front

What is genotype and phenotype?

Back

g= genetic consitution of an organism p=the expression of the genotype of an organism and its interactions with the environment

Card 3

Front

State the hardy-weinberg principle

Back

Preview of the front of card 3

Card 4

Front

Give the 2 hardy-weinberg equations and what they are used for

Back

Preview of the front of card 4

Card 5

Front

What are 2 types of natural selection and how do they affect allele frequencies?

Back

Preview of the front of card 5
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