Biology - Unit 2- Genetic Diversity & Investigating variation & Species diversity

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  • Created by: FireDwarf
  • Created on: 17-03-14 19:05
What makes organisims diffrent? What makes these diffrent?
The protiens in the organisims. Made diffrent from its variety of diffrent structures. All structures primarily due to primary structure which is coded via the DNA.
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What do all members of the same species have in terms of genes? Why are they all not identical?
The same genes BUT can have diffrent alleles of the gene.
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What makes members of a species more varied?
If they contain a large number of total alleles of their genes.
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What is a benefit of having a geneticlly varied species?
If an enviromental change occurs, and most of the species is maladaptive, more likely that some the species will be adaptative to that enviorment and can survive.
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What is selective breeding?
A proccess where members of the species with charactieristics which are desirable are bred to produce offspring. Offspring without the desired characteristics are killed/prevented from breeding. Ones with are left to breed.
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What does this cause eventually?
If you can stop the members of the species without the desired characteristics from breeding, only the desired alleles are left. This means that all offspring will eventually be desirable.
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Producing idea breeds of dogs or usage in plants (eg Wheat which is high with gluten content , short stems and resistant to disease)
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Name of the effect relating to new areas?
The founder effect
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What is it?
Few individuals from a population colonise a new area. They only carry a small number of the varieties of alleles of diffrent gene, not a full representation of population, so genetic diversity is reduced.
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what does this cause?
It causes the new population to have less genetic diveristy then the previous population as the variety of of alleles is smaller.
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What happens however if a disaster occured?
Less variety of alleles so less genetic diversity. Increased likelyhood if a maladaptive change occured that all members of the species would die out.
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What is a genetic bottleneck?
If a disaster occured, it could cause a populations numbers to be massivily reduced. This would cause the suriving population to have a lower genetic diversity as less varieties of alleles are left. New population has restricted
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What is the form of variation relating to other species members?
Interspecific - One species differs from another.
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What is the form of variation relating to members of the same species varying from each other?
Intraspecific- Members of the species differ from each other.
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What is sampling?
Sampling is taking a small proportion of the target population (from a sampling frame) that is a representation of that entire population.
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What are two factors (and why) which effect the validity of sampling?
Sample biast- the sample may be chosen to demostrate certian results. Chance- freak chance of a not representative sample. Results gained may simply be by chance.
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Two ways to improve validity of sampling?
Using a large sample size (more members of a sample, more likely the results you see are representative as you remove chance). Using random sampling (removes biast).
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What are the two causes of variation?
Genetics & enivromental factors
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Geneotype and Phenotype
Genetics & genetics + enviorment.
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3 causes of genetic diffrence?
Meosis, mutations, fusion of gametes (which gamete fuses with which maternal/parental gametee etc).
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How can we genetics data? Enviromental data?
Bar table/pie chart & for enviormental a normal distribution curve.
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How is the mean measured off a normal distribution curve? What is it useful for? What is it not useful for?
Maximum height of curve. Useful for comparing the average amount of a sample agianst another sample. Does not shown the distibution (range) of results.
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What is standard deviation?
Measurement of the width of the curve (goes from concave to convex). Gives an indication of the spread of results around the mean. Large number = reduced validity of the mean.
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Formula for standard deviation?
Square root of (x-x with line across top)2/n -1 (n= Total number of sample values) (x= measured value x with line = mean value.
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What is biodiversity?
Describing the variety of and number of living organisims in a praticular area. Made of 3 componants.
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what are they?
Species diversity (How many species in a specific community), genetic diversity (variety of genes possesed by the individuals of 1 species), ecosystem (range of habitats).
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How do we measure species diversity?
Proportion of the community made up of that species and the number of species in that area.
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Formula for measuring it?
Total number of organisims (Total number -1)/ total of (total number of organisims of that species)(that-1).
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Card 2


What do all members of the same species have in terms of genes? Why are they all not identical?


The same genes BUT can have diffrent alleles of the gene.

Card 3


What makes members of a species more varied?


Preview of the front of card 3

Card 4


What is a benefit of having a geneticlly varied species?


Preview of the front of card 4

Card 5


What is selective breeding?


Preview of the front of card 5
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