Aaron Clarke
Flashcards by Aaron Clarke, updated more than 1 year ago
Aaron Clarke
Created by Aaron Clarke about 7 years ago


AQA as biology Flashcards on Variation, created by Aaron Clarke on 01/22/2014.

Resource summary

Question Answer
The kind of variation between two daises in a field Intraspecific
Two reasons samples taken may not be representative of the whole 1. Sample bias 2. Chance
How can misrepresentation be avoided? Eliminate human involvement in the collection of samples. (Random Sampling)
How can we minimize chance in the sampling process? 1.Use a large sample size. 2. Analysis of data collected.
How do those two things minimise the effect of chance? 1. The greater the sample size, the more reliable the data. 2. Statistical tests help to see if variation is cause by chance or by something else...
Two factors that result in variation 1. Genetic differences 2. Environmental Influences
Mutation A sudden change in genes or chromosomes that may be passed on.
Which cells are made by meiosis? Gametes
How does fusion of gametes at fertilisation increase genetic variability? 1. Offspring inherit characteristics from EACH parent. 2. Which gamete fuses with which is a random process.
How is variation introduced in asexually reproducing organisms? Only by mutation. Sexually reproducing organisms use mutations, meiosis and fusion of gametes.
Relationship between a plant's genes an its environment. Environment affects the way that genes are expressed.
Four environmental factors that could influence a plant's development 1.Climatic conditions. 2.Soil conditions 3.pH 4.Food availability.
Why are conclusions about individuals in variation difficult? Because it's hard to distinguish between the effects of the many genetic and environmental influences that make differences in individuals.
Features of Genetic Factors A few distinct forms, no intermediate types.
Example The ABO grouping for blood types.
Genetic=caused by many different genes? No Only one
Effect of the environment Little effect
Features of environmental factors Some characteristics grade into one another, forming a continuum.
Examples 1. Height 2. Mass
Many genes in environmental? Yes Polygenes
Bell shaped curve on graph Normal Distribution Curve
On Normal Distribution Curve, what does the mean measure? Provides an average value. (measurement at the maximum height of the curve).
What does the standard deviation measure? Indication of the range of values at either side of the mean. (Measure of the width of the curve).
What is the point of inflection? Distance from the mean to the point where the curve changes.
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