Variation Flashcards
Give and explain 2 reasons why measurements may not be representative.
Sampling bias- investigators may be making unrepresentative choices, either deliberately or unwittingly.
Chance- even when bias is avoided, the individuals chosen May, by pure chance, not be representative.
Describe a way to prevent sampling bias.
Use random sampling -
-(e.g. Dividing an area into a grid and randomly choose coordinates to take a sample from the intersects of the grid)
Describe 2 ways in which chance can be minimised from a sampling process.
1) Using a large sample size - the more individuals selected, the smaller the probability that chance will influence the result.
2) Analysis of data collected - using statistical test to determine the extent to which chance may have influenced he data.
Name and describe the factors can cause genetic differences in sexually reproducing organisms.
Mutations- changes in genes may or may not be passed on the the next generation
Meiosis- the production of gametes, mixing up genetic material which are passed into different gametes
Fusion of gametes- which gametes fuse with which is random at fertilisation, further increasing the parent’s variety of offspring.
Name the 2 main factors in the cause of variation.
Genetic Differences
Environmental influences
Name some environmental factors that could affect a species of plant’s variation.
Climate conditions (e.g. Temperature, rainfall and sunlight)
Soil conditions
pH
Food availability
Name the factor for genetic variation in asexually reproducing organisms.
Mutation
Give the names of the variation between different and similar species.
Interspecific variation- variation between species
Intraspecific variation- variation within a species
Explain why a biologist chose to examine 200 cells
Ensures a more representative sample
Explain how the standard deviation helps in the interpretation of data.
Shows the spread of data around the mean
Overlap = no difference / due to chance / not significant
Low SD values shows results are more reliable/repeatable
Explain the importance of scientists choosing the sites to collect insects at random
Removed bias