2.1 Field techniques Flashcards
What is the difference between stratified and systematic sampling?
Systematic sampling involves selecting members of a population at intervals, for instance every 3rd person, and in the context of the environment belt transects collect samples at equal intervals using quadrats.
Whereas stratified sampling has members of a population sorted into categories and proportional samples taken from each category, for instance age ranges.
What is the difference between a line and a belt transect?
A transect collects data where there is an environmental gradient.
A line transect records the species that touch the line, where as a belt transect records species within a wider zone.
Give examples of techniques used to sample elusive species.
Scat sampling and camera traps.
How do you ensure a sample is representative of the population.
It should share the same mean and degree of variation as the overall population.
State three ways organisms can be identified
Biological keys, DNA or protein analysis and classification guides
State two common methods of classification and briefly describe them
Taxonomy - Where organisms are identified and named by classification groups and determined by shared characteristics.
Phylogenetic - The study that uses evolutionary history and traits such as morphology, DNA sequencing and protein structure
State the advantage of using model organisms
It can be applied to species that are more difficult to study
Provide named examples of nematodes, arthropods and chordates.
Nematodes - Hook worm
Arthropods - Scorpion
Chordata - Homo sapiens
Name a model organism
Zebra fish.
