ecology lecture 7 defs Flashcards
scientific method
way of studying natural world through observations, hypothesis, and deductive reasoning. 1) Make Observations 2) Ask Questions 3) Make Hypothesis 4) Generae Testable Predictions from Hypothesis 5) Devise Tests (Experiments) [me: Analyze Data and Draw Conclusions. Hypothesis supported or not supported by experiment]
elements of good scientific experiment
Groups - (control and treatment)(Large)(Similar) 2) consistent/systematic 3) elimante biases (randomize)
SIMILAR keep both groups as similar as possible. Why
you know that one thing you manipulated is really having effect on what you measured. Similar abiotic (climate, water,sunlight, soil) & biotic factors(predators) & time of day
CONTROL group
group does not have manipulation or treatment (most natural or normal situation)
LARGE group
use large groups in your sample - there is a lot of natural variation-larger sample group make sure that this natural variation does not affect your results. The reason larger samples increase your chance of significance is because they more reliably reflect the population mean. Thus it is more convincing.
CONSISTENT and SYSTEMATIC
do same thing each time , measure same way (GPS, tape measure, soil moisture/ph, light meter), same person (so data collected is similar, groups are similar)
ELIMINATE BIASES
use random sampling of subjects into 2 groups that your testing; randomly choose samples
example biased sample
annot pick easiest get too….if you were sampling from a school field, but for convenience only placed quadrats next to a path, this might not give a sample that was representative of the whole field. It would be an unrepresentative, or biased, sample.
quadrat
is a tool (usually square with wire form grid ) used in ecology and geography to isolate a standard unit of area for study of the distribution of an item over a large area (sampling purposes). For instance, a quadrat is placed on ground at random to count the vegetation within the sample–but you would randomize
ideally what should every sample area have
Ideally every place within the sampling area should have an equal chance of being sampled, each time a sample is taken.
quadrat sample
form grid over area, say 1mSQUARED, pick 2 numbers (say 2 and 5) , move across 2 and up 5
any ecologist believe insects are controlled by weather rather than predation.
How would you setup an experiment to test whether predation affect ANT population?
place tents over random areas / plots. * if more ants in tents then it was predation that controls since control and tent both subject to weather
popies - how test taller inland vs coast
break up coast into Northern, Bay , Southern. Each area randomly broken into latitudes. Inland measure distance sea
