| Ecological Techniques Essay, Research Paper
4.5
Ecological Techniques Describe
one method used to measure each of three abiotic characteristics of a habitat
including light
Light o
Intensity o
Duration ?
Determined astronomically, and predictable for any
location o
Quality ?
All Light sensor
Temperature o
Thermometer
PH o
Universal Indicator
Humidity o
Expressed in relative humidity, i.e. the water content
of a given volume of air relative to the same volume of saturated air. Measured
using a whirling hygrometer. Define
random sample A method to ensure that every individual in a population has
an equal chance of being observed. Describe
one technique used to estimate the population size of one animal species based
on capture-mark-release-recapture method. Use capture-mark-release-recapture method. Then use Lincoln Index: Population size = ???? n1
x n2 ???????????????????????????? —————- ???????????????????????????? n3 n1=Number initially caught n2=Total number individuals caught in second
sample n3=Number of marked individuals caught in second
sample Describe
one method of random sampling used to compare the population numbers of two
plant species based on quadrat methods A quadrat is a wooden frame, with guaze-like chequered
internal divisions. Sampling can be systematic: here the quadrat is placed at
regular intervals at regular intervals, perhaps a transect. It can also be
random: here one simply throws the quadrat and measures wherever it lands up.
Quadrats make it easy to estimate large areas of population. Count a single
area and count it as representative of the whole. Evaluate
graphical representations of ecological data Define
mean The average value obtained by dividing the total of a set of
values by the number of values Define
mode The most frequent value in a set of observations Define
median The central value in a set of observations arranged in order State
that the term standard deviation is used to summarise the spread of variables
around the mean and that 68% of the values fall within one standard deviation
of the mean Calculate
the means and standard deviation of two different frequency distributions S.D = Describe
how standard deviation is useful in comparing the means and the spread of
ecological data between two or more sites
Small standard deviation indicates that the data is
clustered around a small mean value
Large standard deviation indicates that the data is
spread around a large mean value
When comparing two means and two standard deviations
the closer the two the more likely that they are drawn from the same population
Dependent on sample size o
Larger samples make more reliable sample results
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