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