Estimating Population Size Using Mark and Recapture Method

1714 Words Aug 11th, 2013 7 Pages
Practical 16: estimating Population Size Using Mark and Recapture Method
Raw and Processed Data
Table 1: Uncertainties of apparatus used in the experiment. Apparatus | Uncertainties | Stopwatch | ±0.01s |

Table 2: Formulae and sample calculations involved in processing data in the experiment. Calculations | Formula | Sample Calculation | Mean
( x ) | x = 1n i=1naiWhere, 1. n refers to the total number of values. 2. ∑ refers to the addition of all values starting with the first value, denoted by i = 1, and ending off with the last value, denoted by n. 3. ai refers to the values in sequence from i = 1 to the nth term or last term. | Mean Lincoln Index: x= 15114+127+194+163+172≈154 | Standard Deviation ( σ ) |
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The marked animals are then released back into the population and left to mingle for a suitable period of time. Once they have become thoroughly mixed into the population again, the population is resampled.
The assumption is then made that the proportion of marked animals in the second sample is the same as the proportion of marked animals to non-marked within the whole population. Enough time must be allowed to elapse for complete mixing to have occurred.
The Lincoln Index is a method which is used to estimate the size of closed populations. Random samples of the population are captured and these individuals are marked and then released to mingle with the general population. The population is resampled after enough time has passed to allow complete remixing of the marked individuals. This will vary depending on the species, as well as its habitat and mobility. For example, it is likely to take longer for a population of snails to remix, than for a population of mice.

Evaluation
Table 5: Limitations and Improvements to procedure. Procedure | Implications on Experiment | Improvements | Step 3: For 10 seconds, capture as many beads as you can, using a plastic spoon and place them into another container. | Restricting the recapture time to only 10 seconds will lead to two sources of error. 1. Firstly, a human error arises, whereby, as we are limited by the short amount of time, we