Lab 2
5
Lab 2
Organization of Invertebrate Communities
Description of the Lab
Use statistical tools to describe and analyze distribution patterns of invertebrate
communities. There is a lab and a field component. Instructors may choose to skip the
Laboratory Materials and Equipment for Student Use
Materials and Equipment
Per
Student
Per Pair of
Students
Per Lab
Group
Per
Room
Measuring Tape (20m)
1
Preparation of Laboratory Materials and Reagents
Quadrat: Made from PVC pipe. 707mm legs make a square with an area of 0.5m2
Lab 2
6
Questions for Lab 2
Exercise 1– Estimating the Population Size
Outline of Investigation
Use mark –and –recapture method to estimate population size
Materials Needed:
• 2 Rectangular plastic containers with lids
Answers to population estimate questions will vary depending on student samples.
What are the limitations of this method in real situations?
1. Sometimes the marking or the handling of the ‘animals’ affects their behavior. They
Materials Needed:
• Hand calculator
Lab 2
7
Exercise 2 – Finding the Distribution Patterns
4. What kind of abiotic factors would affect dispersion? Biotic?
Abiotic factors might include exposure times at low tides, substrate type, exposure to
5. What effect do you think the size of your quadrat has on the accuracy of your results?
Review concept that the sample is an estimate of the population and the larger the
6. What is the effect of the number of quadrat samples taken on the estimate the
coefficient of dispersion?
In general the larger the number of samples the better the estimate of the coefficient of