Students study aspects of orientation behavior in a variety of organisms in order to gain experience with the design, data collection, and analysis phases of scientific investigations. Systems described include orientation to light and humidity in sowbugs, negative klinotactic response to light gradients in fly larvae, factors affecting school formation in tropical fish, phototaxis and thigmotaxis in planaria, and orientation to light quantity and quality in water fleas. Lettuce seeds and seedlings are used to study extrinsic and intrinsic controls of plant development. These exercises facilitate integration of structural data, obtained from an examination of microscope slides or photomicrographs, and physiological data which may be obtained from literature readings or subsequent physiology experiments. Although the examples provided are botanical, these techniques are used by microscopists in all areas of biological research.
Students examine the sample and tally both numbers and kinds of invertebrates into major taxa.
They record size classes and construct a numbers pyramid utilizing these data. Biomass considerations could also be done. A 10 cm x 10 cm sample is collected carefully to maintain its three-dimensional integrity. Then it is inspected live from the upper surface downward through the sample while on the stage of a dissecting microscope. Written observations on the invertebrates' habitat and ecology may be made.