Comparative Behavior Experiment (at the Zoo) Introduction Notes Available online at

Why study behavior? Understanding the way organisms behave in response to their environment is integral to understanding the ecology of those organisms. For example, senses are fundamentally important to how animals interact with both their biological and physical surroundings. BEHAVIORS ARE INITIATED BY SENSES. Most senses like hearing, sight, smell, taste, and touch are familiar to us. Even though most animals have these same five senses, sensitivity to the stimuli vary greatly. Dolphins and bats detect ultrasound. Bees can see ultraviolet light. Some male moths have a sense of smell so acute they can sense the presence of one molecule of the female perfume pheromone. Other animals have senses that seem strange and unimaginable, like infrared detection in many snakes and electromagnetic sensing in fish.

Why study behavior? BETTER UNDERSTAND THE WORLD AND ITS INHABITANTS! Ever noticed swarms of moths, mosquitoes, and other flying insects gathering around your window where your desk lamp shined through? If you move the lamp to the opposite side of the window, sure enough, the insects follow the lamp. "Why did they do this?" "Did all insects that could see the light come to it, or did only a few?" How do so 'many' ants find the dropped ice cream cone on the side-walk? How do migrating flocks of birds know where they are going?

WHAT, HOW and WHY do animals behave? The abc’s of life Senses and behaviors are used for finding food and shelter, for locating mates, for navigation and migration, for triggering hibernation, for communicating with other animals of the same and different species, and for avoiding predators. In short, animal senses are windows to the world around them. Knowing the senses and behaviors of an organism in response to its environment can advance your understanding of its habitat, its relationship with other organisms, and its physical surroundings. These senses and behaviors help with: Growth Reproduction Defense All behaviors have evolved through natural selection to help organisms do these “abc’s”. These behaviors have a genetic basis.

Example of simple organisms: the earthworm and brine shrimp. We’ve already studied the phototaxis, temperature taxis, geotaxis, and chemotaxis of earthworms.

Example of simple organisms: the earthworm and brine shrimp. The brine shrimp, Artemia, is not a true shrimp, but belongs to a group of crustaceans, Branchiopoda, believed by many biologists to represent one of the most primitive group of crustacea. They are generally found in salt lakes and salt flats (not the ocean). They feed on plankton at the surface of the water. On a regular basis, the brine shrimp’s salty habitat completely dries out. They are interesting to study in that they are relatively simple and have a number of interesting responses stimuli.

Example of simple organisms: the earthworm and brine shrimp. The life cycle of the brine shrimp is depicted in the drawing. The shrimp hatch from overwintering cysts in January through May and the first adults appear in the lake around the middle of May. These early adults may bare live young which will mature rapidly in the warm layer of the lake. This life cycle is depicted by the inner loop in the drawing.

The shrimp feed on (filter) planktonic algae, and the algae concentration varies dramatically from month to month within the year. It also varies from year to year depending on the salinity of the lake. Brine shrimp display positive phototaxis; that is, the shrimp are attracted to and move toward light. But that leaves the question of HOW they are attracted: Are the organisms attracted to heat? Do they prefer upper layers of the water column? Do they show preferences for light of different wavelengths? WHAT are brine shrimp behaviors?

WHY do brine shrimp behave? How does being attracted to light help brine shrimp live? What is the function of phototaxis? Do brine shrimp feed on organisms that live in the upper layers of water? What does their behavior tell us about their habitat?

The brine shrimp may be found each summer in the oxygenated upper waters, but they begin to decline in number by September and are almost absent from the plankton by December. The eggs lie dormant (cryptobiosis) on the bottom of the lake until the following winter. WHAT are brine shrimp behaviors? WHY do brine shrimp behave as they do? What are the benefits of cryptobiosis?

Generating questions (WHATs and WHYs) for study Based on initial knowledge, you can generate even more questions that can be investigated relatively easily. Do young and old shrimp behave differently? How is hatching affected by salt concentration? pH? temperature? contaminants? How do brine shrimp find mates?

What will you study about the more complex organisms at the zoo? Requirements: Your experiment must be based on quantitative comparison of two organisms you will quantitatively observe for ten minutes. Generate questions: How do size, eating habits, native climate, locomotion, etc. effect behavior and activity? Design experiment Before the zoo: Research and write Introduction At the zoo: Collect Data and write Discussion and Conclusion