Exploring the Scientific Method using Animal Behavior
1. Demonstrate an understanding of taxis, kinesis, and agonistic behaviors. 2. Think about possible adaptive advantages of each.
3. Observe behaviors, propose hypotheses, design experiments, collect and process data, and discuss results. 4. Present results in a scientific paper (See handout “Writing a Lab Report Help and Grade Sheet”).
Ethology is the study of animal behavior in the context of evolution, ecology, social organization, and sensory abilities of an animal. Behavior can be defined as the sum of all responses an organism has to stimuli in its environment. In other words, behavior is what animals do.
Oftentimes it is difficult to unravel complex behaviors of organisms in their natural environment and therefore ethologists sometimes study behavior in controlled experiments. This approach often uncovers simple and isolated behaviors allowing scientists to uncover complex behaviors and put them in their evolutionary and ecological context more accurately.
Behavior can be broken down into two basic categories: innate (inherited) and learned behavior. Evidence suggests that the basis of both types of behavior lies in the animal’s genes. As you observe the animals in today’s lab try to keep in mind that these behaviors often have a proximate cause and an ultimate cause. A proximate cause is the immediate physiological event that causes the behavior. For example, when you approach a fiddler crab in its feeding area the vibrations from your footsteps stimulate neurons to fire and the crab responds by running into its burrow (proximate). The ultimate cause or most likely “real” reason the crab retreats is to avoid being eaten by a predator.
The questions you will formulate before carrying out your experiments will be causal in nature. Later in your discussion with your classmates and in the discussion section of your paper you will need to think about the ultimate causes for the observed behaviors. Note that anthropomorphic behaviors are not appropriate questions to ask—that is, questions that ascribe human attributes to the animal’s behavior. Anthropomorphic explanations indicate an animal makes a conscious decision about its environment. An example would be that male birds sing loudly in the spring because they are happy and are excited to find a mate.
Ethologists categorize patterns of behavior based on the consequence a particular behavior has on the organism. The three behaviors you will be investigating today are taxis, kinesis and agonistic behaviors.
Taxis and kinesis are both orientation behaviors, which puts the animal in its most favorable environment. Taxis involves movement towards (positive) or away from (negative) a stimulus. Prefixes such as photo, chemo, thromo, are often used to help describe the various forms of taxis (as well as kinesis). For example if an amimal moves towards a warm environment it is said to be positively thermotactic.
Kinesis is a form of orientation behavior in which, unlike taxis, the animal is not moving towards or away from a stimulus. Kinesis is random, undirected movement. Kinesis is measured in terms of intensity of the movement. For example if a bright light is shone on an animal and the animal responds by stopping its movement then the animal is negatively phototactic.
Agonistic behaviors are found in situations where an animal is in a conflict situation where there may be a threat or approach, followed by an attack or a withdrawal. Agonistic behaviors can also be categorized into aggressive and submissive behaviors. Behaviors in which there is a show of force are considered aggression and those in which there is a retreat or avoidance are considered submission. Aggressive behaviors are often simply displays that make an animal look threatening. This is typically an effort to maintain a territory or...