Higley Unified School District / Higley Unified School ...



Investigating Animal Behavior with Isopods Name_____________

Prd.____Date_______

Background:

Terrestrial isopods are land-dwelling crustaceans, commonly known as sow bugs or pill bugs (or rolly-pollies). They are related to lobsters, crabs, and shrimp. Terrestrial isopods breathe with gill-like structures attached to their legs. While they look similar, pill bugs will curl into a ball when threatened, and sow bugs will attempt to flee. Terrestrial isopods are detritivores who generally live in moist, humid environments such as under logs or leaf litter. Females can carry up to 200 eggs in a brood pouch under her abdomen. Juveniles will remain in the pouch for about 3 weeks and emerge looking almost identical to adults except smaller. Isopods can be raised in a terrarium with a layer of soil or sand that is kept moist and has places for them to hide such as a piece of bark or leaf litter. They can be fed with carrots, raw potatoes or apples.

Ethology is the study of animal behavior. Some important generalizations about animal behavior include the following:

Innate Behaviors:

Example:

Learned Behaviors:

Ex:

Imprinting:

Ex:

Orientation:

Ex:

Kinesis:

Ex:

Taxis:

Ex:

It is not always easy to make conclusions about certain types of animal behaviors. Consider the following example: A researcher places a dead rotting mouse in the center of a test area and adds a carrion beetle (an insect that eats dead animals) somewhere on the surface. The beetle crawls forward for three seconds, turns and crawls in a different direction for three seconds and so on. The research concludes that the beetle is moving randomly in relation to the dead mouse. Continued observation reveals that the beetle crawls faster (and covers more ground) when it happens to turn in the direction of the dead mouse. In addition, the beetle crawls more slowly (and covers less ground) when it happens to crawl away from the mouse. In this way, the beetle’s random movements will eventually bring it to the dead mouse. It is important to take in details such as time spent crawling in one direction or another when observing the movements of the animals.

Inference: Would the behavior of the carrion beetle be taxis or kinesis? Explain. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Isopod Observations:

In the first part of this lab activity, you will observe isopods for at least 10 minutes and record what you see. To get started, collect 10 isopods from the containers provided and place carefully in a petri dish. Collect some of the soil and leaf litter as well.

Answer these questions as you observe your isopods:

●How do the isopods seem to sense their environment? What are some stimuli they seem to respond to?

●Are they all the same species? Are there any juveniles?

●Can you tell the difference between males and females?

●How many eyes, antennae and legs do they have?

●Do they exhibit dominance behaviors?

Scientific Illustration

When you make a sketch of an isopod, don’t just draw an oval with a few squiggly legs—you are expected to do a scientific illustration similar to the sketch of an earthworm below:

[pic]

Here are some tips for making an accurate sketch:

● Determine the relative proportions (length, width, height as well as lengths of body parts)

● Count the number of body segments, legs, antennae

●Locate and label the body parts

Draw an accurate scientific drawing of an isopod below, labeling all parts:

Experiment 1

Problem: Which environment do isopods prefer and spend more time in, moist or dry?

Hypothesis: (Write your own hypothesis here): ____________________________________________________________________________________________________________________________________________

Materials:

10 isopods

Choice chamber

2 circles of filter paper the size of the choice chamber

Glue stick

Water

Procedure:

1. Prepare choice chamber with one circle of filter paper moistened (not soaking wet) and the other dry. NOTE: On the dry side, put a small amount of glue on the outside edges so it will stick to the bottom of the choice chamber.

2. Put 5 isopods in each side of the choice chamber and cover the chambers.

3. Observe the isopods’ behavior for the next 10 minutes, counting the number of isopods on each side of the chamber every 30 seconds on the data sheet.

4. When experiment is done, return isopods to the stock container carefully. Wash and dry choice chamber (make sure there is no glue residue left over).

Analysis of Data and Conclusion:

Write a complete conclusion to this experiment on a separate piece of paper. Each student must write their own conclusion. In your conclusion, address the following questions:

1. Did the results of this experiment confirm your hypothesis? Explain.

2. Based on your observations, do isopods prefer a moist or dry environment? Explain.

3. Would their movements be described as taxis or kinesis? Explain.

4. Suggest a reason why this behavior might be advantageous to an isopod.

Experiment 2: Student-Designed Experiment

With your lab group, you must design another experiment that can be performed in the classroom. Keep in mind the following things when you design your experiment:

1. You may choose to do a similar experiment to the moist/dry environment with isopods, but change the factors. For example, you could choose to investigate changes in temperature, pH, light, substrate (surface), odor, food or the presence of other organisms.

2. Your experiment must be able to be carried out in the classroom within one or two class periods.

3. If you choose to work with any kind of animal, you must design an experiment that will not harm them in any way. For example, if you choose to submit them to chemicals, they must be diluted.

4. You may choose to do a seed germination experiment. If so, you should use seeds that germinate quickly such as radishes, lettuce, or beans.

5. You must have your experiment approved in advance by your teacher.

For your experimental design, write out the following and have it initialed by the teacher:

Problem/Question:

Hypothesis:

Materials:

Procedure:

Teachers’ Initials:_______________

Teacher’s Guide To Definitions:

Ethology is the study of animal behavior. Some important generalizations about animal behavior include the following:

• Innate Behaviors: (Also called instinct): behavior determined by the "hard-wiring" of the nervous system. It is developmentally fixed throughout life. A given stimulus will trigger a given response. These behaviors are inborn and inflexible and usually adapt the organism to its environment.

• Example: A salamander raised away from water until long after its siblings begin swimming successfully will swim every bit as well as they the very first time it is placed in the water. Clearly this rather elaborate response is "built in" in the species and not something that must be acquired by practice.

●Learned Behaviors: behavior that is more or less permanently altered as a result of the experience of the individual organism

●Ex: learning to play baseball well, spatial learning (a female digger wasp will always return exactly to her hidden nest), classical conditioning ( Pavlov’s dogs learned to salivate at the sound of a bell), operant condition (trial and error learning).

Imprinting: A type of behavior that includes both learned and innate components. It is the formation at a specific stage in life of a long-lasting behavioral response to a particular individual or object.

Ex: Konrad Lorenz showed that the principal imprinting stimulus in graylag geese is a nearby object that is moving away from the young. When incubator-hatched goslings spent their first few hours with Lorenze rather than with a goose, they imprinted on him and steadfastly followed him from then on. They showed no recognition of their biological mother or other adults of their own species.

Orientation: Behaviors in which animals position themselves with respect to spatial features of their environment. Environmental cues not only trigger some simple behaviors but also provide stimuli that animals use to change or orient both simple and complex movements in a particular direction.

Ex: Change in daylength and/or temperature causes birds to migrate

Kinesis: A change in activity or turning rate in response to a stimulus. It is random turning or movement of an animal in relation to a stimulus. An animal may change the speed of its random movements in response to a stimulus. An organism will tend to settle down in a region that is preferred by tending to move in a particular way or change its’ speed of movement when not present in the preferred location.

Ex: When moths hear bats coming, they will quit flying.

Taxis: An oriented movement toward (positive taxis) or away from (negative taxis) some stimulus.

Ex: Trout and many other river fishes automatically swim or orient themselves in an upstream direction (toward the current) . This taxis keeps the fish from being swept away and keeps it facing the direction from which food will come.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download