Structures of LifeCrayfish

BIG IDEA:All living organisms have identifiable structures and characteristics that serve different functions in growth, survival, and reproduction.

Guiding Questions• What are the structures of crayfish?

• What does a crayfish need to survive?

• What are observable crayfish behaviors?

Word Wall:

crayfish

structures

behaviors

organism

crustacean

Some of us may have never seen a crayfish up close before so lets take a couple of minutes to make a few observations.

Crayfish are a living organism so we need to treat them with respect. They will not harm you, but they can pinch you if not handled correctly.

For now we are just going to observe the crayfish and not handle them.

Background

Focus

What are the structures and behaviors of crayfish?

“Discuss with your group what we need to investigate and record it as the FOCUS QUESTION. This is the problem we are going to investigate and solve.”

Prediction:

Now that we have a focus question, discuss with your group what you think a possible answer might be. Record your prediction in your scientist notebook and be ready to share your ideas with the class.

Prediction: I think that the structures of a crayfish are______________________________________________________because _________________________________________________________

Today we are going to begin by examining our crayfish to learn more about them. It is OK for crayfish to be out of the water for a short period of time. We don’t want to keep them out of the water so long that they dry out. It would also be bad for the crayfish if we drop them on a hard surface.

This is the best way to pick up a crayfish.

Part I: Structures

You can also use a spoon and ¼ liter container if you don’t want to touch one.

What are some of the interesting parts that you notice on your crayfish?

Parts of the crayfish are their structures. Just like the parts of the plants and seeds are called structures.

We are going to keep a list of the structures that we observe in our science notebooks.

Part I: Structures

Crayfish Structures

Part I: Structures

Do crayfish have… Yes or No

How many…Do crayfish have eyes? How many?Do crayfish have ears? How many?Do crayfish have walking legs?

How many?Do crayfish have antennae? How many?Do crayfish have tail flaps? How many parts?Do crayfish have pincers? How many?Do crayfish have joints? How many?Do crayfish have mouths? How many?Do crayfish tails bend? How many places?Do crayfish have bristles? Where?Do crayfish have bumps? Where?What other crayfish structures do you observe?

Some of you were able to notice differences in your crayfish. They were not all the same. Some of these differences may be due to age or handicapping… Loss of an antennae or leg.

What else could cause noticeable differences in our crayfish?Gender: Male and female crayfish will have different structuresWe can compare what we saw with our crayfish diagram and identify these different structures.

Can you predict the gender of your crayfish?

Part I: Structures

Part I: Structures

Female Crayfish Male Crayfish

1. Long antennae2. Short antenna3. Pincer4. Eye5. Mouth6. Walking leg7. Carapace8. Short swimmeret9. Modified

swimmeret10.Egg pore11.Long swimmeret

Word Wall:

carapace swimmeret

pincer

egg pore antenna

bristles

How can you tell the difference between a male and female crayfish?

Part I: Structures

Male Crayfish Female Crayfish

First pair of swimmerets is modifiedBigger pincers Smaller pincers

Narrower tales Wider tails

No egg pores Egg pores

Shorter swimmerets Longer swimmerets

What do we need to know about crayfish in order to keep them in our classroom?

Most living organisms require a certain amount of:• Food… What will they eat, how much, how often?• Water… How deep, what temperature, how clean?• Shelter… Do they need hiding places or rocks?• Air… How will they get air to breath?• Space… Should they live together?

Part II: Habitat

The place where an animal lives is called a habitat. In our classroom the crayfish habitat will be these large tubs.

Part II: Habitat

Natural Habitat Classroom Habitat

In their natural habitat, crayfish find their own food and shelter. In our classroom, they must be fed and given a safe place to live.

Part II: Habitat

Classroom Habitat

It will be your groups responsibility to care for the crayfish habitat and make observations.• Our crayfish will eat elodea and cat food• Crayfish will be fed cat food in a separate basin • The plastic cups are crayfish shelter

Draw and Label your Habitat

When we observe what crayfish “do,” we are observing their behaviors.

Part III: Behaviors

Remember… To learn more about what crayfish do, we need to observe them over the next few weeks. Let’s begin by observing the crayfish when they are removed from their habitat and placed in a basin.

What do they do? How do they behave?Record your observations in your science notebook and be prepared to share what your group observed with the rest of the class.

Part III: Behaviors

Crayfish SheltersHow have you observed crayfish using their houses in the classroom habitat?

Crayfish use their houses for shelter

• Do all crayfish hide in houses? • Does each crayfish have its own house that it always

goes into?• Do you ever see more than one crayfish hide in the

same house?

Part III: Behaviors

This week your groups task is to set-up an investigation to find out how your crayfish use their houses. Your plan must include these elements:• Specific locations of the houses• A way to Identify each individual crayfish• Location of the crayfish during the observation

Part III: Behaviors

Collecting Data:• Your observations should be recorded in your

scientist notebook.• Identify the Date and Time of each observation.• Include detailed drawings with labels.

Part III: Behaviors

Crayfish SheltersWhat did you learn from your investigation about crayfish behaviors and their use of shelters?• Do crayfish like to share their shelter with other

crayfish?• Will they defend their shelter or place in their habitat?

Crayfish are territorial creatures. They will claim a location in their habitat and defend it against others. The biggest or strongest crayfish will normally claim the territory of its choice.

How do you Know?

Making Meaning

What are some of the observable structures of crayfish?

What does a crayfish need for a healthy habitat?

What are some of the behaviors you observed?

How are crayfish territorial?

Based on what you have learned from your investigation of crayfish, you need to record some claims and evidence statements in your science notebook… Your evidence must be based on your data and observations!

I claim that… I know this because…

Possible Examples:I claim that crayfish have observable structures. I know this because…I claim that crayfish need _______________________________to survive. I know this because…I claim that crayfish have behaviors that are observable. I know this because…

Claims and Evidence:

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2011

REFLECTION AND CONCLUSION

• What did you learn…?• What really surprised you…?• What new questions do you have…?• What would you like to know more

about…?