Structures of LifeCrayfish

FOSS Structures of Life, TESLA Science Notebooks

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

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.

Background Knowledge

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 structures

We 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

Molting

• A crayfish’s skeleton is on the outside of its body. It protects the crayfish from predators and other dangers.

• The crayfish has to shed its too-small shell to grow. • A crayfish can also grow a new leg or claw if the old

one breaks off.• What is one advantage and one disadvantage of

molting?

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 CrayfishFirst pair of swimmerets is modifiedBigger pincers Smaller pincersNarrower tales Wider tailsNo egg pores Egg poresShorter 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. Our crayfish will eat elodea and cat food

• Crayfish will be fed cat food in a separate basin • The plastic cups are crayfish shelter

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 III: Behaviors

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?• 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.

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

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?

How does a crayfish compare to you?

Crayfish vs Human

• Have a heart to pump blood• Have a stomach to digest food

and glands to excrete wastes• Crayfish usually live in water and

get oxygen out of water through gills.

• Skeleton on the outside of its body.

• Crayfish have 5 pairs of legs. They can walk quickly. The 5th pair of legs, located near the head, has large claws that are more like arms than legs. They are used to pick up food and defend itself against predators.

• Have a heart to pump blood

• Have a stomach to digest food and glands to excrete wastes

• Humans live on land and have lungs to breathe air.

• Skeleton on the inside of their body.

• Have two legs to walk, run, and climb.

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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…?