5Background KnowledgeCrayfish 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.
6Part I: Structures Crayfish Structures Do crayfish have… Yes or No How many…Do crayfish have eyes?How many?Do crayfish have ears?Do crayfish have walking legs?Do crayfish have antennae?Do crayfish have tail flaps?How many parts?Do crayfish have pincers?Do crayfish have joints?Do crayfish have mouths?Do crayfish tails bend?How many places?Do crayfish have bristles?Where?Do crayfish have bumps?What other crayfish structures do you observe?
7Can you predict the gender of your crayfish? Part I: StructuresSome 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?
8Part I: Structures Long antennae Short antenna Pincer Eye Mouth Walking legCarapaceShort swimmeretModified swimmeretEgg poreLong swimmeretFemale CrayfishMale Crayfish
9MoltingA 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?
11Part I: StructuresHow can you tell the difference between a male and female crayfish?Male CrayfishFemale CrayfishFirst pair of swimmerets is modifiedBigger pincersSmaller pincersNarrower talesWider tailsNo egg poresEgg poresShorter swimmeretsLonger swimmerets
12Part II: Habitat Most living organisms require a certain amount of: 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?
13Part II: HabitatThe place where an animal lives is called a habitat. Our crayfish will eat elodea and cat foodCrayfish will be fed cat food in a separate basinThe plastic cups are crayfish shelterNatural HabitatClassroom HabitatIn their natural habitat, crayfish find their own food and shelter. In our classroom, they must be fed and given a safe place to live.
14Crayfish use their houses for shelter Part III: BehaviorsWhen we observe what crayfish “do,” we are observing their behaviors.Crayfish use their houses for shelterDo 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.
15Part III: Behaviors Crayfish Shelters What 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?How do you Know?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.
16Making 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?
17Crayfish vs Human Have a heart to pump blood Have a stomach to digest food and glands to excrete wastesHumans live on land and have lungs to breathe air.Skeleton on the inside of their body.Have two legs to walk, run, and climb.Have a heart to pump bloodHave a stomach to digest food and glands to excrete wastesCrayfish 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.
18Reflection and Conclusion 201111/8What did you learn…?What really surprised you…?What new questions do you have…?What would you like to know more about…?