Structures of Life
Crayfish
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
Background Knowledge
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.
Part I: Structures
Crayfish 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?
Part I: Structures
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
1. Long antennae
2. Short antenna
3. Pincer
4. Eye
5. Mouth
6. Walking leg
7. Carapace
8. Short swimmeret
9. Modified swimmeret
10. Egg pore
11. Long swimmeret
Female Crayfish
Male Crayfish
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
bristles
egg pore
antenna
Part I: Structures
How can you tell the difference between a male and female
crayfish?
Male Crayfish
Female Crayfish
First pair of swimmerets is
modified
Bigger pincers
Smaller pincers
Narrower tales
Wider tails
No egg pores
Egg pores
Shorter swimmerets
Longer swimmerets
Part II: Habitat
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
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
When we observe what crayfish “do,” we are observing their
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.
Part 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.
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.
REFLECTION AND CONCLUSION
2011
11/8
• What did you learn…?
• What really surprised you…?
• What new questions do you have…?
• What would you like to know more about…?