Questions and Answers
What phylum and class do crayfish belong to?
Crayfish belong to the phylum arthropod and class crustacean.
What characteristics do animals in the phylum arthropod have in common?
Animals in the phylum arthropod are invertebrates, have bilateral symmetry, a digestive system with a mouth and anus, and are mostly aquatic with gills, an exoskeleton, and segmented bodies and appendages.
Which animals are close relatives of the crayfish?
Animals that are close relatives to the crayfish include shrimps and lobsters.
What type of circulatory system does a crayfish have? What does this mean?
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How does blood flow through a crayfish?
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Briefly explain how food is digested in the crayfish. Include the role of the mandibles, cardiac stomach, and pyloric stomach.
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What type of food do crayfish eat?
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In what ways is the crayfish nervous system like that of an earthworm? How is it different?
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Describe the eyes of the crayfish.
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What are the purposes of the antennae and the antennules?
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How does a crayfish obtain oxygen?
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How does fertilization occur in crayfish?
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What is chitin?
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What is the purpose of the swimmerets and where are they located?
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Describe molting and self-amputation/regeneration in crayfish.
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Why is the feathery nature of gills important?
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Which systems are most unlike crayfish?
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What advantages do jointed appendages give an organism? Why do crayfish have this feature and humans don’t?
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List three specific reasons why crayfish are more complex than earthworms.
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Is a crayfish most vulnerable to enemies from the dorsal side or ventral side?
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Why does a crayfish hide after it molts?
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Study Notes
Crayfish Overview
- Crayfish belong to the phylum Arthropoda and the class Crustacea.
- Characteristics of arthropods: invertebrates, bilateral symmetry, digestive system with mouth and anus.
- Crustaceans primarily inhabit aquatic environments, possess gills, exoskeletons, and segmented bodies with appendages.
Relatives and Biology
- Close relatives of crayfish include shrimp and lobsters.
- Crayfish feature an open circulatory system where blood flows in body cavities rather than through veins.
- Blood circulates from the heart through arteries to sinuses in body tissues.
Digestion Process
- Food is aided by mandibles, traveling through the esophagus to the two-chambered stomach (cardiac and pyloric).
- Cardiac stomach grinds food, and the pyloric stomach strains it; digestive glands secrete enzymes for digestion.
Diet
- Crayfish are omnivorous, consuming both plant matter and small animals.
Nervous System and Senses
- Crayfish have a ventral nerve cord leading to a brain-like bundle; they primarily sense using antennae and compound eyes.
- Eyes are located on movable stalks and are classified as compound.
- Antennae are for touch and taste, while antennules serve for touch, taste, and equilibrium.
Respiratory and Reproductive Systems
- Oxygen is obtained through diffusion in gills.
- Fertilization occurs externally, with eggs produced by females and sperm by males; fertilized eggs are stored on female swimmerets.
Structural Components
- Chitin, a carbohydrate, forms the exoskeleton of crayfish.
- Swimmerets, found beneath the abdomen, are used for swimming and reproduction.
Growth and Defense Mechanisms
- Molting enables crayfish to grow by shedding their exoskeleton.
- Crayfish can self-amputate limbs to escape predators and possess regenerative abilities.
Adaptations and Vulnerabilities
- Gills have a feathery structure that maximizes surface area for oxygen absorption.
- Crayfish have jointed appendages for enhanced movement and food capture; humans lack this feature for flexibility.
- Crayfish are more complex than earthworms due to a hard shell, a more sophisticated nervous system, and efficient movement capabilities.
Predator Vulnerabilities
- Crayfish are most vulnerable to predators from the ventral side as they can defend themselves using claws on the dorsal side.
- After molting, crayfish hide to avoid predation due to their lack of protective shell.
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Description
Test your knowledge about crayfish with these flashcards. Learn about the phylum and class of crayfish, as well as their common characteristics. This quiz is perfect for biology enthusiasts and students alike.