Crayfish Quiz Flashcards

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?

Crayfish have an open circulatory system, which means that blood does not travel in veins. Signup and view all the answers

How does blood flow through a crayfish?

Blood starts from the heart, moves through a small section of arteries, and goes to the sinuses in the body tissues. Signup and view all the answers

Briefly explain how food is digested in the crayfish. Include the role of the mandibles, cardiac stomach, and pyloric stomach.

The mandibles push food into the mouth. Food travels through the esophagus to the two-chambered stomach (cardiac and pyloric) where it is ground up and strained. Digestive glands then secrete enzymes, allowing further digestion in the intestine. Signup and view all the answers

What type of food do crayfish eat?

Crayfish eat both plants and animals. Signup and view all the answers

In what ways is the crayfish nervous system like that of an earthworm? How is it different?

The crayfish has a ventral nerve cord leading to a bundle considered the brain. Unlike earthworms, crayfish have compound eyes on stalks and primarily sense with their antennae. Signup and view all the answers

Describe the eyes of the crayfish.

The eyes are found on movable stalks and are compound. Signup and view all the answers

What are the purposes of the antennae and the antennules?

The antennae are used for touch and taste, while the antennules are used for touch, taste, and equilibrium. Signup and view all the answers

How does a crayfish obtain oxygen?

Crayfish obtain their oxygen from diffusion that occurs in their gills. Signup and view all the answers

How does fertilization occur in crayfish?

Eggs are produced by the female and sperm by the male crayfish. Fertilization occurs when the male and female abdomen regions combine, and sperm is released along with eggs, which are stored on the female's swimmerets. Signup and view all the answers

What is chitin?

Chitin is a carbohydrate found in the exoskeleton of the crayfish. Signup and view all the answers

What is the purpose of the swimmerets and where are they located?

Swimmerets are used for swimming and reproduction; they are located underneath the abdomen. Signup and view all the answers

Describe molting and self-amputation/regeneration in crayfish.

Molting is when the crayfish sheds its shell to grow. They can also self-amputate to escape predators and regenerate lost limbs. Signup and view all the answers

Why is the feathery nature of gills important?

It gives them a very large surface area, allowing for more efficient oxygen absorption. Signup and view all the answers

Which systems are most unlike crayfish?

Humans have an internal skeleton while crayfish have an exoskeleton, and crayfish have an open circulatory system while humans have a closed one. Signup and view all the answers

What advantages do jointed appendages give an organism? Why do crayfish have this feature and humans don’t?

Jointed appendages allow for easy movement and the ability to capture food. Humans do not have them because they would restrict movement. Signup and view all the answers

List three specific reasons why crayfish are more complex than earthworms.

<ol> <li>Crayfish have a hard protective shell, while worms have a thin outer layer. 2. Crayfish have a more complex nervous system. 3. Crayfish have a more efficient way of moving.</li> </ol> Signup and view all the answers

Is a crayfish most vulnerable to enemies from the dorsal side or ventral side?

Ventral side, because a crayfish can use its claws to defend against predators from the dorsal side. Signup and view all the answers

Why does a crayfish hide after it molts?

Because it is more vulnerable without a protective shell. Signup and view all the answers

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.