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Arthropods. Characteristics of Arthropods Kinds of Arthropods. Four Main Characteristics. Segmented body with specialized parts: Head: foremost part of a crayfish. Thorax: upper part of a crayfish's body Abdomen: lower part of a crayfish's body. Jointed Limbs
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Arthropods Characteristics of Arthropods Kinds of Arthropods
Four Main Characteristics • Segmented body with specialized parts: • Head: foremost part of a crayfish. • Thorax: upper part of a crayfish's body • Abdomen: lower part of a crayfish's body.
Jointed Limbs • Jointed limbs give arthropods their name. Arthro = joint, and Pod = foot. • Jointed limbs are legs or other body parts that bend at the joints
External Skeleton • Arthropods have a hard outer covering that is called an exoskeleton. • An exoskeleton does the some of the same functions as an internal skeleton. Supports the body. • Also, the exoskeleton has functions unlike an internal skeleton: acts like a suit of armor protecting organs inside the body, keeps water inside the animal’s body so it can survive on land without drying out.
Sensing Surroundings • All arthropods have a head and well developed brain. • Their brain receives information from many sense organs, including eyes, bristles and antennae. • Some arthropods have a compound eye: that is made up of many identical, light-sensitive units, for example the fly.
Kinds of Arthropods • Centipedes and Millipedes • Crustaceans: crayfish • Arachnids: spiders, scorpion, mites and ticks. • Insects
Echinoderms • Echinoderm = spiny skinned. • The spines are on the animal’s skeleton or endoskeleton (internal skeleton).
The Nervous System • All echinoderms have a simple nervous system. Around the mouth is a circle of nerve fibers called the nerve ring.
Water Vascular System • A system of canals filled with fluid. It uses water pumps to help the animal to move, eat breath, and sense its environment.
Types of Echinoderms • Brittle Stars and Basket Stars • Sea Urchins and Sand Dollars • Sea Lillies and Feather Stars • Sea Cucumbers