l o Phylum: Arthropoda Phylum: Arthropoda

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Arthropoda Origin of the word Arthropoda: Jointed Foot Common Examples: Insects, Spiders, Crabs Symmetry: Bilateral Type of body cavity: Coelomate

General Arthropod Body Plan

Characteristics of Arthropods Early arthropods: have appendages on each segment Modern arthropods: have appendages on a few segments. 1)Jointed appendages: Arms and legs with freely moving joints.

Specialization of Appendages Functions of Appendages: 1)Running 2)Catching prey 3)Feeding (Sharp mandibles) 4)Swimming 5)Reproducing 6)Sensory reception

Exoskeleton 2) Exoskeleton: Strong chitin shell found on the outside of the organisms body Used for: - Protection - Skeleton to support muscle - Prevent desiccation (drying out)

Exoskeleton Molt: The exoskeleton is not capable of expanding. When the organism inside the exoskeleton grows too large it must form a new exoskeleton inside the old one. When the new one is ready it will shed the old one. Once free the new exoskeleton expands and hardens

Segmentation 3) Segmentation in arthropods: Segments are fuse into regions.

Nervous System Arthropod Nervous System: Three parts 1) Brain 2)Ventral solid nerve cord 3) Sense organs: - Antennae - Simple eyes - One pair of compound eyes Compound eyes produce a clearer image then the mammalian eye

Subphylum: Crustaceans Crustaceans: Have high levels of calcium in their shells - Mainly marine arthropods. Barnacles, crabs, lobsters and shrimp - Freshwater examples include crayfish, freshwater crabs and shrimp. - Land examples include pillbugs

Subphylum Uniramia Subphylum Unirami: Insects Entomology: The study of insects Characteristics of insects: 1)Three parts of the body: head, thorax, abdomen, 2)One pair of eyes and several smaller eyes

Subphylum Uniramia Subphylum Unirami: Insects Entomology: The study of insects Characteristics of insects: 1)Three parts of the body: head, thorax, abdomen, 2)One pair of eyes and several smaller eyes 3)One pair of antennae 4)Specialized mouthparts

Subphylum Uniramia Subphylum Unirami: Insects Entomology: The study of insects Characteristics of insects: 1)Three parts of the body: head, thorax, abdomen, 2)One pair of eyes and several smaller eyes 3)One pair of antennae 4)Specialized mouthparts 5)One or two pairs of wings - Escape enemies - Finding food - Mating - Dispersing offspring

Subphylum: Chelicerates Subphylum: Chelicerates (Arachnids Scorpions, Spiders, ticks, mites) 1) 6 pairs of appendages -2 chelicerae -2 pedipalps -4 pairs of walking legs 2) Two body parts: -Cephalothorax: Head and legs -Abdomen: Contains the organs

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