19: The Arthropod Body Plan

Goals:
1. Know the basic features of arthropods and their subphyla.
2. Understand the evolutionary relationships of body parts in the different subphyla.

Outline:

Taxonomy: Phylum Arthropoda

  • Subphylum Trilobita (extinct, but very important)
  • Subphylum Chelicerata
    • Class Merostomata - horseshoe crabs
    • Class Arachnida - spiders and scorpions
  • Subphylum Crustacea - crabs, shrimp, lobsters, isopods, copepods
  • Subphylum Myriapoda
    • Class Chilopoda - centipedes
    • Class Diplopoda - millipedes
  • Subphylum Hexapoda
    • Class Insecta
Introduction

There are more species of arthropods than of any other group of living organisms. They have no rival in the complexity of their structural adaptations or in their ability to adapt to life in virtually all types of environments. Their wide geographical distribution has led to many interactions with our own species. Some species affect human crops, clothing, and health. Others are important as major constituents of terrestrial and aquatic food chains. In this laboratory you will investigate the major structural characteristics of arthropods and examine some of the major trends of diversification within the group.