06_intro_Arthropoda_part_3_insecta

Arthropoda Overview

Key Phylogenetic Symbols

• Phylum: Arthropoda
• Subphyla:
  • Trilobitomorpha
  • Chelicerata
  • Mandibulata
  • Myriapoda
  • Hexapoda
  • Crustacea

Distinguishing Characteristics of Myriapoda

• Terrestrial Species
• Legs: Range from 10-200 pairs of appendages
• Habitat: Common in humid environments such as soils, leaf litter, or under stones/wood
• Defensive Adaptation: Many species have repugnatorial glands.

Classification of Myriapoda

• Superclass: Myriapoda
  • Order: Chilopoda (Centipedes)
  • Order: Diplopoda (Millipedes)

Chilopoda (Centipedes)

• Diversity: More than 2,500 species
• Leg Characteristics: One pair of legs per body segment
• Body Form: Flat, elongate shape
• Diet: Predaceous, uses claw-like jaws/fangs known as "lip foot."

Illustrative Anatomy of Chilopoda

• Body Parts:
  • Head: Contains antenna, epistome, labrum
  • Segments: Tergites, spiracles, legs are clearly defined.

Diplopoda (Millipedes)

• Leg Characteristics: Two pairs of legs on most body segments
• Body Form: Cylindrical body structure
• Diet: Scavengers that feed on decaying organic matter, also known as “double foot.”

Comparative Features

Hexapoda (Insecta)

• Class Size: Insects represent the largest class of arthropods
• Legs: Insects typically have six legs
• Diversity: Most species-rich group in the entire animal kingdom.

Insect Anatomy Overview

• Key Features:
  • Head: Contains mandibles, labrum, antennae, and eyes (lateral ocelli and compound).
  • Thorax: Includes forelegs, hindlegs, and wings (if present).
  • Abdomen: Houses spiracles, reproductive organs, and digestive system components.

Lab Activities

• Objective:
  • Distinguish between Centipedes, Millipedes, and various insects.
  • Learn through dissection of Grasshopper and explore Onychophora and insect diversity.