Arthropods

Phylum Arthropoda

Subphylum Trilobita

Subphylum Chelicerata

Class Merostomata

Class Arachnida

Subphylum Crustacea

Class Branchiopoda

Class Maxillopoda

Class Malacostraca

Subphylum Uniramia

Class Diplopoda

Class Chilopoda

Class Insecta

Metamerism

Characteristics of Phylum

1. Exoskeleton

Coat of armor - impregnated with calcium salts (lobster)

2. Segmentation

3. Tracheal System

4. Reduced Coelom

5. Open Circulatory System

Heart, arteries and hemocoel

6. Sensory Organs/Complex behavioral patterns

Compound Eye, touch, hearing, smell and balancing organs.

Exceed most other invertebrates in complexity of activities and behaviors - capable of learning.

7. Metamorphic changes

Limits competition for resources larval form and adult form - different foods/space

Subphylum Trilobita

extinct for over 200 million years.

Three tagmata = head, thorax and pygidium (tail).