HW: Complete page 1 in RB 2 (Resource book 2 – the pink one) Intro To Arthropods HW: Complete page 1 in RB 2 (Resource book 2 – the pink one)

Overview Arthropods have been around for 500 million years. There are about a million known species of arthropods. This are more species in this one phylum than you would get by grouping all members of all other phyla together. There are 160 million insects for each person on this Earth. There are so many copepods & tiny crustaceans that together they outweigh all the whales on Earth.

Habitat Given that there are a million of different species, they are found in almost all habitats on Earth. Many crustaceans live in the sea at depths exceeding 4,000 metres. (That’s 2.5 miles deep) Insect collembolans and jumping spiders have been found on Mount Everest at heights exceeding 6,700 metres. (That’s 4 MILES high.) Collembolans and the orbatid mites live in Antarctica.  Brine shrimp are found in some saltwater lakes. Beetles, mites, and various crustaceans can live in hot springs.  Tiny crustaceans inhabit underground waters. Deserts support a large arthropod population, especially insects and arachnids.

Niches All are free-living, and the aspects of their niche that affect humans include: Many species of insects and mites attack food crops and timber.  Two-thirds of all flowering plants are pollinated by insects. Soil and leaf-mold arthropods, which include insects, mites, myriapods, and some crustaceans (pill bugs), play an important role in the formation of humus from decomposed leaf litter and wood. To protect themselves many arthropods (insects) will sting their attacker.

Medical Importance Medically, arthropods are significant as carriers of diseases, including: Malaria Yellow fever Dengue fever African sleeping sickness (via tsetse flies) typhus fever (via lice) bubonic plague (via fleas) Rocky Mountain spotted fever (via ticks) Lyme disease (via ticks)

Arthropod Characteristics What makes an organism an arthropod? Exoskeleton Segmented Body with paired appendages Bilateral symmetry One way digestive system (mouth and anus) Open circulatory system Separate sexes

Arthropod Subphyla & Classes There are many different classes of Arthropods, including: Class Merostomata (horseshoe crabs, eurypterids:sea scorpions) Class Arachnida (spiders, ticks, mites) Class Crustacea Class Chilopoda (centipedes) Class Diplopoda (millipedes) Class Insecta