Arthropods The “Jointed Foot” Creatures

Characteristics of Arthropods  Arthropods have an exoskeleton made of Chiton and Proteins, Bilateral Symmetry, Coelomate, and jointed structures called Appendages.  The appendage can be used for a variety of functions including: sensing, walking, feeding and mating.  Arthropods must molt to grow.

Respitory structures  Arthropods have a variety of methods of Respiration.  Draw the 3 examples of them on page 764 in the Biology textbook.  Many have simple eyes (used for light detection) and compound eyes.  Terrestrial arthropods excrete waste through Malpighian tubules located on the abdomen.  Some Arthropods reproduce by Parthenogenesis, development of an unfertilized egg.

Arachnids  Spiders, Scorpions, Mites and ticks  First set of appendages are called the Chelicerae which often are modified into pincers or fangs.  Second appendages are called pedipalps which handle food or are used for sensing.  2 major body segments: Cephalothorax and abdomen.

Camel Spider Pictures from Iraq

Crustaceans  Only group of arthropods that have 2 sets of antennae for sensing.  Jaws move from side to side.  Eyes located on Stalks.  Include: Crabs, Lobsters, Shrimp, Crayfish, barnacles, water fleas and sow bugs and pill bugs.  Most breath through sets of feathery gills underneath a carapace.

Water Fleas

Centipedes and Millipedes  Centipedes, class Chilopoda are all carnivores. Bites can be painful to humans. Malpighian tubules are used for waste.  Millipedes, class Diplopoda are herbivores that feed on decaying materials. Millipedes do not bite but can emit an obnoxious smell if disturbed.

Horseshoe Crabs  Class Merostomata  Very Ancient animals unchanged since the Cambrian era (500 million years ago)  Feed on seaweed, worms and molluscs.  Have blue blood due to the chemicals in it.  Draw a picture on page 771 of the horseshoe crab.

Insects  Class Insecta- Only one species is Marine  Almost 7/10 animals are Insects!  All insects undergo some form of metamorphosis.  Draw the picture of the Grasshopper on page 772 and label and explain the function of the following body parts: Antennae, Tympanum, Malpighian Tubules, Spiracles.