Phylum Arthropoda “joint” “foot” 80% of all animals are arthropods….. 76% of those are insects…..

Arthropod means “jointed legs” Contains more species than all other species of animals added together Extreme diversity in habitat (marine, freshwater, terrestrial and air), adaptations and food sources

Some amazing arthropods

Major Classes of Arthropods Above left: Subphylum Myriapoda, Class Chilipoda: includes the centipedes Lower Right: Subphylum Hexapoda, Class Insecta: includes all 6 legged insects Above: Subphylum Myriapoda, Class Diplopoda: includes the millipedes

Above Left: Subphylum Chelicerata Class Arachnida: includes the spiders, mites and scorpions Lower right: Subphylum Crustacea, Class Malacostraca: includes the lobsters, crab and shrimp Above: Subphylum Crustacea, Class Maxillopoda: includes the barnacles

Characteristics of Arthropods Symmetry: Bilateral Level of Organization: Organ Exoskeleton of chitin secreted by the epidermis 3 body regions (head, thorax and abdomen) Open circulatory system Separate sexes (Dioecious): fertilization is usually internal

Male vs. Female crabs Male or Female?

Sensory organs are well-developed: –compound eyes –tympanum (drum-like ear) –antenna (touch, smell, chemical reception) Complete digestive systems with mouth, specialized organs and anus Respiration by body surface, gills, trachea, or book lungs Developed nervous system with a brain and double ventral nerve cords

A closer look at Classes of Arthropods Class Insecta Head with 6 segments, sensory antennae and compound eyes Thorax with attached segmented legs and possibly wings Abdomen with 11 segments which has most of the digestive, respiratory, excretory and reproductive systems

Insects breathe through small tubes and sacs that are directly next to the circulatory system –No closed vessels Most insects hatch from eggs which are formed by sexual reproduction Insects molt as they grow in size (undergo metamorphosis) # #

Class Arachnid Spiders are not insects. Arachnids include spiders, scorpions, mites and ticks. Arachnids have four pairs of legs. cephalothoraxTwo main body sections - abdomen and cephalothorax –This is a –This is a joined head and thorax. No antennae

Subphylum Myriapoda Myriapod means having many legs. Millipedes and Centipedes belong to this subphylum of arthropods Both centipedes and millipedes care for their eggs

Class Chilipoda - Centipedes One pair of legs per body segment. Up to 15 to 170 pairs of legs in total Wriggle when they walk because the legs on either side of their body move alternately. Centipedes have flat bodies Centipedes are carnivores - they have fangs - may have venomous claws to catch their food. They can move very quickly.

Class Diplopoda - Millipedes Two pairs of legs per body segment. Smooth motion because both legs on either side of their body are moving at the same time. They have a round tube shape bodies. Millipedes may give off a bad odor when they are frightened Vegetarian

Class Maxillopoda : The Barnacles The Barnacle Life Cycle Includes 2 larval stages 1.NAUPILUS Floats in the ocean 2. CYPRID Settles in a safe place Glues itself headfirst to surface and undergoes metamorphosis into a barnacle

Nauplius larva (barnacle)

Adult Barnacle develops 6 hard armor plates around its body feathery legs to capture food and gametes when spawning Barnacles are hermaphroditic Famous Barnacle Fact: Barnacles have the largest penis to body size ratio of any species in the animal kingdom

Goose barnacles feeding

Class Malacostraca Cephalothorax –almost completely covered by a carapace 6 abdominal segments often used for swimming –Stick out the end in shrimps and lobsters –Tucked underneath the body in crabs

Compound eyes 5 pairs of walking legs, some with modified pincers 2 chambered stomach Centralized nervous system Spiny King Crab Hermit Crab

Above: Pacific White Cleaner Shrimp Left: Decorator Crab: will cover its body in algae etc. in order to camouflage itself with its surroundings Above: Lobster

Pair of LobsterPrawn Spiny LobsterHermit Crab

Ecological Roles of Arthropods Pollination Production of honey, wax, and silk Recycle biological materials to help make topsoil Form symbiotic relationships with other organisms Part of food chain v=SX4ymCik3iQ Burrowing shrimp and Goby fish living together

The Largest living Arthropod… …is the Japanese Spider Crab with a leg span of 4 meters and a weight of 20kg. This crab has a life expectancy of 100 years.