Symmetry Radial symmetry
Water vascular system that using water pressured for suction in the tube feet.
Small hard plates beneath the epidermis.
Nutrition: Clams and oysters
Digestion: The stomach secretes enzymes to liqife the food so it can be absorded and transported to the digestive glands.
Gases exchange through the gills on the coelom.
Excretion occurs the same way Respiration does, through the gills on the coelom.
A nerve cirlce around the mouth and ties to the radial nerves that go to each ray.
Reproduction is sexual. They send sperm and eggs into the water and they unite.
Classes (list examples) Asteroidea: Starfish
Echinoderoida: Sea urchin
Holpthuroidea: Sea cucumbers
Ophuroidea: Brittle stars and basket stars
Crinoidea: Sea lillies and feather stars
Subphylum Crustacea Arthropoda
Symmetry Bilateral symmetry Bilateral symmetry
Tough exoskeleton made of chitin Exoskeleton
Nutrition: Anything edible.
Digestion: Fine particles are sent to the digestive glands while course particles and indigestable material pass through the anus and are excreted. Nutrition: Insects.
Digestion: Food is transported to the digestive gland, where it is stored for furture use.
Blood travels through the thin gills and realeases carbon dioxide while absorbing oxygen. Book lungs. Oxygen and carbon dioxide are exchanged through the page-like folds in the spider abdomen. Also, some spiders have tracheaes that take oxygen straight to tissues.
Crayfish excrete waste through the anus.
Eyes, antennae and antennules. At the bottom of the antennule is a statocyst which it uses for balance. Pedipalps
Crayfish reproduce sexually. The female stores the sperm until the spring. Spiders reproduce sexually. The male places a tiny sperm filled web sac in his pedipalps. The male then