40 likes | 244 Views
Echinoderms. Shakila McKinney Ahkeen Aaron Jonathan Bailey. Biology of Echinoderms. Have radial symmetry which affects their lifestyle. They are sedentary slow bottom crawlers. The nervous system coordinates movements of tube feet and spines in the absence of a brain.
E N D
Echinoderms Shakila McKinney Ahkeen Aaron Jonathan Bailey
Biology of Echinoderms • Have radial symmetry which affects their lifestyle. They are sedentary slow bottom crawlers. • The nervous system coordinates movements of tube feet and spines in the absence of a brain. • In most groups, five, ten, or more gonads shed sperm or eggs directly into the water. So they are broadcast spawners. • Sea stars, brittle stars, and sea cucumbers are some of the echinoderms that use budding. • Then the two separate halves regenerate to become a whole.
Echinoderms: Five-Way Symmetry • Sea stars, sea urchins, sea cucumbers, and several other forms make up the echinoderms phylum. • Pentamerous: A symmetry based on five parts • Endoskeleton: A skeleton that is secreted within the tissues, rather than externally like the exoskeleton of arthropods. • Spines and pointed bumps give many echinoderms a spiny appearance and are nick-named “spiny-skinned” • Water Vascular System: A network of water-filled canals. • Tube Feet: Are muscular tensions extensions of these canals. • The tube feet help movement, attachment, locomotion, and for receiving chemical stimuli in marine life.
Types of Echinoderms • Sea Stars (class Asteroidea) • Brittle Stars (class Ophiuroidea) • Sea Urchins (class Echinoidea) • Sea Cucumbers (class Holothuroidea) • Crinoids (class Crinoidea)