are the types of animals that you see clinging to the pilings
underneath the Cal Poly pier at Avila. These creatures all have
one thing in common; they all lack backbones. From sea stars
to jelly fish, this group of animals will play an important
role in hands on learning for classes that visit the pier. With
a temporary home in the flowing water lab, the goal is to allow
students to get a closer look at the numerous species that inhabit
the surrounding water.
Phylum – Mollusca
Class – polyplacophora (chitons)
Class – gastropoda (one shelled animals: snails, abalone)
Class – bivalia (two shelled animals: muscles)
Class – cephalopoda (octopus)
Mollusc is a Latin
term meaning “soft-bodied”, and these animals are
often protected by a hard, protective covering. This phylum makes
up an important food source for many marine animals. All molluscas
have mantles or underlying skin which produces the shell. They
also have siphons or fleshy tubes that draw in food and water.
Gills are common organs used to respire by removing oxygen from
the water that all molluscas possess.
Phylum – Echinodermata
Class – asteroidea (sea stars)
Class – echinoidea (sea urchins)
Class – holothuroidea (sea cucumbers)
Echinoderm is a Greek
word meaning “spiny-skinned.” Animals in this phylum
all share a few common characteristics. All echinoderms have an
endoskeleton or and internal skeleton made up of ossicles, a type
of calcareous structure. The compactness of the ossicles determines
the degree of flexibility of the animal. The adult body symmetry
radiates around a central axis as well. Echinoderms also have
tube feet which they use for locomotion and also for respiration.
The tube feet operate using a hydraulic, or water-vascular, system.
Phylum – Arthropoda
Class – merostamata (horseshoe crabs)
Class – crustacea (hermit crabs, lobster)
Arthropod is a Greek
word meaning “jointed appendage.” With perhaps more
than one million known species, this is the largest and most diverse
invertebrate phylum. Arthropods make up more than 80% of all animal
species. Animals in this phylum share common characteristics including
segmented bodies, jointed appendages, and an exoskeleton made
of chitin. As it grows, an arthropod must molt, shedding its old
Phylum – Cnidaria
Class – anthozoa (sea anemonies)
The cnidarians are
a diverse group. About 9,000 species are known worldwide, and
they are found throughout the seas from densely populated intertidal
zones to great depths.
Many cnidarians are large and brightly colored. Some common traits
seen among these animals include symmetrical bodies around a central
axis. Cnidarians lack a head and usually bear a crown of tentacles
around the mouth. In these tentacles, nematocysts or tiny stinging
capsules are present to act as a defense mechanism.