Lab 27 Flashcards
Radial symmetry
body parts are arranged around a central axis to radiate out like the spokes of a wheel.
Bilateral symmetry
Symmetrical arrangement of an organism or part of an organism along a central axis, so that the organism or part can be divided into two equal halves.
Incomplete digestive tract
what goes in the mouth comes back out the mouth.
Complete digestive tract
a digestive tract with two openings, a mouth and an anus.
Coelom
The body cavity in multicellular, eukaryotic animals.
Acoelomates
Do not have a coelom between the digestive system and the outer body wall.
Pseudocoelomates
The coelom is derived from both the endoderm and the mesoderm.
Eucoelomates
The coelem is derived from only mesodermal tissues.
Protostomes
A major group of animals in which the blastopore gives rise to the mouth.
Deuterostomes
A major group of animals in which the blastopore gives rise to the anus.
Sponge
The simplest of the multicellular animals believed to have evolved from choanoflagellates.
Spicules
needle-like anatomical structure that support sponges.
Spongin
the horny or fibrous substance found in the skeleton of many sponges.
Ostia
Allows water to enter the interior of the sponge
Spongocoel
Central cavity lined with choanocytes.
Osculum
Large opening that allows water to leave the sponge.
Mesohyl
A gelatinous matrix that houses the cells of sponges.
Ameobocyte
Absorbs, transports, and digests food.
Asconoid canal system
A canal system in which water enters the sponge via tiny Ostia in the dermis and makes its way towards the spongocoel lined with choanocytes. The water is filtered and exits the sponge through the osculum.
Syconoid canal system
Water enters the sponge through a large number of Ostia into an incurrent canal then passes through prosopyles into the radial canals, where food is ingested by choanocytes. The flagella of the choanocytes moves water to the spongocoel. Filtered water exits through the osculum.
Leuconoid sponges
most common and most complex, Leuconoids generally forms large masses, each member having its own osculum.
Calcera
Vase-shaped, small marine sponges with spicules.
Demospongiae
the largest class of sponges. Have brilliant colors with monotetraxonal or tetraxonal siliceous spicules. Leuconoid canal system.
Hexactinellinda
called “glass sponge” because of six rayed siliceous spicules. Primarily deep water marine forms. Can be simple syconoid or leuconoid.
Phylum Cnidaria
named after cnidoblasts that contain stinging cells, or nematocysts.
25. Dimorphism - the cnidarians ability to exhibit two different body forms.
Medusa
a form cnidarians exhibit that resembles an upside-down cup with tentacles.
Polyp
a form that consists of a tubular sessile body.
Mesoglea
gelatinous nonliving substance that exists between the epidermis and the gastrodermis, or endodermis.
Budding
a form of asexual reproduction that can be carried out by cnidarians.
