Cnidaria & Ctenophores Flashcards
what are the common charatteristics of the Cnidaria and Ctenophores phylums?
they are diploblastic, meaning that they have two embryonic germ layers.
the ectoderm forming the epidermis. (outside)
and the endoderm forming the gastrodermis. (Inside)
They are divided in two groups, blind gut and complete gut.
what are specific charatteristics of the cnidaria phylum?
They are redially symmetric, so no left or right, just top and bottom and multyple planes of symmetry around a central point.
They have two boditypes, polyps and medusa.
They have a layer called mesoglea between the epidermis and the gastrodermis.
they perform extracellular digestion and intracellular digestion
what is the difference between extro/intro cellular digestion?
extrocellular digestion happens in the gastrovascular cavity, and it reduces the prey in smaller parts that are than easier for the gastrodermal cells to take up. the gastrodermal cells than carry out the introcellular digestion.
what sensory organs do the cnidaria phylum uses?
statocysts for balance
and ocelly for photosensitivity
what gives the name to the phylum?
the cnidocytes with nematocysts.
Those are cells with a coiled up flagella with parbs that can react to external stmulus to inject poisons as a form of defense or in order to catch prey.
what is the function of the mesoglea?
the mesoglea function as a flexible skeleton, it provides support for the body and it aids in locomotion when in medusa life stage
what is the function of the epidermis?
the epidermis contain several different types of cells, such as sensory cells, cnidocytes and nerve cells.
what is the gastrodermis?
the gastrodermis lines the gut cavity and is used in intracellular digestion.
what are some charatteristics of the hydrozoa class?
it alternate reproductive stages between polyps and medusa body type. the medusa are very small < 1cm
what does metagenesys means?
the alternation of sexual and asexual reproducing generations
what is the velum and what is its function?
the velum is a layer present on the margin of the bell in the medusa form and it aids with locomotion
