How many germ cell layers do Cnidaria and ctenophora have?
Diploblastic animals, Cnidaria and Ctenophora, show an increase in compartmentalization, having two germ layers, the endoderm and ectoderm.
How are Cnidaria and ctenophora different?
Cnidaria and Ctenophora are two types of phyla composed of coelenterates. Cnidarians exhibit radial symmetry whereas ctenophores exhibit biradial symmetry. Both contain tentacles, surrounding their mouth. The main difference between cnidarians and ctenophores is their body symmetry.
Which type of germ layers best define the cnidarians?
All cnidarians show the presence of two membrane layers in the body that are derived from the endoderm and ectoderm of the embryo.
What germ layer are cnidarians lacking?
In the case of cnidarians there are two layers: the endoderm and the ectoderm. The endoderm is the inner layer (‘endo’ for ‘within’), and the ectoderm is the outer layer (‘ecto’ for ‘outer’). If there was a third layer it would be called the mesoderm, ‘meso’ for ‘middle’. But cnidarians do not have this middle layer.
How many germ layers does platyhelminthes have?
Flatworms have three embryonic tissue layers that give rise to surfaces that cover tissues (from ectoderm), internal tissues (from mesoderm), and line the digestive system (from endoderm).
Which characteristic is shared by both cnidarians and ctenophores?
Both cnidarians and ctenophores are diploblastic animals. Cnidarians exhibit radial symmetry whereas ctenophores exhibit biradial symmetry. Both contain tentacles, surrounding their mouth.
Which of the following characteristics do phylum Cnidaria and Ctenophora share in common?
All have two tissue layers, a single digestive opening, and stinging cells called nematocysts. They have radial symmetry. What are the General characteristics of ctenophores? You just studied 23 terms!
Do cnidarians have germ layers?
Cnidarians nominally develop from two germ layers, the ectoderm and endoderm, whereas the presence of a third germ layer, the mesoderm, traditionally characterizes higher animals. This apparently fundamental developmental difference led to these groups being referred to as diploblasts and triploblasts, respectively.
What is the function of phylum Cnidaria?
Respiration and excretion in cnidarians are carried on by individual cells that obtain their oxygen directly from water—either that in the coelenteron or that of the environment—and return metabolic wastes to it. Thus, all physiological functions are carried out at no more than the tissue level of differentiation.