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Cephalization is an evolutionary trend in animals that, over many generations, the special sense organs and nerve ganglia become concentrated towards the front of the body where the mouth is located, often producing an enlarged head. This is associated with the animal's movement direction and bilateral symmetry.
A chordate (/ ˈ k ɔːr d eɪ t / KOR-dayt) is a deuterostomal bilaterian animal belonging to the phylum Chordata (/ k ɔːr ˈ d eɪ t ə / kor-DAY-tə).All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics (synapomorphies) that distinguish them from other taxa.
' flat animals ') [3] is a phylum of free-living (non-parasitic) marine invertebrates. [4] [5] They are blob-like animals composed of aggregations of cells. Moving in water by ciliary motion, eating food by engulfment, reproducing by fission or budding, placozoans are described as "the simplest animals on Earth."
During gastrulation, deuterostome embryos' anus is given first by the blastopore while the mouth is formed secondarily, and vice versa for the protostomes In deuterostomes, the developing embryo's first opening, the blastopore , becomes the anus , while the gut eventually tunnels through the embryo until it reaches the other side, forming an ...
In Central and East Asia a common calendar system consists of a twelve-year cycle, with each year represented as an animal. The eleventh animal of the twelve-year cycle is the dog. Often such animals are depicted as human figures with an animal head. Thus, the cynocephalic depiction of the eleventh zodiac animal is common (possibly with a tail).
The earliest insects had chewing mouthparts. Specialisation includes mouthparts modified for siphoning, piercing, sucking and sponging. These modifications have evolved a number of times. For example, mosquitoes and aphids both pierce and suck; however, female mosquitoes feed on animal blood whereas aphids feed on plant fluids. This section ...
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The mouth is the body orifice through which many animals ingest food and vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity (or cavum oris in Latin ), [ 2 ] is also the first part of the alimentary canal , which leads to the pharynx and the gullet .