Effect of pressure on students to get good grades
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Vertebrates are animals that are members of the subphylum Vertebrata /-ɑː/ (chordates with backbones). Vertebrates include the overwhelming majority of the phylum Chordata, with currently about 64,000 species
Vertebrates include the jawless fish, bony fish, sharks and rays, amphibians, reptiles, mammals AND ,BIRDS 20 Main Characteristics of Vertebrates
Main Characteristics of Vertebrates are given below:
1) Well developed brain.
2) Brain lodged in to box or cranium.
3) Notochord, forms on the dorsal side of the primitive gut in the early embryo and is present at some developmental stage in all chordates.
4) Most possesses a through gut with a non-terminal anus.
5) Pharyngeal slitsconnect the pharynx, a muscular tube that links the mouth cavity and the esophagus, with the outside.
6) Possess at some stage of their life a hollow dorsal nerve tube.
7) Possess at some stage of their life a dorsal cartilaginous rod called a notochord.
8) Possess at some stage of their life gill slits in the pharyngeal region. 9) Has a partially open circulatory system.
10) They become slits, open to the outside in animals with gills, but disappear in those lacking gills. 11) Two pairs of appendages.
12) The endoskeleton of most vertebrates is made of cartilage or bone.
13) First, collagen is laid down in a matrix of fibers along stress lines to provide flexibility, and then calcium minerals infiltrate the fibers, providing rigidity.
14) The first vertebrates evolved in the oceans about 470 million years ago. They were jawless fishes with a single caudal fin.
15) The appearance of a hinged jaw was a major advancement, opening up new food options, and jawed fishes became the dominant creatures in the sea.
16) All vertebrates have a heart and a closed circulatory system.
17) In both their circulatory and their excretory functions, vertebrates differ markedly from other animals.
18) Reproduction normally sexual and gonochoristic.
19) Feed on a variety of organic materials.
20) Unisexual, gonad only one pair.