Comparative Anatomy of Vertebrates

• Comparative Vertebrate Anatomy is the study of the structure of vertebrates, the functional significance of structure, and the variation in structure and functions in geological times.
• The digestive tract has specialized regions for the acquisition, processing, temporary storage, digestion and absorption of food and for the elimination of unabsorbed residue.
• The study of similarities and differences in vertebrate structure and function is a part of Comparative Vertebrate Anatomy.
• The changes of structure, the role of structure variations in survival, and the historical background and embryogenesis of vertebrate’s organs and systems are also studied in Comparative Vertebrate Anatomy.
• Morphology, the study of structure viewed as a whole, is a branch of Zoology that provides important bases for the study of Comparative Vertebrate Anatomy.
• Modern birds have reduced tail to a nubbin but the first birds had long tails.
• Vertebrates also have three principal anatomical planes: Transverse plane, Frontal plane, Sagittal plane.
• Each repeated part is called a segment, a metamere or a somite.
• Swimming larvae of frogs, toads and wormlike amphibians have a tail that is resorbed at metamorphosis.
• Vertebrates exhibit metamerism, the serial repetition of body structures in longitudinal axis.
• Symmetry refers to the balanced proportions or the correspondence in size and shape of parts on opposite sides of a median plane.
• Some adult vertebrates lack a post-anal tail, although it is present in all embryos.
• Human beings have vestigial post-anal tail early in embryonic life.
• The head differs from the tail and the dorsum differs from the venter, but right and left sides are mirror images of each other.
• The tail consists of the anus or vent, hence it is post-anal.
• The neck is a narrow extension of the trunk of reptiles, birds and mammals, and lacks a coelom.
• The coelom is surrounded by the body wall consisting of muscles, vertebral column and ribs.
• The neck consists primarily of vertebrae, muscle, spinal cord, nerves and elongated tubes such as esophagus, blood vessels, lymphatic vessels, trachea that connects structure of the head with those of the trunk.
• There are three types of animal symmetry: Spherical Symmetry, Radial Symmetry, Bilateral Symmetry.
• At one end of the axis are different from those of the other end.
• The tail consists almost exclusively of a caudal continuation of body wall muscles, axial skeleton and blood vessels.
• If the body is divided into nearly like segments it is referred to as homonomous segments.
• Vertebrates have 2 pairs of appendages- Pectoral and pelvic, which is supported by an internal skeleton and operated by contributions from the trunk musculature but some are vestigial or have been lost completely.
• All animal with this arrangement of body parts exhibit bilateral symmetry.
• Remnants of the tail in adults remain as coccyx.
• All vertebrates have 3 principal axes: Longitudinal (anteroposterior) axis, Dorsoventral (transverse) axis, Left and right (sagittal) axis.
• It is a rod of living cells located immediately ventral to the central nervous system and dorsal to the alimentary canal extending from the midbrain to the tip of the tail.
• Serial or general homology refers to the relation in structures that are repeated on the same organism.
• Notochord is the first skeletal structure to appear in vertebrate embryos.
• Phylogeny is the evolutionary history of a taxon.
• These slits may remain throughout life, or they may be temporary.
• If they remain throughout life, the adult pharynx is the part of the alimentary canal having slits.
• The pouches may rupture to the exterior to form pharyngeal slits.
• The notochord is generally replaced by the vertebral column of vertebrae composed of cartilage or bone or both.
• When animals having analogous structures present striking similarity of appearance or body shape, this is termed convergence or parallelism.
• Ontogeny is the history of an individual.
• Phylogenesis is the study of history.
• If the slit is temporary, the adult pharynx is the part of the alimentary canal connecting the alimentary canal and esophagus.
• It gives rise to speciation, the formation of new species from existing ones.
• Homology refers to body parts that correspond in type of structure or position and have a similar background, such as embryonic origin or evolutionary ancestry.