quinta-feira, 24 de outubro de 2013
COMPARATIVE PHYSIOLOGY IN VERTEBRATE
By: Biologist Valdemir Mota de Menezes
The morphological and physiological similarities of vertebrate animals is nothing compared with the theory of evolution . God created the animals in each group and its species. Animals of the same group have some similarities . There is no fossil evidence to support the absurd theory of evolution .
The form and function are two factors closely related structures asappropriate allow the animal to perform more elaborate tasks .For example , the structures that permit movement and locomotionAnimals are related to each other by various ways , either by typecoating the body skeletal structure or by the provision ofmuscles. In most cases , invertebrates have skeletondrive with internal muscles , as observed in insects , whichhave segmented body , and jointed very presence ofappendices . On the other hand , vertebrates have separate coatingthe internal skeleton , the muscles being located nearthe outer surface of the body.The coating composition also influences the form and function ofanimals, it can be composed of several chemical components ,as chitin or keratin. The outer covering of the animal protectsagainst attacks from predators , provides suitable conditions forprey capture , avoids aggression of the environment or the invasion of agentspathogenic .However, the coating structure that the animal can also provide functionsrelated to the regulation of body temperature , release secretionsattractive or repellent , respond to chemical and / or mechanical .Examples of coating have been in the shell molluscs, the cuticlearthropods , the hair in mammals and feathers in birds .Throughout the zoological scale , vertebrates have shown homologiesin different systems. The different animal groups differregarding the general appearance but have very similar structuresfor digestion , excretion, respiration, circulation and so on. The systems anddevices are not exactly alike, but show progressive adaptationsas the gradual increase of brain mass in fish , amphibians ,reptiles , birds and mammals , culminating in the amplitude of the neural capacityhumans.Besides the morphological similarities are also observed similaritieschemical structure and function to some proteins . many proteinsretain the same function in different phyla , such as trypsin,digestive enzyme found protozoa to man ; amylase enzymestarch degrading located from the sponges and hemoglobin ,respiratory pigment that is present in all vertebrates and someinvertebrates.Another common trait among vertebrates is related todeveloping embryo . In fish , the embryo develops cracksgill pairs of gills , heart and aortic arches with twochambers , this structure persists in the adult . similar structuresappear in the frog embryo , is essential for the larval stage , wheninhabits only the aquatic environment . With the metamorphosis of the larva , the frog goesto adulthood , gills and gill slits disappear andlungs become functional for the uptake of oxygen from the air , the systemcirculatory is modified , through the heart has three cavities . thus,amphibians present in their larval stage , morphofunctional characteristicssimilar to fish , changing later to terrestrial life .Surprisingly these features are also observedfor young embryos of reptiles , birds and mammals .Fossil records indicate that aquatic vertebrates precededterrestrial and amphibious that represent the transition phase of that environment .Because such evidence is a theory that argues that embryonic development recapitulates the ancestral origins of vertebrates ,presenting all major morphological changes occurred invertebrates, along adaptive processes