INSECTS, REPTILES, FISH AND BIRDS

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Anatomical Structures of Insects, Reptiles, Fish and Birds

Insects reptiles fish and birds, The bodies of insects can be divided into a head, thorax and an abdomen. Attached to the head is one pair of antennae and three pairs of gnathites. Their thorax constitutes three distended segments, each comprising of a ventral pair of legs and a dorsal pair of wings (Dönitz et al., 2013).

Their abdomen is divided into numerous segments and accommodates various organ systems. On the other hand, the fish are believed to have been derived from the Ostracoderms which lasted from the Precambrian to the Devonian period and first appeared without jaws and small bodies covered with scales. The Acanthodians appeared as first fish with jaws, followed by the Chondrichthyes and Osteichthyes. The fish are divided into the superclass Agnatha which lacks internal bone formation, jaws as well as scales and paired fins; and Gnathostomata with strong jaws, cartilaginous skeleton and musculature (Springer & Holley, 2013).

Amphibians developed from the fish and later gave rise to the group of reptiles. Reptiles have dry, rough and extremely keratinized skin which has dry scales all over it. They are divided into three groups – anapsids, diapsids and synapsids. They have two sets of paired limbs, with toes that are five in number, and claws. Birds, on the other hand have been considered to be very closely related to theropods – a group of dinosaurs in the Mesozoic era. Insects reptiles fish and birds They have feather-covered bodies, wings in place of forelimbs and hind limbs that are scaled and clawed. Their body is shaped in a spindle form and divided into head, neck, trunk and tail (Springer & Holley, 2013).

Functions According to Group and Habitat

The four groups with a diverse range of anatomical structure have sustained life through the Pre-Cambrian era to the modern times primarily through the diverse range of functions that they perform, as well as their adaptability to the places they are inhabitants of. The insects, for instance comprise of exoskeletons which is not merely used for protection but also locomotion. It has also been observed that according to habitat, many insects use their cocoons to protect themselves from harsh weathers such as the ice during cold temperatures or to trap heat with the help of pigments (Dank, 2004). The development of various systems by the fish is dependent on their habitat. Jawless fish such as hagfish, for example have no accessory appendages or stomach, but have a keen olfactory sense which attracts them to food. Cartilaginous fish on the other hand have powerful musculature that aids their movement in water. Their excretory system facilitates the retention of urea in order to build an osmotic pressure that aids their survival in a marine environment (Bone & Moore, 2008).

Reptiles have a characteristic keratinized skin which is important for locomotion, protection and osmoregulation, especially in areas such as mangroves where species such as Crocodylus actus reside (Lacerda, 2002). Birds, on the other hand were developed as animals that were optimized for flight. Their migratory nature and their feeding habits are…