Endoskeleton and Exoskeleton

Exoskeleton

For example, an animal’s body is supported and protected by its exoskeleton, which is in contrast to the interior skeleton (endoskeleton) of a person, which supports and protects the body of the animal. Some of the larger types of exoskeletons are referred to as “shells” in common language. Insects such as grasshoppers and cockroaches, crustaceans such as crabs and lobsters, the shells of certain sponges, and the many groups of shelled molluscs, including as snails, clams, tusk shells, chitons, and nautilus, are all examples of animals that have exoskeletons. Animals with an endoskeleton as well as an exoskeleton include the tortoise and the turtle (see the shell page for further information).

Role Of Exoskeleton

Protective, excretory, sensing, support, feeding, and functioning as a barrier against desiccation are just some of the functions performed by exoskeletons in a variety of species. Exoskeletons are made up of rigid and resistant components that serve a variety of functions in a variety of animals. Exoskeletons serve a variety of functions, including protection against pests and predators, support, and the provision of an attachment framework for muscle.

Chitin is found in arthropod exoskeletons; the addition of calcium carbonate makes them tougher and stronger, but at the expense of greater weight.

Known as apodemes, the ingrowths of the arthropod exoskeleton that serve as attachment sites for muscles are found around the world. These chitinous structures are approximately six times stronger and twice as rigid as vertebrate tendons, and they are formed primarily of chitin. Apodemes, which are similar to tendons in that they can stretch to store elastic energy for jumping, are particularly common in locusts. Mollusk shells, brachiopod shells, and the shells of some tube-building polychaete worms are composed of calcium carbonates. Silica is found in the exoskeletons of microscopic diatoms and radiolaria, which protects them from predators. One species of mollusc, the scaly-foot gastropod, even makes use of the iron sulphides greigite and pyrite, which are found in abundance in the environment.

Some creatures, such as some foraminifera, agglutinate their exoskeletons by adhering grains of sand and shell to the outside of their bodies. Contrary to popular belief, echinoderms do not have an exoskeleton because their test is always contained within a layer of live tissue, preventing them from developing one.

Exoskeletons have evolved multiple times on their own, with 18 lineages having evolved calcified exoskeletons on their own. Additional evidence suggests that other lineages, such as some mammals, have evolved robust exterior coats that are akin to an exoskeleton. In the case of the armadillo, this coating is made of bone, while in the case of the pangolin, it is made of hair. The armour of reptiles such as turtles and dinosaurs such as Ankylosaurs is made of bone, while crocodiles have bony scutes and horny scales to protect themselves.

Endoskeleton

It is possible to have an endoskeleton on the inside of a body, but this is not common. The endoskeleton is formed either within the epidermis or within the deeper bodily tissues throughout development. The endoskeleton of vertebrates is composed mostly of two types of tissues: skeletal and non skeletal (bone and cartilage). The endoskeleton is formed of the notochord and cartilage during the early stages of embryonic development. In most vertebrates, the notochord is replaced by the vertebral column, and cartilage is replaced by bone in the majority of adult vertebrates. 

Endoskeletons of varying degrees of complexity can be found in three phyla and one subclass of animals: Chordata, Echinodermata, Porifera, and Coleoidea, to name a few. Although an endoskeleton can serve solely as a support structure (as in the case of sponges), it is most commonly used as an attachment place for muscle and as a mechanism for transmitting muscular forces. A genuine endoskeleton is formed by the differentiation of mesodermal tissue. Echinoderms and chordates, for example, have a skeleton similar to this. In addition to microscopic calcareous or siliceous “spicules,” the porifera “skeleton” is composed of an intricate network of spongin fibers. 

Unlike other families of mollusks, the Coleoidae do not have a genuine endoskeleton in the evolutionary sense; instead, a mollusc exoskeleton has evolved into numerous types of internal structure, the most well-known of which being the cuttlebone of the cuttlefish. Though not mineralized, they do contain cartilaginous tissue in their bodies, especially in the head where it forms a primitive cranium. However, they do not have cartilaginous tissue in their bodies. The endoskeleton is responsible for the shape, support, and protection of the body, as well as for the ability to move.

Conclusion

It is extremely beneficial to have exoskeletons on creatures because they act as hard components of an organism, which helps to preserve animals whose soft parts perish before they can be fossilised. Shell fragments, for example, are a good example of how mineralized exoskeletons can be kept “as is.” The possession of an exoskeleton offers a couple of different avenues to fossilisation. For example, the tough layer may be able to withstand compression, allowing a mold of the organism to form beneath the skeleton, which may later decompose. Alternatively, remarkable preservation may result in chitin becoming mineralized, as in the Burgess Shale, or being converted into the tough polymer keratin, which can withstand degradation and be recovered from the environment.An animal’s endoskeleton is an internal support structure made of mineralized tissue that provides structural support to the animal.