Nervous System
The position of the eyes of an animal allows us to determine whether they are predator or prey. If the eyes are forward then they are predator. If the eyes are primarily off to the side then they are considered prey.
Fish, amphibians, reptiles, birds and mammals all have a brain and a spinal cord which make up the central nervous system of all vertebrates and allow them to have more complex interactions with the environment than most invertebrates. Fish have an optic lobe and a cerebellum. Since they live in the water they require an organ to sense the water called the lateral line. It allows them to detect motion and as such prey. The eyes of fish are similar to ours and bony fish are able to detect colour as they usually live in shallower areas where more light can get to and where there is a wider range of possible wave lengths. Most cartilaginous fish cannot because they . Fish that live quite deep underwater have eyes that are adapted to the dark, by either having larger eyes and/or only rods which results in no colour perception as none is really required in deeper waters. Many fish can sense UV light as it might help them in foraging or mating. They have an inner ear, but no outer ear opening and can therefore sense some sound vibrations, but not a wide variety, since sound is not the main form of communication underwater. Some cartilaginous fish can also detect electrical fields through ampullae, but only very weakly. A reason for that could be that fish like sharks travel much longer distances than most bony fish and it could assist them in locating any hindrances in the environment around it that it is not able to see. The larvae of amphibians have a lateral line since they live in an aquatic environment. As they develop to adults they lose that lateral line and instead adapt to life on land by developing olfactory bulbs/lobes to detect particles in the air. Compared to fish they have also developed a more advanced hearing through the tympanic membrane situated behind the eyes and the columella, that allow an amphibian to perceive sound in the inner ear. The brain of reptiles is very similar to that of amphibians, although they have a larger cerebrum, which means that their integration of sensory organs must be much more complex and developed than that of amphibians. In reptiles the eyes are very important and larger therefore. They have evolved to possess a Jacobson’s Organ that assist in detecting scent/smell and is situated in the roof of the mouth. Reptiles are ectotherms and therefore cannot live in cold environments. This means that they are dormant during colder months and they can only run/swim for very short periods of time at a high intensity. Reptiles do have taste buds, but they are very poorly developed. Birds have a very developed cerebrum as well as cerebellum. The developed cerebrum allows them to calculate and perfect their landing and has advanced their sight compared to reptiles, amphibians or fish. The evolved cerebellum has allowed the class birds to have an increased sense of coordination corresponding to their advancement in movement (flying). The brain of a bird is ten times larger and heavier compared to the one of a reptile of the same weight. Just like all vertebrate their central nervous system consists of a brain and a spinal cord. Birds do have ears, but they have evolved in such a way that they provide the least wind resistance and the least wind noise, with feathers blocking the wind noise, allowing optimal reception of sound while flying. Birds have a tongue and taste buds, but they only amount to about 50. This shows that their nervous system is very advanced, but not as developed as a mammal’s. Mammals have the most complex nervous system out of all animals. Every mammal uses their nervous system to regulate basic things such as their heartbeat, and involuntary contractions and relaxations. Humans, as mammals, have the highest brain to body size ratio, meaning that they can have very complex interactions with the environment. The main part of a mammal’s brain is the cerebrum, which allows for very efficient processing and complex sensory functions. The taste of mammals is very advanced, having several thousands of taste buds on their tongues compared to the on average 50 that birds have. The shape of the ear of all terrestrial mammals allows for a very effective way of capturing the sound. Bats, as mammals, use their extreme sense of hearing for echolocation, thereby being able to adapt very well to them being able to catch prey at night (which is only possible due to the fact that they are endotherms). |