Special aDAPTATIONS
The fish have scales for the protection of the skin, but also to prevent either too much water entering their body (freshwater fish) or too little (saltwater) due to osmosis. They also secrete a layer of mucus to prevent the fish from acquiring any infections and it reduces friction while swimming, allowing for more efficient swimming.
Fish have developed different shaped scales to assist in more efficient swimming. They are small stiff plates that function as a protective armour. They overlap each other like shingles of a river, which means that the skin is minimally exposed. Leptoid scale overlap in a head-to-tail direction, which allows a smooth water flow and makes them more flexible. Placoid scales are very small in size and they have tiny vortices, which can reduce the friction and force, which make the swimming much quieter and more efficient. They are also very tough because they are so closely packed. Ganoid scales, which derive from Cosmoid scales, are diamond shaped, shiny and hard, which allows them to act like an armour that is almost an impenetrable barrier for predators. Fish have also improved their fins, specializing them into paired and unpaired fins. Paired fins permit a fish to steer stop and stabilize, while unpaired fins act as a keel, that prevents the fish from rolling over as well as aid in propelling and maneuvering the fish. To aid a fish in swimming it has evolved a swim bladder from an out pocketing of the digestive tube. It contains gas (usually O2) and it functions as a hydrostatic or counterbalance organ, which allows the fish to maintain its depth without floating upwards or sinking while in the water. Like the unpaired fins of fish, reptiles, in specific crocodilians, have a large, long, and strong tail that assists them in steering and swimming. It also helps propel the crocodilian through the water and keep him upright/stabilized. If a crocodilian potentially loses its tail it means that they are tremendously handicapped as they are unable to swim. Especially alligators will have a problem since they rely on fast movement in the water to survive and catch its prey. All amphibians and some reptiles have webbed feet, which allow them to swim through the water swiftly, while still being able to move on land. This adaptation has allowed amphibians and reptiles to live in both aquatic and terrestrial environments. In amphibians, some reptiles, birds and mammals a nictitating membrane (a translucent membrane) is present to protect the eye while still being able to see somewhat what is around them. This is present especially in those animals where a lot of dust is present in the environment and/or the eye has to protected additionally in some form at certain times. Examples are a camel, a frog, a crocodile/alligator, and a bald eagle. Reptiles have scales that are made of keratin, which prevents water loss and provide protection. Since the skin is dry and scaly, it allows them to live in very arid conditions. Like the different fins of fish aid them in swimming, birds have different feathers that aid them in flying. The lifted covert feathers on the wings of birds act as eddy flaps. They have contour feathers that are the outermost and provide shape and colour, down feathers that keep them warm, and filoplumes that act as sensory feathers. Contour feathers are aligned like shingles of a roof like the scales of a fish. The wing feathers are strong and rigid to assist in flying. The contour feathers usually discard rain and therefore keep a bird dry and well-insulated. The way the feathers are arranged through barbs and barbules allow them to be very light, but still help the birds fly. Birds have hollow bones so that they are even lighter and flight becomes easier. The wings of birds are shaped in a way that they are slightly rounded, which means that the air flows over the top much faster, which results in higher pressure to come from below and less from above. Therefore the bird is able to fly. We have taken this adaptation from birds and applied it to humans, over time coming up with the idea for an airplane. Mammals have different/specialized teeth that aid them in eating. Incisors help with cutting, canines grip, puncture or tear the food, premolars shred, cut or grind, and molars grind and crush. This allows the food to be effectively and efficiently pre-prepared to allow for a faster and more efficient digestion of it. All mammals have hairs that are made of keratin like feathers and the scales of reptiles. Hair assist in thermal regulation like the down feathers of birds. They provide protection like the scales of reptiles or fish, by being modified into spines or quills. Eyebrows and eyelashes prevent water, dirt and sweat coming into the eyes just like the nictitating membrane of amphibians and some birds or reptiles. The eyelashes also provide protection in another form by telling the eye to instinctively close if they come in touch with anything, just like the whiskers of cats, dogs or rats. |