HOW DO FISH LIVE IN WATER?

You must have seen how fast and brisk fish are in water. In order to swim, a fish does not need to make any movement other than to wag its tail from side to side. This ease of movement that fish have in water is thanks to their flexible backbones as well as some systems in their bodies.

A fish expends a large amount of energy while swimming. This is not because it swims fast for long times. Fish need considerable amounts of energy in order to reach high speeds from being still. It is vital for a fish to gain speed instantaneously because it needs to do so in order to escape from predators.

Moreover, fish move against the current most of the time. Consider how hard it is for you to move in water and how easy it is to move while you are walking in the street. Compare living underwater and living on the face of earth.

It is the special structure of the backbone and muscles of the fish that provide it such power. The backbone keeps the body straight and is connected to the fins and muscles. Otherwise, it would not be possible for the fish to move in the water. However, the particular shape of the backbone is not sufficient to enable the act of swimming. That is because fish not only move forward and backward, but also upward and downward in order to survive. This movement is made possible by another system in their bodies. Fish have air sacs in their bodies. By emptying these sacs of air, fish can sink to the bottom of the sea, and by filling the sacs with air fish can rise to the surface again.

The picture on the left shows the remains, in other words a fossil, of a fish that lived a very long time ago. Another member of the same species, one that is still alive today, can be seen in the picture below. As you can see, there is no difference between the two.

Have you ever wondered how fish are not damaged at all although they are always in the water? Our skin becomes affected if we stay in water for a while; if we stay for a longer time then our skin becomes injured. But this never happens to a fish. This is thanks to a stiff bright layer in its outer skin. This layer prevents water from entering its body. If fish did not have this layer, their bodies would be damaged, and since water would enter the body the balance would be disturbed and they would eventually die. However, these do not happen and all fish continue to live their underwater lives.

All fish species in the world possess these features. Species that lived long ago possessed them too. Fish have had the same perfect structure for millions of years and have not gone through any change. It is possible to see this in the remnants of fish that lived millions of years ago. These remnants, namely fossils, clearly reveal that fish were the same as they are today and have not changed at all. This is evidence that fish came into existence at one point in time. In other words, they were created. It is Allah Who gave fish all the features they have and Who created everything in the universe. He knows the needs of all creatures.

HOW DO MACAWS KNOW CHEMISTRY?

You have read in this website that macaws feed on rocks that contain clay, as seen in the picture. If you had seen this picture before reading this website, the behaviour of this parrot species would have surprised you. Maybe you would not even have understood what they were doing. But now you know why macaws eat clay. Most importantly, you know that Allah teaches them to do so. Tell others about what you have learnt to enhance their faith in Allah as well.

Some plants have poisonous seeds. This is an effective method of protection against their enemies who try to eat them. Yet a parrot species living in America can feed on these poisonous seeds. This is quite surprising because while other creatures cannot approach the seeds, these birds that continually eat them are not affected at all. You are curious about how this happens, aren't you?

How this parrot species called the macaw is not poisoned has attracted the attention of scientists too. Scientists observed macaws and witnessed a quite extraordinary pattern of behaviour.

Having eaten these nutritious but poisonous seeds, macaws fly towards a rocky place. There they gnaw upon and swallow some clay containing rocks. This is not a random behaviour. Indeed, rocks that contain clay absorb the poison of the seeds. This is how the macaw can digest the seeds without suffering.

How has this bird acquired the medical knowledge to diagnose the poisonous effect of the seed? How does it know how to get rid of this poisonous effect? Could it possibly have had an education in pharmacy to know that a substance that neutralises the effects of the poison is available in rocks that contain clay? Of course not.

A human being could not understand whether a seed is poisonous or not by its appearance. He could not estimate how to neutralise the effects of the poison. In order to be able to do that, he would have needed education or to have consulted those with knowledge. This being the case, it cannot be claimed that a bird with no intellectual faculties might have discovered such a thing after long chemical analyses and study. It is not possible for macaws to acquire this knowledge, which can be learnt by human beings only after years of special education, by chance. All-Knowing Allah, Who creates everything perfectly, teaches macaws this knowledge.

ENGINEERING IN THE COBWEB

Have you ever noticed the shapes of spider webs? Did you know that spiders produce their thread themselves and that this thread has some amazing characteristics? Or have you heard that the techniques used by garden spiders to spin a web are the same as those used by civil engineers today?

A spider needs two separate places in order to spin its web. Webs are generally spun in a corner where two walls join or between two branches. However, some spiders are so skilful that they spin their web using a single surface. How a spider spins its web is spectacular. Now try to visualise what we will tell you here.

A spider first finds a flexible branch that is long enough to spin its web. It firmly fastens a thread to the end of the branch. Walking down the branch, it continues to secrete thread. Once it covers a certain distance, it stops and ceases to secrete. It pulls the thread it has secreted until the branch is bent like a bow. The spider sticks the other end of the thread, which is now as straight as a string, firmly to that point. Then it starts to spin its web inside this bow.

Now consider what you would do if you were to stretch a string two and a half metres long between two walls that are two metres apart from each other. While you are trying to find out how, let us explain how a species of garden spider has solved this problem.

Garden spiders sometimes spin their web between two distant branches. Since such webs are quite large, they have a high capacity to catch prey. Nevertheless, their large size results in a gradual decrease in the tautness of the web, which means a decrease in the ability to catch prey. So spiders need a solution. You might have thought that the spider would spin a new web once the web is not taut enough any more. But instead of replacing the web the spider does something amazing: It secretes a thread from the centre of the web down to the ground, and fixes a small stone on to that end of the thread which is close to ground. Returning to the web and pulling the thread, it lifts the stone. Then it fastens the thread, at one end of which the stone swings in the air, once again on the centre of the web. Consequently, the web is taut again as the weight of the stone hanging from the web stretches it down.

You would probably not come up with such a solution neither would many people who do not have knowledge of construction. However spiders know and apply this technique. How does a spider know such an admirable technique and apply it so well? Moreover, every spider has spun its web applying the same technique for millions of years. There needs to be an "Authority" Who inspires the spider to use this technique because the authority to do it does not belong to the spider itself. This power belongs to the Almighty Allah, Possessor of everything, Who guides and inspires all living creatures with what they should do.

AN INTERESTING CREATURE: NAUTILUS

You must have seen submarines on TV or in journals. These vessels, which are capable of operating far below the surface of the sea without being noticed, are used in ensuring national security and in some scientific research. How submarines operate is: As the special diving tanks in a submarine are filled with water, the vessel becomes heavier than water and sinks deep down in the ocean. If water in the tank is emptied and replaced by pressurised air, the submarine rises up to the surface of the water again.

You have noticed that there is no difference between the fossil of a nautilus that lived a long time ago (below) and the nautilus of our day, haven't you?

Now we will examine the nautilus, a very interesting creature that employs exactly the same method. The nautilus has a spiral, pearly-lines shell and dives as submarines do. It has an organ shaped like a snail shell that is 19 cm (7,5 inch) in diameter, as shown in the picture. This organ contains twenty-eight interconnected "diving chambers". These diving chambers operate in the same way as the tanks in a submarine do; in other words the nautilus needs pressurised air. In submarines, this need is met by a special system established by engineers in relevant places in the submarine. But how does the nautilus find the pressurised air necessary to expel the water?

The answer to this question introduces us to another amazing feature that Allah created. A special gas is produced in the nautilus' body. This gas is conveyed to the chambers through its bloodstream and eventually expels the water from the cells. So a nautilus can sink or float to protect itself against its enemies while hunting. In fact the diving capacity of the nautilus is much higher than that of a submarine. A submarine dives only to 400 metres (1310 feet) while it is so easy for a nautilus to dive to 4,000 metres (2,5 miles).

The special system of this interesting marine animal is created for us to reflect on it. Now consider for a moment. Could a nautilus have attained this system by chance? Could it itself have acquired the bodily structure that enables gas production? Furthermore, this is not the only feature of the nautilus. The pressure underwater is quite intense. This is why you feel pressure in your ears when you dive deep. Nevertheless the pressure you experience is comparatively low; as one descends further in the water, the pressure increases and after a certain depth has deadly effects on living creatures. However, although it is a very small being and has only an external shell to protect itself, the nautilus is not affected by this pressure, which can be extreme.

Obviously, all features that a nautilus has are designed. This being cannot possibly on its own design the bodily structure to resist a pressure of tons underwater. Allah, Who originates everything perfectly, designed this excellent structure. In a verse of the Qur'an, Allah invites people to be heedful:

Is He Who creates like him who does not create? So will you not pay heed? (Surat An-Nahl: 17)

BUTTERFLIES THAT HAVE KNOWLEDGE OF PHYSICS

The appearance of butterflies is admirable. These creatures, which with their colourful wings and elegant flight are like living ornaments, are some of the sources of beauty that Allah creates for us. However, a marvellous appearance is certainly not the only feature of butterflies. These short-lived creatures sometimes do calculations such as a specialist would do. For example, like the moths which we discussed earlier, the body heat of a butterfly should be at a certain temperature in order for it to fly. Let's see what butterflies do to solve this problem.

The colias butterfly cannot fly when its body temperature is below 28^oC (83^oF). In such cases the butterfly opens its wings to expose its upper side to the sun and to soak up the sun's rays at the correct angle. If its body temperature rises as high as 40^oC (104^oF), it rotates by 90 degrees and thus receives the sun's rays horizontally. With this behaviour the butterfly absorbs as little heat through the wings as possible and its body temperature decreases.

Besides that, this butterfly species has little dark spots on its wings. These spots, the function of which is to maintain a higher body temperature, are not located in an unspecified place. They are close to the points that are most needed to be warm. Thanks to this particular design, heat transmission from these spots, which warm quickly, to other parts of the body is facilitated since the distance that needs to be covered to transmit heat is shortened.

Another butterfly species employs a similar method to increase its body temperature. You all know what a lens is. Some are used to produce enlarged images whereas some others are used to produce smaller images of objects. For example glasses consist of a pair of lenses. Besides this function, a lens angled correctly toward the sun can concentrate the sun's rays on a certain spot. Using this method it is possible even to light a fire. The pieris, another butterfly species, angle its wings toward the sun so that all rays are concentrated on certain parts of its body that need most to warm, in a similar way as a lens functions.

Certainly these butterflies have not had an education in physics or in any other field. They cannot know about the features of a lens. They do not know which angle would receive the greatest amount of heat. Allah, Who watches over and protects all things, inspires in butterflies what they should do to regulate their body temperature. As Allah reminds us in a verse:

… Allah is watchful over all things. (Surat al-Ahzab: 52)

MALE CATFISH ON DUTY

It is not generally known that fish build nests and provide continuous protection for their offspring. These nests are generally holes dug among pebbles or in the sand. Eggs develop in these open nests for some time, during which the mother and father fish take turns to keep watch over the nest for enemies.

Catfish are among these creatures that protect their young. Female catfish spawn eggs at the bottom of plants and reeds in shallow water. Eggs cling to the roots of these plants. After a while, the female leaves her eggs and then it is the male's turn to take on the duty. The male's duty is to stay with the eggs and to keep watch for danger. This sentry duty lasts for about 40-50 days after which the young fish become fully mature.

Besides this vigilance, the male also makes a murmuring sound using his gills and in this way keeps other hostile fish away from the eggs. He knows that this sound will threaten other fish and will force them to go away.

Allah inspires male catfish to protect their young in this way. Like all creatures, this fish acts only in the way that Allah inspires in it and thus ensures the continuance of its species.