|
Leaves and Photosynthesis 17th century Belgian physicist, Jan Baptista van Helmont, observed the growth of a willow tree and took various measurements in one of his scientific experiments. First he weighed the tree, then he weighed it a second time five years later, and saw that it was now 75 kilograms heavier. Yet, the soil in the pot in which the plant was grown lost only a few grams over the same time period. The physicist van Helmont revealed in this experiment that the soil in the pot was not the only reason for the growth of the willow tree. Since the plant had used only a very small part of the soil to grow, then it must have been receiving nutrition from somewhere else.34
This occurrence, which van Helmont attempted to discover in the 17th century, was photosynthesis, some stages of which are still not understood in our own time. In other words, plants' producing their own nutrition.
Plants do not just use the soil when producing their own nutrition. Besides the minerals in the soil, they also use water and the CO2 (carbon dioxide) in the atmosphere. They take these basic materials and process them in microscopic factories in their leaves, thereby carrying out photosynthesis. Before examining the various stages of photosynthesis, it will be useful to take a look at leaves, which play an important role in this process.
The General Structure of Leaves
When studied from either the point of view of general structure or of microbiology, it will be seen that leaves possess planned, very complex, and detailed systems to produce as much energy as possible. In order for leaves to produce energy they need to take heat and carbon-dioxide from outside. All the systems in leaves have been designed to take in these two things as easily as possible. Let us first look at leaves' external structures.
The external surfaces of leaves are wide. This enables the exchange of gases (such processes as the absorption of carbon-dioxide and the release of oxygen, for instance) necessary for photosynthesis.
The leaves' flat and wide shape enables all the cells to be near to the surface. Thanks to this, the exchange of gases is made easier, and sunlight can reach all the cells which carry out photosynthesis. Let us imagine what would happen otherwise. If leaves were not flat, wide, and thin, but had any geometrical shape or any random and meaningless one, they would be able to carry out photosynthesis with only those regions directly in contact with the sun. This would mean that plants would not be able to produce enough energy and oxygen. The most important result of this for living things would certainly be the emergence of an energy shortage in the world.
And the specially "planned" systems in leaves do not end there. The tissue of the leaf has another important property. Thanks to this, phototropism, or turning towards the light, takes place. This is the reason for plants' turning their leaves to the direction of the Sun, which can be easily observed in pot plants. In order to understand how these processes which are of vital importance, take place, we shall have to take a brief look at the physiological structure of the leaves. If we look at a cross-section of a leaf, we will see a four-layered structure.
The first is the epidermis layer, which does not include chloroplasts. The role of the epidermis, which covers the top and bottom of the leaf, is to protect the leaf from external influences. The outermost part of the epidermis is covered with a protective and waterproof waxy layer, called the cuticle. When we look at the internal layers of the leaf, we see that it is generally made up of two layers of cells. Of these, cells rich in chloroplast stand in rows, with no gaps between them, making up the palisade layer, which forms the internal tissue. This is the layer which carries out photosynthesis. The spongy layer below this is the layer which enables respiration. There are air pockets between the layers of cells in this tissue. As we have seen, all these layers have very important tasks in the construction of the leaf. This kind of organization is of enormous importance from the point of view of photosynthesis, as it enables the leaf to spread and distribute light better. As well as this, the leaf's ability to carry out processes (such as respiration and photosynthesis) increases with the size of the leaf surface. For example, in dense tropical rainforests there is the tendency for large-leaved plants to grow. There are very important reasons for this. It is rather difficult for sunlight to reach all parts of plants equally in tropical rainforests, where the trees which make them up are all densely packed together and where it rains hard and often. This is what makes it necessary to increase the surface area of the leaf in order to catch the light. In those areas where the sunlight enters with difficulty, it is of vital importance for leaf surfaces to be large in order for plants to produce nutriment. Thanks to this feature, tropical plants are exposed to the sunlight in the most advantageous manner.
The general structures of
plants living in tropical regions and in deserts are very different,
as can be seen in this picture.
Small leaves, on the other hand, are found in dry, harsh climates, because under these climatic conditions the basic point of disadvantage is heat loss. And as the leaf surface becomes greater, water evaporation, and thus heat loss, increases. For this reason, the leaf surface, which catches the light, has been planned in the most economic way for the plant to conserve water. In desert environments the shrinking of leaves reaches exaggerated proportions. Cactus plants have thorns instead of leaves, for instance. In these plants photosynthesis is carried out by the fleshy stems themselves. The stem moreover, is where water is stored.
But that is not enough to control water loss on its own. Because no matter how small the leaf is, the presence of the minute pores in the epidermis called the stomata means that water loss continues. For this reason the existence of a mechanism to compensate for evaporation is essential. And plants do have a way of regulating too much evaporation. This is done by controlling the degree of openness of the stomata, either widening or constricting them as required.
Trying to capture light to carry out photosynthesis is not the leaves' only task. It is also important for them to take carbon-dioxide from the air and direct it to the areas where photosynthesis is carried out. Plants do this by means of the pores on their leaves.
The Stoma: A Flawless Design
These microscopic pores on the surface of leaves have the role of enabling the transfer of light and water and of taking the CO2 necessary for photosynthesis from the atmosphere. The stomata possess a structure which allows them to open or close as necessary. When they open, the oxygen and water vapour between the cells of the leaf are exchanged for the carbon-dioxide required for photosynthesis. In this way, surplus production is given off, and the required substances are absorbed to be made use of.
One of the interesting aspects of the stomata is that they are generally found on the underside of leaves. In this way the harmful effects of sunlight are reduced to a minimum. If the stomata, which give off the water in the plant, were on the tops of the leaves in great numbers, they would be exposed to sunlight for long periods. In such a situation, the stomata would continually be giving off the water in them because of continuous exposure to heat, in which case the plant would die of excessive water loss. Thanks to this special feature, the plant is prevented from being harmed by water loss.
The stomata are formed by sausage-shaped guard cells. Their concave structures permit the opening of the pores, which in turn allow the exchange of gases between the leaf and the atmosphere. The opening of the pores depends upon external conditions (light, heat, moisture, and carbon-dioxide levels) and the internal state of the plant, particularly its water levels. The pore's opening or closing regulates the exchange of gases and water.
There are very fine details in the structure of the pores, which have been designed with all external factors in mind. As we know, moisture levels, the degree of heat, gas levels, air pollution always change. Leaf pores possess structures which can adapt to all these changing conditions.
We can explain all of this with an example. In plants such as sugar cane and cornplant, which are exposed to heat and dry air for a long time, the pores stay completely or partially closed all day in order to conserve water. These plants need to absorb carbon-dioxide in the daytime for photosynthesis. Under normal conditions, the pores would have to remain as open as possible. But this is impossible. Because in that case the plant would continuously lose moisture from its pores and shortly die. For this reason, the pores need to remain closed.
But this problem, too, has been solved. Some plants, which live in hot climates, have a carbon dioxide pump which sucks the gas more efficiently out of the air into the leaf. These plants thus use chemical pumps to absorb carbon dioxide in their leaves, even if their pores are closed.35 If these pumps were absent for a time, the plant would be unable to produce any nutrients, because it could not take in any carbon-dioxide, and would therefore die. This is a sign that these complex chemical pumps could not have come about as the result of a series of coincidences over time. This system in plants can perform effectively only when all its components are together at once. For which reason there is no chance that the stomata could have evolved and emerged as the result of coincidences. The stomata, with their exceedingly special construction, have been planned, in other words created, to perform their tasks in the most sensitive manner possible.
The Evolutionist View of Leaf Development
As we have seen, there are highly complex systems squeezed into a tiny green body. These complex systems in leaves have been functioning perfectly for millions of years. So how did it happen that these systems came to fit into such a tiny area? How did the complex design in leaves come about? Is it possible that such a unique and perfect design came about by itself?
If we ask the defenders of the theory of evolution, their answer will be the same as always. They will put forward explanations and assumptions that have no logic and which are mutually contradictory. They will try to answer the question of how innumerable varieties of plants, trees, flowers, sea plants, grasses, and fungi "came about"-but without success.
When the theories put forward by evolutionists regarding the development of leaves are examined, they will be seen to be full of meaningless, even ridiculous, claims. One of them, the telome theory suggests that the leaf arose through repeated complex branchings and fusions of stem systems. 36 Let us now consider the questions which arise from this baseless claim:
- How did these branchings and fusions come about?
- As the result of what coincidences did they turn into leaves, with their totally different construction and planning?
- How did it happen that the thousands, nay, the millions of varieties of plants, flowers, trees, and grasses emerged from these primitive plants?
Evolutionists have no logical and scientific answers to any of these questions. As on every subject, evolutionists can produce no other explanation regarding the coming into being of plants than imaginary scenarios based entirely on imagination.
Let us once more examine the questions which arise from this.
How did it happen that enations, or flaps of tissue, emerged in certain places in the body to turn into leaves?
And later, how did they turn into leaves? And, not just any leaves, but leaves with flawless constructions in countless varieties?
Let us go back a little. How did the stems, which these enations emerge from, come into existence?
There is no scientific answer from evolutionists to questions of this sort.
What evolutionist theories actually want to explain is, in essence, as follows: Plants emerged as the result of events which came about by coincidence. Stems and branches came about by coincidence, chlorophyll came to be in chloroplasts by another coincidence, the different layers in leaves are another coincidence, once coincidence followed on the heels of another, and eventually, leaves emerged, with their flawless and particular construction.
At this point, the fact that all these structures in leaves, which are claimed to have come about by coincidence, must have come about at the same time is a truth which cannot and must not be ignored. According to evolutionists, all the mechanisms in the leaf arose from coincidences gradually over time. And the same evolutionist logic predicts that organs or systems which are not used will eventually disappear. Since all the mechanisms in leaves are interlinked, it makes no sense to say that one of them came about by coincidence. Because according to the second stage of evolutionist logic, this mechanism would have already disappeared, because it served no purpose. For this reason, in order for the plant to stay alive, all the complex systems in its roots, stems, and leaves have to exist at one and the same time.
As with every living creature in the world, plants were brought into being with flawless systems, and, from the moment they were created, have come down to today, with no changes in their features. From the falling of the leaves, to their turning themselves towards the sun, from their green colour to the woody nature of their bodies, from the existence of their roots, to the emergence of their fruits - all their structures are flawless. Even with today's technology it would be impossible to imitate or reproduce even similar systems (the process of photosynthesis, for instance).
This complexity is one of the proofs that leaves could not have emerged by chance. Leaves possess specially planned structures, to meet plants' needs to produce food and to do respiration. The existence of special planning proves the existence of a planner. The details and perfection of the planning introduce to us the planner's knowledge, intelligence, and art. There is no doubt that it is God, the Lord of all the Worlds, who created leaves with their perfect design.
The Miracle of Photosynthesis
The Earth is a planet specially designed to support life. The Earth provides an environment that can sustain life, thanks to the many very sensitive balances set up on it, from the gas levels in the atmosphere to its distance from the sun, from the existence of mountains to the presence of drinking water, from the wide variety of plants to the temperature of the Earth.
If the components which make up life are to survive, both the physical and the biological balances have to be maintained. For example, in the same way as gravity is indispensable for living things to live on the ground, so the substances plants produce are just as necessary for the survival of life.
As we indicated earlier, the process which plants carry out to produce these organic substances is called photosynthesis. The process of photosynthesis, which can be summarised as plants' producing their own food, is what makes them different from other living things. What makes this difference is the existence of structures in plant cells (unlike human or animal cells), which can make direct use of sunlight. With the help of these structures, plant cells turn the energy from the sun, which human beings and animals absorb by means of food, into energy and store it, again by special means. In this way, the process of photosynthesis is completed.
Of course, it is not the plant itself which carries out this process, nor the leaves, nor even the totality of the plant cells. It is a small organ found in plant cells called the "chloroplast," which gives plants their green colour and carries out these processes. Chloroplasts are one thousandth of a millimetre in size, for which reason they can be seen only through a microscope. The wall of the chloroplast, which plays such an important role in photosynthesis, is just one hundred millionth of a metre in size. As we can see, these figures are extremely small, and all the processes take place in this microscopic environment. This is one of the astounding features of photosynthesis.
The Chloroplast: A Factory Full of Secrets
In a chloroplast there are various formations such as thylakoids, internal and external membranes, stromata, enzymes, ribosomes, RNA, and DNA to bring about photosynthesis. These formations are all interlinked, both structurally and in terms of their functions, and each one has very important functions which it carries out within its own body. For example, the chloroplast's outer membrane regulates the flow of materials into and out of each chloroplast. The internal membrane system consists of flattened sacs, or thylacoids which resemble discs. Pigment molecules (chlorophylls) and enzymes essential for photosynthesis are embedded in the thylakoids. Many of the thylakoids are stacked, forming structures called "grana," which allow maximum absorption of sunlight. This means the plant absorbing more light and being able to carry out more photosynthesis.
Surrounding the thylakoids is a lipid solution, the "stroma," which contains other enzymes as well as DNA, RNA, and ribosomes. With the DNA and ribosomes they possess, chloroplasts both reproduce and produce certain proteins. (49)
Another important point in photosynthesis is that all these processes take place in a period of time so short as to be unobservable. The thousands of chlorophylls found in chloroplasts simultaneously produce their reaction to sunlight in the unbelievably short time of a thousandth of a second.
While scientists describe the photosynthesis event in chloroplasts as a long chemical chain reaction, they are unable to explain some parts of what happens in this chain on account of that speed, and simply look on in amazement. But it is clearly understood that photosynthesis involves two stages. These are known as the "light reactions" and the "dark reactions."
The Light Reactions
Radiations from the sun form a continuous series. The range of radiations that organisms detect with their eyes - visible light - is roughly the same range plants use. Shorter wavelengths (blue light) are more energetic than longer wavelengths (red light). Pigments are substances that absorb visible light; different pigments absorb different wavelengths. Chlorophyll, the main pigment of photosynthesis, absorbs light primarily in the blue and red regions of the visible spectrum. Green light is not appreciably absorbed by chlorophyll; instead, it is reflected. Plants usually appear green because their leaves reflect most of the green light that strikes them.38
The process of photosynthesis starts with the absorption of sunlight by these pigments, which make plants look green. But how do the chlorophylls begin the process of photosynthesis by absorbing sunlight? In order to answer this question it will be useful to first of all examine the structure of the thylakoid, which is found inside the chloroplasts and contains the chlorophylls within it.
There are two types of chlorophylls, "chlorophyll-a" and "chlorophyll-b." The light dependent reactions of photosynthesis begin when chlorophyll a and accessory pigments absorb light. As we can see in the picture where the detailed structure of the thylakoid is explained, chlorophyll molecules, accessory pigments, and associated electron acceptors are organized into units called photosystems. There are two types of photosystems, Photosystem I and Photosystem II. The light energy is transferred to a special "chlorophyll-a" molecule called the reaction center. The energy obtained from the absorption of sunlight gives rise to the loss of energy-rich electrons in the reaction centres. These energy-rich electrons are used in subsequent stages to obtain oxygen from water.
At this stage there is a flow of electrons. The electrons lost by "Photosystem I" are replaced by electrons lost from "Photosystem II." Electrons lost by "Photosystem II" are replaced by electrons removed from the water. As a result, water is separated into oxygen, protons, and electrons.
At the end of the electron flow, the electrons, along with the protons from water are transported to the inside of the thylakoid and combine with a hydrogen-carrier molecule NADP+ (nicotinamide adenine dinucleotide phosphate). The molecule NADPH results from this.
As electrons flow from carrier to carrier along the electron transport system, a proton gradient is established across the thylakoid membrane; the potential energy of the gradient is used to form ATP (an energy package which the cell will use in its own processes). At the end of all these processes, the energy which plants need to create their own nutrition is ready for use.
These events, which we have tried to summarise as a chain reaction, are only the first half of the photosynthesis process. Energy is necessary for plants to produce nutrition. For this to be obtained, the other processes are fully completed, thanks to a specially planned "special fuel production plan."
The Dark Reactions
These processes, the second stage in photosynthesis, known as the Dark Reactions or Calvin Cycle, take place in the regions of the chloroplast known as "stroma." The energy-charged ATP and NADPH molecules produced by the light reactions are used to reduce carbondioxide to organic carbon. The end-product of the dark reactions is used as a starting material for other organic compounds needed by the cell.
It took scientists hundreds of years to understand the main lines of this chain reaction which we have summarised here. Organic carbon, which cannot be produced in any other manner in the world, have been produced by plants for millions of years. This molecule is the energy source for all living systems.
During the photosynthesis reactions, enzymes and other structures with different features and tasks work in complete cooperation. No matter what highly developed equipment it may have, no laboratory in the world can work with the capacity plants have. Whereas in plants all these processes take place in a tiny organ just one thousandth of a millimetre in size. The diverse formulae have been implemented for millions of years, with no confusion of all the variety of plants, no mistakes in the order of reactions, and no confusion in the quantities of basic materials used in photosynthesis.
The process of photosynthesis also has another aspect. The complicated processes outlined above lead plants at the end of photosynthesis to produce the glucose and oxygen essential to living things. These products made by plants are used by humans and animals as food. By means of these foods, they store energy in their cells and use it. By virtue of this system, all living things make use of the Sun's energy.
Like Everything Necessary for Photosynthesis, Sunlight Has Also Been Specially Arranged
While all this is going on in the chemical factory, the features of the energy which will be used in the processes have been identified. When the photosynthesis process is looked at from this point of view, it will be realised in what fine detail the processes which take place have been planned, so that the features of light energy from the Sun may meet the energy requirement of the chloroplast to produce the correct chemical reactions.
In order to completely understand this fine balance, let us examine the functions and importance of sunlight in photosynthesis.
Was sunlight arranged specially for photosynthesis? Or are plants flexible enough to make use of any light that comes their way and initiate photosynthesis with it?
Plants are able to carry out photosynthesis thanks to the sensitivity of chlorophylls to light energy. The important point here is that chlorophyll substances use light of a particular wavelength. The sun rays have just the right wavelength needed by the chlorophyll. In other words, there is total harmony between sunlight and chlorophyll.
In his book, The Symbiotic Universe, the American astronomer George Greenstein has this to say about that flawless harmony:
Chlorophyll is the molecule that accomplishes photosyhthesis… The mechanism of photosynthesis is initiated by the absorption of sunlight by a chlorophyll molecule. But in order for this to occur, the light must be of the right color. Light of the wrong color won't do the trick.
In short, in order for photosynthesis to take place, all of the conditions have to be just right at that moment. It will be useful now to turn to another question that might come to mind. Could there have been any change over time in the order of the processes or the tasks carried out by the molecules?
One of the answers to this question that defenders of the theory of evolution, who claim that the sensitive balances in nature came about as the result of coincidences, is, "If there had been a different environment, plants would have initiated photosynthesis in that environment too, because living things would have adapted to it." But this is completely faulty logic. Because in order for plants to engage in photosynthesis they have to be in harmony at that moment with the light from the sun. George Greenstein, an astronomer who is also an evolutionist, reveals that this logic is faulty in this way:
Photosynthesis Cannot be a Coincidence
Despite all of these obvious truths, let us see that this system could not have come about by chance by asking some questions one more time for those who continue to uphold the validity of the theory of evolution. Who is it who planned this incomparable mechanism, which is set up in a microscopically small area? Can we imagine that plant cells planned such a system, in other words that plants actually thought it up? Of course we cannot. Because it is out of the question for plant cells to plan and think. It is not the plant cell itself which created the flawless system we see when we look inside it. So, in that case, is it a product of a unique human intelligence? No, it is not. It is not human beings who established the most unbelievable factory in the world in a space of just a thousandth of a millimetre. In fact, human beings cannot even see what is going on inside this microscopic factory.
When looked at together with the claims of the evolutionists, it will be seen why the answer to all these questions is "No," and the question of how plants came about will be made more apparent.
The theory of evolution claims that all living things evolved by stages, and that there was a development from the simple to the complex. Let us consider whether this is correct or not by seeing if we can limit the number of parts which exist within the process of photosynthesis. For example, let assume that there are 100 elements necessary for the process of photosynthesis to come about (although in reality there are a great many more). Continuing our assumption, let us imagine that of these 100 elements, one or two came into existence, as the evolutionists claim, by coincidence, and assume that they were self-generated. In that case there would be a waiting period of millions of years for the rest of the elements to come about. Even for those elements which did develop to join together would serve no purpose in the absence of the others. It would be impossible to expect the rest of the elements to form when the system will not function in the absence of even one of its constituent parts. For this reason the claim that such a complicated system as photosynthesis could have come about by the gradual and coincidental development of its constituent parts as they added themselves to one another-as evolutionists propose-is inconsistent with reason and logic, as are similar claims about all systems in living things.
We can see the pointlessness of this claim by having another brief look at some of the stages in photosynthesis. First of all, in order for photosynthesis to take place, all the enzymes and systems have to be present in the plant's cells at the same time. The length of each process and quantity of enzymes have to be arranged absolutely correctly each single time. Because even the smallest hitch in the reactions which take place-the length of the process for instance, or a minute change in the amount of light that enters or of the basic materials-will spoil the product that emerges at the end of the reaction and render it useless. Even if one of the elements we have described is missing, the whole system will be rendered non-functional.
At this point there arises the question of how all these non-functioning elements survived until the complete system was in place. It is also a known truth that as the size of a structure decreases, the intelligence and quality of engineering in its systems increase. When a mechanism reduces in size, it further displays the power of the technology used in it. A comparison between the cameras of our day and those of years ago will make this truth more apparent. This truth increases the importance of the flawless structure in leaves. How is it possible that plants are able to carry out photosynthesis in these microscopic factories, when human beings cannot do so in their huge ones?
Evolutionists are able to offer no credible answers to these and other questions. Instead, they make up various imaginary scenarios. The common tactic resorted to in these scenarios is to swamp the subject in demagoguery and confusing technical terms and explanations. They attempt to conceal the "Truth of Creation," which is clearly to be seen in all living things by using the most complicated terms possible. Instead of answering the questions of why and how, they set out detailed information and technical concepts, and then add that this is a result of evolution at the end.
Nevertheless, most of the time even the most hardened supporters of evolution cannot conceal their amazement in the face of the miraculous systems in plants. We can cite one of Turkey's evolutionist professors, Ali Demirsoy, as an example of this. Professor Demirsoy stresses the miraculous processes in photosynthesis, and makes the following admission in the face of the complexity of the system:
The flawless mechanisms at work in the process of photosynthesis have been present in every plant cell that has ever existed. This process takes place even in what we see as the most ordinary piece of grass. In a given plant, the same substances in the same amounts always play their part in the reaction, and the same products are produced. The sequence and speed of the reaction is the same. This applies to all plants which carry out photosynthesis, without exception.
It is illogical, of course, to ascribe capabilities such as thought and decision to plants. But, at the same time, to explain this system, which exists in all green plants and functions to perfection, by saying, "It developed from a series of coincidences," defies all logic.
At this point we are faced with an obvious truth. Photosynthesis, an extraordinarily complex system, was consciously designed, in other words, it was created by God. These mechanisms have existed from the moment plants came into being. The introduction of such flawless systems into such a tiny space demonstrates to us the power of the designer. The Results of Photosynthesis
The results of photosynthesis, which takes place through chloroplasts are very important for all living things in the world.
Living things are the reason for the continuous increase in carbon-dioxide in the air and the rise in air temperatures. As a result of the respiration of human beings, animals, and micro-organisms in the soil, every year some 92 billion tons of carbon-dioxide enter the atmosphere, and some 37 billion more during plant respiration. Furthermore, the amount of carbon-dioxide given off to the atmosphere from the fuel used by heating systems in factories and homes and in transportation is at least another 18 billion tons. This means that, during the circulation of carbon-dioxide on the land, some 147 billion tons are given off. This shows that the carbon-dioxide levels in the world are constantly rising.
Unless this rise is compensated for, the ecological equilibrium will be disturbed. For example, the amount of oxygen in the atmosphere may go down, temperatures may rise, as a result of which the glaciers might start to melt. Some areas would then be covered with water, and others would turn into deserts. All of this would endanger the survival of life on earth. But none of this happens. Because, with the process of photosynthesis, plants continually produce oxygen and maintain the equilibrium.
It is thanks to the process of photosynthesis that plants absorb carbon-dioxide from the atmosphere (to convert into nutrition) and release oxygen, so that the natural equilibrium-of vital importance to life on earth-is never upset.
There is no other natural source which makes good any deficiency of oxygen in the atmosphere. For this reason plants are indispensable to the maintenance of the systems in all living things.
Nutrients in Plants Emerge as the Result of Photosynthesis
Another essential product of this perfect system is a food source for living things. In that sense, the products of photosynthesis are extremely important for plants themselves and for other living things. Both animals and plants obtain the energy they need to live by consuming these foods produced by plants. Animal-product foods can exist only by virtue of products obtained from plants.
If we imagined that the events we have been discussing took place not in the leaves but in some other place, what kind of set-up would we imagine? Would it be a multi-functional factory with tools which served to create nutriments from the carbon-dioxide from the air, which also had machines with the capacity to make oxygen and release it, and which contained systems capable of maintaining temperature balances?
One would certainly not imagine something the size of the palm of one's hand. As we have seen, leaves, the possessors of perfect mechanisms, maintain temperature, allow evaporation, and at the same time produce food and prevent water loss. They are a wonder of design. All these processes we have listed take place not in different structures, but in just one leaf (of whatever size), moreover in a single cell of a single leaf, and what is more, all at once.
The foregoing facts all point to the functions of plants, all being blessings that have been created with the aim of serving living things. Most of these blessings have been designed for mankind itself. Let us take a look at our environment and what we eat. Let us look at the bone-dry stem of the grapevine, at its thin roots. Fifty or 60 kilos of grapes come from this structure which can easily break with a single pull. Grapes-whose colour, smell, and taste have been specially designed to appeal to man.
Let us consider the watermelon. This water-filled fruit emerges from the bone-dry ground at just the time when a person needs it, in the summer. Let us consider that wonderful watermelon smell and that famous watermelon taste, which it maintains in an expert manner from the moment it emerges. Then let us think about the processes in a perfume-manufacturing factory, from the creation of the scent to its maintenance. Let us compare the quality of the product from the factory and the scent of the watermelon. While manufacturing scents, people carry out quality controls all the time, but there is no need for any quality controls to conserve the scents in fruits. Melons, watermelons, oranges, lemons, pineapples, coconuts, all possess the same unique scents and flavours, wherever they may be in the world, without exception. A melon never smells like a watermelon, nor a mandarin like a strawberry: although they all emerge from the same ground, their smells never get mixed up. They all always conserve their original fragrances.
Let us examine the structure of this fruit in more detail. The sponge-like cells of the watermelon are able to retain large quantities of water. For this reason a large part of the watermelon consists of water. But this water is not all in one place, it is evenly distributed all over the watermelon. Bearing in mind the force of gravity, this water should mostly be in the bottom part of the fruit, with the top part being dry and fleshy. Whereas no such thing happens in the watermelon. Water is evenly distributed inside it, and the same applies to its sugar, taste, and smell.
And there is never any mistake in the setting out of the rows of seeds. Every seed carries the code of that watermelon which will be carried down to other generations thousands of years later. Every seed is coated in a special, protective covering. This is a perfect design, prepared with the intention of preventing any damage to the information inside it. The covering is neither hard nor soft, it has just the right amount of hardness and flexibility. Underneath the outer covering is a second layer. The areas where the upper and lower parts join are clear. These places are specially designed so that the seeds can cling on. Thanks to this construction, the seed only opens once it has reached the appropriate moisture and temperature levels. That flat, white part in the seed later germinates, turning into a green leaf.
Let us also consider the structure of the watermelon rind. What creates this smooth rind and the waxy coating on top of it is again the cells. For this waxy coating to form, every one of the cells has to give off the same level of waxy substance in the rind. Furthermore, what makes the rind smooth and round is the perfection in the layout of the watermelon cells. For this to happen, each cell must know its place. Otherwise there could never be this smoothness and perfect roundness of the outside of the watermelon. As we can see, there is a flawless harmony between the cells which go to make up the watermelon.
We can consider all the plants in the world in the same manner. At the end of such an examination we will arrive at the conclusion that plants have been designed for human beings and other living things, or in other words, created.
God, the Lord of all the worlds, made food for all living things, and created every one with different tastes, smells, and uses:
Plants Are Cool, But Why?
A plant and a piece of stone in the same place do not warm up to the same degree, even though they receive the same amount of solar energy. Every living creature will experience negative effects if it stays out in the sun. So what is it that enables plants to be minimally affected by the heat? How do plants manage this? Why does nothing happen to plants even in great heat, even when its leaves burn in the sunshine all through a hot summer? Apart from their own internal warming, plants also take in heat from the outside and maintain the temperature balance in the world. And they themselves are exposed to this heat while carrying out this heat-retention process. So, instead of being affected by the ever-increasing temperature, how is it that plants can continue to take heat in from outside?
Considering that plants are constantly under the sun, it is natural that they should need more water than other living things. Plants also constantly lose water by the perspiration on their leaves. As we touched on in earlier sections, in order to prevent such water loss, the leaves, the surface of which are always turned towards the sun, are generally covered in a waterproof protective wax known as the cuticle. In this way water loss on the upper surfaces of leaves is prevented.
But what about the under surfaces? Because the plant loses water from there, the pores whose function is to enable the diffusion of gases are generally on the bottom surfaces. The opening and closing of the pores regulates the plant's taking in enough carbon-dioxide and giving off enough oxygen, but not in such a way as to lead to water loss.
In addition to this, plants disperse heat in different ways. There are two important heat dispersal mechanisms in plants. By means of one of these, if the temperature of a leaf is higher than that around it, air circulates from the leaf towards the outside. Air changes stemming from heat distribution lead to the air rising, because hot air is less dense than cold. For this reason the hot air on the surface of the leaf rises, leaving the surface. Because cold air is denser, it descends to the surface of the leaf. In this way heat is reduced and the leaf is cooled down. This process goes on for as long as the temperature on the surface of the leaf is greater than that outside. In very dry environments, such as deserts, this situation never changes.
By means of the other heat dispersal system of plants, leaves can perspire by giving off water vapour. By virtue of this perspiration, the evaporation of water permits the plant to cool down.
These dispersal systems have been designed to suit the conditions where the plant lives. Every plant possesses the systems it needs. Could this exceedingly complicated dispersal system have come about by coincidence? In order to answer this question, let us consider desert plants. The tissues of desert plants are often very thick and fleshy. They are designed to conserve rather than evaporate water. It would be lethal for these plants' heat dispersal systems to work by means of evaporation, because in a desert it is not possible to compensate for water loss. Although these plants can disperse heat by both methods, they only use one, which is also the only way for them to survive. Their design has obviously been carried out with desert conditions in mind. It is not possible to explain this by coincidences.
If plants did not possess these cooling-down systems, being under the sun for even a few hours would be lethal for them. One minute of direct sunlight in the afternoon can heat one centimetre of leaf surface by as much as 37 degrees centigrade. Plant cells start to die when the temperature rises to 50 to 60 degrees, in other words, just three minutes of direct sunlight in the afternoon would be enough for a plant to die.43 But plants are protected from lethal temperatures by means of these two mechanisms. The evaporation which plants also use in heat dispersal is also very important from the point of view of regulating the level of water vapour in the air. This evaporation in plants enables high levels of vapour to be released to the atmosphere regularly. This activity of plants could be described as a kind of water engineering. The trees in a thousand square metre area of forest can comfortably put 7.5 tons of water into the atmosphere.44 Trees are like giant water pumps, passing the water in the soil through their bodies and sending it into the atmosphere. This is a most important task. If they did not possess such a feature, the water cycle on the Earth would not happen as it does today, which would mean the destruction of the balances in the world.
What we have described as the perspiration in leaves or the moisture in the areas where the trees live, actually occur as the result of activities which are essential to the survival of life on the planet.
What we see in these processes of plants is a system of such perfection that it would run down and stop working if even one part of it were taken away. There is no doubt that it was God, the Compassionate and the Merciful, who is aware of all creation, who designed this system and flawlessly installed it in plants.
The Leaf: the Smallest Cleaning Tool
The services that plants carry out for other living things are not restricted to giving off oxygen and water. Leaves at the same time carry out the most highly developed cleansing and purification functions. The cleaning tools we regularly use in our daily lives, are produced and set in operation as the result of long studies by experts, and after the expenditure of a lot of effort and money. These need considerable technical support and maintenance, both during and after use. And after production these things can develop a number of problems. In addition, problems or defects which can arise on a daily basis, and the necessary staff and the need for other tools, and renewals where necessary, can all mean a great many more processes.
As we have seen, there are hundreds of details to consider, even in a small piece of cleaning equipment, whereas plants do the same job as these tools, in return for just sunlight and water, and perform the same cleaning service with the guarantee of greater efficiency. And they also give rise to no waste product problem, because the waste product they give off after cleaning the air is oxygen, which all living creatures need!
Tree leaves possess tiny filters, which catch pollutants in the air. There are thousands of tiny hairs and pores, invisible to the naked eye, on the surface of a leaf. The individual pores trap pollutants in the air and send them to other parts of the plant to be absorbed. When it rains, these substances are washed to the ground. These structures on the surfaces of leaves are only of the thickness of a film: but when one considers that there are millions of leaves in the world, it becomes clear that the amount of pollutants trapped by leaves is not to be underestimated. For example, a 100-year-old beech tree has about 500,000 leaves. The amount caught by these leaves is more than one might guess. About a thousand square metres of plane trees can trap 3.5 tons, and pine trees 2.5 tons of pollutants. These materials then fall to the ground with the first rain. The air in a forest two kilometres from a settlement area is some 70 percent cleaner than in the settlement area. Even in winter, when trees lose their leaves, they still filter out 60 percent of the dust in the air.
Trees can trap dust weighing five to 10 times more than their leaves: bacteria levels in an area with trees is considerably less than in one with no trees.46 These are very important figures.
Each thing that happens in leaves can be described as an individual miracle. These systems in green leaves, in the superb planning as in a microscopic factory, are proof of the creation of God, the Lord of all the worlds, and have come down to our day after hundreds of thousands of years, in the same perfect state, with no changes and no defects.
The Falling Leaves: Something We Have All Seen
Sunlight is very important for plants, and particularly for leaves, where food is produced. With the approach of winter, the air grows colder and the days shorter, and less light reaches the earth from the sun. This reduction causes changes in plants, and the aging process in leaves, or leaf fall, begins.
This leaf fall, which looks like a purely physical process, actually comes about as the result of a sequence of chemical events.
In the cells in the palm of the leaf are pigments, called phytochromes, which are sensitive to light and give colour to plants. It is these molecules which allow the tree to realise that the nights are growing longer and that less light is reaching the leaves. When phytochromes sense this change they cause various changes within the leaf, and begin the leaf's aging programme.
A short while later, ethylene has spread to every part of the leaf, and when it reaches the leaf stalk, small cells there start to swell up and give rise to an increase in tension in the stalk. The number of cells in that part of the stalk which joins onto the trunk increases, and they begin to produce special enzymes. First of all, cellulase enzymes tear apart the membranes formed from cellulose, then pectinase enzymes tear apart the pectin layer which binds the cells to one another. The leaf can no longer bear this rising tension and starts to split, from the outer part of the stalk in.
Before the leaf is completely separated from the trunk, it no longer receives any water from the transport tubes, for which reason its grip on the place it is attached to grows progressively weaker. To break the leaf stalk, it will be enough for a moderate wind to blow.
In the dead leaf which falls to the soil are food substances that fungi and bacteria can make use of. These food substances undergo changes brought about by micro-organisms and become mixed with the soil. Trees can take these substances up again from the soil by their roots as nutriments.
34. John King, Reaching for The Sun, 1997, Cambridge
University Press, Cambridge, p.18 |
Before
trees lose their leaves, they begin to absorb all the nourishing
substances in the leaves. Their aim is to prevent substances such
as potassium, phosphate, and nitrate from disappearing with the
falling leaves. These substances are directed through the pipelines
that run through the layers of bark and the centre of the trunk.
The collection of these substances in the xylem makes it easier
for them to be digested by the tree.
What has been described so far
shows that a string of interlinked events is necessary for just
one leaf to fall. Phytochromes' determining that there is a reduction
in sunlight, all the enzymes necessary to the falling of the leaf
moving into action at the appropriate time, the cells beginning
to produce suberin just at the place where the stalk will break
off: it is clear what an extraordinary chain of events it takes
for a leaf to detach itself. "Chance" cannot be offered as the explanation
of this series of processes, all planned and following one another
in perfect order. The leaf fall plan functions in a perfect manner.
|
|
