I live near a forest near a town called Terrell, which is in northeast Texas and living near a old forest, I have taken the opportunity to write about what I find in this forest. What I intend to show is that studying this forest from the perspective of a scientist, will not only reveal what is present but I hope to show that by adopting this perspective, it may reveal a deeper truth and that is to reveal that my backyard is a small part of a biosphere or sphere of life which coexists with the atmosphere, the sphere of air, the lithosphere or the sphere of rock, and the hydrosphere, the sphere of water. From the basic elements that make up these nonliving spheres that is the carbon, oxygen, and nitrogen comes the sphere of life, the biosphere with its countless species of microbes, plants, fungi, and animals and I believe that my journey to my backyard does reveal that my backyard is a part of the biosphere and to begin my inquiry, I began by visiting the forest so I take a small black notepad to take down notes, a small plastic container, and a digital camera to take photos. With these items, I am off to the forest and I carefully observe what is in the forest whether on the ground, above the canopy, and at eye level where I stand. No detail too small is ever missed and likewise nothing that is large escapes my attention.
As I walk into the edge of the forest I am surrounded by oak trees and these are the most common kinds of trees and in addition there are other species of trees that are also common and they are cedar trees. At this time of year being late summer the cedar trees are already producing fruit of their own but what the fruits are just ways of the cedar trees to make more trees. As I walk I do so with difficulty since there are fallen branches and so I have to watch my step. What do I see? The forest is a little dark because of all the trees with their canopies spread open catching whatever ray of sunshine impinges on their leaves and this is what I notice of the oak trees. As I look upward to each oak tree, the canopies are fully spread out as the photo of some oak tree clearly shows:
Also in addition to looking up at the canopy I look down to the ground and the ground can contain as much information of what life forms are present as there is in canopy and what do I notice? For one thing, the soil is moist and the reason is that the day before I began the observations it was raining. The soil was absorbing the rain but it did not rain long and hard to form standing puddles so since it was sunny, the heat from the sun evaporated whatever standing puddle of water there were so the soil is still damp. The rest of the water was absorbed through the soil and the soil acts like a sponge. The trail that I take that leads to the inside of the forest has plenty of stuff on the ground, mostly leaf litter where all the leaves are brown and have yet to decay into a fine organic residue but there are plenty of leaves and every fall, the oak trees shed their leaves and each dead leaf detaches from each twig and as the fall progresses, every oak tree is bare and there is a layer of dead leaves on the forest floor. It looks as if when all the oak trees have no leaves, and as the winter progresses up until spring, the oak trees appear dead but during the springtime, the oak trees begin sprouting fresh leaves so the trees are not really dead but go into a kind of hibernation until the days begin to get longer, the nights shorter, and the days warmer and each oak tree sprouts leaves to begin the process of photosynthesis , a biochemical reaction that is prevalent in the biosphere where all kinds of green plants, algae, and cyanobacteria use the energy of sunlight, water, and carbon dioxide to make food in the form of sugars which becomes cellulose and that which forms the wood of trees. As I look down on the damp forest floor I notice a thin green covering. It is so fine that it is hard to make out each individual and being small I suspect that it may be a species of algae or cyanobacteria, it’s hard to tell but whatever species it is, it is taking advantage of the moisture by absorbing some of it while using whatever ray of sunlight there is which streams through every tree branch and sunlight like water is in short supply as far as plants growing on the ground are concerned.
On my way, I look at some leaves attached to their stems and one such tree limb has leaves with serrated edges. I also notice that they are bearing fruit which will sooner or later fall from their trees and the fruit will carry the genetic information to make another tree just like it. The shape of the leaf is wide enough to capture sunlight and indeed you can think of tree leaves as a kind of solar panel where the energy of sunlight is transformed into biochemical energy in the form of sugars or carbohydrates and plants have perfected solar panel technology for over hundreds of millions of years as a result of natural selection.
Back to the forest floor. I have photographed the forest floor as well as bare patches of damp soil where there is plenty of green on the surface.
While looking on the ground I am aware of sounds and most of the sounds are of insects. Why are they making those sounds? Perhaps it is likely that the insects are doing this as a way of attracting mates and indeed when studying the animal life, namely insects, I have seen insects caught in the act of mating so song and finding mates are part of life’s ability to make more of themselves or in other words to reproduce, a key characteristic of life as I argued about the definition of life in one my previous blog “What is Life, Really?”. Also as I listen hard there are some bird calls and although some of the calls of birds are pleasant to listen to, in reality the birds are letting members of their kind that they are ready for mating as well as to warn rival birds that they have a claim to their territory since as big as the forest is from my point of view it is still limited mainly as a result of vegetation that is the oak trees encountering barriers such as areas where there is not enough moisture as well the growing influence of humans who destroy parts of natural habitats to make room for ranches to houses, up to subdivisions. Such limitation of oak tree growth then forces species of birds to quickly find any unoccupied oak tree and once found they make their presence known through song. Competition to find mates and a place to raise young are behaviors that are favored by natural selection and allow survival or extinction as was made clear in On the Origin of Species by Charles Darwin and I have read it several times and something I always keep in my mind as I observe the animals and plants in the forest. Each plant and animal is adapted to survive in whatever part of the forest I notice. The green scum on the forest can tolerate low levels of light while easily absorbing moisture so each tiny green plant is competing with other of its kind and for good reason. In the past two months, temperatures were around 90 – 99 Fahrenheit (32-37 degrees Celsius) and as I walked into the forest the floor is dry but it is likely that the green plants have a strategy to survive the long dry summers and that is to hunker down by shutting all of their biochemical activities such as forming spores and remaining dormant until the next time there is sufficient moisture as what had happen yesterday and now the algae as well as cyanobacteria are photosynthesizing and multiplying. So much for living organisms. What about dead organisms? There are plenty of dead trees as well as live ones and I notice a tree stump that is covered with tree fungi. Wherever I see dead wood, fungi are always present in some form are another. Why are dead trees covered with fungi? For one thing when a tree is alive it is photosynthesizing and producing carbohydrates from sugars to cellulose and carbohydrates are composed of three chemical elements, carbon, hydrogen, and oxygen, the carbon coming from carbon dioxide, hydrogen and oxygen from water. Once a tree is dead and that is no longer capable of photosynthesis, growth, and reproduction, fungi start to invade the wood and consume tiny bits of the trees and that is what I’m observing. The fungi are absorbing the carbon present in the cellulose and using the carbon as well as oxygen, nitrogen, and hydrogen to make more fungi so fungi is present in the forest but in truth fungi exists as a kind of cobweb called myceliae and the myceliae is actually present throughout the entire forest mostly underground but through a process called cell differentiation, the myceliae forms what are called fruiting structures and these take the form of the familiar mushrooms and tree fungi and they release spores which carry the information to make more fungi.
The fungi that is eating this stump are thin, white, and round so while in the forest, I proceeded to look for fallen wood and what I saw was that there was not one kind of tree fungi but several varieties of fungi but what they all had in common is their ability to break down cellulose which gives wood its strength. I look at part of a log and although it is decomposing the fungi are in black spots. Many black spots are present on the log but it is no doubt breaking up the cellulose like the round tree fungi.
As I place the camera in my pocket I become aware of movement behind barbed wire. The forest is part of my property but enclosed by a barbed wire fence. What was that movement? I looked and it was a young deer! The deer is probably a doe with her tail up and running rapidly. The deer was moving fast that there was no way I could have taken a photo. Here I saw a large wild animal, a mammal which generally are animals with backbones that care for the young by feeding them milk, warm blooded, and have fur. On my journey, I encounter other animals but most of them are small and are the invertebrates or animals without backbones and the most common invertebrates include the arthropods or animals with outer skeletons or exoskeletons and have jointed legs. The most common groups of arthropods are the insects and spiders and I do encounter them more frequently than large mammals. One of the first insects I encounter is a moth and as I look at the moth, I notice something peculiar. The moth is on the ground and with large pale wings. It was moving its legs but I notice that it is not flying.Why? Upon careful inspection and under the assumption that it injured itself in a way that damaged its flying my assumption turn out to be half correct. What I also noticed is that the moth was being eaten! There is a organism of some sort, a predator, that is eating the moth and the more I poke the moth with a twig, the more the organism that is consuming the moth is moving away. What sort of organism? I look down at the tiny predator carefully and it appears to either be a small spider or a large ant. I couldn’t tell but it had a bright red abdomen and it surely was consuming the moth. This is a clear example of a predator prey relationship where the predator is either a species of spider or large ant that is eating its prey which is the hapless moth.
While I look at the ground, I hear a harsh grating sound. At first I thought the sound was man made since my property does live near another property owned by someone else but I quickly realized that those sounds were made by the deer and it seems that the young deer was with a group of other deer and I could once again make out the same outline of the deer running through the trees and was not seen again. Why that harsh sound? Since deer are always on the lookout for predators perhaps that cry is a sound to distract predators that approach deer. Last year I saw one of those deer up close in the forest and I tried unsuccessfully to take its picture up close and that deer saw me, lifted up its tail and made that noise and ran, as if to say ” You can’t catch me, don’t even try.” Looking down on the leaf litter, I spot a grasshopper but it is dead. I assume that this grasshopper is endemic to this forest and every summer there are a variety of grasshoppers. some with red hindlegs with green and black stripes. other are brown with stripes on abdomen and of course there are the common katydids. Sooner or later every living thing comes to an end and I saw it with the trees and there I saw it with the grasshopper which completed its life style of eating and mating and after it did that, it reached the ends of it life and the atoms composing it are now being slowly returned to the leaf litter where a new generation of plants and animals will use the same chemical elements notably carbon and oxygen for their life processes. Indeed recycling of elements is part of the ecosystem of the forest all powered by sunlight and through growth, consumption and decay, elements cycle between living things as well as their nonliving environment such as the water and soil and air. Living and nonliving are interrelated.
I have walked past the barbed fence and there is a deep curving ravine. a place carved out by flowing water. In the past 2 years of living near this forest, I observe the seasonal changes of this forest and from November up to May, there is water in the ravine but through the hot months of June, July, and August, the water disappears leaving only the bottom of the rain. What I’ve also noticed is that there are plenty of fallen trees. That is because this is the result of a beaver and indeed I’ve seen some beavers chewing those trees and forming of what may the beginning of a beaver lodge. Any other evidence of animals in the forest? Indeed there is plenty of evidence even though I can’t see the animals themselves but I know there are some large animals aside from seeing a deer, I see footprints possibly of raccoons and some animal droppings which indicates the presence of rabbits. Also I mentioned that there are small holes and this is likely made by insects that are adapted to living underground. I have seen some of those insects and they are pretty common during the summer and I presume that they live in these holes and they are red velvet ants. They are large red insects with black markings and despite the name they are a relative of wasps. They move quickly and I have seen some of them walking on the forest. They move so fast that it sometimes difficult to take a picture of them and they sometimes disappear under the leaf litter. I make my way through the forest and I find a ravine that cuts through the center of the forest and the there are plenty of full grown oak trees near the ravine. Living near this forest for 2 years and carefully studying it each season, the ravine is usually empty except for periods of heavy rainfall where it can be full of water but if there are days of rainfall, the water in this kind of ravine usually disappears in a period of 2-3 days depending on the temperature of each season. I mentioned that I carried a small plastic container. I was using this container to collect bits of soil, bits of dead leaves and pieces of green leaves and some soil still damp from the bottom of the ravine.
Since this forest is dominated by oak trees I can make a good guess that this is an old forest and there are plenty of tall and thick oak trees. What this tells me is that maybe this forest is about a few hundreds of years old but chances are I could be wrong about that. The only way to tell is to use a technique from ecology or the science that studies living things and their environment is to use a coring technique where using a specialized metal instrument, a thin core is removed from a tree which reveals the rings and taking plenty of core samples from a large number of trees, each core can be counted and given the age of each tree. With a large number, you get an average age of the forest which can tell you exactly how old this forest is but since I don’t have the right instruments, I can only make guesses. Near the ravine, I notice a small green seedling with leaves. Many of the oak trees as I mention are tall wide and old there is still growth of young saplings presumably of baby oak trees but with the old oak trees dominate, there is little chance for the young seedlings to make it and if that were to occur, then some oak trees will have to die and they would do this once they are incapable of photosynthesis that is death, fungi begins to invade the wood and small animals from wood lice to woodpeckers do some damage. Eventually the dead tree will lose its support and sooner or later it will collapse and when it does, some sunlight can penetrate and wherever there are saplings they will eventually grow and if there is sufficient moisture and nutrients in the soil, courtesy of rain and living things like fungi and bacteria, the sapling will grow until it is a full grown tree complete with leaves for photosynthesis and seeds for reproduction. Indeed life in the forest can begin again if the old parts of the forest are destroyed first and the cycle of life continues and that is what I’m seeing, some saplings as well as spring flowers which bloom during the springtime when the oak trees are just beginning to sprout leaves and then when the canopy is mature, they die but return to bloom again the following spring.
After taking this picture, I spot something near the base of an oak tree. Upon walking towards what caught my attention is a large spider web and it is a pretty big one but it has an interesting shape. It is shaped like a funnel and there is even a center to the funnel. This web is created by a large spider and I have seen those spiders. They are about as big as your fist and they are the right size to make such a large spider web but today I cannot see the spider that made that huge web.
Turning my attention to another part of the ravine there is a fallen tree. The ravine winds its way under a fence and the large dead tree has fallen on the fence over the ravine and it is pretty impressive and what I mean is that there are plenty of fungi mainly black fungi that is slowly decomposing the bark of that tree. Even before I turned my attention to the dead tree I was looking at the live trees and on the bark there are plenty of green crusts called lichen. Lichen are not a single organism but two different kinds of organism that co-exist in a mutual relationship where both partners benefit. Those two organisms are algae which provide oxygen and sugars through photosynthesis and a fungi which delivers water to the algae while the fungus absorbs the sugars. Wherever I look the most common kinds of lichen are pale green and dark green varieties. I have yet to see an oak tree whose bark is not covered with lichen. There are even black varieties of lichen but they seem to be less common than the pale green kind. The growth of lichen creates a kind of competition where other kinds of lichen which uses the same resource that is the oak tree surface is crowded out and becomes rare.
While at the fallen tree near the ravine, there are plenty of black fungi that is slowly decomposing the bark and I peel back the layer of bark and I find that under a piece of bark, there is some myceliae or weblike patterns of fungal growth under tree. I mention that fungi is really myceliae that exists throughout the forest in this form. Here is an example of it in the photo below
I look over the fallen tree, and I notice a small puddle of water in another part of the ravine near the fence and then I get excited! Normally you probably don’t give much thought or for that matter excitement when there is standing puddles of water but as a practicing biologist, albeit an amateur biologist, I tend to get excited because there are microorganisms in every puddle and with my small plastic container, I go to the puddle and collect some water along with bits of soil and leaves into my handy cup and I also spot a large hole nearby.
The hole that is see is large, wide, and round and I can only guess that it was burrow of some kind. Depending on the size of the animal holes in the forest floor can be tiny as to allow insects and large for large mammals but all are entrances to shelters that the animals make to live.
Building shelter is part of an animal’s way of surviving in its own habitat and that kind of behavior would be favored by natural selection. Also I notice that there is a long tree root in the hole now abandoned by whatever animal made that hole. Organisms such as animals end up modifying their environment in a way that favors their survival. For one thing there is about 21% oxygen in our atmosphere and that can only be the result of photosynthesis an activity of life and indeed I know of no other inorganic reaction that can produce that large amount of oxygen on such a huge global scale and with the rise of oxygen it then favored the evolution of organisms such as animals and fungi to adapt to the rise of oxygen by using aerobic or oxygen based metabolism the evolution of animals of course continues on to this day. On a smaller scale such as my forest, the activity of animals break apart the mineral grains composing the soil allowing fresh air to get to the tree roots and fungi as well as water and the excrement of animals and dead animals along with dead plants together with a combination of fungi and bacteria breakdown all organic molecules or carbon based molecules that form life back into the soil in the form of carbon and nitrogen together with small amounts of phosphorous, sulfur, manganese, copper, etc into the top and bottom parts of the forest soil making it rich with small organic compounds such as sugars and amino acids which are absorbed by bacteria and fungi but fungi not only act to break down cellulose and dead animal tissue, they form a symbiotic relationship with plants by forming a myceliae based networks around the tree roots and what it does is to increase water uptake by the roots as well as absorption of small organic compounds such as nitrates and nitrates which through photosynthesis carried out by the leaves are turned into amino acids, the building blocks of proteins such as enzymes and nucleotides, the building blocks of DNA. The fungi in return get sugars which fuels their metabolism and reproduction. Both species benefit and suppose the fungi in my forest collapses. Not only would there would be dead trees but they would be dead because there would be no efficient way to absorb water and nutrients from the slowly. The forest would slowly collapse and become dead. Throughout evolutionary history it seems that the appearance of a new species favors the evolution of another species whether it is two organisms that depend on one another for benefit to one that is a predator to prey. Not only species can adapt mutualistic or beneficial relationships but I also mention that life modifies its environment large or small that will either help the evolution of species or slow it down even perhaps kill it. I continue my trek through the forest and aside from seeing dead trees and leaf litter, I spot an ant beds and the surface of the ant bed is covered with small holes and I see ants scurrying across the surface. Ants like most of the insects are pretty common during the summer months. I have seen ants form trails near my house and it is the same like all insects and spiders: finding food. The ants are pretty frantic scurrying around the antbed so to see how they respond to a damaged part of their colony I use a twig to destroy a part of their nest in order to see how they respond and they respond with vigor and I notice that their pace quicken. They are aware that I destroyed a part of the nest so they respond to the damage. Sooner or later each ant plays a role in repairing the damage; they have too.
Invertebrates like insects and spiders are the most common animals that are present in abundance and everytime I walk into the forest I see the same species of spiders, ants, beetles, grasshoppers, and butterflies but I may see something different like a different colored beetle , or a grasshopper that blends in with the leaf litter. Diversity is the rule not the exception and it is usually taken as a sign that the forest ecosystem is healthy. The more diversity of plants and animals the more likely the forest will rebound in response to a catastrophe such as a tornado or a fire. More species will sooner or later return and rebuild the entire forest until it matures and another cycle of destruction appears. I see growth of plants such as grasses as well as mosses. Wherever there is fresh growth it is balanced by death of old plants like those dead trees. Nothing goes to waste and in fact there is no such thing as waste. It is always recycling of carbon, nitrogen, and oxygen and that is what the fungi do as well as bacteria and small invertebrates that make a living in the wood and leaf litter. I spot near a large long in addition to the ubiquitous tree fungi, some wood lice or pill bugs. There is one large one and a tiny one side by side and I do not hesitate to take a photo.
Despite the name, wood lice are not really lice and are not insects or spiders but a species of crustaceans. Why? Because unlike insects and spiders, wood lice have tiny gills for breathing much like their marine relatives, crabs and lobsters whereas insects and spiders have thin tracheal tubes throughout their exoskeletons. It is counterintuitive at first glance but evolution doesn’t care about artificial human categories, whatever is present in the generation of living things and if its allow survival then natural selection will favor it. I also spot a cluster of mosses which are attached to bits of bark. I have seen these kinds of mosses. It is true that there are some mosses that grow on damp soil and this forest is no exception. This kind of moss however grows on tree bark and it is dark green in color but the day before I began my expedition, it was raining and when it rains, that kind of moss absorbs water and it gives a bright green color like living green emeralds, a lovely reminder of what water can do and that is to aid in the vital processes that lets life live.
Not only do I look down but I look up in the forest. As I walk along I tend to look up and I see a pattern: That pattern is the upward canopy of oak trees and I see the same thing no matter where I go. This is an example of a purpose seeking behavior and in this case it is to spread the canopy as wide as possible and to produce leaves which are as wide in order to maximize the amount of sunlight. Living things like trees grow and reproduce and when living, each organism whether plant or animal is actively seeking sources of energy and to use that energy to stay alive. Starting from the trees the process of photosynthesis releases oxygen which fuels aerobic metabolism, a fancy term for the slow combustion of food mainly sugars as well as proteins which are eaten by animals starting from the small up to the large and sooner or later each animal will die and so will the plants and the atoms that they have in their living tissues will return to the soil and will be utilized by bacteria and fungi. Basically stuff cycles in the forest and this is what I meant that the concept of waste, a humancentric term, is kind of meaningless, as what is waste from our perspective such as a cut tree that is allowed to fall on the floor becomes food as well as shelter for various kinds of critters. There are not only trees like oak and cedar but I spot a small tree that is bearing fruit. I look at the fruits and I remind myself that a fruit is a tree’s way of making more trees. Curious, as usual, I take a closer look at the fruit and I smell the flesh and it smells like plums. I moved here around December of 2012 and I have been exploring the forest ever since but I also the house was built in 1989 and the previous owners already planted flowers. I do not know if what I saw is a plum tree perhaps a wild plum tree that is indigenous or at one time, the previous owners decided to plant a plum tree but it is likely that the first owners of the house may have done that. I assume that most plants and animals are indigenous that is evolved in that kind of habitat but I have to reminded myself that in addition to indigenous life forms there are also invasive species so it is likely that the plum tree could be an invasive species and usually invasive species may or may not survive in their new habitat. Although the plum smells sweet, I do not attempt to eat it and generally I don’t eat anything that looks even edible. I have noticed that some people have a tendency to think that anything that grows in the wild or is natural is safe and good for you but as a practicing biologist, I would disagree with that kind of logic. For one thing not every living thing that grows is safe. Every summer there are venomous creatures that invade my house, scorpions as well as paper wasps that make colonies near the edge of doors and windowsills. Also there are centipedes and venomous snakes. All of them are natural but produce venom which can harm humans. Also some animals like turtles which I have found on one occasion in the forest carry E.coli which can cause blood poisoning in humans. I have even observed water from the forest under the microscope and observed plenty of bacteria some of which can cause that horrible disease, cholera. Acknowledging this, I move on. While I turn around in one corner of the forest, I not only look up but I look down and I spot plenty of logs and branches on the forest floor. I decide to look what is under there but as I do I am cautious of what may under there since as I mentioned before some of the animals can be dangerous especially the smaller one such as snakes and scorpions which tend to live under logs and I carefully look out at one log and indeed my use of caution is proven and on top of this one log is a live scorpion.
Curious as well as cautious, I take a long twig and I attempt to find a response by gently poking at with the twig. I expect that the scorpion will uses it stinger at the probing twig, and indeed the shape of the stinger can be made out but what I observe is that the scorpion curls up upon itself. I poke it a second time and it slowly moves both its claws but makes no quick moves towards it. I poke it a few more times and it looks unwillingly to fight back. After that, I leave it alone and proceed to find what is under tree branches. Carefully flipping over one of the branches to see what is under and being careful after my little encounter with the scorpion, I see dark patches of soil and plenty of crumbling wood but what looks like white cotton and cobwebs is really that common organism that is an integral part of the forest, the myceliae or fungi and I quickly realize that it is the fungi that is responsible for the wood’s slow decay into rich organic powder that becomes a part of soil.
You can say that in a sense the soil of the forest is like an active organic entity absorbing not just moisture but all the organic compounds that are part of live organisms that return their vital carbon back to the soil and although looking at the all branches, it may be a good place to gather firewood but in truth the forest needs all that wood as well as the dead lives, which makes up what ecologists call detritus and all the detritus is as essential for the health of the ecosystem as all the living organisms big and small that inhabit the forest. Life is not only affected by the environment but life modifies the environment in such a way that allows for life to survive and as I feel soil under the branch, it does feel damp and it is perfect for the fungi and the wood lice and I do see wood lice scurrying through little tunnels in the decaying wood. The cool, damp, and dark environment under the wood suits the little wood lice just fine. From casual inspection of the mycelia, it forms a network throughout all of the forest floor, that seeks out carbon in the form of fallen trees and dead animals along with some animal droppings and I do see some what appears to be animal droppings and I look and see what appears to be fungal threads consuming the animal waste. After that I decide to walk home but a question you may have as I do is: Was it all of the life in the forest that I saw? Although I’ve seen oak trees, the remains of dead trees, insects, spiders and their webs, tracks of animals, burrows of small animals, an occasional deer, and the sound of insects and birds and this is such a good question to ask. The truth is every time I go into the forest, I see various species of insects and there are familiar kinds as well as different kinds so in a sense I can never step in the same forest twice so in this sense no and for good reason. Recall that I carried a plastic container which I used to gather up soil, leaves, and some fresh water in a ravine. You probably know that microbes are present in any ecosystems and this one is no exception. As I head to my house I carry the plastic cup and place it near a laboratory where I set up and it is where I do my amateur biology experiments where my interests is in microbiology and indeed this forest ecosystem is where I study live microbes from bacteria to amoebas. I place the plastic cup outside where I attempt to simulate what is called an open systems or a system of study where it is open to matter and energy and that would include carbon dioxide, oxygen, sunlight, as well as airborne bacteria and spores which enter the cup which is what in a way mimics what happens in the forest but in a smaller scale and such a small scale system is what is called a microcosm or a miniature version of an ecosystem that is used for scientific study. I have done this because I am curious to see what kind of microbes are present in the forest. In my laboratory where I do my own scientific experiments I first use a microscope which a digital microscope with a built in camera where I can view any living thing and if I want to, I can take pictures and make videos and so I decide to take photos of any living organisms that are present in the water and indeed at a higher magnification, I do see microbes present mainly bacteria and with some difficulty I was able to take photos. They are round and small but I also notice other kinds of bacteria and they are thin and long compared to the common small bacteria. They may be small but they move as if they have a purpose much like larger organism; they move and sense their surrounding and I can easily see these kinds of long and thin bacteria moving and they move so quickly that I have to move the stage holding the slides in order to keep up with their movements. I attempt to grow some bacteria using nutrient agar, a special kind of jelly that allows the growth of bacteria and fungi in the form of mold and using a sterile cotton tip swab I dunk it in the water of the plastic cup, swirl it around and I streak the surface of the agar in a small round dish, the Petri dish, which holds agar and allows viewing of bacteria in the form of slimy round growths called colonies and they form when a bacterium that is on fresh agar, takes up the nutrients and agar has sugars, amino acids, vitamins, and water all of which are required for bacterial growth and a single bacteria when it has access to these nutrients and water will multiply quickly and within 24 to 48 hours growth is visible on the agar surface. In the second day, I see that there is bacterial growth and there are small streaks of white slimy patches along with plenty of dots.
I will then attempt to look at the bacteria and see what it looks like using the techniques of microbiology the first being growing bacteria in solid agar but isolating bacteria from each colony and using a hand held inoculating loop or a thin metal rod with a thin metal loop which can transfer bits of bacteria from a colony I smear it on a glass slide and over a hot flame I dry the smear , basically killing once live bacteria on the slide and after that I put a drop of stain called methylene blue and every cell absorbs the stain. I place the stain under the microscope , which is a binocular microscope and under higher magnification, the relief of each bacterial cell is evident and many are in clusters. Bacteria normally form clusters with one another, a consequence of multiplying on the food source which is agar. I also notice that there are cells caught in the act of dividing and most of them can be seen. I make two slides from each colony and in both slides the bacteria appear as tiny rods and spheres. Most are in clusters reflected in the fact that different bacteria have different ways of aggegrating with one another. After all this, my journey into the forest in my backyard is done but far from complete. What I know is that the forest is a small part of the biosphere or the sphere of life and from my studies of the forest out in the field as well as in the laboratory that the forest as a natural part of the biosphere is a living dynamic entity. Every aspect of the biosphere is always about making a living and they are many ways of going about doing that. For one thing there is growth of each organism. They start out small but depending on the species they grow big like all these seedlings and grasses that is present. To live means to do something such as gathering food whether it is plants that use carbon dioxide, water, and sunlight or animals like the big red ant eating a moth or a running dear in search of leaves to munch on , and the fungi decomposing wood. Every organism that gets its matter and energy for growth and reproduction comes in two forms, autotrophs or organisms that have the ability to synthesize their own food and this include the plants such as the oak trees and algae that make sugars, starches, and cellulose, through photosynthesis where these molecules are made from combining water and carbon dioxide and under sunlight these molecules called carbohydrates are made while oxygen gas is released as a waste product. The other organisms, heterotrophs, are those organisms that must consume organic molecules in order to live or in other words they must eat to stay alive. I see evidence of heterotrophic organism small to large and at the leaves which are part of trees that carry out photosynthesis I notice that each leaf has holes and what this tells me is that there are plenty of small organisms mainly insects that eat leaves and so far I have never seen any leave that was free from damage as caused by the hunger of each insect. Each living has a niche in each part of the forest and I see the niches or parts of the habitat where each organism makes its own unique living in the form of the soil where some insects like ants can form colonies, some large animals can burrow underground, some can form nests in the trees, while other kinds of organisms can make their living as autotrophics like all the plants that are common in the forest while some can live off on dead things like fallen trees. So many different ways of being alivewhether as autotroph or heterotroph. I have mentioned that there is no such thing as waste and indeed there isn’t and whatever dies in the forest the forest and the soil as well as the air recycles the elements so the new generation of life forms can use them and the forest recycles ; nothing ever goes to waste and how could it if recycling is nature’s way of using the same chemical elements? The forest consists of ecological layers called trophic levels and a trophic level is defined by the kinds of organisms that are either autotrophic and heterotrophic. Simply, a trophic level is defined by whom eats whom and that nutrients are passed from one level to the next, in what is called the food chain. I could tell which organisms define each trophic layer; the trees, grasses, flowers, and algae form the base of the food chains as autotrophic organisms or specifically photoautotrophic organism or those kind of autotrophs that carry out photosynthesis and above each trophic layer there are the heterotrophs and these organisms includes the insects, spiders, frogs, snakes, lizards, small birds, and owls. In ecology these lists of animals from small to large define the second, third, and fourth, the plants define the first trophic level. Beginning with the animals that are herbivores such as insects they eat the plants in order to stay alive and use the nutrients from the plants for survival and reproduction while breathing oxygen released from each living plant and giving carbon dioxide and heat into the forest habitat. Other animals from lizards up to birds eat the insects as an example, the red ant consuming that moth where one organism of one trophic level upward is feeding on a moth that previously consumed part of plants such pollen and nectar, and some birds eat some of the reptiles also to survive well up to the top of the food chain which as I far as I can tell are the owls and hawks that eat the small animals. Energy in the form of nutrients end up at the highest level of the food chain and it is this flow of energy that allows communities of organisms to live and the vitality of the forest is powered by the flow of sunlight. Nutrients in the form of carbon and nitrogen recycle and for these vital nutrients to do so, sooner or later each organism from the bottom to the top will have to die and once dead, fungi and bacteria reclaim the elements that were once part of live organisms and this is evident in the fungi invading the wood of fallen trees and absorbing nutrients as an example. Generation after generation of recycling allows life to continue and so it has for this old forest near my backyard. The nutrients in the form of minerals are absorbed by every plant through the roots from the soil, the soil being derived from the bedrock underground through the action of water, frost, wind, and the action of small animals and tree roots. Water from the sky in the form of rain and snow moistens the soil and whatever organic compound is on the soil gets slowly leached into the soil and every hungry microbe snaps up the morsels delivered by the percolating water in the soil. Fungi forms symbiotic relationships with every plant by delivering water to the roots while the fungi gets some sugars from the plants that they help. A seedling grows from the ground and may eventually become a towering tree producing seeds where each seed will grow into a new generation of trees just like its parent more or less. A big tree provide shelter for small animals such as birds that form nests. The bark of trees like each oak will harbor lichen, two organisms , an algae and fungus that cooperates one another for mutual benefit. The leaves provide sustenance for the tree while also providing sustenance for hungry insects. The insects of course go about their business of flying, making noise, moving under leaf litter, and looking for food and mates. Sooner or later a small insect will end up being a snack for a lizard or small bird. A lizard or small bird will also end up being a snack for a larger hungry predator such as a raccoon or owl. Insects and large animals will sooner or later die and once was once active flesh and blood becomes part of the soil. Atoms that were a part of live animals are channeled in each cell of bacteria and also through the network of fungi so life goes on as it recycles elements. Oxygen is released as a waste gas from photosynthesis but becomes part of the process of respiration of small and large animals where a molecule of oxygen combines with glucose, a building block of sugar as well as an amino acid, a building block of proteins, and through a complex elaborate step by step process, energy is released and utilized in each cell of an animal and that energy is what allows an animal to move towards a mate, to seek out shelter , and of course to seek out sources of energy, in order to spend more energy all up until death. Other gases are released such as carbon dioxide which is a waste gas from respiration and will be a part of the atmosphere together with the increase of carbon dioxide mainly from human sources, as a result of large scale burning of fossil fuels in order to support a growing human population but a carbon dioxide molecule whether from an animal’s breath or from a fire will sooner or later get absorbed into a plant whether it is algae or an oak tree leaf and through the complex process of photosynthesis oxygen is released and becomes part of the atmosphere. Forests big and small replenish the oxygen absorbed by animals while animals respire the carbon dioxide from respiration and it has been like this for millions and millions of years or more. Respiration and photosynthesis are mirror images of each other and it through these biochemical processes that carbon and oxygen are cycling in between trophic layers of a ecosytem such as my forest. Water flows from sky as rain and during the winter months snow and sleet. Most of it falls on the grounds while in some parts of the forest it is accumulated as water in the form of puddles to filled up ravines and when the ravines are full every microorganisms becomes fruitful and multiply in order to take advantage of being in an aqueous or water based environment. There are algae and photosynthetic bacteria that release oxygen while there are aerobic or organisms that use oxygen for energy as well as organic compounds. I have seen paramecia, chilomonas or oval shaped organisms with two flagella, diatoms or algae that encase themselves in beautiful shells of silica, and funnel shaped organisms called vorticellas which are like little vacuum cleaners and they create whirlpools that suck in organic particles. Every time I observe water from the forest in a way I’m observing a microscopic version of the forest ecosystem where the forests consists of communities of photoautotrophic and communities of heterotrophic organisms, I see communities of photosynthesizing and respiratory organisms on a much smaller scale. Water eventually returns to the atmosphere and falls back again as rain or snow. Water flows into the ground or forms bodies of standing water where microbes, insects, small fish, and large animals like beavers swim and make the most of the water that is there. Water gets incorporated into leaf tissues. The hydrosphere is a part of the biosphere as well as the lithosphere in the form of minerals and the atmosphere in the form of carbon dioxide and oxygen. There is never any single aspect of life that is not affected by the each of these three major parts of the earth. With these combinations the biosphere is one of the most active and purpose seeking of the planet and in my journey into the forest of my backyard. By purpose seeking I mean that every living thing does something to stay alive and I see this in the form of oak trees spreading out their canopies, insects eating other insects, and fungi absorbing nutrients from wood. These are just three of the examples which define the biosphere in the form of the forest in my backyard. References: Darwin, C (1859) On the Origin of Species By Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life. London, England: Murray London Lindeman, R.L (1942) The Trophic Dynamic Aspects of Ecology. Ecological Society of America Vol 23, 399-417 Morowitz, H.J, Morowitz L.S (1974). Life on the Planet Earth New York, NY: Norton & Company Sagan,D, Margulis,L (1995) What is Life?: Los Angeles, CA, The University of Californa Press