PURPOSE OF THIS POST
The purpose of this post is to introduce readers to the process of evolution, biodiversity, and population economy. Moreover, the question whether biodiversity is important or not will be made, and analyzed in details. My final goal is to make readers more interested and sceptical about diversity, and maybe; if I am lucky, persuade those who did not think that diversity is important that actually it is vital.
Picture 1. © David Hall/SeaPhotos.com (1)
All organisms on Earth are descended from a common ancestral gene pool. Today, some of them share similarities, some not, and none of the organisms on Earth are exaclty the same. Evidence shows that we have passed from prokaryotes, (3-4 billion years ago), to the extraordinary biodiversity of life we experience today. The way to identify Earth’s different organisms is by grouping them into species and then into populations. More specifically, species is a population whose members share similarities in terms of characteristics, can freely breed with one another, and produce fertile offsprings. Population, on the other hand, is a group of idividual of the same species that live the same area. Both smaller and bigger organisms appeared to be highly successful and dominant on Earth throughout time, yet others were unable to change in time in order to adjust to environmental changes, and were extinct.
“According to the concept of transformational evolution, first clearly articulated by Lamarck, evolution consists of the gradual transformation of organisms from one condition of existence to another”.
Ernst Mayr (2)
As Mayr quotes, Lamarck was the first one to clearly worded the concept of evolution; which in the broad sense means that an individual of a species changes over time in order to adapt to its environment, and these changes are passed onto next generations as genes. These genetic changes in genes lead to alternations in appearence, behavior, or functioning. As mentioned in Withgott’s and Brennan’s textbook “Environment, The Science Behind The Stories”, biological evolution is the result of two causes. Firstly, biological evolution could result from “random genetic changes, and it may proceed randomly” or it “may be dir
Picture 2. Lamarck’s Giraffe (4)
Natural selection is the process by which traits that enhance survival and reproduction are passed on more frequently to future generations, altering the genetic makeup of populations through time (5).
In 1858, Charles Darwin and Alfred Russel Wallace introduced the notion of natural selection trying to comprehend the variety of living organisms.
By just observing nature, one can see that the ultimate goal of each organism is to survire and reproduce, or perpetuate the species, he can note out that organisms produce more offsprings than can possibly survive, and individuals of the same species share some similar characteristics, but also vary in some. Some characteristics that give individuals advantage in surviving might be inherited by their offsprings. These characteristics become more predominant in future generations. In this case, if a trait promotes success, it is called an adaptive trait, or an adaptation.
Biological diversity, or biodiversity, is the sum total of all organisms in an area, taking into account the diversity of species, their genes, their populations, and their communities (5). From the above, it can be said that evolution generates biological diversity. Even though scientist claim there are about 1.8 million species, we cannot really say there are not other organisms waiting to be discovered (Withgott and Brennan,55) (3).
Speciation produces new types of organisms.
As mentioned above, there are about 1.8 million species on Earth. The process by which new species are generated is called speciation. The most usual way of speciation in the allopatric speciation. Allopatric speciation is the species formation due to physical seperation of populations over some geographic distance. The other way of speciation is sympatric speciation. In order to understand the two concepts watch the following video!
Video 1. Speciation
We can infer the history of life’s diversification by comparing organisms
In order to understand how major groups of organisms diverged from one another over the course of evolutionary time, the scientists use treelike diagrams called cladograms or phylogenetic trees. More specifically, scientists find similarities among the genes or external characteristics of present organisms, and relate those species.
Video 2. Understanding Phylogenetic Trees
Speciation and extinction together determine Earth’s biodiversity
Speciation is one way to generate Earth’s biodiversity. We know from fossils (the remains, impression, or trace of an animal or plant of past geological ages has been preserved in rock or sediments), that there have been organisms that have disappeared. The phenomenon of disappearence of an organism from Earth is called extinction. The point is that some organisms are vital for our existance; for instance, food, medicine, fiber, and those organisms that are not as vulnerable as others.
Ecology is studies at several levels. In the first level of this hierarchy, life happens. Life goes from atoms, molecules, and cells to the biosphere; which is the sum of living things on Earth and the areas they inhabit. Ecology studies the organismal, population, community, and ecosystem. At the level of organisms, ecology studies organisms and their relationship with the environment surrounding them. Population ecology examines the changes in population, the factors that drive these changes; why some individuals leave a population, and why some populations increase when some other decline. Community ecology on the other hand investigates the relationships among species, from one-to-one interactions to more complex relationships involving entire communities (Withgott and Brennan,62) (3).
A group of individuals of the same species living in a specific area consist a population. It is a known fact for scientists that populations show characteristics that help predict their dynamics. The ability scientists have to predict growth or decline is of great importance, for this way they can foresee possible threats concerning endangered species. In order to study the population of species, scientists use several tools; such as population size, population density, population distribution, sex ratio, and age structure.
Population size is the number of organisms that exist at a given time. This number can increase, decrease, and remain the same over time. Population density is the number of individuals in a population per unit area. Population distribution is the spatial arranement of organisms withins a particular area. Sex ratio represents the proportion of males to females. And age structure describes the relative numbers of organisms of each age withing a population ((Withgott and Brennan,62) (3).
Video 4. Population Ecology
WHY IS BIODIVERSITY SO IMPORTANT?
From the above, we realize the ecological complexity of our environment, and the fact that every individual organism on Earth belong to a species, those species to a population, those populations to communities, those communities to ecosystems, and all the ecosystems to the biosphere. All organisms share similarities and differences. These differences make the biological diversity in the world. Yet there is a great rate of extinction in the world and extinction of species determines Earth’s biodiversity. The question is whether this should alarm us. Is biodiversity that important? And if so, why is biodiversity so important?
Firstly, we have to admit that all living organisms, including humans, need to satisfy their basic needs; breath, food, water, and shelter, in order to survive. The natural environment provides all the above so that organisms survive. (8) In case this natural environment alters and faces problems of extinction, then the balance of the environment would be upset.
In order to understand the importance of biodiversity we should first analyze the positives of a healthy biodiversity; which provides free natural services for everyone.
At first, it provides servives to ECOSYSTEMS. More specifically, it regulates global processes; such as the atmosphere and the climate. Oxygenated atmosphere, vital for our survival, is created by photosynthetic biodiversity (9). Climate stability is successed by forests and other vegetations by sun reflectance, water vapor release, wind, and humidity (9). In addition to that, biodiversity protects soils and water through conservation. Moreover, biodiversities help in the nutrient storage and recycling. For instance, various organisms are considered natural fertilizers of land. Hence, they attribute to the cycling of nutrients and the proitection of soils, and both small and bigger organisms in the biodiversity attribute to the control of agricultural pests. Pollution is a great problem in specific places; still, several organisms help in pollution breakdown and absorbtion (10). Pollination of plants and seed dispursal is also an important free service. It is implied that 30% of human crops depend on free pollination by animals. Lastly, Earth has experiences many unpredictable events; such as earthquakes. Still, living organisms helped the recovery of these unpredictable events (10).
Video 5. Biodiversity begins with a B
Except for the services biodiversity provides to the ecosystems, it also provides natural services of BIOLOGICAL importance (10). More specifically, biodiversity contributes in providing food. Trees provide food for micro-organisms, fungi, animals, insects, birds, and also human (crops). Also, species are hunted by humans for food. Other species are hunted by other species for food. Therefore, each individual organism finds food in its biodiversity (8). Moreover, biodiversity is crucial for medicinal resources and pharmaceutical drugs (10). Medical resources necessary for the production of pharmaceutical drugs are obtained from biodiversity, and this includes both traditional medicines and processed drugs (8). For instance, hibernating bears can improve the treatment of kidney decease (9), and penicillin is produced by mould (8). Moreover, raw materials; such as wood, paper products, fiber for clothing,industrial products; such as oils and rubber, pensils, and fuels are provided by the Earth’s diversity (8), (10). Certainly, biodiversity provides storage for future resources. A balance in the above biological resources helps the continuous struggle of individuals for reproduction and diversity in genes, species, and finally ecosystems.
Picture 5. How do Farmers Benefit from Biodiversity?
SPIRITUAL AND CULTURAL VALUES
Certainly, the spiritual and cultural importance of biodiversity are of great significance. More specifically, specific areas; such as national parks and animals, are very important for some individuals. Such individuals could be the entire humanity (all human should respect and protect virgin forests, national parks, rare animals), or it could be a specific culture. For instance, as mentioned in my previous post, the Aborigines in northern Australia claim the rich-in-uranium land to be sacred land. Therefore, it has a spiritual and cultural value. The same thing could apply to human cultures and societies as well. For example, people should try to maintain a diversity in cultures, societies, tribes, and generally differences (9).
Picture 6. Tiwi Islanders – For the Living (12)
For the aesthetic value is very important as well. The world would be dull if everything was the same. Biodiversity offers us such pleasure in the eye, and all we have to do is to respect and protect this beauty. Wheather this has to do with the environment, the animals, or the preservation of human differences.
Picture 7. A biodiversity program defined for the Gamba Complex (13)
The interaction of all the above makes a web of life. In case this web is destroyed even partially, there will be a major future threat. Humans are dominating this planet, yet we do not preserve the diversity. I believe that by not respecting diversity we do not respect ourselves. Unfortunately, I believe that there will be a major problem in the future. More and more species will be extinct, and eventually significant species in the food web will cause major problems. The goal for us is to start doing something about it, even if we think that this would be a small action and nothing will change. I believe that if each of us tried to preserve the diversity as much as he could, even a little bit, our mother Earth would be able to recover, for our planet has incredible power and we do not support that power at all.
Video 6. Biodiversity Final Video
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