The biosphere is the layer of the atmosphere supporting life. It sustains life and extends from a few miles in space to the depths of the ocean. The biosphere is a global ecosystem that consists of life referred to as biota and non-living things referred to as abiotic elements. The biosphere is the living space, compromising the outer layer of the geosphere.
A biosphere is a system characterized by continuous rotation and the corresponding flow of solar energy in which certain large molecules and cells form. Water is a major threat to life, for all living things depend on it. The important elements like carbon, nitrogen, hydrogen, phosphorus, oxygen, and sulfur are combined to form essential macromolecules proteins, carbohydrates, fats, and nucleic acids. These macromolecules provide nutrients, fuel, and are important functional moieties for life. Energy flow is required to maintain the biological structure through the formation and separation of phosphate bonds.
Origin of the biosphere:
The biosphere originated about 3.5 billion years ago. Prokaryotes are the early species that originated in the biosphere which survived without oxygen and were single-celled organisms. Ancient prokaryotes consisted of single-celled organisms, such as bacteria and archaea.
During evolution, certain prokaryotes established a unique chemical process. They utilized sunlight for the production of carbohydrates and oxygen during photosynthesis. These photosynthetic creatures were so numerous that they changed the biosphere. Over time, the atmosphere produced a mixture of oxygen and other gases that could support new species.
The addition of oxygen to the biosphere was a turning point. It leads to the evolution of more complex organisms. Millions of plants and other forms of photosynthetic plants have emerged. Germs and other living things appeared to decompose, or destroy dead animals and plants.
Life in the Biosphere is sustained through the food web. Decomposers release the nutrients from dead organic matter into the soil and sea. These nutrients are then absorbed by the developing plants. This exchange of food and energy makes the biosphere a self-sustaining and self-governing system.
There are two main components of the biosphere. Biotic and abiotic components.
The biotic components include:
Atmosphere: It is the layer containing gases essential for life and water droplets. The main role of the atmosphere is the protection from harmful UV rays.
Lithosphere: The lithosphere consists of the earthly and solid part of the biosphere which includes the non-living part. Islands and solid earthy material have inclusion in the lithosphere.
Hydrosphere: It consists of the water part of the biosphere. All the water bodies form the hydrosphere. The hydrosphere is essential for the maintenance of temperature.
The biotic components include:
Plants: Plants are the first producers of the biosphere which produces nutrients through photosynthesis. They are familiar as autotrophs of the biosphere. However, they are the only major source of life for all living things, including animals and humans.
Animals: Animals are heterotrophic consumers who feed on autotrophs for their food needs. They also feed in small animals for food consumption. The food they eat provides energy and store it for future use.
Microorganisms: Microorganisms are an essential component of the biosphere. The micro-organisms include mold, algae, bacteria, viruses, etc.
The importance of the biosphere
The continued functioning of the biosphere is dependent not only on the maintenance of the intimate interactions among the myriad species within local communities but also on the looser yet crucial interactions of all species and communities around the globe. Earth is cover with so many species and so many different kinds of biological communities because populations have been able to adapt to almost any kind of environment on Earth through natural selection. Life-forms have evolved that are able to survive in the ocean depths, the frigid conditions of Antarctica, and the near-boiling temperatures of geysers. The great richness of adaptations found among different populations and species of living organisms is Earth’s greatest resource. It is a richness that has evolved over millions of years and is irreplaceable.
Resources of the biosphere
The flow of energy
The photosynthetic process
Life on Earth depends on the harnessing of solar energy by the process of photosynthesis. Photosynthetic plants convert solar energy into the chemical energy of living tissue, and that stored chemical energy flows into herbivores, predators, parasites, decomposers, and all other forms of life (see also photosynthesis). In the photosynthetic process, light energy is absorbes by the chlorophyll molecules of plants to convert carbon dioxide and water into carbohydrates and oxygen gas. Proteins, fats, nucleic acids, and other compounds also are synthesize during the process, as long as elements such as nitrogen, sulfur, and phosphorus are available.
The efficiency of solar energy utilization
Most solar energy occurs at wavelengths unsuitable for photosynthesis. Between 98 and 99 percent of solar energy reaching Earth is throws back from leaves and other surfaces and absorbed by other molecules, which convert it to heat. Thus, only 1 to 2 percent is available to be capture by plants. The rate at which plants photosynthesize depends on the amount of light reaching the leaves, the temperature of the environment, and the availability of water and other nutrients such as nitrogen and phosphorus.
The measurement of the rate at which organisms convert light energy (or inorganic chemical energy) to the chemical energy of organic compounds is crying out primary productivity. Hence, the total amount of energy assimilated by plants in an ecosystem during photosynthesis (gross primary productivity) varies among environments. (Productivity is frequently measures by an increase in biomass, a term used to refer to the weight of all living organisms in an area. Biomass reports in grams or metric tons.)
Much of the energy assimilated by plants through photosynthesis is not spent as organic material but instead is used during cellular respiration. In this process organic compounds such as carbohydrates, proteins, and fats are broken down or oxidized, to provide energy (in the form of adenosine triphosphate [ATP]) for the cell’s metabolic needs. The energy not used in this process deposits in plant tissues for further use and is called net primary productivity. About 40 to 85 percent of gross primary productivity is ignorant during respiration and becomes net primary productivity. The highest net primary productivity in terrestrial environments occurs in swamps and marshes and tropical rainforests; the lowest occurs in deserts. In aquatic environments, the highest net productivity occurs in estuaries, algal beds, and reefs. Consequently, these environments are especially critical for the maintenance of worldwide biological productivity.
Most organisms are narrow to either a terrestrial or an aquatic environment. An organism’s ability to tolerate local conditions within its environment further restricts its distribution. One parameter, such as temperature tolerance, may be important in determining the limits of distribution, but often a combination of variables, such as temperature tolerance and water requirements, is important. Extreme environmental variables can evoke physiological and behavioral responses from organisms. The physiological response helps the organism maintain a constant internal environment (homeostasis), while a behavioral response allows it to avoid the environmental challenge—a fallback strategy if homeostasis cannot preserves.
The ways in which modern living organisms tolerate environmental conditions reflect the aquatic origins of life. With few exceptions, life cannot exist outside the temperature range at which water is a liquid. Thus, liquid water, and temperatures that maintain water as a liquid, are essential for sustaining life. Within those parameters, the concentrations of dissolved salts and other ions, the abundance of respiratory gases, atmospheric or hydrostatic pressure, and rate of water flow all influence the physiology, behavior, and distribution of organisms.
The temperature has the single most important influence on the distribution of organisms because it determines the physical state of water. Most organisms cannot live in conditions in which the temperature remains below 0 °C or above 45 °C for any length of time. Adaptations have enabled certain species to survive outside this range—thermophilic bacteria have been found in hot springs in which the temperatures may approach the boiling point, and certain polar mosses and lichens can tolerate temperatures of −70 °C—but these species are the exceptions. Few organisms can remain for long periods at temperatures above 45 °C, because organic molecules such as proteins will begin to denature. Nor are temperatures below freezing conducive to life: cells will rupture if the water they contain freezes.
Most organisms are not able to maintain a body temperature that is significantly different from that of the environment. Sessile organisms, such as plants and fungi, and very small organisms and animals that cannot move great distances, therefore, must be able to withstand the full range of temperatures sustained by their habitat. In contrast, many mobile animals employ behavioral mechanisms to avoid extreme conditions in the short term. Such behaviors vary from simply moving short distances out of the Sun or an icy wind to large-scale migrations.
What are Biosphere Reserves?
Biosphere reserves are ‘learning places for sustainable development. They are sites for testing interdisciplinary approaches to understanding and managing changes and interactions between social and ecological systems, including conflict prevention and management of biodiversity. They are places that provide local solutions to global challenges. Biosphere reserves include terrestrial, marine, and coastal ecosystems. Each site promotes solutions reconciling the conservation of biodiversity with its sustainable use.
Biosphere reserves nominate by national governments and remain under the sovereign jurisdiction of the states where they are located. Biosphere Reserves are designate under the intergovernmental MAB Programme by the Director-General of UNESCO following the decisions of the MAB International Coordinating Council (MAB ICC). Their status is internationally recognizes. Member States can submit sites through the designation process.
In order to assist the stakeholders with the designation process, as well as periodic reviews, Technical Guidelines are being progressively created by the MAB International Co-ordinating Council.
Organizational Structure of Biosphere
The biosphere is mainly describes by the reference of the whole life and living organisms around the Earth. It consists of five levels of organizational structure:
The large biosphere is divide into large parts of biomes. Scientists classified biomes into five different types: tundra, grassland, forests, deserts, and aquatic biomes. Rivers, lakes, seas, oceans, and other aqueous habitats are inhabite by a large diversity of plants and animals. Conversely, desserts are the driest areas of the Earth with the lowest measurement of rain per year. Grasslands cover the green areas of the Earth. However, it experiences moderate rainfall but not enough to grow large trees. Forests are areas dominant by large trees. Tundras are the vast treeless Arctic region wherein the subsoil is permanently frozen.
structure of ecosystem diagram
Figure 1: the components of an ecosystem. Credit: Maria Victoria Gonzaga of BiologyOnline.com.
The ecosystem is built up of a biological community and the physical environment. And so it includes both the biotic and abiotic factors. The living things and their physical environment function together as a unit. Four types of ecosystems are terrestrial, freshwater, marine, and artificial. The terrestrial ecosystem is the ecosystem occurring on land and is exemplified by the grassland ecosystem and the forest ecosystem. The freshwater ecosystem is an aquatic ecosystem and is exemplified by lentic and lotic ecosystems. The marine ecosystem is a saltwater ecosystem and is therefore found in seas and oceans. The artificial ecosystem is a man-made system, such as a terrarium.
(3) The community of Species
As the biosphere shows wide diversity, different species build up the community. These species survive in areas where abiotic factors like temperature, ph, and nutrients are tolerable or optimum. A biological community, though, define as the assemblage of interacting organisms (either of the same or different species) coexisting in a particular area and time.
All the members of the particular species living in the single habitat consider as the population. The population size can vary from a few to thousands of members. Overpopulation is a condition wherein the population of a species exceeds the carrying capacity of an ecological niche. A population decline, on the contrary, is one in which the size declines. The reduction of population size for a short period of time is reffer to as a population bottleneck.
An excess of population size may lead to a struggle for survival. Species will compete against everybody for limited resources. Thus, various symbiotic relationships have been establishing. Those that tend to give and take in a relationship says to be in a mutualism whereas those that tend to cause or bring harm to other organisms may be in a parasitic or predatory kind of symbiosis. This is also where natural selection comes into place. Species that have useful or beneficial variations are “favor” and so are able to thrive and reproduce over those that have less favorable traits.
The organisms are the living entities of the biosphere. One of the features that made them distinct from non-living material is possessing a cellular organization and system that enable various life processes. Inside the cell is a genetic material that carries the code for all biological activities and for reproduction. . They can be eukaryotes and prokaryotes. For instance, humans, plants, and animals are eukaryotes, and bacteria are prokaryotes. They can be identified by the presence of an endomembrane system and internal compartmentalization leading to the formation of different organelles. Eukaryotes possess such features whereas prokaryotes don’t.