Ecosystems
An ecosystem is a natural unit consisting 1___ all plants, animals and micro-organisms (biotic factors) in an area functioning together 2___ all of the non-living physical (abiotic) factors of the environment.
Central to the ecosystem concept is the idea that living organisms are continually engaged 3___ a highly interrelated set 4___ relationships with every other element constituting the environment in which they exist. Eugene Odum, one of the founders of the science of ecology, stated: "Any unit that includes all of the organisms (ie: the "community") in a given area interacting with the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity, and material cycles (ie: exchange of materials between living and nonliving parts) within the system is an ecosystem."The human ecosystem concept is then grounded in the deconstruction of the human/nature dichotomy, and the emergent premise that all species are ecologically integrated 5____ each other, as well as with the abiotic constituents of their biotope.
A greater degree of species or biological diversity - popularly referred 6___ as Biodiversity - of an ecosystem may contribute to greater resilience of an ecosystem, because there are more species present at a location to respond to change and thus "absorb" or reduce its effects. This reduces the effect before the ecosystem's structure is fundamentally changed to a different state. This is not universally the case and there is no proven relationship 7_____ the species diversity of an ecosystem and its ability to provide goods and services on a sustainable level: Humid tropical forests produce very few goods and direct services and are extremely vulnerable to change, while many temperate forests readily grow back to their previous state of development within a lifetime after felling or a forest fire. Some grasslands have been sustainably exploited 8___ thousands 9___ years (Mongolia, Africa, European peat and mooreland communities).
The term ecosystem can also pertain to human-made environments, such as human ecosystems and human-influenced ecosystems, and can describe any situation where there is relationship between living organisms and their environment. Fewer areas on the surface of the earth today exist free 10___ human contact, although some genuine wilderness areas continue to exist without any forms 11___ human intervention.
(Retrieved from: https://en.wikipedia.org/wiki/Natural_environment)
Task 9. Choose one of the topics to make a report and present it in front of the class.
1. The notion of ecosystem.
2. Examples of ecosystems in your country.
3. The main problems of modern ecosystems.
III. BIOSPHERE
PRE-READING
Before reading the passage,answer the following questions and discuss them with your partner. Then read the passage and find the facts supporting your ideas.
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1. What do you know about the term biosphere?
2. What is the role of the Russian scientists in establishment of the term biosphere ?
3. Which sciences study biosphere?
4. What systems invented by men help to study the world around us?
5. Can life exist on the other planets of the solar system? Why?
TEXT
Task 1. Read, translate the text and do the exercises.
Biosphere
The biosphere is the biological component of earth systems, which also include the lithosphere, hydrosphere, atmosphere and other "spheres" (e.g. cryosphere, anthrosphere, etc.). The biosphere includes all living organisms on earth, together with the dead organic matter produced by them.
The biosphere concept is common to many scientific disciplines including astronomy, geophysics, geology, hydrology, biogeography and evolution, and is a core concept in ecology, earth science and physical geography. A key component of earth systems, the biosphere interacts with and exchanges matter and energy with the other spheres, helping to drive the global biogeochemical cycling of carbon, nitrogen, phosphorus, sulfur and other elements. From an ecological point of view, the biosphere is the "global ecosystem", comprising the totality of biodiversity on earth and performing all manner of biological functions, including photosynthesis, respiration, decomposition, nitrogen fixation and denitrification.
The biosphere is dynamic, undergoing strong seasonal cycles in primary productivity and the many biological processes driven by the energy captured by photosynthesis. Seasonal cycles in solar irradiation of the hemispheres is the main driver of this dynamic, especially by its strong effect on terrestrial primary productivity in the temperate and boreal biomes, which essentially cease productivity in the winter time. The biosphere has evolved since the first single-celled organisms originated 3.5 billion years ago under atmospheric conditions resembling those of our neighboring planets Mars and Venus, which have atmospheres composed primarily of carbon dioxide. Billions of years of primary production by plants released oxygen from this carbon dioxide and deposited the carbon in sediments, eventually producing the oxygen-rich atmosphere we know today. Free oxygen, both for breathing (O2, respiration) and in the stratospheric ozone (O3) that protects us from harmful UV radiation, has made possible life as we know it while transforming the chemistry of earth systems forever.
As a result of long-term interactions between the biosphere and the other earth systems, there is almost no part of the earth's surface that has not been profoundly altered by living organisms. The earth is a living planet, even in terms of its physics and chemistry. A concept related to, but different from, that of the biosphere, is the Gaia hypotheses, which posits that living organisms have and continue to transform earth systems for their own benefit.
The term "biosphere" originated with the geologist Eduard Suess in 1875, who defined it as "the place on earth's surface where life dwells". Vladimir I. Vernadsky first defined the biosphere in a form resembling its current ecological usage in his long-overlooked book of the same title, originally published in 1926. It is Vernadsky's work that redefined ecology as the science of the biosphere and placed the biosphere concept in its current central position in earth systems science.
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The biosphere is a core concept within Biology and Ecology, where it serves as the highest level of biological organization, which begins with parts of cells and proceed to populations, species,ecoregions, biomes and finally, the biosphere. Global patterns of biodiversity within the biosphere are described using biomes.
In earth science, the biosphere represents the role of living organisms and their remains in controlling and interacting with the other spheres in the global biogeochemical cycles and energy budgets. The biosphere plays a central role in the biogeochemical processing of carbon, nitrogen, phosphorus, sulfur and other elements. As a result, biogeochemical processes such as photosynthesis and nitrogen fixation are critical to understanding the chemistry and physics of earth systems as a whole. The physical properties of the biosphere in terms of its surface reflectance (albedo) and exchange of heat and moisture with the atmosphere are also critical for understanding global circulation of heat and moisture and therefore climate. Alterations in both the physics (albedo, heat exchange) and chemistry (carbon dioxide, methane, etc.) of earth systems by the biosphere are fundamental in understanding anthropogenic global warming.
Researchers make direct observations on the biosphere using global remote sensing platforms. Beginning in the 1980s (AVHRR), this effort has evolved into advanced remote sensing systems that can scan the entire surface of the earth at least once each day (MODIS). These observations are now used to quantify the activities of the biosphere, primarily in terms of vegetation cover and function, using spectral indices such as NDVI. Future remote sensing efforts will directly observe global patterns of carbon dioxide exchange with the biosphere caused by photosynthesis, respiration and the combustion of biomass and fossil fuels (OCO).
(Retrieved from: http://www.eoearth.org/view/article/150667/)
Glossary
AVHRR (Advanced Very High Resolution Radiometer) - - ,
MODIS (Moderate Resolution Imaging Spectroradiometer) -
NCVI (Normalised Difference Vegetation Index) - -
OCO (operational capabilities objective) -
Word study
Task 1. This is just a partial listing of some of the many, many different possible fields of study within science. Many of the fields listed here overlap to some degree with one or more other areas. Consult the dictionary and read the names of the sciences correctly.
Biology
| Anatomy | Immunology |
| Astrobiology | Marine biology |
| Biochemistry | Microbiology |
| Bioinformatics | Molecular Biology |
| Biophysics | Morphology |
| Botany | Neuroscience |
| Cell biology | Physical anthropology |
| Developmental biology | Physiology |
| Ecology | Population dynamics |
| Entomology | Structural biology |
| Epidemiology | Taxonomy |
| Evolution (Evolutionary biology) | Toxicology |
| Freshwater Biology | Virology |
| Genetics | Zoology |
Chemistry
| Analytical chemistry | Polymer chemistry |
| Biochemistry | Physical chemistry |
| Computational chemistry | Quantum chemistry |
| Electrochemistry | Spectroscopy |
| Inorganic chemistry | Stereochemistry |
| Materials science | Thermochemistry |
| Organic chemistry |
Physics
| Acoustics | High Energy Physics |
| Astrodynamics | Materials physics |
| Astronomy | Mechanics |
| Astrophysics | Nuclear physics |
| Biophysics | Optics |
| Classical mechanics | Particle physics |
| Computational physics | Plasma physics |
| Condensed matter physics | Polymer physics |
| Cryogenics | Quantum mechanics |
| Dynamics | Solid State physics |
| Fluid dynamics | Thermodynamics |
Earth Science
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| Environmental Science | Meteorology |
| Geodesy | Oceanography |
| Geography | Paleontology |
