Characteristics of Life and Living Organisms - Essay Example

An organism can be defined as an individual form of life, such as a plant, animal, bacterium, protist, or fungus; a body made up of organs, organelles, or other parts, that work together to carry on the various processes of life.1 Characteristics of Life and living organisms1 Organization is found in the basic living unit, the cell, and in the organized groupings of cells into organs and organisms. Metabolism includes the conversion of nonliving material into cellular components (synthesis) and the decomposition of organic matter (catalysis), producing energy. Growth in living matter is an increase in size of all parts. Adaptation, is the accommodation of a living organism to its present or to a new environment, is fundamental to the process of evolution and is determined by the individuals heredity. The division of one cell to form two new cells is reproduction; usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from two differing parent organisms.) Taxonomy1 may refer to either a hierarchical classification of things, or the principles underlying the classification. The root is the Organism (as this applies to all living things, it is implied rather than stated explicitly). Below this are the Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species, with various other ranks sometimes inserted. Structure of the Atom and molecules:1 The atom consists of a central, positively charged core, the nucleus, and negatively charged particles called electrons that are found in orbits around the nucleus. Molecules are made up of two or more atoms, either of the same element or of two or more different elements, joined by one or more covalent chemical bonds. Cell1 In biology, it is the unit of structure and function of which all plants and animals are composed. The cell is the smallest unit in the living organism that is capable of integrating the essential life processes. Cells can be separated into two major groups—prokaryotes, cells whose DNA is not segregated within a well-defined nucleus surrounded by a membranous nuclear envelope, and eukaryotes, those with a membrane-enveloped nucleus. Within cells there is an intricate network of organelles ( nucleus, nucleolus, cytoplasm, mitochondria, golgi apparatus etc.) that all have unique functions. These organelles allow the cell to function properly. Deoxyribonucleic acid (DNA) or deoxyribose nucleic acid1 is a nucleic acid that contains the genetic instructions specifying the biological development of all cellular forms of life (and many viruses). DNA is often referred to as the molecule of heredity, as it is responsible for the genetic propagation of most inherited traits. During reproduction, DNA is replicated and transmitted to the offspring. Heredity, is the transmission from generation to generation through the process of reproduction in plants and animals of factors which cause the offspring to resemble their parents. Role of energy in biology2 Roles of Organisms Organisms can be either producers or consumers in terms of energy flow through an ecosystem. Producers convert energy from the environment into carbon bonds, such as those found in the sugar glucose. Plants are the most obvious examples of producers; plants take energy from sunlight and use it to convert carbon dioxide into glucose (or other sugars). Algae and cyanobacteria are also photosynthetic producers, like plants. Other producers include bacteria living around deep-sea vents. These bacteria take energy from chemicals coming from the Earths interior and use it to make sugars. Other bacteria living deep underground can also produce sugars from such inorganic sources. Another word for producers is autotrophs. Consumers get their energy from the carbon bonds made by the producers. Another word for a consumer is a heterotroph. In the flow of energy and inorganic nutrients through the ecosystem, a few generalizations can be made: 1. The ultimate source of energy (for most ecosystems) is the sun 2. The ultimate fate of energy in ecosystems is for it to be lost as heat. 3. Energy and nutrients are passed from organism to organism through the food chain as one organism eats another. 4. Decomposers remove the last energy from the remains of organisms. 5. Only inorganic nutrients are cycled, energy is not. Consequences of excess energy consumption 3 1. Burning of fossil fuels for industrial, commercial and domestic energy use, as well as transportation, is the primary human source of greenhouse gases. This causes the greenhouse effect, wherein a layer of gases suspended in the atmosphere around the earth prevents the sun’s rays being reflected from the earth’s surface back in to space. This means that the warmth of these rays is trapped within the earth’s atmosphere, creating a layer of insulation that maintains warmth enough for plants, animals and people to exist. Greenhouse Gases (GHGs) enhance the heat retaining ability of this insulating layer, and hence the average temperature on earth increases. Extreme weather events like drought, torrential rain, hurricanes, floods, typhoons, monsoons and forest fires are due to changing weather patterns brought about by global warming. 2. Excessive biomass burning causes domestic air pollution, which affects the general health of the population. Water pollution affects marine organisms and indirectly, humans. Human activity needs to adapt to these conditions –which impact economic activity, food security, rural and urban settlements, and freshwater supply. This shift also affects biodiversity. Many species adapt to long term temperature changes very gradually, and as such will be unable to adapt to more rapid changes in climate conditions. There may be a number of unpredictable feedback effects to natural systems, such as the irreversible loss of key habitats and species. To create a sustainable energy culture, two action areas are advocated: 1. Increased energy efficiency: including efficient production and consumption and use of cleaner fossil fuel technology. 2. Diversification of the energy mix: The use of alternative fuels (emitting low or no CO2) is growing . Initially these will help reduce reliance on fossil fuels and eventually allow for cessation of all fossil fuel combustion. These include: Substitution: Use of natural gas is growing. This is relatively cleaner than coal or oil, and is seen as an interim alternative until new technologies are more readily available. Fuel Cell Technology: Hydrogen is thought to be the fuel of the future. Fuel cells use a reaction between hydrogen and oxygen to release electricity, with only waste produced being water. Leading technologies include the Proton Exchange Membrane Fuel Cell (PEMFC), the Solid Oxide fuel cell and the Alkaline Fuel cell. In the future, the fuel cell will primarily be used to replace the internal combustion engine but may also suitable for local electric power generation. Renewable Fuels Technology: Renewable sources include solar - thermal and photovoltaic, wind - on and off shore, tidal, wave, hydro, geothermal, aqua-thermal, biomass and waste-to-energy - agricultural waste, energy plantations, landfill gas, sewage sludge digestion, municipal solid waste combustion, and thermo-photovoltaic cells. Nuclear: The continued role of nuclear reactors for energy supply remains a source of contention. Some argue that if reactor safety could be assured, including the transport and disposal of radioactive waste and the non-proliferation of nuclear weapons technology assured, then nuclear is a viable alternative as it is a relatively clean energy producer. However, radioactive waste is a bi-product with a lifetime of thousands of years. Bibliography 1. Retrieved and modified from www.answers.com 2. Environmental Biology – Ecosystems. Retrieved and modified from http://www.marietta.edu/~biol/102/ecosystem.html 3. Climate Change and Energy: Can We Weather the Switch to Sustainable Energy. Extracted and modified from: Towards Earth Summit 2002 project of UNED Forum Read More