Organisms and their Environment
Organisms and their Environment – All organisms live in a varying physical environment of temperature, moisture, light and nutrients. These factors differ from location to location like in latitude, region and locality. In addition, at any location, the physical environment varies with time to time, yearly seasonally and daily. One important example of environmental variation is the flux of solar radiation reaching Earth’s surface. It defines the general physical environment in which organisms live. Solar radiation directly influences air temperature, atmospheric moistures and light.
Interaction with the Environment
All living organisms are constantly interacting with their environment. Plants absorb carbon dioxide from the air through their leaves and water and mineral nutrients from the soil through their root system. They return water and oxygen to the atmosphere. Animals consume plants and other animals. They digest food, absorb nutrients, and discharge waste products. Organisms and their Environment
Adaptation to the Environment
An organism needs to find essential resources and supporting conditions for adjustment in a set of environmental conditions. If the organism can survive, grow, a reproduce under a given set of environmental conditions, it is said to be adapted to that environment. If the environment does not offer resources and conditions essential for its survival, the organism dies.
In an ever-changing physical environment, an organism must maintain a fairly constant internal environment. An Increase or decrease of only a few degrees from this value could prove fatal. The maintenance of conditions within the range that the organism can tolerate is called homeostasis.
The internal environment can be kept constant by feedback mechanism. It provides environmental information to which a system responds.
Environmental tolerance of the Organism
The minimum and maximum values of environment beyond which the organism cannot survive are referred to as environmental tolerance of the organism. The value at which response of the organism is highest is called optimum. Organisms and their Environment
It has been observed that there are limits to the range of environmental conditions over which homeostasis works. If the environmental temperature become the homeostasis system breaks down. When it becomes too warm, the body cannot lose heat fats enough to maintain the normal temperature. Similarly, if the environmental temperature drops too low, metabolic process slows down, further decreasing the body temperature, until death by freezing.
Leibeg’s Law of Minimum
Because organisms respond to a variety of environmental factors, any one factor has the potential to limit survival, growth and reproduction. In 1840, a German organic chemist named Jusus von Leibeg put forth a concept the Leibeg’s law of the minimum. It states that the performance (survival, growth and reproduction) of an organism will be a function of the most limiting environmental factor. In his study of relation between soil and plants, Leibeg noted that plants require certain kinds and quantities of nutrients. If one of those nutrients is absent the plant dies. If it is present in minimal quantities only, the growth of the plant will be minimal. Organisms and their Environment
Law of Tolerance
Since the organisms are limited by a number of conditions and often by interaction among them and the organisms live within ranges from too much to too little, the limits of tolerance. This concept, the maximum and minimum conditions limit the presence and success of an organism is called the law of tolerance. Organisms and their Environment
Environmental Variations Affect Distribution of Organisms
Distribution and abundance of organisms relates to variations over the earth. Distribution means presence or absence. The abundance refers to numbers or population size. High degree of tolerance allows a widespread geographic distribution. The minimum and maximum temperature tolerances define the limits of species distribution. The abundance of a species would increase towards optimal environmental conditions. Organisms and their Environment
Habitat: An organism can inhabit a location when all the environmental factors to which it responds are within the range of tolerance. The actual location or place where an organism lives is called its habitat.
Niche: niche includes all the physical and biological variables that affect an organism’s well-being.
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