14.Ecosystems and Energy flow

1.      An ecosystem is a self-regulatory and self-sustaining structural and functional unit of nature (biosphere).

2.       Ecosystem contains both biotic and abiotic components.

3.      Biotic components interact with each other and also with the surrounding environment.

4.      Ecosystem term is conined by Tansley (1935).

5.      Ecosystems varies  in size from a small pond to large oceans or small farmland to village.

6.       Entire biosphere can be considered as one global ecosystem, made up of many local ecosystems. Since the earth ecosystem is too big and more  complex .

7.      Ecosystem is divided into two basic categories, -

A. terrestrial ecosystems

B. Aquatic ecosystems.

8.      Forest, grassland and desert are the types of terrestrial ecosystems .  

9.      lakes, wetlands, rivers and estuaries are the types of aquatic ecosystems.

10.  The ecosystems can also be classified as-

A. Natural ecosystems

B.  Artificial ecosystems.

11.  Natural ecosystems do not require any human inputs, in other words they are self-sustainable.

12.  Artificial ecosystems e.g. a farm land, a fish tank or even a large pond used for rearing fish, require constant input in terms of energy or materials.

Ecosystem:

Structure and Function:

Biotic and abiotic components differ as the locations vary in space and time. The variation due to space results in spatial pattern. There are two types of spatial patterns. –

1.  Stratification

2.  Zonation.

1.Stratification- Vertical distribution of different species of plants and animals occupying different levels, is known as stratification.

For example, trees occupy top vertical strata or layer of a forest, shrubs the second and herbs and grasses occupy the bottom layer. Similar stratification is also observed in the open seas as epipelagic, meso-pelagic, bathy-pelagic and benthic zones.

2.  Zonation -Horizontal distribution of plants and animals on land or in water, is called zonation.

Zonation is observed in aquatic (wetlands) as well as terrestrial ecosystems, but it is easily seen at the junction of the two. Edges of a large lake or beach show pronounced zonation in the form of Inter-tidal, Littoral, Sub-littoral zones.

13. Organisms and Populations

Introduction:                                                                                                                                        Natural world around us shows amazing diversity of forms and complexity of relations. To understand these, we have to study levels of organization in the living world viz. macromolecules, cells, tissues, organs, individual organism, population, communities,  biomes.                                                                                                              Ecology is a study of the interactions among organisms and between the organisms and their physical (abiotic) environment. Term ecology was first used by Reiter but E. Haeckel.

Ecological grouping of organisms is nothing but ecological hierarchy. There are four sequential levels with increasing complexity of ecological (biological) organizations viz, Organism, Populations, Communities and Biomes.

     Individual organism is the basic unit of ecological hierarchy.

           Organisms of same kind inhabiting a geographical area constitute  population. Several populations of different species in a particular area constitute community that interact with one another in several ways.

There are six major groups of terrestrial biomes. We shall explore first two levels viz, organism and populations.

xii biology 12.biotechnology

Biotechnology-an applied branch of biology which show interaction between the biological science and technology.

The term biotechnology was first used by Karl Ereky in 1919

 Biotechnology

Biotechnology is defined as ‘the development and utilization of biological forms, products or processes for obtaining maximum benefits to man and other forms of life

         According to OECD (Organization for Economic Cooperation and Development, 1981)- ‘It is the application of scientific and engineering principles to the processing of materials by biological agents (Biological agent means plants and animal cells, microorganisms, enzymes or their products.) to provide goods and service to the human welfare’

         It uses scientific principles of microbiology, genetics biochemistry, chemical engineering, mathematics, statistics, computers, industrial processes, etc.

         History of origin of biotechnology is as old as human civilization.

Development of biotechnology occurred in two phases 

1. Traditional biotechnology

2. Modern biotechnology.