Environmental Science

Level of Organization

We know that multicellular organisms are made up of millions of cells. Most of these cells are specialized to carry out a few functions. 

Cells are the building blocks of life. They are the basic structural and functional units from which life takes shape. Cells are the smallest living entities in a living organism. The cells perform functions necessary for the survival of the organism, such as respiration, digestion, excretion, protection from pathogens and so on. each cell performs a specific function in the body. Therefore, cells specializing in one function are often grouped together in the body. This means that a particular function is carried out by a cluster of cells at a definite place in the body. In this way, different functions are performed by different groups of cells in an organism. This constitutes the organization at cellular level.

A group of cells that are similar in structure and are organised together to perform a specific task is known as a tissue.

So, groups of cells make tissues.

What do tissues form together?

A group of tissues are organised to form an organ. Two or more different organs work together in a coordinated manner to form an organ system. Organ systems work together in the body of an organism.

Are plants and animals made up of the same types of tissues?

To answer this question, we need to compare the structure and functions of plants and animals. There are a lot of differences between plants and animals.

i) Plants are stationary, i.e., they do not move. Therefore, they are composed of tissues that provide them structural strength. Hence, most of the tissues in plants are made up of dead cells. This is because, dead cells provide strength and are easy to maintain. On the other hand, animals consume more energy by moving from one place to another in search of food, shelter, etc. Hence, the tissues present in animals are of a different type.

ii) There is a difference in the growth pattern of plants and animals. In plants, growth occurs only in certain regions, such as the root tip, shoot tip, etc. Therefore, the dividing cells or growth tissues are present only in these regions. This is not true for animals, in which growth is uniform. Therefore, in animals, dividing cells are present in almost all the regions.

So, by now we know that cells make up tissues that in turn make up organs. When many inter related organs work to perform a specific task they constitute organ system. Different organ systems make up an organism.

Now let us study about the higher levels of organisation which include populations, community, ecosystem and finally the biosphere that represents the sum total of all living things present on the Earth.

Population

All organisms that we see around us are the members of one or other species. The species refer to the group of individuals that are alike in their key features and…