1.1    What is 'LIVING’?

When we try to define 'living', we conventionally look for distinctive characteristics exhibited by living organisms. Growth, reproduction, ability to sense environment and mount a suitable response come to our mind immediately as unique features of living organisms. One can add a few more features like metabolism, ability to self-replicate. self-organise. Interact and emergence in this list. Let us try to understand each of these. All living organisms grow. Increase in mass and increase in number of individuals are twin characteristics of growth. A multicellular organism grows by cell division. In plants, this growth by cell division occurs continuously throughout their life span. In animals, this growth is seen only up to a certain age. However, cell division occurs in certain tissues to replace lost cells. Unicellular organisms grow by cell division. One can easily observe this in in vitro cultures by simply counting the number of cells under the microscope. In majority of higher animals and plants, growth and reproduction are mutually exclusive events. One must remember that Increase In body mass is considered as growth. Non-living objects also grow if we take increase in body mass as a criterion for growth. Mountains, boulders and sand mounds do grow. However, this kind of growth exhibited by non-living objects is by accumulation of material on the surface. In living organisms, growth is from inside. Growth, therefore. cannot be taken as a defining property of living organisms. Conditions under which it can be observed in all living organisms have to be explained and then we understand that it is a characteristic of living systems. A dead organism does not grow.


Find out the wrong statement out-

a. Increase in mass and increase in number of individuals are twin characteristics of growth

b. Growth, reproduction and ability to respond are the only unique features of living organisms

c. a and b both

d. Metabolism, ability to self-replicate and self-organise are the unique features of living organisms

b

 

 

The living organisms can be unexceptionally distinguished from the non-living things on the basis of their ability for [2007]

(a) interaction with the environment and progressive evolution

(b) reproduction

(c) growth and movement

(d) responsiveness to touch

(b)

 

 

In------------- of higher animals and plants-------- and ------- are mutually------ events.

a. All, cell division, replacement, dependent

b. Majority, growth, reproduction, exclusive

c. All, growth, cell division, dependent

d. Majority, cell division, replacement, exclusive

b

 

 

The growth and reproduction are mutually exclusive events in

(a) Plants only

(b) Animals only

(c) Higher animals and plants

(d) Lower organisms

(c)

 

 

What is correct with respect to Growth?

a. Increase in body mass is not a criterion for growth

b. Increase in body mass is not observed in non-living things

c. Accumulation or increase in mass from inside is the basis of growth in living beings

d. Growth is considered as defining property of living beings

c

 

 

Growth is not considered as a defining property of living beings because

a. It is difficult to observe or measure

b. Not a single criterion for the measurement of growth

c. Also observed in non-living

d. Cannot be tracked as growth is from inside

c

 

 

Growth is a characteristic of----------.

a. Living systems

b. Living organisms

c. Non-living organisms

d. Both b and c

d

 

 

How many of the following will show the growth or increase in mass?
Mountain, Boulders, sand mound, Dead organism, plants.

a. 3

b. 4

c. 1

d. 2

b

 

 

Select the correct combination:

a. Plants: limited cell division

b. Animals: Cell division throughout life span in all type of cells

c. Unicellular organisms: Growth observation by microscope

d. Living organisms: external growth

c

 

 

Mark the correct statement

(a) Only living organisms grow

(b) Plants grow only up to a certain age

(c) The growth in living organisms is from inside

(d) All of these

(c)

 

 

Choose an appropriate option to complete the given statement. In plants, growth takes place by.... throughout their life span.

(a) Cell dedifferentiation

(b) Cell differentiation

(c) Cell multiplication

(d) None of these

(c)

 

 

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