Problem 6 - Objective Biology for NEET

Question

Growth cannot be taken as a defining property of living organisms because (a) All living organism do not show growth. (b) Non-living things also grow from inside. (c) Non-living things also grow. (d) Some living organism does not exhihit th

Step-by-Step Solution

Answer

The correct answer is (b) Non-living things also grow from inside.

Step 1: Identify the Characteristics of Living Organisms

Living organisms are characterized by certain traits including growth, reproduction, metabolism, response to environment, adaptation and self-regulation.

Step 2: Contrast these with Non-living things

Non-living things do not possess these characteristics of life. Though they may seem to 'grow', they do so not by biological mechanisms (e.g., by adding cells and increasing in size), rather it's a physical phenomenon like accumulation of matter.

Step 3: Asses the Provided Options

Option (a) is incorrect as all living organisms show growth. Option (d) is incorrect because every living organism exhibits at least some form of growth. In contrast, options (b) and (c) hint at a sort of ‘growth’ in non-living things which is not biological.

Step 4: Choose the Correct Answer

Option (b) implies that non-living things can also 'grow' but this growth is not biological, instead, it is due to accumulation or addition of matter from within. Hence, 'growth' can't be taken universally as a defining property for distinguishing between living and non-living things.

Key Concepts

Growth in Biology

In biology, growth refers to the process where living organisms increase in size through cell division and enlargement. This process occurs at both cellular and organic levels. Unlike non-living things that may appear to grow due to the accumulation of external materials, biological growth involves the production of new living material.
Growth in living organisms is a true biological phenomenon driven by the cell cycle, where cells divide through mitosis to make more of themselves.
Some interesting points about biological growth include:

• Growth is an irreversible process in most living organisms.
• Biological growth involves metabolic processes, which convert nutrients into building blocks for increased mass.
• Growth is generally regulated by genetic and hormonal factors.

Understanding growth helps us appreciate its significance as a fundamental characteristic of life while distinguishing it from any visible increase in size in non-living objects.

Defining Properties of Life

Life is defined by a set of specific properties that distinguish living organisms from non-living entities. These properties must historically occur together for an organism to be considered 'alive'.
Some of the defining properties of life are:

• Cellular Organization: All living organisms are composed of one or more cells, which are considered the basic unit of life.
• Metabolism: Living organisms exhibit metabolic processes, which are the biochemical processes necessary to maintain life.
• Growth and Development: Living organisms grow and undergo regulated changes through their life cycles.
• Reproduction: Living organisms have the ability to produce new individuals, ensuring the continuation of the species.
• Response to Stimuli: Living organisms can sense changes in their environment and respond accordingly.
• Adaptation: Over time, populations of living organisms undergo genetic changes that allow them to survive in changing environments.

These properties collectively add to the definition of life and aid in differentiating living things from those that do not possess such qualities.

Living vs Non-living Distinction

The distinction between living and non-living entities is foundational in biology. Even though some non-living things may superficially exhibit characteristics like growth, the mechanisms underlying these processes are different.
For instance, while a crystal might grow in size by adding layers, this is a mere physical accumulation and not biological growth. It lacks the cellular processes and metabolic activities that characterize living organisms.

• Living organisms are made up of cells, whereas non-living things are not.
• Living entities manifest growth, reproduce, and respond to environmental changes actively through biological processes.
• In contrast, non-living things don't have these complex processes.

Understanding these distinctions helps in the proper classification of objects and organisms in various scientific studies, and emphasizes the unique processes that sustain life.