Question

Reproduction cannot be an all-inclusive defining characteristic of living organisms because (a) All living organism do not show growth. (b) Many organism do not reproduce. (c) Non-living things show reproduction. (d) All living organism show small period of reproductive phase in their life.

Short answer

Option (b), Many organisms do not reproduce, is correct. This is the reason why reproduction cannot be an all-inclusive defining characteristic of living organisms as there are organisms that do not reproduce.

Step-by-step solution

Evaluate Option (a)

Consider the statement 'All living organism do not show growth'. Growth is actually a universal characteristic of living organisms. So, this option is incorrect.

Evaluate Option (b)

Look at the statement 'Many organisms do not reproduce'. This is true in the case of sterile organisms, or mules which are unable to reproduce. Therefore, if reproduction were to be an all-inclusive defining characteristic, these organisms would not be considered living. This option is valid.

Evaluate Option (c)

Analyze the claim 'Non-living things show reproduction'. Actually, non-living things do not show biological reproduction. Replication or duplication of non-living objects is not the same as biological reproduction. Therefore, this option is incorrect.

Evaluate Option (d)

Consider the statement 'All living organism show small period of reproductive phase in their life'. While most living organisms have a reproductive phase in their life, not all do. For example, some organisms may die before they reach reproductive maturity or some might be sterile. Therefore, this statement is not universally true, making this option incorrect.

Key concepts

Reproduction in Biology

Reproduction is a fundamental process for living organisms, encompassing the various ways life on Earth perpetuates itself. It seems intuitive to suggest that because all species need to reproduce to continue their lineage, reproduction should be an essential defining characteristic of life. However, there are exceptions. For instance, sterile organisms, such as certain hybrids like mules, cannot reproduce naturally. Some individual organisms may also lose their ability to reproduce due to genetic defects, diseases, or environmental factors.

Two primary forms of reproduction exist: sexual and asexual. Sexual reproduction involves the exchange of genetic material between two organisms, leading to offspring with genetic contributions from both parents. In contrast, asexual reproduction allows an organism to produce offspring without the need for a partner, leading to genetically identical clones. Despite this variance, the inability of some members of a species to reproduce challenges the idea of classifying reproduction as a universally all-inclusive defining characteristic of living organisms.

Growth in Living Organisms

Growth is a distinctive feature of living organisms, defined as an increase in mass or cell number, and typically occurs throughout an organism's life. Unlike reproduction, growth is generally considered a universal characteristic of living entities. All living things undergo some form of growth, which can be evident in height, weight, or size increase, and cellular division.

Biological growth has two main aspects:

• Cellular Growth: Enlarge in cell size.
• Cellular Division: Increase in the number of cells.

Growth is not linear and can vary significantly based on environmental conditions, genetic factors, and the life stage of the organism. However, growth is not endlessly sustainable due to physical, genetic, and environmental limitations. Thus, while growth is a reliable indicator of life, it too, like reproduction, has its complexities.

Sterile Organisms

Sterile organisms are those living beings unable to produce offspring. Sterility can occur due to various reasons including hybridization, where two different species mate and produce offspring that cannot reproduce. Mules, the offspring of a donkey and a horse, are one such example.

Sterility might also be caused by genetic mutations, diseases, or environmental stressors. For certain species, sterility is a natural occurrence that can benefit the group. For instance, in a bee colony, worker bees are sterile and devote their lives to supporting the queen and the colony instead of reproducing themselves. While sterile organisms cannot contribute to the gene pool, they can still play crucial roles in their ecosystems and exhibit other defining characteristics of life. Therefore, it's important to understand that sterility does not diminish an organism's status as a living being.