What is Living? Definition, Characteristics, and Difference

What is Living: Living refers to the state of being alive, encompassing the myriad of biological processes that sustain existence. Every individual around us relies on essential life functions such as respiration, growth, and reproduction to remain healthy and happy. Living organisms exhibit a range of characteristics, including the ability to grow, move, reproduce, and respond to stimuli.

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What is Living?

Characteristics of Living Organisms

• Growth : All living organisms have the capacity to grow, with plants experiencing continuous growth throughout their lifespan while animals grow only until a certain age.
  • Growth is characterized by an increase in body mass and an increase in the number of individuals.
  • In unicellular organisms, growth occurs through cell division, observable in in vitro cultures.
• Reproduction : Reproduction is a fundamental characteristic of living organisms, with no non-living object capable of self-replication.
  • In multicellular organisms, reproduction produces progeny that resemble their parents, occurring through both sexual and asexual means.
  • Examples of asexual reproduction include budding in fungi and lower organisms like Hydra, while true regeneration occurs in organisms like Planaria.

• Metabolism and Cellular Organization : Living organisms consist of various chemicals, constantly undergoing metabolic reactions, which can be categorized into anabolism (constructive metabolism) and catabolism (destructive metabolism).
  • Metabolism encompasses all chemical reactions occurring within an organism, essential for maintaining life.
  • Isolated metabolic reactions outside a living organism do not constitute life, highlighting that cellular organization is a defining feature of living organisms.
• Consciousness : Living organisms possess the ability to sense and respond to their environment, a feature that varies from simple prokaryotes to complex eukaryotes.
  • Organisms respond to external factors such as light, water, and temperature, indicating a level of awareness of their surroundings.
  • All living organisms exhibit some form of awareness and responsiveness to environmental cues.
• Self-Consciousness: Humans are unique in possessing self-consciousness, or the awareness of oneself as an individual.
  • This capacity for self-awareness is considered a defining property of living organisms, distinguishing humans from other life forms.
• Interactions : Interactions at various levels of biological organization give rise to emergent properties, where the characteristics of higher levels cannot be fully understood by examining the individual components alone.
  • For example, the properties of a tissue arise from the interactions among the constituent cells, demonstrating that life is characterized by complex interdependencies.
  • This structured overview highlights the unique characteristics that define living organisms, illustrating their complexity and the essential qualities that distinguish them from non-living entities.

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Difference Between Living and Non-Living Things

MCQs of What is Living

Q1. How many (in number) of the following properties are the defining characteristics of living organisms?

1. Growth

2. reproduction

3. metabolism

4. consciousness.

1. 2
2. 3
3. 4
4. 1

Q2. Which of the following is a defining characteristic of living organisms?

1. Growth
2. Ability to make sound
3. Reproduction
4. Response to external stimuli

Q3. Growth in plants is:

1. diffused
2. localized
3. determinate
4. reversible

Answers to MCQs of What is Living