Introduction and Characteristics of Living Beings
Introduction:
- All the living organisms present in the biosphere collectively form the living world.
- living beings are characterized by growth, reproduction, metabolism, ability to detect their surroundings and respond appropriately.
Detailed explanation:
Characteristics of Living Organisms
Following are characteristics of living beings
1. All Living Organisms Grow:
- In a living organism, growth occurs by an increase in mass and an increase in the number of members
- In multicellular organisms, growth occurs through both increases in mass & by an increase in the number of cells by cell division.
- Plants continue to grow throughout their lives due to the presence of certain meristematic tissues.
- while in animals growth happens up to a particular age, after which cell division occurs in specific tissues to replace the lost cells.
- In Unicellular organisms growth occur by both increases in the quantity of protoplasm & number of cells by cell division, which results in an increase in a number of individuals i,e reproduction.
- So In unicellular organisms, growth & reproduction seems similar.
- Living beings grow from the inside hence growth is intrinsic or internal i.e growth by intussusception.
- Non-living formations like mountains, boulders, and sand dunes also grow by deposition or buildup of material on the surface.
- Therefore, growth cannot be considered as distinguishing or defining feature of living beings because it also occur in non-living objects
2. Reproduction in Living Organisms:
- All multicellular and unicellular organisms produce new individuals of their own kind.
- Organisms can reproduce both sexually and asexually.
- Fungi reproduce and spread by the production of millions of asexual spores.
- Planaria reproduce through fragmented parts.
- Reproduction and growth are synonymous in unicellular organisms such as bacteria, amoeba, and unicellular algae, i.e., an increase in the number of cells.
- There are living beings who don't reproduce. For example mule, worker honey bee, and infertile couple.
- Therefore, reproduction cannot be considered a distinguishing trait of living beings.
- Though, no nonliving thing has the ability to reproduce or replicate on its own.
3. Metabolism in Living Organisms:
- Organic substances referred to as biomolecules found in living beings form the basis of variety of classifications
- Biochemical events, also known as metabolic reactions, are constantly producing these in the body.
- Thousands of these metabolic events take place at the same time inside live organisms.
- These reactions are carried out by all plants, animals, fungi, and microbes.
- In cell-free systems, metabolic reactions can be carried out outside the body. However, an isolated metabolic response outside of an organism's body is neither living nor non-living.
- In vitro/ isolated metabolic processes are just living reactions.
- As a result, metabolism is a distinguishing characteristic of all living species.
4. Living Organisms shows Cellular organization:
- All living organisms, from the simplest to the most sophisticated, are made up of one or more cells with similar basic structures and functions.
- As a result, the body's cellular organization is a distinguishing trait of living organisms.
- Cells contain everything that is required for life.
- They have different parts, and each part has a varied set of functions.
- On the basis of cells arrangement organisms are of two types:
- Unicellular
- Multicellular
5. Consciousness:
- The ability of all living organisms to detect their surroundings or environment and respond to environmental stimuli, which might be physical, chemical, or biological, is the most sophisticated attribute of living.
- This is referred to as consciousness.
- Our sense organs assist us to perceive our surroundings.
- Seasonal breeders, both plants and animals, are affected by photoperiod, or the duration of light.
- Light, water, temperature, pollution, and other organisms all have an impact on plants.
- Chemicals that enter an organism's body are dealt with in the same way by all species.
- The human being is the only organism that is aware of or cognizant of itself.
- As a result, consciousness is the defining characteristic of all living things.
Difference between the consciousness and subconsciousness
- The conscious mind is completely aware, whereas the subconscious mind is not.
- Access to knowledge stored in the conscious mind is simple, but accessing information stored in the subconscious mind takes a little more work.
- Controllable acts are associated with the conscious mind, whereas "instinctive" activities are associated with the subconscious mind.
- While the conscious mind is in charge of logic and thinking, the subconscious and unconscious minds are in charge of a person's emotions, personality traits, attitudes, and wants, among other things.
Consciousness and person in coma:
- During a coma, a person does not react to external stimuli and does not show normal reflexes/responses.
- For a person to be categorized under living there are certain properties that are required to be present. One of those defining characteristics is consciousness i.e. awareness for the external environment.
- In a comatose person, this awareness is not found, as the brain of such a person can not respond to external stimuli.
- But such a person is not dead, because with the help of life support system, the physiological system can be kept functional. Also at the same time, external support keeps metabolic activities going( Metabolism is also one of the defining properties of living).
- Thus, the person is not brain dead. So, such a person can not be clearly dead or alive, but as dead alive.
Frequently Asked Questions - FAQs
Q1. What do you mean by in vitro culture?
Ans.
It is a technique of maintaining or cultivating cells or tissues generated from a living creature in a culture medium.
Q2. Do mountains, boulders, and sand mounds grow?
Ans.
● Mountains, boulders, and sand mounds are all non-living entities. They tend to show growth by accumulating material on the surface.
● Though this growth differs from growth in living beings, as in them growth occurs from the inside out.
Q3. How to assess growth in unicellular organisms?
Ans.
● Growth has two key characteristics: an increase in mass and an increase in the number.
● But in unicellular organisms no increase in mass is seen, therefore growth is predicted only by the increase in the number of cells.