NCERT says growth and reproduction aren't defining properties of living things, but metabolism is. Why? Feels backwards
Sara Fernandes11th Sample
21 Aug 2026 Β· 1 min read
I'm in class 11 and day 2 of The Living World already has me frowning. Football practice taught me that a thing that is alive grows and plays, so I'm not buying some of this.
NCERT lists the features of living organisms as growth, reproduction, metabolism, cellular organisation, and consciousness (response to stimuli). Then it says growth and reproduction are NOT defining features, but metabolism, cellular organisation, and consciousness are. I understand this is "NEET theory" but I don't see why.
Growth: surely every living thing grows? Reproduction: surely every living thing reproduces? NCERT's argument seems to be that mountains and boulders also "grow", and some living things can't reproduce (mule, sterile worker bees, infertile human couples). Fine, but isn't a mountain's growth totally different from a child's growth?
Metabolism: a metabolic reaction can happen in a test tube with isolated enzymes. Does that make the test tube alive? NCERT says no, so how can metabolism be a "defining" property then?
And is consciousness only for humans? A plant doesn't have a brain, is a plant not conscious?
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[+][β]Aman YadavDropperSampleΒ· 2mo ago
Growth is the defining property of life. Non-living things don't grow. Metabolism is just chemistry, you can have chemistry in a beaker.
[+][β]Rahul DubeyDropperSampleΒ· 2mo ago
Aman, that's the exact opposite of what NCERT concludes, and the NCERT reason is worth knowing. Non-living objects do "grow" in a sense: a mountain, a boulder, a sand mound all increase in size. The difference is how. Non-living objects grow by accumulation of material on the surface (outside). Living organisms grow from inside (cells divide and increase in number or size). So NCERT says growth from inside is the living kind, but because the word "growth" alone can apply to non-living things, and because some living organisms stop growing or don't grow in the usual way, growth cannot be taken as a defining property.
[+][β]Sara Fernandes11thSampleΒ· 2mo agoAuthor
"grows from inside vs piles on from outside" is the line I was missing. Thank you rahul bhaiya. Aman, we can still be friends π
[+][β]Pooja Iyer12thSampleΒ· 2mo ago
Reproduction is a great one for the exam. Mule: sterile, alive. Worker bees: sterile, alive. Infertile couples: alive. So reproduction can't be defining for an individual. Also in single-celled organisms like bacteria and Amoeba, reproduction is just an increase in cell number, which is the same thing as growth for them. So the two aren't even separate events there. Safe line for the exam: unicellular organisms: reproduction = growth.
[+][β]Zoya Khan12thSampleΒ· 2mo ago
On metabolism. Metabolism = the sum total of all chemical reactions in a living organism (anabolic and catabolic). Every living organism, from bacteria to humans, shows metabolism. NCERT says metabolic reactions can be demonstrated in a cell-free system (isolated from an organism), which are not living things, but they are definitely living reactions. So a test tube with enzymes doesn't mean the test tube is alive; but the only place you can see organised metabolism sustained inside a cell, by itself, is a living organism. Metabolism being "defining" means: no metabolism, not living.
That's also why it pairs with cellular organisation: all living organisms are made of cells, either one or many, and metabolism happens in an organised way within them.
[+][β]Kavya NaikDropperSampleΒ· 2mo ago
Consciousness: NCERT's usage is "the ability to sense the environment and respond to it". All living organisms do this: plants respond to light, water, temperature, pollutants, other organisms. Photoperiod affects reproduction in seasonal breeders and flowering in plants. So plants are "conscious" in NCERT's sense, though they aren't self-aware.
The next step is self-consciousness, awareness of oneself, which is unique to human beings. NCERT calls sensing and responding the most obvious and technically complicated feature of all living things; self-consciousness is what separates human beings from the rest. So the answer: consciousness (response to stimuli) = all organisms. Self-consciousness = humans only.
