Living versus non-living things

Understand the idea

Once you know the signs of life, you can sort anything you see. Living things reproduce, grow, sense stimuli, metabolise, respire, and die. Non-living things do not do these on their own. A phone can ‘move’ if you throw it, but it does not move itself, feed, or make offspring.

Reproduction may be sexual (two gametes form a zygote) or asexual (one parent: binary fission, budding, vegetative propagation). Growth is more cells or bigger cells. Animals use stem cells; plants use meristems. Organisms detect change with receptors. Plants show nastic movement rather than walking.

Every living thing has a lifespan. Senescence is biological ageing that ends in death. Non-living objects have no lifespan in this biological sense.

What to remember

• Living: life, reproduction, food/air/water, stimuli, metabolism, growth, lifespan, self-movement, respiration.
• Non-living: none of those requirements.
• Sexual reproduction uses two parents; asexual uses one.

Recap

Use a checklist, not a single clue. If it cannot grow, respire, respond, or reproduce, treat it as non-living, even if it looks busy.