Lessons · Teaching · what makes something living
Seven things a living thing does, and a car does four of them
Living things move, respire, sense their surroundings, grow, reproduce, excrete and take in nutrition. A thing is alive only if it does all of them. A car moves, takes in fuel, senses and excretes, and it is not alive, because it cannot grow or reproduce.
Hone is a place to practise a career, one idea a day. This is one of its lessons, written out in full and free to read without an account.
In beta. This lesson was written for Hone and has not yet been checked by a state certification officer. Practice material, not professional advice. What that means.
What it is for
'Is fire alive?' is a question a class will genuinely ask, and it is a good one: fire moves, grows, uses oxygen and produces waste. The answer is that it does not sense, and it does not reproduce in the sense meant. A teacher with the list can answer honestly rather than saying 'because it isn't'.
How to think about it
Run the whole list against the thing. Being unable to name which criterion fails is the sign that the answer is a guess. Seeds, eggs and a dormant bacterium are alive: doing a thing slowly or later is not the same as not doing it.
Worked example
The seven: movement, respiration, sensitivity, growth, reproduction, excretion, nutritionAll seven, not a majority.
A car: moves, takes fuel, has sensors, produces exhaust, and does not grow or reproduceNaming the criterion that fails is the answer, not the verdict.
Respiration is not breathing: it is releasing energy from food inside a cellA plant respires, and it does not breathe. This distinction is examined.
A seed is alive and dormant, not deadSlowly is not never, which is why a list and not a stopwatch decides.
Your turn
Name the process that releases energy from food inside a cell.
Energy is released from food by
Solve one, graded on the server
The trap
Treating respiration and breathing as the same word. Breathing moves air; respiration releases energy in the cell. A plant does the second and not the first, and an examination will ask exactly that.