;colony/science / Biology
✿ Biology
Biology
Cells, senses, and ecosystems — the machinery that builds and balances itself.
Read it your way
Every answer here is written twice. Flip the switch and the page rewrites itself.
Try it now · Plate 28
How does an ecosystem balance itself with nobody in charge?
Watch the waves chase each other; then make the foxes greedier.
PLATE 28 · THE RABBIT–FOX WALTZ
Hunting pressure balanced
Greedier hunting doesn't mean more foxes for long. Watch.
Rabbits
60
Foxes
18
Round and round it goes: lots of rabbits → foxes feast and multiply → too many foxes
eat too many rabbits → foxes starve → rabbits bounce back. Neither side ever
wins; they chase each other in waves, with the fox wave always one step behind.
Every question
Biology, answered twice.
Plate 28Open → How does an ecosystem balance itself with nobody in charge? Nobody is in charge of the meadow — and that is exactly why it works, in waves. Plate 29Open → How fast can you actually react? Between the light hitting your eye and your finger moving lies a quarter of a second — and you just lived it without noticing. Plate 43Open → How does DNA copy itself? Every time a cell divides it must hand each half a complete copy of your three-billion-letter instruction book. The trick is a ladder whose rungs only fit one way. Plate 59Open → How do plants eat sunlight? A leaf is a solar-powered kitchen that builds sugar out of thin air and water, using nothing but light — and hands out the oxygen you're breathing as the leftover. Plate 60Open → How does natural selection work? Nobody designs a camouflaged moth. It emerges on its own, generation by generation, from nothing more than dying, breeding, and small inherited differences. Plate 81Open → What is inside a living cell? A single cell is a fully staffed factory smaller than a speck of dust, running itself every second of your life. Plate 82Open → How do nerves carry signals? Touch a hot pan and your hand pulls back before you even feel pain. The signal that just raced up your arm travels nothing like electricity in a wire. Plate 83Open → Why are there fewer lions than gazelles? On the savanna you might see a thousand gazelles for every lion. That lopsided ratio is a law of energy at work, and it sets the shape of every food chain on Earth. Plate 124Open → How does your immune system fight germs? You don't have a wall keeping germs out. You have a patrol — millions of cells wandering your body, checking ID, and swarming anything that doesn't belong. Plate 125Open → How do muscles work? A muscle has no gears and no pistons. It is built from rows of filaments that grab each other and pull themselves shorter, millions at once. Plate 126Open → Why do we breathe? Breathing is a swap: fresh oxygen drifts into your blood while a waste gas drifts out the other way, each moving from crowded to empty. Plate 127Open → How does a disease spread? One sick person, one number. If each infected person passes it to more than one other, it explodes. Below one, it fizzles out. Everything hangs on that single tipping point. Plate 128Open → How does your eye focus? A camera focuses by moving its lens back and forth. Your eye can't do that — so instead it squeezes the lens into a different shape, fatter for near, flatter for far. Plate 170Open → How does water climb to the top of a tall tree? A tree has no pump. Water reaches the highest leaf because sunshine and wind evaporate water at the top, and the whole chain of clinging water molecules is pulled up from the roots — like one very long sip. Plate 174Open → Why do leaves turn red and gold in autumn? The yellow and orange were in the leaf all summer, hidden under green. As the days shorten the green breaks down and unmasks them, while some trees brew brand-new red from trapped sugars.
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