On the right is a food web of named organisms. Grass (a producer) feeds the grasshopper and rabbit; those feed the frog and snake; and the hawk sits on top. Each arrow points from the eaten to the eater — the way energy flows. Because the chains overlap, a predator can switch prey, so a web is more stable than one chain. ▶ Play to light up the energy arrows.
Switch to the Energy pyramid tab. The same chain is now stacked: producers at the wide base, then primary, secondary and tertiary consumers. ▶ Play and watch only about 10% of the energy climb to the next level — the rest is lost as heat in respiration and movement. That is why each bar is a tenth of the one below, and why chains rarely exceed 4–5 links.
Open the Carbon cycle tab. Follow one CO₂ molecule. Photosynthesis in the plant fixes it into food; respiration by the plant and animals returns it to the air; decomposition of dead matter releases it again; and combustion of fossil fuels in the factory pumps out even more. ▶ Play to send the CO₂ around the loop and ⏭ Step through each transfer.
Stay on the same loop — now it shows nitrogen. Fixation by Rhizobium in legume root nodules turns N₂ gas into nitrates; nitrification by soil bacteria builds ammonia → nitrites → nitrates; plants assimilate them into protein; and denitrification returns N₂ to the air. ▶ Play to watch the four labelled steps complete the cycle.
Open the Greenhouse & us tab. ▶ Play and watch the Sun's short-wave rays pass through the atmosphere and warm the ground. The Earth re-radiates infra-red heat — but the layer of greenhouse gases (CO₂, methane) absorbs and bounces it back. Add more CO₂ from burning fuel and more heat is trapped → global warming. Watch the temperature gauge climb.
Switch to the same tab's contrast — a polluted landscape on the left (smog, dead trees, dirty water) versus a conserved one on the right (forest, clean river, solar & wind). ▶ Play to see conservation — the 3 Rs, reforestation, clean energy and protecting biodiversity — turn the grey side green. This detect-the-damage, act-to-reverse-it logic is what protects the whole ecosystem. Revisit it all in the Lecture.