Ecology

Producers, consumers, decomposers, food webs, and the 10% rule. Pattern recognition wins this section.

🍃 Roles in an ecosystem

🌱

Producers

Make their own food via photosynthesis. Plants, algae, some bacteria.

🦌

Consumers

Eat other organisms. 1° (herbivores) → 2° (carnivores eat herbivores) → 3° (top predators).

🍄

Decomposers

Bacteria & fungi break down dead matter → recycle nutrients back to soil.

⚡ Energy pyramid (10% rule)

Only ~10% of energy passes to the next level. The rest is lost as heat from movement, body warmth, and life processes.

3° Consumer (hawk)

1 kcal

2° Consumer (snake)

10 kcal

1° Consumer (mouse)

100 kcal

Producer (grass)

1000 kcal

That's why food chains are usually 3–5 links — energy runs out.

🔗 Sample food chain

🌾 Grass→🦗 Grasshopper→🐸 Frog→🐍 Snake→🦅 Hawk

Arrows point in the direction of energy flow (eaten → eater).

🌐 Biodiversity simulator

Species diversity: 7Stability: Resilient

More biodiversity = ecosystems can absorb shocks (disease, drought). Lose a key species → ripple effects through the whole web.

🪜 Levels of organization

Organism→Population→Community→Ecosystem→Biome→Biosphere

Population = same species. Community = different species together. Ecosystem = community + nonliving (water, air, soil).

🤝 Symbiosis (memorize the pattern)

Mutualism (+/+)

Both win. Bee & flower.

Commensalism (+/0)

One wins, other unaffected. Barnacle on whale.

Parasitism (+/−)

One wins, one harmed. Tick on dog.

🧠 Quick reveals

What's a limiting factor?▾

Anything that caps how big a population can grow — food, water, space, predators, disease. Carrying capacity is the max a habitat can support.

If producers disappear?▾

Whole ecosystem collapses. They're the only ones bringing in new energy from the sun.

Why do food chains rarely have more than 5 links?▾

The 10% rule — by the 5th level there's basically no energy left to support a population.

🎯 Quiz yourself

Ecology · QuizQ1 / 6