Food Web / Chain Basics
What is a Food Web?
A network of interconnected food chains showing how energy moves through an ecosystem.
What is a producer?
An organism that makes its own food through photosynthesis, like plants or algae.
How does energy enter most ecosystems?
Through sunlight, which producers use to create energy-rich food.
What happens if a population of prey decreases?
Predator populations may decrease due to less available food.
What shape represents energy flow?
A pyramid, because energy decreases at each trophic level.
What role do consumers play?
They eat other organisms to gain energy, transferring it through the food web.
Define " trophic level"
A trophic level is an organism's position in a food chain or web, based on what it eats.
What percent of energy transfers to the next level?
Around 10% of energy goes into the next level. This is known as the Rule of 10.
Why are decomposers important?
They break down dead matter and recycle nutrients back into the ecosystem.
What data does an energy pyramid show?
It shows the amount of energy available at each trophic level.
Is there a difference between Food Webs and a Food Chain? If yes, what is the difference?
Yes! A food chain is a single path of energy flow; a food web shows multiple, interconnected paths.
What is a secondary consumer?
An organism that eats primary consumers; usually a carnivore or omnivore.
Why does energy decrease as it moves up the pyramid?
Most energy is lost as heat or used for life processes like movement and digestion.
Why are food webs more stable than food chains?
They have multiple pathways, so the ecosystem can survive if one species is removed.
If a producer has 10,000 cal, how much reaches secondary consumers?
About 100 cal ( 10% to primary, then 10% to secondary).
What would happen if producers were removed?
The entire food web could collapse, as producers are the energy source for all other levels.
What is a tertiary consumer?
An organism that eats secondary consumers and is near the top of the food chain.
What happens to the " lost" energy at each level?
It is released into the environment as heat.
How does removing a predator affect lower levels?
Prey populations may grow too large, affecting plants and lower consumers.
How could you use an energy pyramid to spot ecosystem imbalance?
If levels are unusually small or missing, it could signal environmental stress or species loss.
What does the complexity of a food web tell us about an ecosystem?
A more complex web shows a more stable and resilient ecosystem due to more feeding connections.
Rank Producer to Apex predator in a 4-level food chain.
Producer - Primary Consumer - Secondary Consumer - Tertiary Consumer ( apex predator)
If only 1% is energy reached the tertiary level, how much started at the producer level?
1000% of energy. 10% transfers per level: 1000-100-10- 1
Explain the ripple effects of removing a keystone species.
It can cause collapse or major shifts in population sizes, disrupting the entire food web.
Use an energy model to presict effects of producer loss.
Energy input would drop sharply, leading to population declines at all higher trophic levels.