Energy Flow Energy and matter flow in each

Energy Flow • Energy and matter flow in each stage of a food web. • Sunlight is the primary source of energy in an ecosystem. • A large part of energy is lost going from trophic level to trophic level: – Organisms use energy to grow, move and reproduce – Organisms release energy in the form of waste – Organisms lose energy in the form of heat

Disturbances • An event that damages an ecosystem. It can lead to the elimination of organisms and alter the availability of resources.

Natural Disturbances • Triggered by environmental phenomena. Ex: storms, volcanic eruptions, floods, forest fires, periods of frost, heat waves, droughts, etc.

Human Disturbances • Caused by human activity • More damaging than natural disturbances because their frequency is higher (they happen daily compared to natural disturbances which happen more randomly) Ex: littering, logging, mining, extraction of oil

What would happen to the following food chain if: a) A wildfire killed off all the grass? b) The rabbit population increased? c) The snake and mouse population went extinct?

Ecological Succession • Series of changes that occur in an ecosystem after a disturbance and that continue until the balance of the ecosystem is restored

Try This! 1. Which of the following events would lead to the disturbance of an ecosystem? a) Planting trees b) Mud slide c) Composting d) Fog 2. Apply your understanding of the definition of a disturbance to explain how the construction of a hydroelectric dam is detrimental to an ecosystem.

Try This! 1. Which of the following statements is false? a) Drought is a natural disturbance. b) An oil spill is a natural disturbance. c) Flood from heavy rain is a natural disturbance. d) The fishing industry is a human disturbance 2. Which is a major source of environmental disturbance, natural or human? Explain your answer.