Ecosystems

Ecosystem: a group of organisms interacting with each other and the abiotic and biotic facts in the environment

Thermodynamics help us understand how energy flows through biological systems

A system is a set of interacting or interdependent components.

Classify systems into three types:

• Open system - allows both energy and matter to be exchanged with its surroundings

• Closed system - allows for the exchange of energy with the surrounding environment but restricts the flow of matter

• Isolated system - are ideal systems in which neither energy nor matter are exchange with the surroundings

Matter: anything that occupies space and has mass

Energy: the ability to perform work or cause change

Sunlight as a Source of Energy

Initial source of energy for most food chains

Light energy is converted by producers and autotrophs into chemical energy during photosynthesis

• plants, eukaryotic algae and cyanobacteria carry out photosynthesis

--> heterotrophs use the sunlight indirectly as they feed on autotrophs

Ecosystems that don't receive a lot or any sunlight adapt to decrease the amount of energy available

• rely on bacteria gaining energy from chemical processes

Some energy may pass to these ecosystems in dead organic matter transferred form other ecosystems

Some caves don't receive any influx so energy is produced by chemoautotroph bacteria through chemical reactions with inorganic materials

Light must pass through water to reach producers - transmission isn't 100%

• only shorter wavelengths will penetrate further in pure water (blue the shortest wavelength)

Source of energy in deep sea originates from bacteria which can use sulphides from the emission of black smokers to synthesise glucose