Food Chains + Pyramids

Levels to organise all living things on Earth:

Biosphere

Biome

Ecosystem

Community

Population

Individual

Biotic

• Biotic factors are living things

• (e.g: plants, protists, animals)

Abiotic

• Abiotic factors are non-living things

• (e.g: soil, pH, temperature)

MRS GREN:

How to figure out if smth is living or not:

• Movement: Living things can move

• Respiration: They take in and use energy

• Sense: They can sense and respond to their environment

• Growth: They grow and develop

• Reproduction: They make more of their own kind

• Excretion: They get rid of waste

• Nutrition: They take in and use nutrients for energy and growth

Food Chain:

A food chain is the simplest path that energy takes through an ecosystem.

The First Law of Thermodynamics (energy):

Energy is neither created nor destroyed but can be converted from one form to another.

• The arrow in a food web represents the flow of energy - not who eats who

• Approximately 90% of energy is lost as heat from each trophic level via cellular respiration

1st Trophic Level:

• Consists of primary producers (autotrophs)

• (e.g: land plants + phytoplankton)

2nd Trophic Level:

• Consists of primary consumers (heterotrophs)

• (e.g: grasshoppers + rabbits)

3rd + Any Higher Trophic Level:

• Consists of consumers

• Carnivores + omnivores

• (e.g: humans + wolves)

Decomposers

• They break down dead organisms and waste

• (e.g: fungi + bacteria)

Food Web:

A food web represents many interconnected food chains describing various paths that energy takes through an ecosystem