Introduction to ecology

Ecology (definition)

The study of the interaction between groups of organisms and their environment

Biosphere (definition)

The part of the earth and its atmosphere in which life can exist

Biotic (definition)

An organism’s influence on another organism

Abiotic (definition)

The influence of a non-living part of the environment on an organism

Climatic factors (definition)

The weather conditions that affect organisms in an ecosystem

Edaphic factors

Soil factors that affect organisms. E.g. soil pH, soil temperature

Aquatic factors (definition)

Factors that affect organisms that live in water

Producer (definition)

Organisms which make their own food using energy from the sun (green plants)

Consumers (definition)

Organisms that feed on other organisms

Who are producers eaten by?

Primary consumers (herbivores)

Who are primary consumers/herbivores eaten by?

Secondary consumers (carnivores)

Who can secondary consumers/carnivores be eaten by?

Tertiary consumers (top carnivores)

Food chain (definition)

The feeding relationships between organisms in which energy is transferred

Trophic level (definition)

The feeding level in a food chain

What are the two main types of food chains?

Grazing food chain. Detritus food chain

Who is the first member of a grazing food chain?

A living plant

Who is the first member of a detritus food chain?

Dead plants

What member of a food chain is at trophic level 1?

Producer

What member of a food chain is at trophic level 2?

Herbivore

What member of a food chain is at trophic level 3?

Carnivore

What member of a food chain is at trophic level 4?

Top carnivore

Name a detritus food chain

Dead oak leaves (producer) → earthworm (decomposer) → blackbird

Food web (definition)

Consists of two or more intersecting food chains

What does an ecological pyramid do?

Compare trophic levels of different communities of organisms in an ecosystem

Pyramid of numbers (definition)

Used to show the number of organisms at each trophic level of a food chain

Community (definition)

All different populations living together

Draw a usual/typical ecological pyramid (labelled + energy)

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Draw a distorted ecological pyramid

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Draw an inverted pyramid of numbers (ecological pyramid)

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Habitat (definition)

Where an organism lives

Niche (definition)

The role of an organism in an ecosystem

What is the niche of a decomposer?

Recycle nutrients

Decomposers (definition)

Bacteria and fungi that feed on dead and decaying plants and animals

Explain how Decomposers recycle nutrients

Dead animals and plants are broken down. Minerals released pass into soil + water. Nutrients absorbed by plants and form new plant tissues. Nutrients passsed on to animals when plants are consumed

Draw a diagram of the carbon cycle

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How do plants contribute to the carbon cycle?

Green plants take carbon dioxide from the atmosphere for photosynthesis. The release carbon dioxide when undergoing respiration.

How do animals contribute to the carbon cycle?

Eat plants as food, release carbon dioxide during respiration

How do Decomposers contribute to the carbon cycle?

Break down dead plants and animals. They respire and release carbon dioxide

How does the burning of fossil fuels contribute to the carbon cycle?

Combustion releases carbon dioxide e.g. coal, petrol, oil

Name two ways to ensure the carbon cycle is balanced

Plant more trees. Cut down in fossil fuels

Function of the nitrogen cycle

Allows organisms to get nitrogen in a usable form

What is the form of nitrogen that plants can absorb?

Nitrate

What plants have nodules on their roots?

Legumes

Where are nitrogen-fixing bacteria found?

Nodules on roots or soil

Function of nitrogen fixing bacteria

Converts nitrogen to nitrate ions

What do plants use nitrogen for?

Protein

What do fertilisers contain?

Nitrogen

Function of fertilisers

Encourage growth

What produces ammonia in the nitrogen cycle?

Decomposition of plants and animals. Urea

Can ammonia be used by the body?

No

What is ammonia converted to?

Nitrite

What bacteria converts ammonia to nitrite to nitrate?

Nitrifying bacteria

What is nitrite converted to by nitrifying bacteria?

Nitrate

Where is nitrifying bacteria found?

Soil

What is denitrification?

Process that returns nitrate into the atmosphere as nitrogen gas

What bacteria performs denitrification?

Denitrifying bacteria

Where is denitrifying bacteria found?

Soil

Draw a diagram of the nitrogen cycle

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