food relationships among living organisms

Food Relationships Between Living

Organisms

FOOD RELATIONSHIPS AMONG LIVING ORGANISMS

• Food is the main source of energy for all living organisms.

• Green plants have the ability to benefit from sunlight as a source of energy during photosynthesis process to make their own food from simple substances (carbon dioxide gas and water) .

• Animals depend directly or indirectly on plants in their feeding.

The types of food relationships between living organisms

Predation Symbiosis saprophytism

1. Predation• "It is the food relationship among living organisms, where one living organism

devours another one“

• In predation, the living organisms get their food by

1) Attacking.

2) Killing.

3) Devouring the other organisms.

• The predator is the living organism which devours the other living organism.

• The prey is the devoured animal.

• Predation is a temporary relationship which ends up by devouring the prey or a part of it.

First: Predation In Plants:• Plants are called autotrophic organisms (self – feeder organisms) as they make their own

food (carbohydrate and protein) by photosynthesis process.

• Predation is less common in plant world than in animal world.

• But, there are some plants that cannot make protein substances, because they cannot absorb some compounds from the soil.

• These plants are known as insect eaters or insectivorous plants, because they have to prey some tiny animals such as insects.

• Examples of insectivorous plants:

• 1. Drosera. 2. Halophila.

Second: Predation in animals :• There are many examples for predator animals such as lions, tigers, wolves,

cats and sharks.

• Examples :

1) A lion preys a deer. 2) A wolf preys a rabbit. 3) A cat preys a rat.

Some ways of self-defence against predation in living organisms

Many living organisms use different ways (methods to defend themselves against enemies

such as:

A. Camouflage. B. Mimicry.

A. Camouflage

"A phenomenon in which the living organism protects itself (hides) from enemies by changing its color to simulate the color of its surrounding

environment“• This phenomenon is found in:

• Fish. - Frogs. - Birds. - Chameleon. - Most insects as butterflies.

A. Camouflage1. A butterfly stands on a tree with similar color.

2. A frog changes its color to hide from its enemies

3. A chameleon simulates the color of the surrounding environment.

4. A cuttlefish (sepia) ejects a black fluid in the surrounding water

when attacked by enemies.

B. Mimicry"A phenomenon in which the harmless living organisms imitate other

harmful or poisonous living organisms to fear their enemies and escape from them"

• Examples:Some bees which look like wasps in forming lines on

their bodies.