1) Food is the main source of energy for living organisms. Green plants produce their own food through photosynthesis while animals depend directly or indirectly on plants. 2) There are three main types of food relationships: predation, symbiosis, and saprophytism. Predation involves one organism attacking, killing, and devouring another for food. 3) Predation is common in the animal world with examples like lions preying on deer. Some plants also prey on insects. Organisms use defenses like camouflage and mimicry to protect themselves from predators by blending in with their environments.

1. Food Relationships
Between Living
Organisms

2. 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.

3. The types of food relationships between
living organisms
Predation Symbiosis saprophytism

4. • "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.

5. • 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.

6. • 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.

7. Many living organisms use different ways (methods to defend
themselves against enemies
such as:
A. Camouflage. B. Mimicry.

8. "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.

9. 1. 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.