Ecosystems and relationships

• An ecosystem consists of living and non-living organisms.
• A biological community is a group of different species in an ecosystem.
• A biotic population is a group of the same species.
• An individual is a single living organism.

Nutritional Relationships

• Predation is a relationship where one organism (predator) benefits and the other (prey) is harmed.
  • Example: Zebra and lion; chameleon and insects; dionea (venus flytrap) and insects.
• Competition occurs when two individuals of the same species compete for limited resources like food, growth, and survival.
  • Example: Two lions competing for a zebra.
  • When competition increases, the number of individuals decreases.
• Mutualism involves both individuals benefiting.
  • Example: A bee extracting nectar from a plant, while the plant benefits from pollen transfer for reproduction.
• Commensalism is when one individual benefits and the other is neither benefited nor harmed.
  • Example: Plover bird cleaning crocodile teeth.

Living Organism Classification

• Living organisms are classified into producers, consumers, and decomposers.
• Producers (autotrophs) can make their own food, such as plants and algae.
• Consumers (heterotrophs) depend on producers to get food; they are animals.
• Decomposers break down organic matter in dead bodies into simpler substances like fungi and bacteria.

Consumers Classification

• Consumers are further classified into herbivores, carnivores, omnivores and scavengers.
• Herbivores eat only plants, such as horses and rabbits.
  • They have incisors (front teeth).
• Carnivores eat only meat, such as lions and snakes.
  • They have sharp canines.
• Omnivores eat both plants and meat, such as bears, ravens, mice, and hedgehogs.
• Scavengers eat remains of dead bodies; for example, hyenas, eagles, and cockroaches.

Food Chains

• A food chain is the path of energy flow from one living organism to another: Producer → Consumer → Decomposer.
• A trophic level is each stage in which energy is transferred in a food chain.

Food Webs

• A food web is an interconnection of multiple food chains.
  • Example: Grass → Rabbit → Snake → Eagle; Grass → Rabbit → Eagle → Fox.

Types of food chains

• Terrestrial food chains: found on land,
• Aquatic food chains: found in water. Algae (producer) → Copepod (primary consumer) → Fish (secondary consumer) → Seal (tertiary consumer) → Polar Bear (quaternary consumer).
• Desert food chains: found in deserts

Biological Control

• Biological control utilizes living organisms through the food chain to eliminate agricultural pests.
• Example: Using dotted beetles to eat aphids that harm fruits.

Food Webs

• Producers like grass and carrots.
• Primary consumers like birds, locusts, mice, and rabbits.
• Top predators like owls and foxes.

Ecological Balance

• Number of primary consumers increase:
  • Producers will decrease.
• Number of secondary consumers decrease:
  • Increase number of primary consumers
  • Decrease number of tertiary consumers.

Energy Pyramid

• An energy pyramid represents the flow of energy.
  • Tertiary
  • Secondary Consumer
  • Primary Consumer
  • Producer
• Each trophic level gets 10% of the energy. 90% is lost.
• Example:
  • Grass: 10000 Energy Unit
  • Rabbit: 100 Energy Unit
  • Snake: 10 Energy Unit
  • Hawk: 1 Energy Unit