The ecosystem is the sum total of everything living in it. These includes the trees, rivers, forests, desert, seas and such. These make up for the living system providing it with the food needed for its survival.
The ecosystem is divides into the Autitrophs and the Heterotrophs.
These are organisms that produce their own food. These autotrophs are of two types namely;
Photosynthetic autotrophs which use solar energy to synthesize their own food. E.g. all green plants.
Chemosynthetic autotrophs use energy from chemical reactions in the soil to synthesize their own food.
They are organisms mainly green plants that synthesize organic food from inorganic matter such as carbon (IV) oxide, water and mineral salts. Producers are therefore autotrophs. Green plants are examples of terrestrial producers while plant Planktons and algae are examples of aquatic producers. These producers belong to the First Trophic level.
Green plants are producers and are usually more abundant. They start any food chain and can produce carbohydrates during photosynthesis from carbon (IV) oxide and water in the presence of chlorophyll and solar energy.
These are the organisms that depend on the autotrophs for their food or energy requirements. they maybe holozoic, saprophytic and parasitic heterotrophs.
They are animals which feed on plants or on other animals. Consumers are heterotrophs. E.g. cows, tigers, and dogs. Consumers are subdivided into four main groups
1. PRIMARY CONSUMERS: They are animals that feed directly on plant materials. E.g. herbivores such as goats, sheep, cow and rabbits.. Herbivores belong to the second trophic level. Thus, herbivores are known as Primary consumers. They feed directly on plants’ materials and build energy or food for carnivores.
2. SECONDARY CONSUMERS: These are animals that feed on primary consumers. E.g. carnivores such as dogs, cats, and lizards. These carnivores belong to the Third trophic level in the food chain.
3. OMNIVORES: They are animals that feed on both plants and animals. E.g. man belongs to this trophic level.
4. TERTIARY CONSUMERS: They are animals that feed on secondary consumers. Thus, higher or top carnovores are tertiary consumers. E.g. Lion, Hawk, Tigers, etc. These consumers belong to the Fourth trophic level in the food chain.
Thus, carnivores are known as Secondary and Tertiary consumers and are few in number. They feed on herbivores for energy.
Food chain is the transfer of food energy from producers to a series of organisms in a habitat. All food chains must start with a producer or an autotroph.
1. Grass ——————–grasshopper———–lizard————snake
2. Plankton———–Tilapia————Water snake
Each level of consumption in a food chain is called a trophic level.
Trophic levels are stages at which the energy is found as it moves through the various organisms or levels of transfer in the ecosystem. Thus, trophic level refers to the part of the food chains.
Food web is the two or more inter-connecting of food chains within an ecosystem. It’s a complicated form of a food chain.
NON CYCLIC NATURE OF CHEMICAL ENERGY TRANSFER
The energy flow in an ecosystem is not cyclic because being an energy pyramid, it moves from the producers at the bottom of the pyramid up to a point where it cannot be used by living things anymore.
Chemical energy in form of carbohydrates, fats and proteins and other nutrients are distributed among producers, consumers and decomposers.
PYRAMID OF NUMBERS
This is the progressive drop in number of individuals in the population at each higher or successive trophic level of the food chain or it is the relative decrease in the number of organisms in a food chain as one ascends the higher trophic levels.
PYRAMID OF BIOMASS
The pyramid of biomass in standing crop indicates by weight the total mass of total organisms at each trophic level.
REMOVAL OF CARBON (iv) OXIDE
Photosynthesis by green plants during the day removes large amount of carbon(IV) oxide from the air.