TROPHIC LEVELS ENERGY TRANSFER AND ECOLOGICAL PYRAMIDS Dr

TROPHIC LEVELS, ENERGY TRANSFER AND ECOLOGICAL PYRAMIDS Dr. Soumita Ghosh Assistant Professor in Geography Hooghly Women’s College

VOCABULARY Trophic Levels – is the position an organism occupies in a food chain. It refers to food or feeding. Apex predator – top level predators with few or no predators of their own.

FOOD CHAIN (DIAGRAM)

FOOD CHAINS The energy flow from one trophic level to the other is know as a food chain Producers Primary are at the first TROPHIC LEVEL Consumers are the SECOND TROPHIC LEVEL Secondary LEVEL consumers are at the THIRD TROPHIC

TROPHIC LEVELS (FEEDING LEVELS) 3 2 1

FOOD WEBS Food webs show ALTERNATIVE PATHWAYS other possible pathways through which an organism can obtain energy

FOOD WEBS (DIAGRAM)

Trophic Level Producer, primary consumer, secondary consumer, tertiary consumer Producer Grass 1 st Mouse 2 nd Primary consumer Grasshopper 2 nd Primary consumer Frog 3 rd Secondary consumer Owl 3 rd and 4 th Hawk 3 rd Secondary and tertiary consumer Secondary consumer

ENERGY PYRAMID

THE PYRAMID SHAPE IS USED TO REPRESENT THE FLOW OF ENERGY BECAUSE OF THE WAY THAT ENERGY IS USED UP AND LOST THROUGHOUT THE SYSTEM

ECOLOGICAL PYRAMID • • Which level has has the the most energy? most organisms? least energy?

PYRAMID OF NUMBERS • Shows the numbers of individual organisms at each trophic level in an ecosystem. tertiary consumers 5 secondary consumers 5000 primary consumers 500, 000 producers 5, 000 • A vast number of producers are required to support even a few top level consumers.

BIOMASS PYRAMID Biomass is a measure of the total dry mass of organisms in a given area. tertiary consumers 75 g/m 2 150 g/m 2 secondary consumers primary consumers producers 675 g/m 2 2000 g/m 2

CONCLUSION Energy is used up for all life processes such as respiration, movement, metabolic processes, and reproduction. So, of the 100% total energy available to the plants, only around 10% is made into plant tissues, while 90% is used up and is lost as heat. At each of the subsequent trophic levels, the same amount of energy (90%) is lost as heat, while 10% is turned into available biomatter. By the time the energy reaches the top trophic level, the apex predators will only receive 0. 01% of the primary energy! Because there is so little energy available at the highest trophic level, food chains are typically limited to a maximum of six levels. Throughout the entire energy pyramid, decomposers and detritavores break down the tissues and other organic matter which has not been consumed by animals higher in the food chain. In doing so, these organisms recycle the nutrients back into the soil, playing a vitally important role in the carbon and nitrogen cycles.

TERMS RELATED WITH THE PRESENTATION Trophic Level – Each of the hierarchal levels in an ecosystem, in which organisms share the same function and nutritional relationship within the food chain. Food Web – The biological community in which organisms interact with each other and their physical environment. Autotroph – An organism which is able to produce its own nutrition in the form of organic substances from inorganic substances such as carbon dioxide. Heterotroph – An organism which must derive its nutrition from organic substances, usually plant and animal matter.