PPT2.3 Food chains food web.ppt
- 1. Lecture on Food Chains, Food Webs and Energy Pyramids By Ravi Gedela M.Tech IITG, (PhD IITG) Assistant professor Department of Bio-Sciences RGUKT SKLM Rajiv Gandhi University of Knowledge Technologies
- 2. Energy Flows through Ecosystems in Food Chains and Food Webs • As energy flows through ecosystems in food chains and food webs, the amount of high- quality chemical energy available to organisms at each successive feeding level decreases. • The chemical energy stored as nutrients in the bodies and wastes of organisms flows through ecosystems from one trophic (feeding) level to another.
- 3. Natural capital: The main components of an ecosystem are energy, chemicals, and organisms. Nutrient cycling and the flow of energy—first from the sun, then through organisms, and finally into the environment as low-quality heat— link these components.
- 4. Trophic Levels • A trophic level means a feeding level. – First level – all producers – Second level – all herbivores – Third level – first level carnivores – Fourth level – second level carnivores • Energy moves from one organisms to another when it is eaten • Each step in this transfer of energy is know as a trophic level – The main trophic levels are producers, consumers, and decomposers
- 5. Conti.. • Energy and Nutrients passed through the ecosystem by food chains and webs from lower trophic level to the higher trophic level. • However, only 5% to 20% energy and nutrients are transferred into higher trophic level successfully. • For this reason, first trophic level has the largest number of organisms, and second trophic level is less than first one; the third level is less than second level, and so on.
- 6. Food Chain • A sequence of organisms, each of which serves as a source of nutrients or energy for the next, is called a food chain. • The energy flow from one trophic level to the other is know as a food chain. • The particular pathway of nutrient and energy movement depends on which organism feeds on anther.
- 7. • It involves one organism at each trophic level – Primary Consumers – eat autotrophs (producers) – Secondary Consumers – eat the primary consumers – Tertiary Consumers – eat the secondary consumers – Decomposers – bacteria and fungi that break down dead organisms and recycle the material back into the environment
- 10. Food Web • In natural ecosystems, most consumers feed on more than one type of organism, and most organisms are eaten or decomposed by more than one type of consumer. • Because of this, organisms in most ecosystems form a complex network of interconnected food chains called a food web • Food webs are more complex and involve lots of organisms. • Food chains and food webs show how producers, consumers, and decomposers are connected to one another as energy flows through trophic levels in an ecosystem.
- 13. Ecological Pyramids • An ecological pyramid is a graphical representation of an ecological parameter like number, biomass, and energy depicted in a systematic and stepwise manner in an ecosystem. • The ecological pyramid was initially developed by Charles Elton in 1927. Hence they are also called as Eltonian pyramids. • Three types of pyramids may be performed per each ecosystem and they are as follows: I. Pyramid of numbers II. Pyramid of biomass III. Pyramid of energy
- 14. Conti.. • Shows the amount of energy or matter contained at each trophic level; the relationship between consumers and producers • The Pyramid shows which level has the most energy and the highest number of organisms
- 15. FoodChain 1 Foodchain 2 Food Chain What do ‘ecological pyramids’ show? Energy Numbers Biomass Inverted pyramids?
- 16. I. Pyramid of numbers • This pyramid deals with the relationship between the number of primary producers and consumers of a different order.
- 18. II. Pyramid of biomass • Biome are defined as – “the world’s major communities, classified according to the predominant vegetation and characterized by adaptations of organism to that particular environment.
- 19. Biomass • Biomass means the total combined weight of any specified group of organisms. • The biomass of the first trophic level is the total weight of all the producers in a given area. • Biomass decreases at higher trophic levels.
- 21. III.Pyramid of energy • The pyramid of energy depends upon the energy levels. In the pyramid structure energy level increases from bottom to top. • Here, producers have low energy level but the consumers have high energy level.
- 25. WHAT HAPPENS TO ENERGY IN AN ECOSYSTEM • Gross primary productivity (GPP) is the rate at which an ecosystem’s producers (usually plants) convert solar energy into chemical energy stored in compounds found in their tissues. • To stay alive, grow, and reproduce, producers must use some of their stored chemical energy for their own respiration.
- 26. • Net primary productivity (NPP) is the rate at which producers use photosynthesis to produce and store chemical energy minus the rate at which they use some of this stored chemical energy through aerobic respiration. • NPP = (Produce and store chemical energy - Consumed some of the stored chemical energy through aerobic respiration). • NPP measures how fast producers can make the chemical energy that is stored in their tissues and that is potentially available to other organisms (consumers) in an ecosystem.
- 28. ENERGY FLOW IN AN ECOSYSTEM • The flow of energy from one organism to another organism in an ecosystem is known as energy flow. In biological activities, energy flows from the sun to plants and to all heterotrophic organisms like animals and human beings. The flow of energy takes place in the following way: • Sun to plant • Plant to primary consumers • Primary consumers to secondary consumers • Secondary consumers to tertiary consumers • Tertiary consumers to quaternary consumers • Quaternary consumers to sun ecosystem
- 29. Ecological Energy Pyramid : 10 % Law
- 30. Thank you