Ecosyestem structure and function

introduction
defination
structure
function
clasification
forest as an ecosystem
grassland as an ecosystem

1. Presented By- Dabhi Monali A. CBO-405 M.sc.(sem-2)Botany Department of life Sciences, H.N.G.U., PATAN Ecosystem - Structure and function, Types-terrestrial(forest and grassland)

2. CONTENT Introduction of ecosystem Ecosystem Definition Structure of ecosystem Function of ecosystem 1.Productivity 2.Decomposition 3.Enegry flow 4.Nutrient cycling Classification of ecosystem Forest as an ecosystem Grassland as an ecosystem

3. Introduction of Ecosystem The term ‘Ecosystem’ was proposed by a British ecologist A. G. tansley in the year 1953. What is ecosystem ? A community, along with its physical environment, has a living (biotic) component and a non-living(a biotic) component . Ecosystem consists of two words: Eco-Environment Ecosystem System-Interaction

4. Ecosystem:Definition Acording to E.P. odum , an American Ecologist, the ecosystem is the basic functional unit of organism and their environment interacting with each and with their one components. e.g. Grassland, forest, Aqurium, Pond, Lake, River and Ocean.

5. Structure of ecosystem : A biotic – Eg. Soil, Water, light. Ecosystem Biotic – Eg. Producers and consumers

6. Biotic -Organic matter -Living things -Oysters -Blue crabs -Zooplankton -Phytoplankton -Jellyfish A biotic -Climate -Nonliving things -Sun light -Temperature -Nutrient enrichment -Humidity -Soil

7. Function of ecosystem : The components of the ecosystem are seen to function as a unit when we consider the following a spects: Productivity Decomposition Energy flow Nutrient cycling. Productivity : The productivity of an ecosystem is the rate at which solar energy is fixed by the vegetation of the ecosystem; it is further classified into primary productivity, Secondary productivity and net productivity.

8. Decomposition: The breakdown of complex organic matter into inorganic substances like carbon dioxides, water and nuterients and the process is called decomposition. Steps in decomposition : -Fragmentation -Leaching -Catabolism -Humification -Mineralization.

9. Energy flow : The flow of energy is one way direction from producer to consumers, and ends in decomposition process. -However, a part of the energy is lost as heat and agrees with the phenomenon of second low of Thermodynamic. Nutrient cycle : A nutrient cycle (or ecological recycling) is the movement and exchange of organic and inorganic matter back into the production of living matter. -The process is regulated by food web pathways that decompose matter into mineral nutrients. -Nutrient cycles occur within ecosystems.

10. Forest as an Ecosystem : Forest ecosystem is the best example of a terrestrial ecosystem .Like other ecosystem,there are two main components of forest ecosystem: A biotic component. Biotic component. A . A biotic component : In a forest ecosystem soil, moisture, air and sunlight from the a biotic or physical component. B. Biotic component : There are three important classes of biotic components: 1. Producers, 2. Consumers, 3. Decomposers and transformers.

11. 1. Producers: All the green plants of a forest are producers. They are the main sources of food for all the animals. There are several layers of vegetation in the forest. The plants of top stratum are angiospermous and gymnospermous trees. These plant utilize radiant energy of sun to the greastest extent. Below the level of trees there is layer of shrubs which consume light energy of low intensity coming through trees. Just below the shrubs there are gasses, herbs, lichens and mosses. These also manufacture food. These plants get least light.

12. 2. Consumers : There are a number of consumers in an old dense forest. Consumers of first order in the forest are grasshoppers, rabbit, deer, monkey, birds and many other wild herbivorous animals which utilize plants directly as their food. Secondary consumers are wolves, pythons, jackals etc. Which consume the flesh of herbivores. Lion, tiger, hawks are the consumers of top level.

13. 3. Decompsers and transformers : These are micro-organisms, chiefly bacteria and fungi which attack dead bodies or producers and consumers and convert complex organic compounds into simpler inorganic compounds and elements. These free elements again return to the a biotic component and are re- utilised by producers in their nutrition.

14. F Fig. forest ecosystem

15. Grassland as an Ecosystem: Grassland occupy about 19 pre cont of the earth’s surface. The major grassland ecosystem of the world are the great plains of Canada and United states, S. Argentina to Brazil and S . Asia to Central Asia. The various components of a grassland ecosystem are as fellows: A . A biotic Components : The nutrients present in soil and the aerial environment are the a biotic components (the elements like C,H,O,N,P,S etc. are supplied by CO2, Water, nitrates, Phosphates and sulpltates ) .

16. B. Biotic Components: These include mainly (a) grasses, like Dichanthium, Cynodon , Desmodium, Digitaria, Dactyloctenium, Setaria etc. as producers; (b) animals like Cow, buffaloes, deers, sheep, mouse and many insects as consumers, (c) Fungi like Mucor, Asperillus, Penicillium, Cladosporium, Fusarium, and (d) bacteria as the decomposers.

17. fig. Grassland

18. Producers : These are mainly grasses of the family Graminae , a large variety of herbs, some shrubs and Scattered trees. Consumers: Herbivores such as grazing mammals( eg. Cows, sheep, deer, rabbit,buffaloes,etc.),insects (eg. Dysdercus, Coccinella, Leptocorise, etc.),some termites and millipendes are the primary consumers. The animals like fox, jackals, snakes, frogs, lizards, brids ,etc. are the camivores feeding on herbivores. These are the secondary consumers of the grassland ecosystem Hawks occupty the tertiary trophic level as these feed on the secondary consumers.

19. Decomposers : These include bacteria of death and decay, moulds and fungi (eg. Mucor, Penicillium, Aspergillus, Rhizopus, etc.) These buing the minerals back to the soil to be available to the producers again.

20. Reference: Essentials of Plant Taxonomy & Ecology M.P. Singh S.G. Abbas

21. Thank you