Ecosystem concept and types
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The document discusses ecosystems, including their structure, functions, and examples. It defines an ecosystem as a natural unit consisting of living and non-living components that interact. The key components are producers, consumers, and decomposers. Food chains and webs show energy transfer between trophic levels, which is typically only 10% efficient. Ecosystems include both natural and man-made examples like forests, grasslands, ponds, oceans, and agricultural fields. Ecological pyramids illustrate the biomass and numbers at each trophic level. Succession over time leads to a stable climax community.
Ecosystem concept and types
- 1. ENVIRONMENTAL STUDIES Presented by – Dr. Parul Tyagi Assistant Professor
- 2. Structure and Functions of Ecosystems Presented by - Dr. Parul Tyagi Assistant Professor Environmental Studies
- 3. An ecosystem is a natural unit consisting of all plants, animals, and micro- organisms in an area functioning together with all the non-living physical factors of the environment. According to British ecologist Arthur Tansley (1935), an ecosystem is a system that arises from the integration of all living and non-living factors of the environment. Ecosystem An ecosystem is a self-sustained community of plants and animals existing in its own environment. The term ecosystem may be defined as a system resulting from the integration of all the living and non living factors of the environment. Desert, Forest, Ocean, Grasslands, Mountains, etc. are all ecosystems.
- 4. What is an ecosystem? Ecosystem is a system of living things that interact with each other and with the physical world.
- 5. However…….. •An ecosystem can be as large as the Sahara Desert, or as small as a puddle!!! •Ecosystems are more than just the organisms they contain. •Geography, weather, climate and geologic factors also influence the interactions within an ecosystem.
- 6. A puddle is a small accumulation of liquid, usually water, on a surface puddle
- 8. Kinds of Ecosystems Natural Ecosystems Man-made Ecosystems Terrestrial Ecosystems Aquatic Ecosystems Fresh water Ecosystems Marine Ecosystems Lentic Ecosystems (Static water) Lotic Ecosystems (Running water)
- 9. Natural Ecosystems Man-made Ecosystems Ecosystems which are the gifts of nature are called natural ecosystems. Deserts, forests, oceans, grasslands, etc. are natural ecosystems . Ecosystems which are engineered by man are called Man Made or artificial ecosystems. Examples : Gardens, Man made lakes, agricultural fields, etc.
- 10. Natural Ecosystem Artificial Ecosystem (i) Plants of one species are often scattered (i) Plants of the small species grow in close proximity (ii) Natural ecosystems usually have alternate sources of food available if one fails. (ii) Artificial ecosystems usually contain less food choices. (iii) Natural ecosystem is developed under natural conditions. (iii) Artificial ecosystem is created and manipulated by human activities. (iv) In a natural ecosystem the inorganic nutrients are returned to the soil from which they were taken. (iv) In artificial ecosystems, the inorganic nutrients do not return to the soil but are carried away at some other places. (v) Natural ecosystems have no distinct boundaries. (v) Artificial ecosystems have distinct boundaries. Natural Vs Artificial Ecosystems
- 11. Structure of an Ecosystem
- 12. Structure of an Ecosystem Living (Biotic) Components • Producers • Consumers • Decomposers Non-living (Abiotic) Components • Physical factors • Chemical factors • Limiting factors
- 13. Biotic Components of Ecosystems • Producers (or autotrophs) Green plants and some bacteria which manufacture their own food. • Consumers (or heterotrophs) Animals which obtain their food from producers •Primary consumers •Secondary consumers •Tertiary consumers • Decomposers Bacteria and fungi that decompose dead organic matter and convert it into simpler parts
- 15. Abiotic Components of an Ecosystem Physical Factors Rainfall Humidity Temperature Nature of soil Water currents Sunlight Chemical Factors Percentage of Water and air in soil Salinity of Water Oxygen dissolved in water Nutrients present in soil Limiting Factors Food, water, shelter and space are limiting factors for the growth of population of human and animals.
- 16. • Food chain and food web • Energy flow • Ecological pyramids Functions of an Ecosystem
- 17. The transfer of food energy from the source (plants) through a series of organisms by repeated eating and being eaten up is referred to as food chain. Food Web The interlocking pattern formed by several food chains that are linked together is called a food web. Food Chain
- 18. Food Chain The process of eating and being eaten • A series of organism by repeated eating and being eaten up is referred as food chain. Types: • Grazing food chain-a common chain • Detritus food chain- chain derived by the organic wastes and dead matter from grazing food chains
- 19. Grazing and Detritus Food Chain Detritus (Dead organic matter) Food Chain Grazing Food Chain
- 20. The Producers •Producers are the beginning of a simple food chain. Producers are plants and vegetables.
- 21. The Producers •All energy comes from the Sun and plants are the ones who make food with that energy. •They use the process of photosynthesis. •Plants also make loads of other nutrients for other organisms to eat.
- 22. The Consumers •Consumers are the next link in a food chain. There are three levels of consumers. •Primary •Secondary •Tertiary
- 23. Feeding Relationships • A food chain shows a simple feeding relationship. • Sun → • All food chains start with the sun
- 24. Feeding Relationships • A food chain shows a simple feeding relationship. • Sun → grass →
- 25. Feeding Relationships • A food chain shows a simple feeding relationship. • Sun → grass → rabbit →
- 26. Feeding Relationships • A food chain shows a simple feeding relationship. • Sun → grass → rabbit → fox
- 27. All food chains start with ENERGY from the sun
- 28. carbon dioxide from the air energy from sunlight (or light) water from the roots food transported to the rest of the plant
- 29. Because plants produce their own food, they are called ‘Producers’
- 30. •The energy is then passed on to animals when they eat the plant.
- 31. •Animals of all shapes…
- 33. …and sizes!
- 34. Because these animals are the first to take the food energy from the plants, They are called primaryconsumers
- 35. Aphids are eaten by….
- 36. Ladybirds
- 37. Animals that eat primary consumers are called secondary consumers
- 38. • So far this is a straightforward food chain • Sun →aphid →ladybird • But in reality it is more complicated than that
- 39. This bird eats smaller birds, mice, and rabbits
- 40. Sometimes it’s not entirely clear who eats who!
- 41. Biomagnification “Result of the process of bioaccumulation and biotransfer by which tissue concentrations of chemicals in organisms at one trophic level exceed tissue concentrations in organisms at the next lower trophic level in a food chain.”
- 43. Biomagnification of DDT was observed in some birds like as Osprey, in the results of sharp decline in their population. The young ones of these bird were found to hatch in a premature condition which led to their death. This was later found to be due to biomagnification of DDT through the food chain. DDT is one of the pesticide, a chemical used to control pests in very low concentration The concentration of DDT was magnified several thousands times in the birds which caused thinning of shells in the birds eggs, causing deaths. Means, animals occupying higher trophic levels are at a greater risk of biomagnification of toxic chemicals. A build- up of DDT concentration
- 44. Food web Intermixing of food chains
- 45. Energy Flow in Ecosystems First Law of Thermodynamics energy can neither be created nor destroyed but only is transformed from one form to another. Second Law of Thermodynamics-The second law of thermodynamics states that no energy transformations are 100% efficient. 10 Percent Rule of Energy As a rule of thumb, 90 percent of the energy involved is degraded at each trophic transfer and only 10 percent of the energy is conserved in the organism's tissue.
- 46. Energy Flow in Ecosystems
- 47. Energy flow in ecosystem and 10% Rule
- 48. Ecological Pyramid The graphical representations of different trophic levels in an ecosystem where producers occupy the base and the top consumer occupy the apex of the pyramid, is known as ecological pyramid . They are used to illustrate the feeding relationships between organisms. Types of Ecological Pyramids •Pyramid of number •Pyramid of biomass •Pyramid of energy
- 49. ECOLOGICAL PYRAMIDS •Food chains and food webs do not give any information about the numbers of organisms involved. •This information can be shown through ecological pyramids.
- 50. Pyramid of Number • Pyramid of number is used to show the number of individuals in each trophic level. • It is upright in case of grassland and pond ecosystems.
- 52. Pyramid of Biomass Pyramid of biomass records the total dry organic matter of organisms at each trophic level in a given area of an ecosystem. The pyramid of biomass is used to show the total biomass of individuals at each trophic level. It is better than the pyramid of number for showing the relationships between organisms.
- 54. Pyramid of Energy Pyramid of energy is used to show the amount of energy transferred between trophic levels. It provides the best representation of the overall nature of an ecosystem. The pyramid of energy flow is always upright because there is always loss of energy while moving from lower trophic level to higher trophic level. Therefore, the energy reaching the next trophic level is always less compared to that in the previous trophic level.
- 55. Energy Pyramid In nature, ecological efficiency varies from 5% to 20% energy available between successive trophic levels (95% to 80% loss). About 10% efficiency is a general rule.
- 57. Ecological Succession Ecological succession is the gradual process by which ecosystems change and develop over time. It is therefore a series of predictable temporary communities or stages leading up to a climax community. Each stage/temporary community is called a successional stage. Each step prepares the land for the next successional stage. All habitats are in the state of constant ecological succession. Environment is always kept on changing over a period of time due to (i) variations in climatic and physiographic factors, and (ii) the activities of the species of the communities themselves. Ecological Succession is an orderly sequence of different communities over a period of time.
- 58. Primary Succession Secondary Succession Primary succession is the process by which an area first changes from bare rock into a functioning ecosystem. Secondary succession is the process by which an already existing plant community is replaced by another plant community. Types of ecological succession
- 59. 59 Primary Succession • The development of an ecosystem in an area that has never had a community living within it occurs by a process called PRIMARY SUCCESSION. • An example of an area in which a community has never lived before, would be a new lava or rock from a volcano that makes a new island.
- 60. Primary succession is the process by which an area first changes from bare rock into a functioning ecosystem.
- 61. 61 Secondary Succession • SECONDARY SUCCESSION begins in habitats where communities were entirely or partially destroyed by some kind of damaging event. • When an existing community has been cleared by a disturbance such as a fire, tornado, etc...and the soil remains intact, the area begins to return to its natural community. Because these habitats previously supported life, secondary succession, unlike primary succession, begins on substrates that already bear soil. In addition, the soil contains a native seed bank. • Since the soil is already in place, secondary succession can take place five to ten times faster than primary succession.
- 62. Secondary succession is the process by which an ecosystem that has been destroyed gradually returns to its previous state.
- 64. 64 The Circle of Life in Secondary Succession
- 65. 65 The Climax Community • A climax community is a mature, stable community that is the final stage of ecological succession. In an ecosystem with a climax community, the conditions continue to be suitable for all the members of the community. • Any particular region has its own set of climax species, which are the plants that are best adapted for the area and will persist after succession has finished, until another disturbance clears the area.
- 67. Nudation- Succession begins with the development of a bare site, called Nudation (disturbance). Invasion • Migration- It refers to arrival of propagules (seeds), dispersion. • Ecesis- It involves establishment and initial growth of vegetation. • Aggregation- It involves increase in number of various species. Competition- As vegetation became well established, grew, and spread, various species began to compete for space, light and nutrients. This phase is called competition. Stabilization- Reaction phase leads to development of a climax community. Process / Stages of Ecological Succession
- 68. Study of some common ecosystems •Terrestrial ecosystem oGrassland ecosystem oDesert ecosystem oForest ecosystem •Aquatic ecosystem oPond ecosystem oOcean ecosystem
- 69. Forest Ecosystem Inorganic and organic substances found in the soil, climatic factors, e.g., temperature, humidity, rainfall, and light. Abiotic Components Producers Different kinds of trees depending upon the climate Consumers Different kinds of primary, secondary, and tertiary consumers, e.g., deer, elephant, moles, snakes, lizards, lion, and tiger Decomposers These are various kinds of bacteria and fungi Biotic Components
- 70. Grassland ecosystem • All grasslands in the world are categorize into the following two types: • Tropical grasslands- closets to equator and are hot throughout the year. • Temperate grasslands - farther from the equator and have both hot summers and harsh winters.
- 71. Grassland Ecosystem Producers Mainly grasses with a few scattered trees Consumers Deer, rabbit, giraffe, etc., are herbivores, while wolf, leopard, etc., are carnivores Decomposers Mainly bacteria and fungi Abiotic Components Inorganic elements (C, H, O, N, P, S), climatic components, temperature, rainfall, light, etc. Biotic Components
- 72. Desert Ecosystem Producers Predominantly thorny shrubs, cactus, opuntia, etc. Consumers Different insects, lizards, reptiles, nocturnal rodents, birds, etc. Decomposers Various bacteria and fungi Low rainfall, high temperature, and sandy soil Abiotic Components Biotic Components
- 73. Pond Ecosystem It includes organic and inorganic substances, atmospheric gases dissolved in water, minerals found in dissolved state, etc. Producers Submerged floating and emergent aquatic plants For example, nelumbo, hydrilla, chara, etc. Consumers May be primary, secondary, or tertiary, e.g., small fishes, beetles, mollusca, crustaceans, etc. Decomposers Chiefly bacteria, actinomycetes, fungi, etc. Abiotic Components Biotic Components
- 74. Ocean Ecosystem It includes organic and inorganic substances, atmospheric gases dissolved in water, minerals found in dissolved state, etc. Producers Submerged floating and emergent aquatic plants For example, nelumbo, hydrilla, chara, etc. Consumers May be primary, secondary, or tertiary, e.g., small fishes, beetles, mollusca, crustaceans, etc. Decomposers Chiefly bacteria, actinomycetes, fungi, etc. Abiotic Components Biotic Components