276_78343_276_50728_04 Ecosystem.ppt

276_78343_276_50728_04 Ecosystem.ppt - The study of the...

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Unformatted text preview: The study of the relationships between biotic and abiotic factors in environments Examples of Biotic Factors Abiotic Factors All non living components of the environment are abiotic factors. They include air, water, soil, temperature, rainfall, humidity, minarals, source of energy. Biome A A major major regional regional or or global global biotic biotic community, community, aa super super ecosystem, ecosystem, defined defined chiefly chiefly by by the the dominant dominant forms forms of of plant plant life life and and the the prevailing prevailing climate climate Major Biomes of the World Desert Desert Grassland Grassland Tropical Tropical rain rain forest forest Deciduous Deciduous forest forest Coniferous Coniferous forest forest Tundra Tundra Ocean Ocean Life Organization Levels of Organization large smallest group one all organisms interacting living individual region of and similar different organs unit nonliving ofpopulations of living living cells the working typical kinds thing same of smallest group one all large region unitwith with typical organized tissues together kind in things plants an ecosystem interacting and working in to animals one work area within that aa organized tissues together kind in things plants anliving living interacting working in onetogether together area within together certain includes several togetherarea certain includes ecosystems ecosystems cell Ecosystems: Fundamental Characteristics • Structure: – Living (biotic) – Nonliving (abiotic) • Function: – Energy flow – Cycling of matter Ecosystem Structure Biotic Producers Consumers Abiotic Physical Food Chain, Chemical Solar flux, Temperature, Carbon, Nitrogen, Phosphorus, Rainfall, Potassium, Wind, Decomposers Functions Water Latitude, Altitude, Soil type etc Hydrogen, Oxygen, Salts, Organic substances in the soil Food web, Ecological Pyramids, Bio-geo Chemical Cycles Ecological Succession In an ecosystem the biological cycling of materials is maintained by three groups • Producers • Consumers • Decomposers / Recyclers Producers, Consumers and Decomposers: Producers: Autotrophic organisms, largely green plants which are able to manufacture the required food material from simple inorganic substances. Consumers: Heterotrophic organisms, chiefly animals, which ingest other organisms or particulate organic matter, are included in this category (i) Primary Consumers – Herbivores (ii) Secondary Consumers – Carnivores (iii) Tertiary Consumers – Carnivores or Omnivores Examples of producers: Photosynthetic Bacteria Grasses Trees Shrubs Herbivores: Also primary consumers, feed directly on living plants or plant residues. They have vegetarian diet. Carnivores: Also secondary/ tertiary consumers, which feed on consumers, i.e. they have non- vegetarian diet. They are also called “Predators” Omnivores: Consumers, which feed on producers as well as on primary consumers, i.e. they have vegetarian as well as nonvegetarian diet. Micro-consumers: Also Saprotrophs/ Detritivores . They are popularly known as decomposers, such as bacteria, fungi, flagellates & actinomyctes. They feed on organic compounds of dead or living protoplasm of plants and animals for their food and energy They absorb some of the decomposition or breakdown products & release inorganic compounds (nutrients) in the ecosystem, making them available again to producers. Trophic Levels A trophic level is the position occupied by an organism in a food chain. Producers Primary consumer Secondary consumer Tertiary consumer Decomposers Producers Consumers FLOW OF ENERGY HERBIVORES PRODUCERS Carbohydrates, fats, proteins, nucleic acids etc. CARNIVORES DECOMPOSERS NUTRIENT POOL material energy Law of 10% Calories Solar Energy 1,000,000 1% 10,000 Producers 10% 1,000 Herbivores 10% Carnivores Consumers 10% Top Carnivore Law of 10% proposed by Lindeman 100 10 Food Chains The transfer of food energy from the producers, through a series of organisms (herbivores, carnivores and decomposers) with repeated eating and being eaten, is known as food chain. 1. Grazing food chain 2. Detritus food chain Trophic level Feeding strategy 5 Quaternary consumer Decomposer food chain Grazing food chain Cooper’s hawk 4 3 2 1 Tertiary consumer Robin Cooper’s hawk Earthworm Robin Bacteria, archaea Cricket Dead maple leaves Maple tree leaves Secondary consumer Primary decomposer or consumer Primary producer Grazing Food Chain This food chain starts from the living green plants and goes to grazing herbivores and onto carnivores. These chains are extremely important from energy stand point. Grass Rabbit Fox Lion Food Webs: Food chains in natural conditions never operate as isolated sequences, but are inter connected with each other forming a sort of inter locking pattern, which is referred to as food web. The linear arrangement of food chains hardly occurs and they are interconnected under natural conditions, thus there are found alternatives in nature. In a grazing food chain of grassland, in the absence of rabbit, grass may also eaten by mouse. The mouse may in turn be eaten directly by hawk or by snake first which is then eaten by hawk. 1. Grass 3. Grass 4. Grass 5. Grass Grasshopper Rabbit Hawk Hawk (Vulture/Fox/Man) Mouse Mouse Hawk Snake Hawk A balanced ecosystem is essential for the survival of all living organisms of the system. Thus food chains and food webs form a natural check to balance the ecosystem. Ecological Pyramids The graphical representation of the trophic structure and trophic function is referred to as “Ecological Pyramids” In this, producer level forms the base and successive levels or tiers make up the apex. Ecological pyramids may be of 3 general types: 1. 2. 3. Mar 30, 2018 The Pyramid of Numbers The Pyramid of Biomass The Pyramid of Energy Environmental Studies 31 Pyramid of Numbers Gives the relationship between producers, herbivores and carnivores at successive trophic levels in terms of their numbers. Pyramid of Biomass: To produce a pyramid of biomass the dry weight of each species present is calculated. Pyramid of Energy: In this pyramid, the number and weight of organisms at ay trophic level depends on the rate at which food is being produced but not on the amount of fixed energy at any level in a given time. The pyramids of numbers and biomass may be upright (or) inverted depending upon the nature of food chain in the particular ecosystem but the pyramids of energy are always upright. 03/30/18 Source: Confidential 34 Cycling of Matter: by Biogeochemical cycles Hydrological cycle Carbon cycle Nitrogen cycle Phosphorous cycle Sulfur cycle The Water Cycle (Hydrologic cycle) Mar 30, 2018 Environmental Studies 38 Carbon cycle Nitrogen cycle Mar 30, 2018 Environmental Studies 41 Mar 30, 2018 Environmental Studies 42 Types of Ecosystem Man-Made Natural Aquatic Terrestrial Fore st Grassla nd Desert Freshwater Estuaries Lentic Lotic Eg: Ponds , Lakes Eg:Rive rs canals, stream s Marine Types of Ecosystem On the basis of particular type of habitat, they are further sub divided as: Terrestrial Ecosystems (Biomes): They are often defined by the vegetation types that dominate the community. Terrestrial vegetation has a rapid exchange of oxygen, water & carbon dioxide. Moisture is the major limiting factor, faces the problem of dehydration. Examples of terrestrial ecosystem are: Forest ecosystem, Grassland ecosystem, Desert ecosystem. Aquatic Ecosystems (Biomes): Aquatic ecosystems deal with biotic community present in water bodies. In terrestrial ecosystem, carbon dioxide and oxygen are present in gaseous form, but in aquatic ecosystem these are made available in dissolved state. 03/30/18 Source: Confidential 44 Aquatic ecosystems fall into two categories: Freshwater Ecosystem and Marine Ecosystem. Freshwater ecosystem may be: Lotic (Running water) Example: Streams, Rivers, Springs Lentic (Standing water) Examples: Lakes, ponds, swamps Marine ecosystems includes Deep sea and Oceans. Ecological Succession • Ecological succession is the gradual process by which ecosystems change and develop over a period of time. • In the process of succession, the species present in an area will gradually change. There are two types of ecological succession: 1. Primary Succession 2. Secondary Succession 03/30/18 Source: Confidential 46 ...
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