Chapter # 4.2 Ecological systemand .pptx

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1. Ecological Principles and Process in Agroecosystems Concepts, structure, function, biotic and abiotic components of agroecosystesms and their linkages Energy flow, ecological pyramids, food chains and food webs, trophic level. Biogeochemical cycles

2. Three Big Ideas •Life is sustained by the flow of energy from the sun through the biosphere , the cycling of nutrients within the biosphere, and gravity. •Some organisms produce the nutrients they need, some survive by consuming other organisms, and others recycle nutrients back to producers . • Human activities are altering the flow of energy through food chains and webs, and the cycling of nutrients within ecosystems and the biosphere.

3. Ecosystems A place in which matter and energy are moved, transformed, or stored Ecosystems components Abiotic Landscape Geology Climate Microclimate? Biotic Producers Consumers Trophic interactions Energy Flows Nutrient Cycles

4. 1.Concepts of Ecosystem and Agroecosystems The concept of ecosystem was first put forth by A. G. Tansley (1935). According to Odum , ecosystems generally include four categories of basic structural components: Abiotic components(physical factors) Producers, mainly green plants Consumers, almost exclusively animals Decomposers, mainly bacteria and fungi

5. Abiotic components Ecological relationships are manifested in physico-chemical environment. Abiotic component of ecosystem includes basic inorganic elements and compounds , such as soil, water, calcium, oxygen, carbonates, phosphates and a variety of organic compounds ( by-product of organic activity or death). It also includes such physical factors and gradients as moisture, wind currents and solar radiation. Radiant energy of sun is the only significant energy source for any ecosystem. The amount of non-living components, such as phosphorus, nitrogen etc. that are present at any given time, is known as standing state or standing quantity

6. Symbiosis A close and permanent association between organisms of different species Commensalism – a relationship in which one organism benefits and the other is not affected Example: Barnacles (a type of crustacean) on a whale, epiphytic orchids(humidity, light), tree frogs Mutualism – a relationship in which both organisms benefit from each other Example: Birds eating pest off a rhino’s back, lichens( fungi+algae), root nodules, mycorhiza Parasitism – A relationship in which one organism benefits and the other is harmed Example: Ticks on a dog Competition: both harmed Antibiosis: one is harmed other neither benefited nor harmed. Example: Allelopathy aggregation: survival significance e.g. may fly, mosquito swarm for mating

7. Functions of Ecosystems The principal steps in the operation of ecosystem are as follows: Reception of radiant energy of the sun. Manufacture of organic materials from inorganic ones by producers. Consumption of producers by consumers and further elaboration of consumed materials. After the death of producers and consumers, complex organic compounds are degraded and finally converted by decompose rs and converters into such forms as are suitable for reutilization by producers.

8. Three Factors Sustain the Earth’s Life •One-way flow of high-quality energy from the sun and back into space •The cycling of nutrients through the biosphere •Gravity – holds in the atmosphere, assists in the cycling of nutrients, and prevents us from flying off into space!

9. Energy Flow in Ecosystems Plants are called producers because they make carbohydrates during photosynthesis. CO 2 + H 2 O + sunlight → C 6 H 12 O 6 + O 2 Consumers get their energy by feeding on producers or other consumers. - Decomposers break-down wastes & dead organisms, through the process of biodegradation.

10. ‹#› Sunlight Solar energy that reaches the earth’s surface is in, or near, the visible light wavelengths. Drive photosynthesis. More than half of the incoming sunlight may be reflected or absorbed by atmospheric clouds, dust, or gases. Short wavelengths are filtered out by gases in the upper atmosphere.

11. ‹#› Photosynthesis Chemical reaction where green plants use water & carbon dioxide to store the sun’s energy in glucose ENERGY is stored in glucose Glucose is stored as starch in plants copyright cmassengale

12. ‹#› CELLULAR RESPIRATION is the chemical reaction that releases the energy in glucose . 6O 2 + C 6 H 12 O 6 -->  6H 2 O + 6CO 2 + energy copyright cmassengale

13. Producers A groups of organisms that can use the energy in sunlight to convert water and carbon dioxide into a sugar called Glucose (food) Energy for all ecological systems begin with producers. Ex. Plants and Algae

14. Autotrophs

15. ‹#› Niche of a Producer Captures energy and transforms it into organic, stored energy for the use of living organisms. May be photoautotrophs using light energy (e.g. plants ) May be chemoautotrophs using chemical energy (e.g. cyanobacteri a) copyright cmassengale

16. ‹#› On Land Plants In The Sea Algae Tidal Flats & Salt Marshes Cyanobacteria Habitat of Photoautotrophs copyright cmassengale

17. ‹#› Chemoautotrophs Capture energy from the bonds of inorganic molecules such as Hydrogen Sulfide Process is called Chemosynthesis Often occurs in deep sea vents or gut of animals Called a Black smoker (thermal vent) copyright cmassengale

18. ‹#› Tube Worms living in Black Smoker copyright cmassengale

19. ‹#› Photoautotroph Producer That Captures Energy from the sun by: Photosynthesis Adds Oxygen to the atmosphere Removes Carbon Dioxide from the Atmosphere Algae copyright cmassengale

20. Heterotrophs

21. ‹#› Trophic Levels An organism’s feeding position in an ecosystem is called as trophic level . Organisms can also be identified by the kinds of food they consume: Herbivores – cows eat plants. Carnivores – lion eat animals. Omnivores - man eat plants and animals. Detritivores – ants & beetles eat detritus ( litters) Decomposers - bacteria and fungi breakdown complex organic matter into simpler compounds.

22. ‹#› Trophic Levels

23. Herbivores Consumers 2. Herbivores – eat ONLY plants Ex. – Cows, Elephants, Giraffes

24. Carnivores Consumers 3. Carnivores – eat ONLY meat Ex. – Lions, Tigers, Sharks

25. Omnivores Consumers 4. Omnivores – eat BOTH plants and animals Ex. – Bears and Humans

26. Scavengers Consumers 1. Scavengers – feed on the tissue of dead organisms (both plants and animals) Ex. – Vultures, Crows, and Shrimp

27. Decomposers Consumers 5. Decomposers – absorb any dead material and break it down into simple nutrients or fertilizers Ex. – Bacteria and Mushrooms

28. ‹#› Energy Exchange

29. Feeding Relationships Energy flow through an ecosystem in one direction , from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers). Food Chains are a series of steps in which organisms transfer energy by eating or being eaten . Food webs show the complex interactions within an ecosystem. Each step in a food chain or web is called a trophic level. Producers make up the first step, consumers make up the higher levels.

30. Energy Flow & Energy Loss in Ecosystems Methods to represent energy moving through ecosystems. Food chains : show the flow of energy in an ecosystem. Food webs : represent interconnected food chains. They model the feeding relationships in an ecosystem Food pyramids : show the changes in available energy from one trophic level to another in a food chain. They’re also called ecological pyramids

31. ‹#› The transfer of energy from the sun to producer to primary consumer then to higher order consumers can be shown in a FOOD CHAIN. copyright cmassengale

32. Food Chains A food chain is simple and direct 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

33. Food Chain

34. ‹#› copyright cmassengale

35. ‹#› More Food Chains copyright cmassengale

36. Food Webs This food web represents a terrestrial ecosystem that could be found in British Columbia . Most organisms are part of many food chains. Arrows in a food web represent the flow of energy and nutrients. Following the arrows leads to the top carnivore(s).

37. ‹#› Food Web copyright cmassengale

38. Ecological Pyramids An ecological pyramid is a diagram that shows the relationship amounts of energy or matter contained within each trophic level in a food web or food chain. Energy Pyramid only 10% of the energy available within one trophic level is transferred to organisms at the next trophic level. Food chains and food webs do not give any information about the numbers of organisms involved. This information can be shown through ecological pyramids.

39. ‹#› copyright cmassengale

40. Ecological Pyramid

41. Ecological Pyramid Which level has the most energy? Which level has the most organisms? Which level has the least organisms? Which level has the least energy?

42. PYRAMID OF NUMBERS Shows the number of organisms at each trophic level per unit area of an ecosystem.

43. Pyramid of Numbers Pyramid of numbers displays the number of individuals at each level. 1 owl 25 voles 2000 grass plants Tree Fruit eating Birds Lice and bugs Bacteria and fungi Producer Herbivores Parasites Hyper parasites Grassland ecosystem Forest/ agroecosytem

44. PYRAMID OF BIOMASS The total amount of matter present in organisms of an ecosystem at each trophic level is biomass. Biomass is preferred to the use of numbers of organisms because individual organisms can vary in size. It is the total mass not the size that is important . Pyramid of biomass records the total dry organic matter of organisms at each trophic level in a given area of an ecosystem.

45. Biomass Pyramids Displays the biomass at each trophic level. Grasses Rabbit, mice, insect Snakes lizard Hawk Grassland ecosystem

46. Bigger fishes Smaller fishes, water beetles Rotifers Phytoplankton, algae Pyramid of biomass in pond ecosystem

47. PYRAMID OF ENERGY Shows the amount of energy input to each trophic level in a given area of an ecosystem over an extended period. Why will this type of pyramid never be inverted?

48. Energy Pyramid Fig. 4–19 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.

49. Another Energy Pyramid Annual pyramid of energy flow (in kilocalories per square meter per year) for an aquatic ecosystem in Silver Springs, FL. Note: More individuals can be supported at lower trophic levels. Less energy is lost.

50. Models of Energy Flow in a Community Model # 1. Single Channel Energy Flow Model: This model depicts a community boundary and, in addition to light and heat flows, it also includes import, export and storage of organic matter.

51. Model # 2. Y-Shaped/two Channel Energy Flow Model: In this type of model, the grazing and detritus food chains are shown as sepa­rate flows.

52. Model # 3. Universal Model: This is applicable to any living component, which may be plant, animal, microorganism, individual, population or trophic group.

53. ‹#› Hydrologic Cycle

54. ‹#› Carbon Cycle

55. ‹#› Nitrogen Cycle

56. ‹#› Phosphorus Cycle

57. ‹#› Sulfur Cycle

58. Biomass The total mass of the organic matter at each trophic level is called biomass Biomass is just another term for potential energy – energy that is to be eaten and used. The transfer of energy from one level to another is very inefficient (10% Law)

59. Productivity concept The energy accumulated by producers is called 'production' or more especially 'primary production’. There are three fundamental concepts of productivity: Standing crop. Measurements of standing crop reveal the concentration of individuals in the various populations of the ecosystem. The materials removed. It includes the yield to man, organisms removed from the ecosystem by migration, and the material withdrawn as organic deposit. The production rate.. The amount of material formed by each link in the food chain per unit of time unit area or volume is "the production rate".

60. Plant indicators Indicators of agriculture : Forests and grasslands Indicators of soil type: sandy loam, deeply rooted and taller species . Indicators of soil erosion and soil formation : Choris spinarum and Capparis spiaria are indicators of soil erosion where on Ziziphus rotundifolia is an indicator of soil formation. Indicators of soil water : Several plants like Enicostum littorale indicate well-drained soil. Indicators of minerals : Viola calamine grows in soils rich in zinc, Stellaria setacea in mercury rich soil, Equisetum plebejum in soil containing gold

61. Indicators of pollution : Certain aquatic plants such as Utricularia, Chara and Wolffia indicate polluted water. Indicators of bogs and swamps : Typha, Phragmites, Juncus, Carex and some species of Polygonum indicate bogs and swamps. Indicators of saline and alkali soils : Rhizonphora, Sonneratia, Avceenia, Ceriops and Hevitiera indicate saline waterlogged soils. Plants like Salyrla foetida, Salicornia and Suaeda fruticosa are indicators of saline and alkali soils. Such soils are not fit for agriculture till the accumulated salts are not removed. Even then, only salt-tolerant plants like sugarbeet, rice, patsan and wild indigo should be cultivated in the beginning.

62. Thank you……..