Ecology

1. Ecology

2. What is Ecology? Ecology is the study of interactions among organisms and between organisms and their environment. Biosphere contains the combined portions of the planet in which life exists, including land, water, and air or atmosphere.

3. Levels of Organization Species is a group of organisms so similar to one another that they can breed and produce fertile offspring. Population are groups of individuals that belong to the same species and live in the same area. Communities are assemblages of the different populations that live together in a defined area. Ecosystem is a collection of all the organisms that live together in a particular place as well as their nonliving or physical environment. Biome is a group of ecosystems that have the same climate and similar dominant communities.

4. Animals get their food … or (c) other animals ... plant products, by eating plants or ... 5 Plants make their food by photosynthesis

5. Energy Flow Sunlight is the main source of energy for life on Earth. Organisms are divided into two groups based on how they obtain their Energy 1. Autotrophs : Make their own food by converting energy and chemicals into food 2. Heterotrophs: Must eat other organisms for their food.

6. Energy FlowAutotrophs The best know autotrophs are those that harness the power of the sun through photosynthesis. They use this energy to convert carbon dioxide and water into oxygen and glucose. The second type of autotrophs use chemical energy to make carbohydrates. This is performed by several types of bacteria.

7. Energy FlowTypes of Heterotrophs Herbivores obtain energy by eating plants. Carnivores eat animals. Omnivores eat both plants and animals. Detritivores feed on the remains of plants, animals and other dead matter. Decomposers breaks down organic matter.

8. Feeding Relationships Energy flows 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.

9. Food Chain A Food Chain is a series of steps in a community of organisms that is used to transfer ENERGY and MATTER by eating or being eaten.` The Steps are Called TROPHIC LEVELS

10. Food Web A Food Web is a series of interconnected food chains Can You Still Identify the Trophic Levels here?

11. Food Web

12. Ecological Pyramids An ecological pyramid is a diagram that shows the relarive 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.

13. Roughly 10% of the energy is transferred

14. Pyramids Continued Biomass pyramids show the total amount of living “food” available at each trophic level. Numbers pyramid shows the number of species at each trophic level. Because each trophic level harvests only about one tenth of the energy from the level below, it can support only about one 10th the amount of living tissue.

15. BIOMASSPyramid

16. 2 73.943kg soil 74kg soil In the 17th Century, A Belgian physician, van Helmont, set up an experiment in which he planted a willow sapling in a weighed amount of soil. How do plants get their food ? The soil was watered but nothing else was added. After 5 years, the tree had gained 74kg in weight but the soil had lost only 57g. van Helmont concluded that the tree had made 74kg of new growth from water alone

17. van Helmont’s experiment was effective in showing that the plant’s food did not come from the soil. But he had overlooked the fact that airwas available to the plant as well as water. Could it be that the plant made 174kg of material from just airand water? This might seem unlikely but we now know that plants do indeed make their food from carbon dioxide from the air and water from the soil. 3

18. carbon dioxide sunlight (energy) water water 9

19. 6 Photosynthesis Green plants take in carbon dioxide (CO2) from the air They take up water (H2O) from the soil The plants combine the CO2 with the H2O to make the sugar, glucose (C6H12O6) 6CO2 + 6H2O = C6H12O6 + 6O2 Oxygen (O2) is a by-product of this reaction

20. Photosynthesis

21. Photosynthesis

22. Energy It takes energy to make CO2 combine with H2O This energy comes from sunlight The energy is absorbed and used by a substance called chlorophyll 9

23. Leaf Anatomy

24. 10 Chlorophyll is a green coloured chemical It is present in the leaves of green plants The chlorophyll in the cells is packaged into tiny structures called chloroplasts The next slide shows a diagram of leaf cells with their chloroplasts Chlorophyll

25. Plant Cell

27. Anatomy of a Leaf

29. What happens to the glucose? The glucose made by the chloroplast is either (a) used to provide energy for the chemical processes in the cell ( by respiration) (b)turned into sucrose and transported to other parts of the plant or (c) turned into starch and stored in the cell as starch grains In darkness the starch is changed back into glucose and transported out of the cell 15

30. Plants combine carbon dioxide from the air, and water from the soil to make glucose. The energy needed for this process comes from sunlight The sunlight is absorbed by chlorophyll contained in the chloroplasts of the leaf. The glucose can be used for energy or to make other substances. To make other substances, the glucose must be combined with other chemical elements such as nitrogen and potassium. These chemical elements are present in the soil and are taken up in solution by the roots. 23 TO SUM UP

31. Respiration = use of oxygen to burn food for energy

32. Respiration Chemical Formula It’s the Reverse of Photosynthesis

33. 4 Animals get their food by eating plants, orother animals Carnivores eat animals Herbivores eat plants Plants make their own food They combine carbon dioxide from the air with water and dissolved salts from the soil Plants do NOTget their food from the soil The process by which plants make food is called PHOTOSYNTHESIS Feeding

34. Question 1 For a plant to make glucose it needs (a) CO2 and H2O (b) CO2, H2O and sunlight (c) CO2, H2O, sunlight and chlorophyll (d) CO2, H2O, sunlight, chlorophyll and nitrates 25

35. Question 2 A by-product of photosynthesis is (a) Water vapour (b) Oxygen (c) Carbon dioxide (d) Nitrogen 26

36. Question 3 The food made by photosynthesis is stored as the plant in the form of (a) Glucose (b) Sucrose (c) Starch (e) Cytoplasm 29

37. Cycles of Matter Unlike the one-way flow of energy, matter is recycled within and between ecosystems. These cycles are the water cycle, Nutrient Cycle, Carbon Cycle, nitrogen cycle and phosphorus cycle. These cycles are important so that the matter can be re-used by living things.

38. Carbon Cycle

39. Oxygen/Carbon Cycle

40. Nitrogen Cycle

41. The Nitrogen Cycle Nitrogen gas (N2) Plants Make Proteins with Nitrates Animals Make Proteins by consuming Plant or other organisms Waste Soil Bacteria Soil Bacteria Nitrite (NO2) Nitrate NO3 Nitrate (NO3)

42. Nitrogen Cycle FOOD contains PROTEIN Nitrogen is in the fish in the form of PROTEIN__ NO3 is absorbed by the plant roots and made into __________________________ that can be used in food Nitrogen in the waste is in the form of AMMONIA NH3 WASTE (NH3) (NH4+) Uneaten food is decomposed into Ammonia (NH3) by BACTERIA NO3 is eaten “decomposed by a bac3erial called __NITROBACTER__ into ____NITRATE, NO3___ Ammonia is eaten “decomposed” by a bacteria called _NITROSOMONAS into NITRITE, NO2 (NO2) Nitrite

43. Nitrates Nitrates are present in the soil, dissolved in water The plants take up nitrates in the soil water The nitrates are conducted through the roots to the stem and then to the leaves In the leaves, the nitrates and glucose are combined to make proteins This process is called assimilation 19