Chapter 3

1. Chapter 3 Ecosystems: What Are They and How Do They Work?

2. Core Case Study: Have You Thanked the Insects Today? • Many plant species depend on insects for pollination and plant reproduction. • Insects can control other pest insects by eating them. • They also mix up the soil Figure 3-1

3. Core Case Study: Have You Thanked the Insects Today? • …if all insects disappeared, humanity probably could not last more than a few months [E.O. Wilson, Biodiversity expert]. • Insect’s role in nature is part of the larger biological community in which they live. why are honeybees dis.flv honeybees part 2.flv

4. THE NATURE OF ECOLOGY • Ecology is • How organisms interact with one another and with their nonliving environment. ( we have to learn about how species interact with their environment, so we can understand how our actions are effecting this delicate balance) Figure 3-2

5. So, really intricate and amazing interrelationships occur between plants and animals.

6. Well, as mentioned earlier, plants rely on insects, birds, and rodents for pollination

7. And, of course birds and animals need plants……what what

8. Biosphere!!!!!!!

9. Re-wind: from this diagram I would like you to remember the differences between good and bad ozone, and the greenhouse vs. the ozone layer

10. What Happens to Solar Energy Reaching the Earth? Solar energy • Warms and lights up the troposphere • Drives the cycling of matter • Evaporates water and drives weather and climate • 1% generates winds • Green plants/algae use less than .1% in photosynthesis Figure 3-8

11. What are the abiotic factors in this diagram? Sun Oxygen (O2) Producer Carbon dioxide (CO2) Secondary consumer (fox) Primary consumer (rabbit) Precipitation Producers Falling leaves and twigs Soil decomposers Soluble mineral nutrients Water Fig. 3-10, p. 57

12. Factors That Limit Population Growth • Availability of matter and energy resources can limit the number of organisms in a population. • Examples of limiting factors: (temperature, sunlight, nutrients, dissolved oxygen, salinity…etc) Figure 3-11

13. Lower limit of tolerance Upper limit of tolerance No organisms Few organisms Few organisms No organisms Abundance of organisms Population size Zone of intolerance Zone of intolerance Zone of physiological stress Zone of physiological stress Optimum range Low Temperature High Fig. 3-11, p. 58

14. Producers: Basic Source of All Food • Most producers capture sunlight to produce carbohydrates by photosynthesis: • KNOW THE FORMULA

15. Write the chemical equations for photosynthesis and respiration. Explain how these two processes are intertwined; include the terms oxygen, carbon dioxide, light reaction, dark reaction, chloroplasts, mitochondria, photosynthesis, respiration, glucose, water, sunlight, ATP, plants, animals. Good luck!!

16. Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs • In accordance with the 2nd law of thermodynamics, there is a decrease in the amount of energy available to each succeeding organism in a food chain or web.

17. Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs • Ecological efficiency: percentage of useable energy transferred as biomass from one trophic level to the next.(2-40% range) Figure 3-19

18. Productivity of Producers: The Rate Is Crucial • Gross primary production (GPP) • Rate at which an ecosystem’s producers convert solar energy into chemical energy as biomass. Figure 3-20

19. Gross primary productivity (grams of carbon per square meter) Fig. 3-20, p. 66

20. Net Primary Production (NPP) • NPP = GPP – R • Rate at which producers use photosynthesis to store energy minus the rate at which they use some of this energy through respiration (R). Figure 3-21

21. Sun Photosynthesis Energy lost and unavailable to consumers Respiration Gross primary production Net primary production (energy available to consumers) Growth and reproduction Fig. 3-21, p. 66

22. What are nature’s three most productive and three least productive systems? Figure 3-22

23. Chemosynthesis: • Some organisms such as deep ocean bacteria draw energy from hydrothermal vents and produce carbohydrates from hydrogen sulfide (H2S) gas .

24. Consumers: Eating and Recycling to Survive • Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. • Herbivores • Primary consumers that eat producers • Carnivores • Secondary consumers eat primary consumers • Third and higher level consumers: carnivores that eat carnivores. • Omnivores • Feed on both plant and animals.

25. Respond to this statement: An ecosystem could not withstand the absence of producers, but would be fine without consumers.

26. Decomposers and Detrivores Burying Beetles Video -- National Geographic • Decomposers: Recycle nutrients in ecosystems. • Detrivores: Insects or other scavengers that feed on wastes or dead bodies. Generally scavengers are considered to be larger animals and detrivores are insects. Figure 3-13

27. Detrivores Decomposers Termite and carpenter ant work Carpenter ant galleries Bark beetle engraving Long-horned beetle holes Dry rot fungus Wood reduced to powder Mushroom Time progression Powder broken down by decomposers into plant nutrients in soil Fig. 3-13, p. 61

28. Aerobic and Anaerobic Respiration: Getting Energy for Survival • Organisms break down carbohydrates and other organic compounds in their cells to obtain the energy they need. • This is usually done through aerobic respiration. • The opposite of photosynthesis

29. Aerobic and Anaerobic Respiration: Getting Energy for Survival • Anaerobic respiration or fermentation: • Some decomposers get energy by breaking down glucose (or other organic compounds) in the absence of oxygen. • The end products vary based on the chemical reaction: • Methane gas • Ethyl alcohol • Acetic acid • Hydrogen sulfide

30. Two Secrets of Survival: Energy Flow and Matter Recycle • An ecosystem survives by a combination of energy flow and matter recycling. Figure 3-14

31. Biodiversity Loss and Species Extinction: Remember HIPPO • H for habitat destruction and degradation • I for invasive species • P for pollution • P for human population growth • O for overexploitation

32. Why Should We Care About Biodiversity? The health of a species reflects the health of an ecosystem which reflects of the health of the biosphere which is where humans live. “We are all connected”

33. Some species are so critical to the functioning of an Ecosystem that they are called KEYSTONE SPECIES 1800’s sea otters hunted for fur Sea otters eat sea urchins, so with no predators, they began to multiply Fish begin to decline because Kelp are the breeding grounds for fish, this affected fishermen's catches. Sea urchins eat kelp, which then began to disappear California Sea Otter Tax Check-Off - Defenders of Wildlife

37. Food Webs • Trophic levels are interconnected within a more complicated food web. Figure 3-18

38. Which of the following ecosystems has the highest average net primary productivity? a. agricultural land b. open ocean c. temperate forest d. swamps and marshes e. lakes and streams Which of the following ecosystems has the lowest level of kilocalories per square meter per year? a. open ocean b. tropical rain forest c. agricultural land d. lakes and streams e. temperate forest

39. SOIL: A RENEWABLE RESOURCE • Soil is a slowly renewed resource that provides most of the nutrients needed for plant growth and also helps purify water. • Soil formation begins when bedrock is broken down by physical, chemical and biological processes called weathering. • Mature soils, or soils that have developed over a long time are arranged in a series of horizontal layers called soil horizons.

40. SOIL: A RENEWABLE RESOURCE Figure 3-23

41. Wood sorrel Oak tree Organic debris builds up Lords and ladies Dog violet Rock fragments Grasses and small shrubs Earthworm Millipede Moss and lichen Fern Honey fungus O horizon Mole Leaf litter A horizon Topsoil B horizon Bedrock Subsoil Immature soil Regolith Young soil C horizon Pseudoscorpion Mite Parent material Nematode Root system Actinomycetes Red Earth Mite Fungus Mature soil Bacteria Springtail Fig. 3-23, p. 68

42. Animation: Soil Profile PLAY ANIMATION

43. Layers in Mature Soils • Infiltration: the downward movement of water through soil. • Leaching: dissolving of minerals and organic matter in upper layers carrying them to lower layers. • The soil type determines the degree of infiltration and leaching.

44. Soil Profiles of the Principal Terrestrial Soil Types Figure 3-24

45. Mosaic of closely packed pebbles, boulders Weak humus-mineral mixture Alkaline, dark, and rich in humus Dry, brown to reddish-brown with variable accumulations of clay, calcium and carbonate, and soluble salts Clay, calcium compounds Desert Soil (hot, dry climate) Grassland Soil (semiarid climate) Fig. 3-24a, p. 69

46. Acidic light-colored humus Iron and aluminum compounds mixed with clay Tropical Rain Forest Soil (humid, tropical climate) Fig. 3-24b, p. 69

47. Forest litter leaf mold Humus-mineral mixture Light, grayish-brown, silt loam Dark brown firm clay Deciduous Forest Soil (humid, mild climate) Fig. 3-24b, p. 69

48. Acid litter and humus Light-colored and acidic Humus and iron and aluminum compounds Coniferous Forest Soil (humid, cold climate) Fig. 3-24b, p. 69

49. Leaf mold, a humus-mineral mixture, and silty loam are indicative of a. coniferous forest soil. b. deciduous forest soil. c. tropical forest soil. d. grassland soil. e. desert soil. • Soil comprised of litter and humus, and is acidic due to the accumulation of needles • a. desert soil • b. grassland soil • tropical rainforest soil • coniferous forest soil • deciduous forest soil

50. Soils found in mid-latitude grasslands would be most accurately described as having • a high acid content with little organic matter • a deep layer of humus and decayed plant material • a layer of permafrost right below the O-horizon • d. a high content of iron oxides and very little moisture • e. a small amount of nutrients but an abundant decomposer food web