Ecosystems and Energy

1. Ecosystems and Energy Unit 2

2. What is ecology? • The study of the relationships between organisms and their environment • Biotic factors = living factors; other organisms such as bacteria, plants, animals, fungi, etc. • Abiotic factors = non-living factors, such as water, sunlight, rocks, air, etc.

3. Biological organization • Atom  basic unit of matter • Molecule • Cell  basic unit of life • Tissue • Organ • Organ system • Organism • Population • Community • Ecosystem • Landscape • Biosphere

4. Words to know… • Population – a group of organisms of the same species that live together in the same area at the same time • Species – a group of similar organisms whose members freely interbreed in the wild to produce fertile offspring; members of one species do not interbreed with other species of organisms • Community – All the populations of different species that are living together in the same area at the same time

5. Words to know… • Ecosystem – a community and its physical environment; biotic and abiotic factors • Landscape – a region that includes several ecosystems • Biosphere – the layer of Earth containing all living organisms. As an ecological system, the biosphere interacts with the land, the water, and the atmosphere.

6. Earth’s Four Realms • Hydrosphere – Earth’s supply of water (liquid and frozen, fresh and salty) • Atmosphere – gaseous envelope surrounding the earth • Lithosphere – soil and rock of Earth’s crust • Biosphere – all living organisms

7. Life on Earth depends on 3 interconnected factors… • 1. High quality energy flows in one direction:Sun  Living things (food web trophic levels)  Environment  Back to space (infrared energy) • 2. The cycling of matter or nutrients through different parts of the biosphere (ex. Water cycle, nitrogen cycle, etc.) • 3. Gravity, which allows the earth to hold down its atmosphere and causes the downward movement of matter in the matter cycles.

8. What is energy? • The capacity or ability to do work, includes the ability to grow, move, reproduce, and maintain or repair damaged tissue • Several different forms: • Chemical = stored in chemical bonds of molecules • Radiant = transported from sun in electromagnetic waves • Heat = thermal energy that flows from an object with a higher temperature to one with a lower temperature • Mechanical = energy in the movement of matter • Nuclear = energy found within atomic nuclei • Electrical = energy that flows as charged particles

9. How do we measure energy? • Kilojoules – kJ, units of work • Kilocalories – kcal, units of heat energy • 1 kcal = the amount of energy required to raise the temperature of 1 kg of water by 1°C • 1 kcal = 4.184 kJ

10. The conversion of energy • Potential energy = stored energy • Kinetic energy = the energy of motion • Thermodynamics = the study of energy and its transformations • System = object being studied • Surroundings = rest of universe other than object being studied • Closed system = does not exchange energy with its surroundings • Open system = can exchange energy with its surroundings

12. Laws of thermodynamics • 1. Energy cannot be created or destroyed, but it can be transformed from one form to another. • 2. Whenever energy is converted from one form to another, some usable energy is degraded into heat, a less ordered, less usable form of energy. • Entropy = the measure of disorder or randomness. Organized, usable energy has low entropy; disorganized energy has high entropy.

13. Examples • When a car is driven, only about 20% of the high-quality energy available in its gasoline fuel is converted into mechanical energy (to propel the vehicle) and electrical energy (to run its electrical systems). The remaining 80% is degraded to low-quality heat that is released into the environment and eventually lost into space. • When electrical energy flows through filament wires in an incandescent light bulb, it is changed into about 5% useful light and 95% low-quality heat that flows into the environment. In other words, this so called light bulb is really a heat bulb.

14. The Sun • Supplies energy for photosynthesis  basis of most food webs • Powers the cycling of matter • Drives the climate and weather systems that distribute heat and fresh water over the Earth’s surface • Provides the natural green house effect

15. Photosynthesis • Biological process in which light energy from the sun is captured and transformed into the chemical energy of carbohydrate (sugar) molecules • Chlorophyll – photosynthetic pigment that absorbs radiant energy, gives plants and algae their green color • 6CO2 + 6H2O light> C6H12O6 + 6O2 • Carbon dioxide + water light> glucose + oxygen • Carbon dioxide, water, and light must be present for photosynthesis to occur

16. Cellular Respiration • Method used by plants, animals, or other organisms to release the chemical energy stored in carbohydrates • Two kinds of respiration: • Aerobic respiration = occurs if oxygen is present • Anaerobic respiration = occurs if oxygen is not present • Cellular respiration:6O2 + C6H12O6 6CO2 + 6H2O + Energy (ATP) • Recall – Photosynthesis equation: 6CO2 + 6H2O light> 6O2 + C6H12O6

17. Can life exist without the sun? • Yes, but there must be another source of energy • 1977 – the Alvin studied the Galapagos Rift and found hydrothermal vents where sea water had been heated by the rocks below • There was life, even though there was no light • The base of the food web was archaebacteria that are capable of surviving at extreme temperatures and use chemosynthesis instead of photosynthesis • Chemosynthesis – using inorganic compounds to obtain energy and make carbohydrate molecules, no light required

18. The Flow of Energy Through Ecosystems • Producers = (autotrophs) make their own food from simple inorganic substances, form base of the food chain • Consumers = use the bodies of other organisms as a source of food energy and bodybuilding materials (heterotrophs) • Primary consumers = exclusively herbivores • Secondary consumers = eat primary consumers • Tertiary consumers = eat secondary consumers

19. The Flow of Energy Through Ecosystems • Herbivores = eat only plants • Carnivores = eat only meat • Omnivores = eat plants and meat • Detritivores = eat detritus, which is organic matter such as carcasses, leaf litter, and feces • Saprotrophs = decomposers, microbial heterotrophs that break down dead organic material and use the decomposition products to supply themselves with energy, releasing simple inorganic substances that can be reused by producers

20. The Path of Energy Flow • Food chain = energy from food passes from one organism to the next in a sequence • Trophic level = each level or “link” in a food chain, energy flows from level to level • Arrows flow in direction of energy transfer

21. The Path of Energy Flow • Food web = complex of interconnected food chains in an ecosystem, energy can flow along many different paths

22. The Path of Energy Flow • Energy flow is linear  one-way • Some energy is lost when the organism uses it to do work • This energy is lost as heat and is unavailable for use by any other organism in the ecosystem • “10% rule” = only 10% of the energy is transferred to the next highest trophic level

23. Ecological Pyramids • Recall: What is the 2nd law of thermodynamics? • Ecological pyramids graphically represent the relative energy values of each trophic level • Three main types: • Pyramid of numbers = shows number of organisms at each trophic level in a given ecosystem • Pyramid of biomass = shows the total biomass (quantitative estimate of total mass of living material) at each trophic level • Pyramid of energy = shows the energy content (usually kcal/sq. m/year) of the biomass of each trophic level

24. Pyramid of numbers

25. Pyramid of biomass

26. Pyramid of energy

27. Productivity of Producers • Gross primary productivity (GPP) = the rate at which energy is captured during photosynthesis, the total amount of energy captured during photosynthesis in a given period of time • Net primary productivity (NPP) = energy that remains in plant tissues after cellular respiration, the rate at which organic matter is incorporated into plant tissues for growth • NPP = GPP – Plant respiration

29. Net Primary Productivities for Selected Ecosystems

30. Human Impact on NPP • Any NPP that is taken for human use (survival, economy, etc.) cannot be transferred to other organisms in the ecosystem • Humans consume 32-40% of the annual NPP

31. What else flows through a food chain? • Energy is not the only thing transferred from trophic level to trophic level • Bioaccumulation = accumulation of a substance, such as a toxic chemical. In the tissues of a living organism • Biomagnification = the increasing concentration of these toxins at successively higher trophic levels in a food chain

32. Where do we find these various ecosystems? • Biomes = Extensive areas of similar climate and vegetation • Ecotones = transitional area between two ecosystems • Ecozones (ecoregions) = smaller regions within ecosystems that share similar physical features

33. Marine Ecosystems • Photic zone – relatively thin (200 meters) upper layer where light can penetrate  photosynthesis can occur • Aphotic zone – permanently dark, chemosynthetic producers only • Marine biologists divide ocean by photic and aphotic zones as well as depth and distance from shore • And now, to learn about some biomes…

34. Antarctic • Area surrounding south pole • Rainfall: <5 cm per year • Dominant animals: penguins and marine mammals

35. Benthos (Hadal) • Bottom of oceans, too deep for sunlight  no plants • Primary source of energy = dead organic matter settling and chemosynthesis • Creatures that live here are called benthos

36. Coastal Ocean • Extends from low tide mark to outer edge of continental shelf • Shallow enough to mostly fall in photic zone  allows plankton, kelp, etc. to survive

37. Coral Reef • Warm, shallow water of tropical coastal oceans • Named for coral animals whose hard, calcium carbonate skeletons make up their primary structure • Need warm water, bright sun, and salt, grow with help of algae • Three kinds: fringing reefs grow on continental shelves near the coastline, barrier reefs grow parallel to the shoreline but further out, and coral atolls grow in rings around the top of sunken ocean volcanoes

38. Desert • Between 15° and 25° north and south latitude • Rainfall: <25 cm per year • Soil: coarse texture, abundant minerals, lack organic matter • Dominant plants: cacti and other succulents; plants with short growth cycles • Geographic distribution: Africa, Asia, Middle East, United States, Mexico, South America, Australia

39. Estuaries • Wetlands formed where river meets sea • Brackish = fresh water + salt water • Most organic material enters as detritus • Salt marshes = temperate zone estuaries • Mangrove swamps = tropical coastal regions

40. Flowing Freshwater • Rivers, streams, creeks, and brooks • Animals have adaptations, such as hooks, suckers, streamlined bodies, etc. • Often come from underground water source • Turbulent water = plenty of dissolved oxygen

41. Freshwater Wetlands • Wetland – ecosystem in which water either covers the soil or is present at or near the surface of the soil for at least part of the year • Bogs, marshes swamps • Support very specific plants and animals • Soil is low in oxygen

42. Grasslands • 10-60 cm rain • Warm to hot summers; cold winters; moderate, seasonal precipitation; fertile soils; occasional fires • Dominant plants: lush, perennial grasses and herbs; most are resistant to drought, fire, and cold • Geographic distribution: central Asia, North America, Australia, central Europe, and upland plateaus of South America

43. Hydrothermal vents • Occur in the deep ocean where hot-water vents rich in sulfur compounds are found • Provide energy for chemosynthetic bacteria

44. Intertidal zone • Submerged in sea water once or twice a day, otherwise exposed to air and sunlight • Zonation – prominent horizontal banding of organisms that live in a particular habitat • Water movement brings in nutrients and removes waste

45. Open Ocean • Begins at edge of continental shelf and extends outward • 90% of the surface area of the world’s ocean • Organisms are exposed to high pressure, frigid temperatures, and total darkness • Most productivity occurs in photic zone • Low amounts of nitrogen and phosphorus  not much plant life

46. Savannas • Warm temperatures; seasonal rainfall; compact soil; frequent fires set by lightning • Dominant plants: tall, perennial grasses; sometimes drought-tolerant and fire-resistant trees or shrubs • Geographical distribution: large parts of eastern Africa, southern Brazil, northern Australia

47. Standing Freshwater • Lakes and ponds • Water flows in and out, usually circulates  helps distribute heat and oxygen • Relatively still water allows organisms like plankton to survive

48. Taiga (Coniferous or Boreal forests) • 45°-60° north latitude • Long, cold winters; short, mild summers; moderate precipitation; high humidity; acidic, nutrient-poor soils • Dominant plants: coniferous trees such as spruce and fir; some broadleaf deciduous trees; small, berry-bearing shrubs • Soil: deep layer of litter, decomposition is slow due to cold temperatures • Geographic distribution: North America, Asia, and northern Europe

49. Temperate deciduous forests • Cold to moderate winters; warm summers; year-round precipitation; fertile soils  heavy population • Dominant plants: broadleaf deciduous trees; some conifers; flowering shrubs; herbs; a ground layer of mosses and ferns • Geographic distribution: eastern United States; southeastern Canada; most of Europe; and parts of Japan, China, and Australia

50. Temperate shrubland (chaparral) • 50-75 cm of rain, mostly in winter • Hot, dry summers; cool, moist winters; thin, nutrient-poor soils; periodic fires • Dominant plants: woody evergreen shrubs with small, leathery leaves; fragrant, oily herbs that grow during winter and die in summer • Geographic distributions: western coasts of North and South America, areas around the Mediterranean Sea, South Africa, and Australia