Chapter 3

1. Chapter 3 Ecology, ecosystems and food webs

2. Ecology • Groupings • Organism – single living thing • Species – several of same type of organism • Population – several of same species interacting • Community – several populations interacting in a certain area • Ecosystem – community interacting with each other and the environment

3. Biosphere Biosphere Ecosystems Communities Populations Organisms Fig. 4.2, p. 72

4. Parts of the planet • Planet as a solid – inner/outer core, mantle, crust • Lithosphere is the crust and asthenosphere • Hydrosphere is the water regions • Atmosphere is the 5 layers of air • Troposphere (11 miles) 78% N2, 21% O2, 1% Ar • Stratosphere (11 – 30 mi) O3, blocks UV

5. Atmosphere Biosphere Vegetation and animals Soil Crust Rock core Lithosphere Mantle Crust (soil and rock) Crust Biosphere (Living and dead organisms) Atmosphere (air) Hydrosphere (water) Lithosphere (crust, top of upper mantle) Fig. 4.6, p. 74

6. Incoming solar energy • 34% reflected by clouds • 42% heats earth and atmosphere • 23% evaporates water • 1% creates wind • <1% photosynthesis

7. Solar radiation Energy in = Energy out Reflected by atmosphere (34%) Radiated by atmosphere as heat (66%) UV radiation Lower Stratosphere (ozone layer) Visible light Greenhouse effect Troposphere Absorbed by ozone Heat Absorbed by the earth Heat radiated by the earth Earth Fig. 4.8, p. 75

8. Greenhouse effect • Solar energy (light) that reaches the earth is converted into short wave radiation (heat) infrared. • This infrared radiation has a hard time passing through the gasses in our atmosphere thereby trapping heat and keep the planet about 30 degrees (Celsius) warmer • Important gasses – H2O, CO2, CH4, N2O, O3

9. Biomes • Large regions characterized by a distinct climate and adapted vegetation Remember climate is weather patterns over a long period of time, usually several decades Because certain plants are adapted to a particular biome, so too are certain animals which depend on those plants for food

10. Biomes • There are not distinct boundaries between biomes, rather there are ecotones. • An ecotone is a blending of biomes and generally carries a greater quantity and variety of species

11. Components of Ecosystems • Abiotic – nonliving • Sunlight • Temperature • Precipitation • Wind • Latitude • Soil • Salinity (aquatic)

12. Terrestrial Ecosystems Aquatic Life Zones • Sunlight • Temperature • Precipitation • Wind • Latitude (distance from equator) • Altitude (distance above sea level) • Fire frequency • Soil • Light penetration • Water currents • Dissolved nutrient concentrations (especially N and P) • Suspended solids Fig. 4.13, p. 79

13. Components of Ecosystems • Range of tolerance – how much of an abiotic factor can an organism withstand • Limiting factor – the one factor that is holding back a population from reaching its biotic potential (max growth) • Important limiting factors in aquatic systems • Dissolved oxygen, salinity, temperature, light, nutrients, etc.

14. 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 physiological stress Optimum range Zone of physiological stress Zone of intolerance Low Temperature High Fig. 4.14, p. 79

15. Food webs (chains) • Producers (autotrophs) plants • Using chemosynthesis (some bacteria) • Using photosynthesis (plants) 6 CO2 + 6 H2O + sun (yields) C6H12O6 + 6 O2 Plants convert only about 1-5% of the light they absorb into chemical energy, and absorb only about half the light that strikes them

16. Herbivores • Primary consumers – eat producers (oh the humanity) • Teeth designed for grinding

17. Carnivores • Secondary consumers – meat eaters only • Feed on primary consumers (herbivores) • Teeth designed for tearing (large canines and sharp molars) cats for example

18. Omnivore • Tertiary consumer – eat anything, feeding on other carnivores makes them tertiary • We are omnivores, just look at our teeth, • but we really should eat more veggies and less meat (in my opinion)

19. The other consumers • Scavengers – feed on dead organism they did not kill, but found dead • Detritivores – feed on parts of dead organisms • Decomposers – bacteria and fungi, break down small detritus into raw nutrients • Biodegradable means can be broken down by decomposers

20. Aerobic respiration • Normal cellular process for most organisms • Convert sugar and oxygen into energy leaving water and carbon dioxide as products • C6H12O6 + 6O2 yields 6 CO2 + 6 H2O + energy

21. Anaerobic Respiration • Also called fermentation • The breakdown of glucose without oxygen present • Produces: methane, ethyl alcohol, acetic acid, and hydrogen sulfide

22. Food chains • Trophic level – feeding level • First trophic level – plants • Second trophic level – primary consumers • Third trophic level – secondary consumers • Fourth trophic level – tertiary consumers • Remember heat is lost in every transfer between trophic levels

23. Pyramid of energy flow • Only about 10% of the usable energy transfers between trophic levels (5-20%) • For this reason we must rely on the transfer of solar energy from producers to consumers • This is why it is so important to care for the plants of this planet

24. Biomass • Organic matter produced by producers (photosynthesis) • Total dry weight of organic matter in plants and animals in an ecosystem

25. Biomass Productivity • Highest net biomass productivity per square meter is in wetlands, estuaries, and rain forests • Highest gross (but lowest per sq. meter) is the open ocean. Because of its size it has a lot of algae that add up to high productivity

26. Nutrient cycles • Atmospheric – Carbon and Nitrogen • Sedimentary – Phosphorus and Sulfur • Hydrologic cycle – water cycle helps to transport many nutrients

27. Hydrologic cycle • Evaporation/transpiration • Condensation • Precipitation • Infiltration • Percolation • Runoff • Powered by the Sun and gravity

28. Carbon cycle • Atmosphere • Photosynthesis/respiration • Fossil fuels • Limestone • Dissolved in the ocean

29. Nitrogen cycle (very important) • Nitrogen in the air • Nitrogen fixation by bacteria to ammonia • Nitrification by bacteria to nitrite NO2- • Nitrification by bacteria to nitrate NO3- • Assimilation by plants • Ammonification of dead organic material by bacteria and fungi • Denitrification of nitrate by bacteria back to atmosphere

30. Phosphorus cycle • Very slow • Limited amount found in the soil • Limiting factor for plant growth • Excess causes prolific plant growth (algal blooms in water) • We add phosphates to detergents/fertilizers

31. Sulfur cycle • Passed as sulfates (salts) mostly • Hydrogen sulfide (swamps/volcanoes) • Sulfur dioxide (volcanoes) • Ammonium sulfate (sea spray) • Reacts in atmosphere to create hydrogen sulfate (H2SO4) sulfuric acid (acid rain)

32. Ecosystem services • Waste removal pest control • Soil formation biodiversity • Water purification matter resources • Air purification aesthetic pleasure • Climate control • Recycling vital chemicals • Renewable energy

33. Achieve sustainability • Use renewable energy (especially solar) • Recycle chemical matter • REALIZE WE LIVE IN A CLOSED SYSTEM! The END!!!