Chapter 55 ~ Ecosystems

1. Chapter 55 ~ Ecosystems OBJECTIVES: • Understand how energy and matter flow through ecosystems

2. Objectives • To understand the ecological levels of organization • To understand climate and how it affects biodiversity • To review terrestrial and aquatic biomes • To understand how to create a food chain, web, and energy pyramid • To understand the water, carbon, and nitrogen cycles

3. I. Trophic Relationships, I • Trophic levels~ feeding relationships in an ecosystem • Primary producers~ the trophic level that supports all others; autotrophs • Primary consumers~ herbivores • Secondary and tertiary consumers~ carnivores • Detritivores/detritus~ special consumers that derive nutrition from non-living organic matter (decomposers) – found on all levels, recycles elements back to abiotic reservoirs • Food chain~ trophic level food pathway

4. Trophic Relationships, II • Food webs~ interconnected feeding relationship in an ecosystem • Omnivores – can be found on multiple levels • Energy Flow – originates from sun, not completely efficient, most lost as heat • Matter cycling – C, H2O, N2, P continuously recycled

5. The Sun is the source of all energy

6. Do you care? • The sun makes up 99.84% of the solar system’s mass • Earth is 92 million miles away from the sun (Earth’s diameter is 25,000 miles) • That just a pinhead of the Sun's raw material could kill someone up to 100 miles away! • That the energy in the sunlight we see today started out in the core of the Sun 30,000 years ago - it spent most of this time passing through the dense atoms that make the sun and just 8 minutes to reach us once it had left the Sun! • That the amount of the Sun's energy reaching the Earth's atmosphere (known as the Solar constant) is equivalent to 1.37 kw of electricity per square meter!

7. Spectoral Type of Star G2 V • Age 4,600 million Years • Mean Distance to Earth 150 Million Kilometres (1 AU) • Rotation Period (equator) 26.8 days • Radius 695,000 Kilometres • Composition 71% Hydrogen [H] 26.5% Helium [He] 2.5% Other • Mass 1.99 x 1030 Kilograms • Effective Surface Temperature 6,000o C • Core Temperature 15 millioon C • Luminosity [Energy Output] 3.83 x 1033 ergs / second Solar Constant0.137Watts / cm2 • Inclination of Solar Equator to Ecliptic7.25o

8. Today • Fill out the food web practice sheet and as much of the nutrient cycle sheet as possible • We will go over them in 10-15 minutes

9. Important Dates • Ch. 52 and 55 Quiz – Tomorrow • Ch. 53 and 54 – Friday • Test – Tuesday of next week

10. So far • Biomes/Adaptations • Human Impact • Flow of energy • Flow of matter • What we have left • Population Ecology • Community Interactions

11. II. Energy Flow - Primary • Primary productivity(amount of light energy converted to chemical energy by autotrophs) – 1% •Gross (GPP): total energy •Net (NPP): represents the storage of energy available to consumers •Rs: respiration • NPP = GPP - Rs • Biomass: primary productivity reflected as dry weight of organic material

12. Relative to Total Biomass • 4. Total biomass - total dry weight of all plants vs Primary production – • Amount of NEW biomass produced • 5. Other Trends • Open ocean is not that efficient at producing new biomass, but its such • a large area it makes up a large percentage of primary production • b) Coral reefs have a high production rate, but are small in size • 6. Temperature, light, and nutrients can limit primary production

13. Energy Flow - Secondary • Secondary productivity: the rate at which an ecosystem's consumers convert chemical energy of the food they eat into their own new biomass • Ecological efficiency: % of E transferred from one trophic level to the next (5-20%) • Pyramid of productivity: multiplicative loss of energy in trophic levels • Biomass pyramid: trophic representation of biomass in ecosystems • Pyramid of numbers: trophic representation of the number of organisms in an ecosystem

14. Pyramid of Energy (Productivity) Ecological Efficiency = net secondary production/assimilation of primary productivity 1/1000 of energy can be transferred to tertiary consumers (that’s why energy pyramids are only 4 or 5 levels)

15. Alternative Pyramids BIOMASS NUMBERS HIGH REPRODUCTION RATE

16. Practice

17. Chemical Cycling • Biogeochemical cycles: the various nutrient circuits, which involve both abiotic and biotic components of an ecosystem • Water • Carbon • Nitrogen • Phosphorus

18. WATER CYCLE

19. Water Cycle Evaporation – the process by which water changes from liquid form to an atmosphere gas. Transpiration – when water enters the atmosphere by evaporating from leaves of plants. Nutrient Cycles Nutrients – all the chemical substances that an organism needs to sustain life. Every living organism needs nutrients to build tissues and carry out essential life functions. Like water, nutrients are passed between organisms and the environment through biochemical cycles.

20. CARBON CYCLE

21. NITROGEN CYCLE

22. Nitrogen Cycle • Nitrogen is plentiful in the atmosphere as N2 • But plants cannot use N2 • Nitrogen Fixation • Various bacteria in soil (and legume root nodules) convert N2 to nitrogen compounds that plants can use • Ammonium (NH4+) and nitrate (NO3–) • Some bacteria break down organic matter and recycle nitrogen as ammonium or nitrate to plants • Denitrification • Other bacteria return N2 to the atmosphere by converting nitrates into N2

23. PHOSPHORUS CYCLE

24. Phosphorus Cycle Phosphates (compounds containing PO43-) and other minerals are added to the soil by the gradual weathering of rock. Consumers obtain phosphorus in organic form from plants. Phosphates are returned to the soil through excretion by animals and the actions of decomposers. Phosphorus is essential to living organisms because it forms part of important life-sustaining molecules such as DNA & RNA.

25. CO2 N2 PO43- NO3/NH4+ PO43-

26. New/Important Terms • Water – evapotranspiration, percolation • Carbon – photosynthesis, cellular respiration, detritus, detritivores • Nitrogen – ammonification, nitrification, denitrification, nitrogen fixation, assimilation • Phosphorus – geologic uplifting, leaching, sedimentation

27. Practice

28. Rest of today • Work through demographic lab • Answer questions and fill in data tables • Show me when you are done • Work through virtual population lab • Answer questions

29. Demographic Transitions • Stage 1 – pre-industralization (high birthrate, high deathrate) • Stage 2 – (developing country) death rate decreases due to medical and agricultural advances • Stage 3 – birth rate decreases due to contraception and urbanization • Stage 4 – low birth rates and death rates

31. Today • Finish Demographic Study • List as many factors you can think of that could of lead to the decreasing population trend in Italy. Place them into these 3 categories • Governmental • Social • Economical

32. Governmental Factors • Regressive – tax single men to get them to marry, tax married couples w/o children • Positive – tax break for families w/ children, pass laws or create programs to protect single mothers and children

33. Social Factors • Education for women • Less stay-at-home mothers • Materialism – another child means a smaller house or cheaper car • Culture of independence – children take away from this • General cultural hostility to children – not welcome at restaurants/apartments • Men’s virility not linked to procreation but rather cash

34. Economic Factors • Industrialization leads to materialism • Employers not wanting to hire women who want children right away • Increase in higher education – start families later • Aging population puts more strain on public funds (Medicaid, social security) – government must pass along cost to tax –payers

35. Human Impact • Biological magnification: trophic process in which retained substances become more concentrated at higher levels • Greenhouse effect: warming of planet due to atmospheric accumulation of carbon dioxide • Ozone depletion: effect of chlorofluorocarbons (CFC’s) released into the atmosphere • Rainforest destruction • Cause: Overpopulation?