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Ecology Unit- part 2 Modified by Beth Roland Jacobs Fork Middle School.

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1 Ecology Unit- part 2 Modified by Beth Roland Jacobs Fork Middle School

2 All living organisms need certain elements/compounds for life processes –Ex: your cells need Carbon,Hydrogen,Oxygen,Phosphorus,Nitrogen & Sulfur in order to live and reproduce (make more cells) Cycles in nature keep these elements moving from organisms to organism (and sometimes into the atmosphere) Biogeochemical Cycles (Matter moving through the environment)

3 The flow of a nutrient from the environment to living organisms and back to the environment Main reservoir for the nutrient is in the environment Transfer rates to and from reservoir are usually lower than the rates of exchange between and among organisms. Matter is recycled through an ecosystem – not one way flow

4 Three Categories Hydrologic cycle –Water Atmospheric cycles –Nitrogen and carbon Sedimentary cycles –Phosphorus and sulfur


6 Carbon Cycle Carbon moves through the atmosphere and food webs on its way to and from the ocean, sediments, and rocks Sediments and rocks are the main reservoir


8 Carbon Cycle photosynthesis TERRESTRIAL ROCKS volcanic action weathering diffusion Bicarbonate, carbonate Marine food webs Marine Sediments Atmosphere Terrestrial Rocks Soil Water Peat, Fossil Fuels Land Food Webs


10 Carbon in the Oceans Most carbon in the ocean is dissolved carbonate and bicarbonate Ocean currents carry dissolved carbon

11 Carbon in Atmosphere Atmospheric carbon is mainly carbon dioxide Carbon dioxide is added to atmosphere –Aerobic respiration, volcanic action, burning fossil fuels, decomposition of organic materials Removed by photosynthesis

12 Nitrogen Cycle Nitrogen is used in amino acids and nucleic acids (all living organism need nitrogen to make proteins) Main reservoir is nitrogen gas in the atmosphere Decomposers are vital to convert ammonia into: 1. usable nitrites & nitrates for plants (nitrogen fixation) 2. nitrogen gas (denitrification = puts it back into the atmosphere)



15 Phosphorus Cycle Phosphorus is part of phospholipids and all nucleotides –What are these? The basis of all DNA and cell membranes It is the most prevalent limiting factor in ecosystems Main reservoir is Earths crust; no gaseous phase (it never enters the atmosphere – like carbon and nitrogen)

16 Phosphorus Cycle GUANO FERTILIZER ROCKS LAND FOOD WEBS DISSOLVED IN OCEAN WATER MARINE FOOD WEBS MARINE SEDIMENTS excretion weathering mining agriculture uptake by autotrophs death, decomposition sedimentationsetting out leaching, runoff weathering uplifting over geolgic time DISSOLVED IN SOILWATER, LAKES, RIVERS uptake by autotrophs death, decomposition


18 Chapter 3 – Communities & Biomes Vocabulary to Know: –Limiting Factor –Succession Primary Secondary –Climax Community

19 Community All the populations that live together in a habitat Habitat is the type of place where individuals of a species typically live Type of habitat shapes a communitys structure

20 Biogeography The study of the distribution of organisms and the processes that underlie distribution patterns

21 Factors that Affect Distribution Geologic history Topography Climate Species interactions

22 Climate Average weather condition in a region Affected by: –amount of incoming solar radiation –prevailing winds –elevation

23 Rotation and Wind Direction Earth rotates faster under the air at the equator than it does at the poles Deflection east and west

24 Seasonal Variation Northern end of Earths axis tilts toward sun in June and away in December Difference in tilt causes differences in sunlight intensity and day length The greater the distance from the equator, the more pronounced the seasonal changes

25 Ocean Currents Upper waters move in currents that distribute nutrients and affect regional climates

26 Rain Shadow Air rises on the windward side, loses moisture before passing over the mountain

27 Biomes Regions of land characterized by habitat conditions and community structure Distinctive biomes prevail at certain latitudes and elevations

28 Biomes

29 Population Size Factors that affect: –Natality –Mortality/Fatality –Immigration –Emigration

30 Population Density

31 Environmental Limits on populations Density-dependent –Disease –Food –Parasitism –Predation –Competition Intraspecific Interspecific Density-independent –Temperature –Storms –Floods –Drought –Habitat Disruption

32 Organism Interactions Limit Populations Predation Competition –Both types Parasitism Crowding/stress

33 Chapter 5: Diversity & Conservation Importance to nature Importance to people –Oxygen –Diet –Medicines

34 Loss of Diversity Threatened Species Endangered Species Extinction of Species

35 Threats to Biodiversity Habitat Loss Habitat Fragmentation –Biotic Issues –Abiotic Issues Habitat Degradation –Air Pollution –Water Pollution –Land Pollution

36 Exotic Species Non-native organisms that move-in to a particular area There can be a lack of competitors = exponential growth Can take over the niches of native species Example: Page 124

37 Conservation Sustainable use: –Use what you need, but dont damage the ecosystem Is this a good example of sustainable use?

38 Humans & The Environment Ozone (O 3 ) Depletion –O 3 forms a good layer around the Earth –CFC release is breaking down the protective ozone layer –UV rays increase skin cancers & other cell mutations to plants & animals!

39 How is Acidity Measured? When we observe acid rain, acidity is measured in units called pH. The pH scale is from 0 to 14 –pH 7 indicates neutral –higher pH numbers = alkalinity (base) –smaller numbers = acid Well do more on pH in the Biochemistry chapter

40 Natural Acid Precipitation CO 2 combines with water to form a weak acid H 2 CO 3 (carbonic acid) But we are adding to the problem… –by adding nitric and sulfuric acids Look at the clean rain – its already slightly acidic???

41 Effects of Acid Precipitation In Japan, rain which registers pH 5.6 or less is considered acid rain; some 80-90% of the rain that falls in Japan in a year is acid rain. In Japan, acid rain with acidity equal to lemon juice has been observed at Mount Tsukuba in 1984 (pH 2.5) and at Kagoshima in 1987 (pH 2.45). The problem is even more serious in North America and Europe. In those regions, forests are withering and lakes becoming uninhabitable to fish, and stone structures such as buildings and bronze statues are being damaged by corrosion


43 Humans & The Environment Global Warming –The Greenhouse Effect –Fossil fuels give off lots of CO 2 –This builds a blanket around the earth –It is predicted that the Earth temp. will increase ~5 0 C before 2050 = Ice age????

44 Carbon Dioxide Increase Carbon dioxide levels fluctuate seasonally The average level is steadily increasing Burning of fossil fuels & deforestation are contributing to the increase

45 Greenhouse Effect Greenhouse gases impede the escape of heat from Earths surface


47 Global Warming Long-term increase in the temperature of Earths lower atmosphere

48 Other Greenhouse Gases CFCs - synthetic gases used in plastics and in refrigeration Methane - produced by termites and bacteria Nitrous oxide - released by bacteria, fertilizers, and animal wastes

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