biob50-ecology chapters 1,2,3,5,19,7 .docx

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Biological Sciences
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Marc Cadotte

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Ecology The web of life 8/31/2013 6:23:00 AM Concept 1.1: events in the natural woalrd are interconnected Connections in nature  Connections to nature: events in natural wolrd are connect: connections when organisms interact with one another in environment. Early observations suggest that parasites cause amphibian deformaties. Amphibian: ambystoma macrodactylum. Parasite: ribeiroia ondatrae.  Laboratory experiment tests the role of parasites. Control group- h. regilla eggs not known to have frog deformation . given treatment: increase number of parasite.  A field experiment suggest that multiple factors influence frog deformities. Pesticide. Increase pesticide=increase infection  Connections in nature can lead to anticipated side effect; increase fertilizeralgae growthsnail eat alge, snail growth. Concept 1.2: ecology is the scientific study of interactions between organisms and their environment Ecology: study of interaction between organisms and environment./ study of interactions that determine distribution-geographic location and abundance of organisms. Environment science: field that incorporates natural science (ecology)/ social science( politic,economic,ethic).  Public and professional ideas about ecology often differ. Public think that there is a balance of nature-natural stystem are stable and return to original after disturbance / each species have role of maintaining balance. But! They do not return to original condition. o 8 ecollogical maxims  you can never do just one thing-things are connect  everything goes somewhere-waste don’t go away  no population can increase size forever-limits  there is no free lunch-reproduction trade or growth?  Evolution matters-changes  Time matter-ecosystem change over time  Space matter-abiotic/biotic change. Local to global  Life would be impossible without species interaction- species depend on each other for reosource.  The scale of an ecological study affects what can be learned from it. Scale-collecting observation including time/space.  Ecology is broad in scope. Population: group of one species in area. Community: group of population in area . Biotic=living things. Abiotic-non living things. Ecosystem: community of organism and environment. Landscape: one place to another with many ecosystem. Biosphere: all living organism and environment.  Some key terms are helpful for styding connections in nature. o Adaptation: feature of an organism that improves it ability to survive/reproduce in environment o Natural selection: evolutionary process in which individual that possess characteristic to surviv/e reproduce at higher rates than others. E.g antibiotic.s o Consumer: organism that obtain energy by eating others o Producer: organism that use energy from external source= sun= to produce food o Net primary production: energy that producers fix by photosynthesis minus cellular respiration = photosynthesis- cellular respiration o Nutrient cycle: movement of nutrient between organism and environment. o Evolution:  Change in genetic characteristic of population  Descent with modification: process where organism accumulate differences with ancesteors. Concept 1.3 Ecologists evaluate competing hypotheses about natural system with observation, experiment and models Anwering ecological questions  Ecologists use experiment, observation, model to answer ecological questions. Climate change; directional change in climate that occurs over 3 decade or longer.  Experiments that are designed and analyzed in consistent ways. Replicate=perform more than once / random treatment/ analyze result. Plots. Statistical analysis=t test.  What we know about ecology is always changing. Scientific method: o Observe nature and ask question about these observations o Use previous knowledge to create hypothesis o Evaluate hypothesis by xperiment o Results. Deformity and decline in amphibian population.  Habitat loss, parasite, disease, pollution, overexploitation, climate change, introduce species, UV light may contribute to amphibian reducing. unit 1: organisms and their environment Chapter 2: the physical environment. 8/31/2013 6:23:00 AM Concept 2.1 Climate is the most fundamental component of physical environmnent .  Anadromous; born in freshwateroceanreturn to freshwater: salmon  Physical environment: climatetemperature/wind/precipitate/sun/soil  Chemical environment: salinity-concentration of dissolved salt/ acidity-pH / concentration of gase/ dissolved water. Climate: long term weatherat location, based on average/ variation measured over decade  Weather: temperature, humidity, precipitation, wind, cloud cover.  Climate variation: change over year/intensity distribution of solar ratdiation/concentration of co2 emit.  Climate conctorls where and how organism live. Temperature determine rate of biochemical reaction/physiological activity. Distribution of organism often reflect extreme condition=temperature/moisture extreme affect forest tree=drought. Variability: not just average conditions. o Timing o Abiotic. Periodic disturbance=fire/avalanche  Global energy balane drives the climate change. Aerosol: solar radiation reflected by clouds of aerosol. 1/3 from aerosol. 1/5 radiation absorbed by ozone,cloud, water vapoour. o If temperature is the same, solar radiation observe by infrared radiation=longwave radiation. o Latent heat flux: heat loss due to evaporation. Conduction: kinetic energy transfer direct contact. Convection: kinetic energy transfer by wind/air/water. Sensible heat flux: convection and conduction=above earths’ surface from warm to cool air. o Greenhouse gase: radiatively active gas: absorb and reradiate infrared radiation= h2-/co2/ch4/n20.. without greenhouse gas, temperature would be colder. Concept 2.2. winds and ocean currents result from differences in solar radiation across earth’s surface Atmospheric and oceanic circulation.  Earths’ movement cause:more radiationin equator and cause seasonal climate variation.  Atmospheric circulation cells are established in regular latitudinal patterns. Atmospheric pressure: force exerted on packet of air/earth’s surface by air molecule above so it decrease with increase altitude. As warm air rise higher, it expands, cools rising air. condense. o Condensation of water into clouds is warming process/ another form of latent heat transfer. o Troposphere: atmospheric layer above earth surface. Above clouds. o Stratosphere: next atmospheric layer above troposphere. o Topics receive most precipitation because most solar radiationmore heatinguplift of air/cloud formation. When air between stratosphere and troposphere, it moves to poles and meet cooler airsubsidence: descend toward earth’s surface when moving air meets surrounding air at same temperature  high atmospheric pressure that inhibit formation of cloud=desert. o Hadley cell: tropical uplift of air creates atmospheric circulation in each hemisphere. Polar cell: north/south poles where dense cool air moves toward equator. Subsidence occurs at poles=polar desert o Ferrel cell: mid latitude between Hadley and polar cell.j polar front: ferell cell move Hadley and polar cell by exchange energy between tropical/polar air mass.  3 atmosphereic circulation cells: o tropical: 30N and S o temperate zone: 30 and 60 N and S o Polar zones: above 60 N S  Atmospheric circulation cells create surface wind patter. Prevailing winds: high to low pressure wind in atmospheric circulation cells toward air movement patterns. Coriolis effect: pattern of wind appears curved because observer is moving with earth’s surface due to earth’s rotation. This is apparent deflection. Outer space fixed position is no apparent deflection. o Trade wind: surface wind on 30N S appear west. Westerlies: east blowing towards pole. o Heat capacity: water can absorb and store more energy without temperature changing than land can. Seasonal changes in land more extreme than water. High pressure cells form over oceans=around 30 n s. northern hemisphere have more semipermanent pressure cells than southern because north have more land mass. Wind blows from high to low pressure.  Ocean currents are driven by surface winds. o Wind blows ocean surface  frictional drag  move surface water  coriolis effect where water seems to move at an angle. Right in north hemisphere. Left in south. This is why ocean current similar to prevailing wind. o Ocean water do not mix because of different temperature / salinity. Dense downwalling current moves cold polar to warm tropical ocean. Upwelling: ocean water rises to surface: prevailing wind blow parallel to coastline. Upwelling also brings nutrients back into the ocean. When surface water organism die, they go to bottom and upwelling brings it up to form photic zone and phytoplankton eats it then zooplankton eat phytoplankton. o Ocean currents responsible for 40% heat exchange between trpic/polar. Wind responsible for 60%. Heat pumps/thermal conveyer=ocean current=pacific, indian, atlantic ocean. o  Concept 2.3: large-scale atmospheric and oceanic circulation patterns establish glal batterns of temperature and precipitation Global climatic patterns  Oceanic circulation and distribution and topography of continents influence global temperatures. Annual temperature variation is where air temperature over land show seasonal variation in warm temperature than cold temperature.  Why is it colder in mountains than lowlands? o Atmospheric pressure=density of air decrease, elevation increase sea level. Few air molecules absorb infrared energy radiating from earth’s surface. So even if high land have more solar radiation, heating of ground is less effective because low air density. o High land exchange air more effectively with cool air in surrounding atmosphere because atmosphere is warmed by infrared radiation. Temperature decrease with increase distance from ground. Lapse rate: decrease temperature increase height. Increase wind velocity increase elevation because less friction,  decrease air temperature increase elevation lapse rate  Patterns of atmospheric pressure and topography influence precipitation. Pressure cells influence movement of moist air from oceans to continent/could formation. E.g high pressure in south pacific ocean decrease precipitation in west coast. Mountains influence precipitation by forcing air moving across them to rise Concept 2.4 regional climates reflect influence of distribution of oceans/continent/mountain/vegetation. Regional climatic influences  In different climate change: air temperature increase, humidity decrease, precipitation decrease.  Proximity to oceans influences regional climates. Maritime climate: coastal terrestrial regionas influenced by ocean. Little variation in daily/seasonal temperature/high humidity. Continental climate: greater variation in daily and seasonal temperature. o Maritime climate occur in all climatic zones from tropical to polar o Temperatre zone influence oceans in coastal climates on est coast in northern hemisphere & east coast in sourther hemisphere because of prevailing wind. mid+high latitude=temperatue zone where large seasonal change because solar radiation and low heat capacity of land mass.  Mountains influence wind patterns and gradients in temperature and precipitation. What cause vegetation change? From grassland to forest? Climate of mountain produce effect on topography/elevation on air temperature/behavior of air mass/ own local wind pattern. o Rainshadow effect: in leeward slope L: lower precipitation and soil moisture on flope facing away from prevailing wind. Windward: higher precipitation/moisture on slope facing on prevailing wind.  It affects: types/amount of vegetation on mountain range. Windward: luch productive plant. o Mountains can generate own local wind/precipitation pattern. Slope exposure or slope aspect. In Hadley cells, differences in solar heating cause air to become warming.--> more solar radiation when sun rise in eastupslope wind. At night: cold air drainage: at high elevation: cold air flow downslope that cause valley bottom to be cold: it influence vegetation distribution in temperate zone because higher subfreezing temperature in low areas. o Cordilleras: large mountain chains channel movement of air masses. At continental: mountain influence movement, position, ehaviour of air and temperature of lowland.  Vegetation affects climate through surface energy exchange. o Albedo: capacity of a land surface to reflect solar radiation is influenced by presence/type of vegetation/soil/topography. Light color surface=high albedo. Coniferous forest is dark color=low albedo and soil absorbs more energy. Evapotranspiration: sum of water loss through transpiration and evaporation increases with area of leaves of ground surface area. Evapotranspiration transfer energy (latent heat) and water into atmosphere by affecting air temperature/moisture. Loss of tree increase albedo as bare soil is exposed. High albedo decrease absorption of solar radiation=less heating on land surface.=low evapotranspirative cooling 9lower latent heat transfer) because of loss of leaf area=reduce surface cooling=lower precipitation = less moisture. 2.5 seasonal and long term climatic variation are associated with changes in earth’s position relative to the sun Climatic variation over time.  Seasonality results from annual orbit of earth around the sun. closet to sun on jan, farthest on july. Seasonality in tropics-change in precipitation rather than temperature because solar radiation change is small in temperate/polar zone. o ITCZ intertropical convergence zone=zone of maximum solar radiation between n/s hemisphere. Zoen of maxmum solar radiation =zone of max warm air uplift and precipitation. E.g in northern hemisphere: N to S brings wet in jul to oct. In south; N to S have wet in oc to feb o Seasonal change in temperate and polar zone: affect temperature/solar radiation/length of the day  Seasonal changes in aquatic environment as associated with changes in water temperature and density. o Stratification: layer of water in ocean/lake with water temperature differences. (mixing occurs in upwelling0. In temperate lakes: epilimnion: n summer where warmest is surface water. Below epilimion is thermocline. Below thermocline is hypolimnion/benthic zone. During fall: air coolswater evaporateconduction/convectionheat transferincrease densityall water depths:epilmnion/epiliminion/hypolimnion will have same temperature and densityturnover: mixing of epimnion and hypolimnion recycle nutrient/move oxygen. Turnover occurs in spring and fall too when ice melts.  Climatic variation over years and decades results from changes in atmospheric pressure cells. o El nino southern oscillation: south America: high pressure to low cells over pacific and weaken east winds that normally push warm water to southeast asia. Less upwelling. La nina: stronger phases with high pressure in south America, low pressure in west pacific. Le nino then la nina happens.  La nina brings dry condition in indonasia  droughtsfire. La nina brings precipitation to mexico. o North atlantic oscillation: affects climate variation in Europe, north asia, east NA. o Pacific decadal oscillation ; pdo; pdo similar to enso.; northwest na central America/asia/austrailia  Long term climate change is associated with variation in earth’s orbital path. Continental drift: movement of land mass across earth. High greenhouse effect=increase warmer period. But radiation is increasing does not show affect on long term global change. o Glacial maxima: peak of glacial  interglacial period : called milankovitch cycle o in earth elliptical orbit=greater distance from sun=less solar radiation. Earth angle has hange which cause more seasonal angle is 23.5 concept 2.6 salinity, acidity and oxygen concentrations are major determinants of the chemical environment the chemical environment. Chemical influence biological function: salinity/acidity/oxygen available all waters contain dissolved salts  salinity: concentration of dissolved salt in water. Near equator: high salinity. Ocean salt: nacl, mg, ca, sulfate, bicarbonate, K. salt came from volcanic euroption cooling of minerals that soon break off. o High salinity that occur naturally is water soil near ocean. E.g salt marshes. Soil can become more saline by: plant roots/irrigation pump deep soil to surface soil. Salinization: when less precipitation and built up salt in soil: desert soils. Cause of Mesopotamia agriculture decline.  Organisms are sensitive to acidity of their environment. o Acidity/alkalinity: measure of ability of solution to behave as acid/ base. In ocean, pH does not vary becaue salt act as buffer. There is pH difference in land and surface water because: water become more acidic as more acidic compound added such as soil development.  2 parts of soil: mineral particles from breakdown rock/organic matter such as dead plant. Some raocks such as granite have acidic salt/while others basic salt. Soil become more acidic becase basic salt leach away/decompose.  Oxygen concentrations vary with elevation, diffusion, consumption o Hypoxic: archaea/bacteria/fungi can live in these low oxygen. Low oxygen in deep sea because slow rate of diffusin. Oxygen concentration highest in freshwater/moving water/stream,rivers because mixing of atmosphere occurs. o  Climatic variation and salmon abundance; pdo. Pdo shorter than enso.  Climatic variation and ecology: pdo exist to understand animal population. We don’t know what cause pdo. The Biosphere 8/31/2013 6:23:00 AM The American Serengeti-12 centuries of change in the great plains: case study. Central NA=great plains because it looks like Africa. Large animals became extinct in NA. megafauna. Reason: climate change limit food supply / humans./fire/grazing/precipitation/intensity of water. Biosphere: zone of life on earth between lithosphere(earth surface crust and upper mantle ) and troposphere (lowest layer of atmosphere). Biomes: diversity of terrestrial life on earth. Concept 3.1 terrestrial biomes are characteriszed by growth forms of dominant vegetation. Terrestrial biomes  Biomes do not categorize taxomic relationship but similarities in morphological response to environment. Similar biotic assemblage=similar response to climate force in locations.  Terrestrial biomes are classified by: o growth form (size/morphology) of plants (trees), o leaves (deciduous-shedding) o thickness o succulence –development of fleshy water storage tissue.  We use plants because it is immobile nad occupy site for a longer time and cope with environmental extreme and pressure – competition for water/nutrient/light- aridity, high and subfreezing temperature, solar radiation , nutrient poor soil, grazing animal, crowding. o To cope: use convergence: evolution of similar growth forms among distantly related species to respond pressure. E.g woody tissue/grow from their leaves.  We don’t’ use microorganisms-archaea, bacteria, fungi, because they are too rapid to changes and tiny size.  Terrestrial biomes reflect global patterns of preceipitation and temperature. o Climatic variation and terrestrial biome predict biome distribution through precipitation and tmerpaterature  Other factures affecting biome distribution: soil texture, chemistry, mountains, bodies of water.  The potential distributions of terrestrial biomes differ from thei actual distribution due to human activies. o Land use change: human effects where land resource extracted. Agriculture/logging/livestock grazing. o Climate diagram: characteristic of seasonal patterns of air temperature and precipitation at location of that biome. Yellow=water shortage. Blue=subfreezing 9 biomes Tropical rainforest. Low latitude. ITCZ has high precipitation. Seasonal climatic rhythms absent, and plants grow continuously. Most productive ecosystem.  Africa, central/S America, austrailia, southeast asia.  Highest to lowest plants: emergent treescanopy (evergreen) lianas; woody vines and epiphytes: tree branches  understoryforbs: broad leave herbaceous plants on forest floor rely on little light. Tropical seasonal forest and savannas  Rainfall become more seasonal. Shorter vegetation, more drought.  Plants: complex vegetation: tropical dry forest, thorn woodland: tree and strub, tropical savannas: grasses mixed with trees and strub  Was once greater than rainforest, now lower.  Asia, central S America. Hot desert.  Descending Hadley cells.  Convergence in plants: stem succulent store water for dry periods. Another convergence: active only in precipitation.  Irrigation in desert fail because of salinization. Desertification: long term drought with unsustainable grazing resulting loss of plants and soil erosion. Temperate grassland  Greater seasonal temperature variation with increasing subfreezing temperature. Enough precipitation to support forest/ grassland mainly for agriculture/pastoral development because the grass needs to grow deeper root to reach water=more fertility.  Salinization because of irrigation and desertification occurs. Temperate shrublands and woodlands.  Woodlands: open canopy of short tree. Shrubland: winter rainy season. Mediterranean type climate: west America, Africa, Europe, austrailia 30-40N.  Precipitation and summer growing season=the time only when temperature supp
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