Presentation on theme: "An Introduction to Ecology and the Biosphere (cont’d)"— Presentation transcript:
1 An Introduction to Ecology and the Biosphere (cont’d) Chapter 50An Introduction to Ecology and the Biosphere(cont’d)
2 RECALL:Concept 50.1: Ecology is the study of interactions between organisms and the environmentConcept 50.2: Interactions between organisms and the environment limit the distribution of speciesConcept 50.3: Abiotic and biotic factors influence the structure and dynamics of aquatic biomes
6 Varying combinations of both biotic and abiotic factors Concept 50.3: Abiotic and biotic factors influence the structure and dynamics of aquatic biomesVarying combinations of both biotic and abiotic factorsdetermine the nature of Earth’s many biomesBiomesare the major types of ecological associations that occupy broad geographic regions of land or water
7 Aquatic zones Many aquatic biomes are stratified into zones or layers defined by light penetration, temperature, and depthMarine zonation. Like lakes, the marine environment is generally classified on the basis of light penetration (photic and aphotic zones), distance from shore and water depth (intertidal, neritic, and oceanic zones), and whether it is open water (pelagic zone) or bottom (benthic and abyssal zones).Zonation in a lake. The lake environment is generally classified on the basis of three physical criteria: light penetration (photic and aphotic zones), distance from shore and water depth (littoral and limnetic zones), and whether it is open water (pelagic zone) or bottom (benthic zone).(a)Littoral zoneLimnetic zonePhotic zoneBenthic zoneAphotic zonePelagic zoneIntertidal zoneNeritic zoneOceanic zone200 mContinental shelfPelagiczone2,500–6,000 mAbyssal zone (deepest regions of ocean floor)(b)Figure 50.16a, b
8 Lakesphysical environment: standing body of water; can be stratified; seasonal thermoclinechemical environment: oligotrophic = deep, nutrient-poor, oxygen rich; eutrophic lakes = shallower, increased nutrients, oxygen depleted in winter; mesotrophic = moderate amount of nutrients, phytoplankton productivitygeologic features: oligotrophic lakes have less surface area compared to depth; oligotrophic lake can become eutrophic over timephotosynthetic organisms: ps. rates higher in eutrophic lakes; plants in littoral zone; phytoplankton + cyanobacteria in limnetic zoneanimals: zooplankton in limnetic zone; invertebrates in benthic zone; fish present throughout if O2 presenthuman impact: runoff from fertilizers, dumping of municipal waste = nutrient enrichment – algal blooms, O2 depletionAn oligotrophic lake in Grand Teton, WyomingA eutrophic lake in Okavango delta, BotswanaLAKESFigure 50.17
9 Wetlandsphysical environment: area covered with water for long enough period to support aquatic lifechemical environment: high organic production, decomposition;low dissolved O2geologic features: basin wl.= shallow basin; riverine wl. = shallow, flooded banks of rivers, streams; fringe wl. = along coasts of lakes, seas depending on tidesphotosynthetic organisms: plants with adaptations to grow in water with low O2animals: invetebrates – birds; herbivores, carnivoreshuman impact: draining & filling destroyed up to 90% of wl. in some regionsWETLANDSOkefenokee National Wetland Reserve in Georgia
10 Streams and Riversphysical environment: current; headwater streams = cold, clear, turbulent; downstream = warmer, more turbid; stratifiedchemical environment: salt, nutrient content increases from headwater to mouth; headwater O2 richgeologic features: headwater narrow, rocky bottom; downstream – wider, bottom siltyphotosynthetic organisms: streams through grassland or dessert are rich in algae or rooted plants; in forests leaves etc. from terrestrial plants primary food source for consumersanimals: fishes, invertebrateshuman impact: municipal, agricultural, industrial pollution, dammingSTREAMS AND RIVERSA headwater stream in the Great Smoky MountainsThe Mississippi River far form its headwaters
11 Estuariesphysical environment: transition area between river & sea; complex flow patterns; higher density sea water bottom of estuary channelchemical composition: salinity variable; nutrient from river make estuaries very productivegeologic features: tidal channels, islands, levees, mudflatsphotosynthetic organisms: grasses, algae including phytoplanktonanimals: invertebrates, fishes; important breeding grounds for marine species; feeding area for waterfowlhuman impact: pollution from upstream, filling, dredgingAn estuary in a low coastal plain of GeorgiaESTUARIES
12 Rocky intertidal zone on the Oregon coast Intertidal ZonesINTERTIDAL ZONESRocky intertidal zone on the Oregon coastphysical environment: periodically submerged & exposed by tides; upper zones greater exposure to air, more variation in environment (temp., salinity, wave action)chemical environment: O2, nutrient levels highgeologic features: rocky or sandy substrate; variable influence of tides depending on coastlinephotosynthetic organisms: attached marine algaeanimals: invertebrates with special adaptations to attach to substratehuman impact: oil pollution, recreational use
13 Open ocean off the island of Hawaii Ocean pelagic biomephysical environment: open water, mixed by ocean currents; higher clarity that coastal zones, photic zone is deeperchemical environment: O2 high; nutrient levels low; temperate regions there is surface turn overgeologic features: vast, deep waters; 70% of Earth’s surfacephotosynthetic organisms: phytoplanktonanimals: zooplankton, free swimming invertebrates, vertebrateshuman impact: overfishing, pollution (oil spills, waste dumping)Open ocean off the island of HawaiiOCEANIC PELAGIC BIOME
14 A coral reef in the Red Sea Coral reefsphysical environment: limited to photic zones of stable tropical environments with high water claritychemical environment: high O2, stable salinity, stable nutrient levelsgeologic features: coral reef formed from calcium carbonate of corals; needs solid substratephotosynthetic organisms: dinoflagellate algae within tissues of corals; red, green marine algaeanimals: cnidarians predominant animals; fish, invertebrateshuman impact: poisons, explosives for aquarium trade, global warming, pollutionA coral reef in the Red SeaCORAL REEFS
15 A deep-sea hydrothermal vent community Marine benthicA deep-sea hydrothermal vent communityMARINE BENTHIC ZONEphysical environment: seafloor below neritic zone (WATER THAT IS ABOVE THE CONTINETIAL SHELF & pelagic zone; no sunlight in benthos beneath pelagic; deep benthic = abyssal zone (cold 3ºC, high pressure)chemical environment: O2 sufficient for diversity of animalsgeologic features: soft sediments; some rocky substrate; submarine mountains; volcanoesfood producing organisms: ps organisms only in shallow benthos; some organisms associated with deep-sea hydrothermal vents- chemoautotrophic prokaryotesanimals: neritic benthic – invertebrates, fishes; deep water tube worms; arthropods, echinodermshuman impact: overfishing, dumping
16 Concept 50.4: Climate largely determines the distribution and structure of terrestrial biomes is particularly important in determining why particular terrestrial biomes are found in certain areas
17 Climate and Terrestrial Biomes Climate has a great impact on the distribution of organisms, as seen on a climographDesertTemperate grasslandTropical forestTemperatebroadleafforestConiferousArctic andalpinetundraAnnual mean precipitation (cm)Annual mean temperature (ºC)100200300400301515Figure 50.18
18 The distribution of major terrestrial biomes Tropic ofCancerEquatorCapricorn30SKeyTropical forestSavannaDesertChaparralTemperate grasslandTemperate broadleaf forestConiferous forestTundraHigh mountainsPolar iceFigure 50.19
19 General Features of Terrestrial Biomes are often named for major physical or climatic factors and for their predominant vegetationStratificationis an important feature of terrestrial biomes
20 A tropical rain forest in Borneo Tropical forestdistribution: equatorial, subequatorialprecipitation: tropical rain forests -relatively constant, cm annually; tropical dry forests – cm annually (6-7 month dry season)temperature: 25-29ºCplants: stratified – canopy, subcanopy trees; rain forest -broadleaf evergreen dominant; deciduous broadleaf in tropical dry forestanimals: most animal diversity than any other terrestrial biomehuman impact: destruction for agriculture, developmentTROPICAL FORESTA tropical rain forest in Borneo
21 The Sonoran Desert in southern Arizona distribution: in band near 30º N & S latitude or interior of continentsprecipitation: low, highly variable; less than 30 cm per yeartemperature: variable; can exceed 50ºC; some cold deserts -30ºCplants: low, scattered vegetation; high proportion of bare ground; succulents, shrubsanimals: reptiles, rodents, insects; many species nocturnal; adaptations to deal with scarce waterhuman impact: conversion to irrigated land, urbanizationDESERTThe Sonoran Desert in southern Arizona
22 A typical savanna in Kenya distribution: equatorial, subequatorialprecipitation: cm per year; dry season 8-9 monthstemperature: 24-29ºCplants: scattered trees; adapted for seasonal drought; grasses + forbs dominantanimals: large herbivores; insectshuman impact: cattle ranching, overhuntingSAVANNAA typical savanna in Kenya
23 An area of chaparral in California distribution: midlatitude coastal regionsprecipitation: rainy winters, dry summers; cm annualtemperature: fall, winter, spring 10-12ºC; summer 30-40ºCplants: shrubs, small trees; high plant diversity; adaptations to droughtanimals: browsing herbivores, high diversity of small animals (amphibians, birds, reptiles)human impact: agriculture,urbanizationCHAPARRALAn area of chaparral in California
24 Sheyenne National Grassland in North Dakota Temperate grasslandsdistribution: throughout various regionsprecipitation: dry winters, wet summers; cmtemperature: cold winters -10ºC; hot summers 30ºCplants: grasses & forbs; adapted to drought, fireanimals: large grazers, burrowing animalshuman impact: agricultureSheyenne National Grassland in North DakotaTEMPERATE GRASSLAND
25 Rocky Mountain National Park in Colorado Coniferous forestRocky Mountain National Park in ColoradoCONIFEROUS FORESTdistribution: broad band across northern N America & Erasia to edge of arctic tundraprecipitation: cm, periodic droughts; coastal coniferous forests 300 cmtemperature: winters cold, long; summers may be hotplants: cone-bearing treesanimals: large herbivores, carnivoreshuman impact: logging
26 Temperate broadleaf forest distribution: midlatitude in northern hemisphereprecipitation: cm annuallytemperature: winter 0ºC; summers 30ºCplants: high diversity; deciduous trees dominantanimals: mammals, birds, insectshuman impacts: logging, agriculture, urban developementTEMPERATE BROADLEAF FORESTGreat Smoky Mountains National Park in North CarolinaFigure 50.20
27 Denali National Park, Alaska, in autumn Tundradistribution: arctic (20% of surface)precipitation: cm; some areas 100 cmtemperature: winters long, cold -30ºC; summers short cool 10ºCplants: herbaceous (lichens, mosses, grasses, forbs, dwarf trees); permafrost prevents water infiltration into soilanimals: large grazing herbivores, large carnivores, migratory birdshuman impact: mineral, oil extractionTUNDRADenali National Park, Alaska, in autumn
28 Take home questions:Which of the following statements best describes the effect of climate on biome distribution?Knowledge of annual temperature and precipitation is sufficient to predict which biome will be found in an area.Fluctuation of environmental variables is not important if areas have the same annual temperature and precipitation means.It is not only the average climate that is important in determining biome distribution, but also the pattern of climatic variation. On final Test.Temperate forests, coniferous forests, and grasslands all have the same mean annual temperatures and precipitation.Correlation of climate with biome distribution is sufficient to determine the cause of biome patterns.
29 Imagine some cosmic catastrophe that jolts Earth so that it is no longer tilted. Instead, its axis is perpendicular to the line between the Sun and Earth. The most predictable effect of this change would be:No more night and day.A big change in the length of the year.A cooling of the equator.A loss of seasonal variations at northern and southern latitudes. In the textbook.The elimination of ocean currents.
30 Which of the following events might you predict to occur if the tilt of Earth's axis relative to its plane of orbit was increased beyond 23.5 degrees?Summers in the United States might become warmer.Winters in Australia might become more severe.Seasonal variation at the equator might decrease.Both A and B are correct.A, B, and C are all correct.
31 If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced sunlight reaching Earth's surface by 70% for one year, all of the following marine communities would be greatly affected except adeep-sea vent community.coral reef community.benthic community.pelagic community.estuary community.