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1、生态学中的环境因子第1页，共40页，编辑于2022年，星期日Biotic:organisms.Organisms compete with,parasitize,eat or are eaten by and change the environment for other organisms.第2页，共40页，编辑于2022年，星期日Ecology explores a wide range of questions about what factors control the distribution,abundance and behavior of organisms.For exam
2、ple,Red Kangaroos occur primarily in the Australian interior in semiarid regions.第3页，共40页，编辑于2022年，星期日Distribution of Kangaroos suggests an abiotic factor(precipitation)influences it,but perhaps populations also influenced indirectly by biotic factors such as competitors,predators,food availability
3、and parasites.Ecologists have to consider multiple factors to explain patterns of abundance and distribution.第4页，共40页，编辑于2022年，星期日第5页，共40页，编辑于2022年，星期日Ecology has many subfields of study ranging from ecology of individual organisms to dynamics of landscapesOrganismal EcologyPopulation EcologyCommuni
4、ty EcologyEcosystem EcologyLandscape EcologyWe will explore these sequentially第6页，共40页，编辑于2022年，星期日第7页，共40页，编辑于2022年，星期日Distribution of species Biogeography:study of the broad patterns of distribution of organisms across the globe.Patterns strongly influenced by historical factors such as continenta
5、l drift(see chapter 26)and barriers including mountain ranges and seas.第8页，共40页，编辑于2022年，星期日第9页，共40页，编辑于2022年，星期日For example,Australia populated by marsupial mammals(e.g.kangaroos,wombats,koalas)because placental mammals did not colonize it before it separated from other landmasses.Tapirs found only
6、 in southeast Asia and South America.Ancestral populations separated when land masses diverged.第10页，共40页，编辑于2022年，星期日Role of dispersal in distributionAbility to cross barriers affects distribution.Thus,species of birds often more widely distributed than mammals.第11页，共40页，编辑于2022年，星期日However,inabilit
7、y to reach an area not only factor that limits distribution.Ability to survive in new area is critical.To survive and thrive species must be able to cope with both biotic and abiotic factors.第12页，共40页，编辑于2022年，星期日Biotic factorsThe presence of competitors or predators may limit an organisms ability t
8、o establish itself.For example,algae are eaten by sea urchins and limpets,which limits the ability of seaweeds to establish themselves on rocks第13页，共40页，编辑于2022年，星期日第14页，共40页，编辑于2022年，星期日Biotic factorsConversely,absence of predators and competitors has allowed many organisms introduced into new area
9、s to increase so much they become pests.E.g.Japanese beetles(from Asia),zebra mussels and purple loosestrife from Europe)(Melaleuca(Eucalyptus trees from Australia)and many other invasive species have spread widely in the U.S.第15页，共40页，编辑于2022年，星期日Abiotic factorsThe major factor affecting distributi
10、on of terrestrial organisms is climate,which incorporates temperature,sunlight,wind and precipitation.第16页，共40页，编辑于2022年，星期日Abiotic factorsClimate is determined by global factors such as inputs of solar energy and the movement of the earth through space.Study discussion of climate patterns pages 108
11、8 and 1089第17页，共40页，编辑于2022年，星期日第18页，共40页，编辑于2022年，星期日第19页，共40页，编辑于2022年，星期日ClimateLocal factors such as the presence of mountains and large bodies of water also affect climate.Mountains force up moist air moving across them.As the air cools the water condenses and falls as rain.The result is that o
12、ne side of the mountain range is wet and the other side is drier(and perhaps a desert e.g.Mojave and Gobi Deserts.)第20页，共40页，编辑于2022年，星期日第21页，共40页，编辑于2022年，星期日ClimateLarge bodies of water moderate climate.Land heats faster than water and warm air rises.Cooler air over water moves in and replaces the
13、 warm air.The warm air that was over land cools at high altitude and sinks over water.Results is steady flow of cool air over land.第22页，共40页，编辑于2022年，星期日第23页，共40页，编辑于2022年，星期日Terrestrial BiomesBiomes are major types of ecosystems that cover large areas of the earth and are classified by their domina
14、nt vegetation types.(an ecosystem is the community of organisms in an area and their physical environment)第24页，共40页，编辑于2022年，星期日Each biome also is populated by a diverse array of animals,fungi and microorganisms adapted to that environment.第25页，共40页，编辑于2022年，星期日Major terrestrial biomes includeTropic
15、al forestDesertTemperate GrasslandSavannaTemperate broadleaf forestConiferous forest(Taiga)Tundra(see descriptions pages 1100-1104)第26页，共40页，编辑于2022年，星期日Savannah第27页，共40页，编辑于2022年，星期日Terrestrial biomesTerrestrial biomes often vertically stratified.Layers defined by different size plants(e.g.in fores
16、ts there is an upper canopy of tall trees,low tree layer,shrub layer,ground layer of herbaceous plants,litter layer and root zone).第28页，共40页，编辑于2022年，星期日Stratification provides multiple different habitats for animals which occupy specialized feeding niches.第29页，共40页，编辑于2022年，星期日Convergent evolutionA
17、ctual species in a biome differ from one area to another but they possess similar adaptations.This is convergent evolution(development of same evolutionary solutions to ecological problems)第30页，共40页，编辑于2022年，星期日Convergent evolutionFor example vegetation in all deserts worldwide characterized by exte
18、nsive root systems,long-term water storage capability,thick waxy coverings to reduce water loss,and extremely small(if any)leaves第31页，共40页，编辑于2022年，星期日Biomes often maintained by disturbance.Wildfires are an essential factor in maintaining many biomes(e.g.grasslands,savannahs,some coniferous forests)
19、.Fire favors trees such as longleaf pine whose bark resists fire and grasses,which recover quickly after burning.第32页，共40页，编辑于2022年，星期日Aquatic biomesAquatic biomes less influenced by climate than terrestrial biomesWhy?第33页，共40页，编辑于2022年，星期日Aquatic biomesWater is more thermally stable.It takes a lot
20、of heat to change the temperature of a body of water.第34页，共40页，编辑于2022年，星期日Major aquatic biomesLakesRiversEstuariesIntertidal zoneMarine pelagic zoneCoral reefsMarine benthic zone(benthic zone is sea/lakefloor)See pages 1094-1097.第35页，共40页，编辑于2022年，星期日Aquatic biomes often stratified by light and tem
21、perature.Light intensity decreases with depth.Upper(photic)zone supports photosynthesis.In ocean photic zone narrow but contains most organisms.第36页，共40页，编辑于2022年，星期日第37页，共40页，编辑于2022年，星期日Aphotic zone sparsely populated.Benthic zone(bottom)organisms often depend on rain of dead organic matter(detrit
22、us)from above.第38页，共40页，编辑于2022年，星期日Thermal stratification of lakesIn temperate areas lakes are thermally stratified in summer and winter.Water densest at 4C so water at this temperature sinks through colder or warmer water.Thus,in spring and fall all water in lake mixes which redistributes nutrients throughout the lake.第39页，共40页，编辑于2022年，星期日第40页，共40页，编辑于2022年，星期日