专业英语-生态学教材PPT课件

1. Ecological role of solar radiation1.1 Photosynthesis: Photosynthesis is a light-dependent process in which the rate of photosynthetic fixation of both CO2 and solar energy is largely dependent upon light intensity.CP: compensation SP: saturation pointPhotosynthesis increases rapidly , but initially there is no net CO2fixation because the rate of CO2 loss in respiration is greater than the rate of CO2 fixation . As light intensity continues to increase, a point is reached at which respiratory losses are exactly balance by photosynthetic gains. This light intensity is called the CP. Above the CP. The rate of photosynthesis continues to increase rapidly with increasing light intensity, but this relationship is not sustained. With continued increases in light, the rate of increase in photosynthesis diminishes until the saturation point is reached, beyond which further increases in light intensity result in little or no further increases in net CO2 fixation. At very high light intensities, net fixation may drop because of damage to the photosynthetic apparatus or for other reasons. When expressed graphically, this relationship is called the photosynthetic light saturation curve.Plants with a high ratio of photosynthetic biomass to living supporting bio mass will have lower CPs than plants with a low ratio because they have less respiratiory loss of CO2 for which to compensate. Plants with low CPs often have lower SPs than plants with high CPs. It takes less light to provide all the solar energy that the photochemical system can use in an algal cell than in a tree leaf. Within a tree crown , leaves that grow in full sunlight have higher CPs and SPs than do leaves that grow in deep shade because of differences in leaf morphology.1.2 The relationship between light intensity and net photosynthesis is complex and under the control of many factors, it is no surprising, therefore, that net photosynthesis in natural stands of plants does not always follow the daily variation in light intensity. In clear weather, there may be a morning peak in net photosynthesis followed by a midday dip and a second peak in the afternoon, it has been suggested that this midday dip may result from one or more of the following factors: overheating of leaves; excessive respiration; water deficits; accumulation of products of photosynthesis in the leaves; photooxidation of enzymes and pigments; closure of stomata; depletion of CO2 in the air surrounding the crown that accompanies highintensities of solar radiation in the middle of the day.Photoperiodism in plants plays a major role in the control of the cessation of growth and the onset of dormancy in the late summer or fall, and in many plants, it regulates flowering and fruiting in the spring and summer. It also plays a role in the breaking of dormancy and resumption of growth in the spring in some perennial plants.2. temperature as an ecological factorTemperature exhibits a number of well-defined cycles of variation that are directly attributable to the rotation of the earth around its axis and around the sun. these rotations lead to a daily and seasonal variation in the amount of radiant energy that reaches a particular part of the earth and consequently in its temperature. In the tropics , the diurnal variation in temperature may be only a few degrees, whereas in continental regions , it can be as much as 50℃ in either winter or summer .2.1Role of topographyHigh-elevation areas have lower average temperatures than do low-elevation areas, because air temperatures normally decrease at a rate of approximately 0.4℃per 100m of elevation as one proceeds up a mountain.Temperature inversion:inversions can also occur as the result of topography. Radiant cooling of high ground flanking a valley gives rise to a layer of cold, dense air in contact with the surface. This air flows slowly down the valley slopes, displacing warmer air in the lower part of the valley and creating an inversion. When the cold air that drains into the valley is below 0 , frost occurs on the valley floor, whereas much warmer temperatures will be experienced in the “thermal belt” higher up the slopes. This is of great importance to fruit growers, and orchards are often located in the thermal belt.2.2 There is a great temptation to describe climates as severe, extreme, favorable, or unfavorable. Other adjectives that are commonly used to describe temperature as optimum, maximum, minimum.2.3 All plants experience variations in temperature associated with diurnal variations in the net radiation budget. Plants that live away from the equator also experience seasonal temperature variations. Plants are generally sensitive to these variations and will grow normally only when exposed to the particular diurnal and seasonal temperature changes to which they are adapted, a phenomenon called thermoperiodism.2.4 Temperature-related injuriesLow-temperature injury:frost cracks: efficient emission of radiation and low conductivity lead to rapid surface cooling of woody stems on clear nights with low air temperatures. The outer layers of the stem contract more rapidly than inner layers, which creates tensions that can cause the stem to crack. These frost cracks are particularly common in regions subject to sudden drops in air temperature.Ice crystals (needle ice): rapid radiation cooling results in the freezing of soils from the surface downward. Water is drawn up to the frozen layer, where it freezes and forms a gradually thickening layer of vertically oriented ice crystals.Frost-heaved:the frozen surface soil together with small plants can be lifted as much as a decimeter by this needle ice and then lowered again as the ice melts. Roots that are pulled up from lower unfrozen soil layers cannot return to their original position, and over several freeze-thaw cycles, small plants such as tree seedlings may be lifted right out of the soil.Physiological drought:warm air temperatures in winter or an early , warm spring in areas where the soil is still frozen can remove water from plants at a time when it cannot be replaced. Even if the water is not frozen, winter water stress can occur because of the doubling of the viscosity of water between 25 and 0 , which makes water uptake more difficult at temperatures approaching freezing. Plants that grow on soils that are cold or frozen in winter often exhibit the same morphological adaptations as plants that grow on summer-dry sites. The water imbalance caused by high air temperatures and low soil temperatures is referred to as physiological drought. When severe, it can cause browning of the foliage and even the death of theentire plant.High-tmeperature injuryStem girdle:because of the low albedo and low conductivity of many soils, surface temperatures frequently become very high, and young plant stems that are not yet protected by thick layers of bark may be damaged where they contact the soil surface. A band of cambium a few millimeters wide is killed around the stem, and this results in the death of the plant either because of the interruption of internal translocation or because of the entry of pathogens.3. WaterLike nutrient cycles in general, the water cycle is driven by inputs of solar energy. V ast quantities of radiant energy are absorbed in the process of evaporating water from the warm areas of the world’s oceans. The energy is transferred to the atmosphere as the water vapor condenses, thereby driving our climate and creating our weather. The warm, moist air creates clouds as it rises, and the winds formed by the resulting processes of atmospheric stirring move the clouds over the land, where some of the moisture falls as precipitation. Some of this is re-evaporated directly back to the atmosphere, and some is subsequently transpired by plants. The rest enters water courses and returns to lakes and eventually to oceans, from which it is once again evaporated.3.1Forests influence water cyclesInterception of precipitation by vegetation: the loss back to the atmosphere of precipitation that has been intercepted by vegetation is called interception loss. The magnitude of interception loss depends on the interception storage capacity of the vegetation. Interception storage for tree and shrub cover has been reported to ranger between 0.25 and 7.6mm of rain and up to 2.5cm (water equivalent) of snow. Table 1 presents some figures for interception loss in various forest types in the United States.Redistribution of water by vegetation :water that is intercepted by tree crowns isredistributed into two major subtypes and reaches the floor very nonuniformly: (1) throughfall—the portion of the incident precipitation that drips from or falls through the vegetation canopy; (2) stemflow—the portion that reaches the soil by flowing down the stem. Stemflow is also affected by bark roughness. Smooth-bark species have little stem water storage capacity, and stemflow will commence on smooth-barked species such as beech after only a little more than 1mm of rain has fallen, but rough-barked species have a large stem storage capacity, and appreciable stemflow may not reach the ground until more than 2cm of rain has fallen.Infiltration into the soil:Water that reaches the ground can either flow laterally over the surface or penetrate the soil in a process called infiltration. Once within the soil, the movement of water is known as percolation. The term infiltration can apply either to the organic forest floor or to the underlying mineral soil, but because the rate of water movement into the forest floor almost always exceeds rates of precipitation and because the condition of the forest floor is subject to modification and is therefore less permanent than the mineral soil as a site feature, the term is applied most frequently to the mineral soil.Entry of water into the forest floor is normally rapid because of the many large pores and the organic nature of the forest floor, which gives it a high moisture-holding capacity. However, forest floor that have become very hot and dry during the summer may exhibit hydrophobicity, which makes them very difficult to wet.Once wet, forest floor can hold between one and five times their own weight of water, the more decomposed the organic matter and the more rotting wood in the forest floor, the more water it can hold. Only the water in excess of the field capacity of the forest floor will infiltration into the mineral soil.Water in the soil is classified as gravitational, available and unavailable. The relative proportions of these three types of water vary according to the relative abundance of different pore sizes, which in turn depends on soil structure and texture.Loss of water to evaporation and transpiration:Water is lost from soil by three major pathways: drainage to groundwater, evaporation back to the atmosphere, and uptake by plants. The equivalent of 760mm of precipitation is delivered to the 48coteminous U.S. states each year, and of this, approximately 370mm is lost back to the atmosphere by evaporation from forests and wildlands.Evaporation from the soil surface requires two preconditions: energy in the form of solar radiation (2.24 MJ are required to evaporate 1kg of water) and an upward flow of water from lower in the soil to maintain water in the surface layer, where the energy is available for evaporation.Transpiration: loss of water from which the living cells of plant tissues to the atmosphere by vaporization is called transpiration. Water that is absorbed by roots from soil is translocated upward to the foliage in the xylem of the roots and stem. This uptake and translocation is driven by solar energy falling on the leaves and stems, which causes water to evaporate from the moist outside surfaces of mesophyll cells into air spaces within the leaf. The water vapor either diffuses out to the atmosphere through stomata or evaporates directly through the cuticle of leaves.。

1. Ecological role of solar radiation1.1 Photosynthesis: Photosynthesis is a light-dependent process in which the rate of photosynthetic fixation of both CO2 and solar energy is largely dependent upon light intensity.CP: compensation SP: saturation pointPhotosynthesis increases rapidly , but initially there is no net CO2fixation because the rate of CO2 loss in respiration is greater than the rate of CO2 fixation . As light intensity continues to increase, a point is reached at which respiratory losses are exactly balance by photosynthetic gains. This light intensity is called the CP. Above the CP. The rate of photosynthesis continues to increase rapidly with increasing light intensity, but this relationship is not sustained. With continued increases in light, the rate of increase in photosynthesis diminishes until the saturation point is reached, beyond which further increases in light intensity result in little or no further increases in net CO2 fixation. At very high light intensities, net fixation may drop because of damage to the photosynthetic apparatus or for other reasons. When expressed graphically, this relationship is called the photosynthetic light saturation curve.Plants with a high ratio of photosynthetic biomass to living supporting bio mass will have lower CPs than plants with a low ratio because they have less respiratiory loss of CO2 for which to compensate. Plants with low CPs often have lower SPs than plants with high CPs. It takes less light to provide all the solar energy that the photochemical system can use in an algal cell than in a tree leaf. Within a tree crown , leaves that grow in full sunlight have higher CPs and SPs than do leaves that grow in deep shade because of differences in leaf morphology.1.2 The relationship between light intensity and net photosynthesis is complex and under the control of many factors, it is no surprising, therefore, that net photosynthesis in natural stands of plants does not always follow the daily variation in light intensity. In clear weather, there may be a morning peak in net photosynthesis followed by a midday dip and a second peak in the afternoon, it has been suggested that this midday dip may result from one or more of the following factors: overheating of leaves; excessive respiration; water deficits; accumulation of products of photosynthesis in the leaves; photooxidation of enzymes and pigments; closure of stomata; depletion of CO2 in the air surrounding the crown that accompanies highintensities of solar radiation in the middle of the day.Photoperiodism in plants plays a major role in the control of the cessation of growth and the onset of dormancy in the late summer or fall, and in many plants, it regulates flowering and fruiting in the spring and summer. It also plays a role in the breaking of dormancy and resumption of growth in the spring in some perennial plants.2. temperature as an ecological factorTemperature exhibits a number of well-defined cycles of variation that are directly attributable to the rotation of the earth around its axis and around the sun. these rotations lead to a daily and seasonal variation in the amount of radiant energy that reaches a particular part of the earth and consequently in its temperature. In the tropics , the diurnal variation in temperature may be only a few degrees, whereas in continental regions , it can be as much as 50℃ in either winter or summer .2.1Role of topographyHigh-elevation areas have lower average temperatures than do low-elevation areas, because air temperatures normally decrease at a rate of approximately 0.4℃per 100m of elevation as one proceeds up a mountain.Temperature inversion:inversions can also occur as the result of topography. Radiant cooling of high ground flanking a valley gives rise to a layer of cold, dense air in contact with the surface. This air flows slowly down the valley slopes, displacing warmer air in the lower part of the valley and creating an inversion. When the cold air that drains into the valley is below 0 , frost occurs on the valley floor, whereas much warmer temperatures will be experienced in the “thermal belt” higher up the slopes. This is of great importance to fruit growers, and orchards are often located in the thermal belt.2.2 There is a great temptation to describe climates as severe, extreme, favorable, or unfavorable. Other adjectives that are commonly used to describe temperature as optimum, maximum, minimum.2.3 All plants experience variations in temperature associated with diurnal variations in the net radiation budget. Plants that live away from the equator also experience seasonal temperature variations. Plants are generally sensitive to these variations and will grow normally only when exposed to the particular diurnal and seasonal temperature changes to which they are adapted, a phenomenon called thermoperiodism.2.4 Temperature-related injuriesLow-temperature injury:frost cracks: efficient emission of radiation and low conductivity lead to rapid surface cooling of woody stems on clear nights with low air temperatures. The outer layers of the stem contract more rapidly than inner layers, which creates tensions that can cause the stem to crack. These frost cracks are particularly common in regions subject to sudden drops in air temperature.Ice crystals (needle ice): rapid radiation cooling results in the freezing of soils from the surface downward. Water is drawn up to the frozen layer, where it freezes and forms a gradually thickening layer of vertically oriented ice crystals.Frost-heaved:the frozen surface soil together with small plants can be lifted as much as a decimeter by this needle ice and then lowered again as the ice melts. Roots that are pulled up from lower unfrozen soil layers cannot return to their original position, and over several freeze-thaw cycles, small plants such as tree seedlings may be lifted right out of the soil.Physiological drought:warm air temperatures in winter or an early , warm spring in areas where the soil is still frozen can remove water from plants at a time when it cannot be replaced. Even if the water is not frozen, winter water stress can occur because of the doubling of the viscosity of water between 25 and 0 , which makes water uptake more difficult at temperatures approaching freezing. Plants that grow on soils that are cold or frozen in winter often exhibit the same morphological adaptations as plants that grow on summer-dry sites. The water imbalance caused by high air temperatures and low soil temperatures is referred to as physiological drought. When severe, it can cause browning of the foliage and even the death of theentire plant.High-tmeperature injuryStem girdle:because of the low albedo and low conductivity of many soils, surface temperatures frequently become very high, and young plant stems that are not yet protected by thick layers of bark may be damaged where they contact the soil surface. A band of cambium a few millimeters wide is killed around the stem, and this results in the death of the plant either because of the interruption of internal translocation or because of the entry of pathogens.3. WaterLike nutrient cycles in general, the water cycle is driven by inputs of solar energy. V ast quantities of radiant energy are absorbed in the process of evaporating water from the warm areas of the world’s oceans. The energy is transferred to the atmosphere as the water vapor condenses, thereby driving our climate and creating our weather. The warm, moist air creates clouds as it rises, and the winds formed by the resulting processes of atmospheric stirring move the clouds over the land, where some of the moisture falls as precipitation. Some of this is re-evaporated directly back to the atmosphere, and some is subsequently transpired by plants. The rest enters water courses and returns to lakes and eventually to oceans, from which it is once again evaporated.3.1Forests influence water cyclesInterception of precipitation by vegetation: the loss back to the atmosphere of precipitation that has been intercepted by vegetation is called interception loss. The magnitude of interception loss depends on the interception storage capacity of the vegetation. Interception storage for tree and shrub cover has been reported to ranger between 0.25 and 7.6mm of rain and up to 2.5cm (water equivalent) of snow. Table 1 presents some figures for interception loss in various forest types in the United States.Redistribution of water by vegetation :water that is intercepted by tree crowns isredistributed into two major subtypes and reaches the floor very nonuniformly: (1) throughfall—the portion of the incident precipitation that drips from or falls through the vegetation canopy; (2) stemflow—the portion that reaches the soil by flowing down the stem. Stemflow is also affected by bark roughness. Smooth-bark species have little stem water storage capacity, and stemflow will commence on smooth-barked species such as beech after only a little more than 1mm of rain has fallen, but rough-barked species have a large stem storage capacity, and appreciable stemflow may not reach the ground until more than 2cm of rain has fallen.Infiltration into the soil:Water that reaches the ground can either flow laterally over the surface or penetrate the soil in a process called infiltration. Once within the soil, the movement of water is known as percolation. The term infiltration can apply either to the organic forest floor or to the underlying mineral soil, but because the rate of water movement into the forest floor almost always exceeds rates of precipitation and because the condition of the forest floor is subject to modification and is therefore less permanent than the mineral soil as a site feature, the term is applied most frequently to the mineral soil.Entry of water into the forest floor is normally rapid because of the many large pores and the organic nature of the forest floor, which gives it a high moisture-holding capacity. However, forest floor that have become very hot and dry during the summer may exhibit hydrophobicity, which makes them very difficult to wet.Once wet, forest floor can hold between one and five times their own weight of water, the more decomposed the organic matter and the more rotting wood in the forest floor, the more water it can hold. Only the water in excess of the field capacity of the forest floor will infiltration into the mineral soil.Water in the soil is classified as gravitational, available and unavailable. The relative proportions of these three types of water vary according to the relative abundance of different pore sizes, which in turn depends on soil structure and texture.Loss of water to evaporation and transpiration:Water is lost from soil by three major pathways: drainage to groundwater, evaporation back to the atmosphere, and uptake by plants. The equivalent of 760mm of precipitation is delivered to the 48coteminous U.S. states each year, and of this, approximately 370mm is lost back to the atmosphere by evaporation from forests and wildlands.Evaporation from the soil surface requires two preconditions: energy in the form of solar radiation (2.24 MJ are required to evaporate 1kg of water) and an upward flow of water from lower in the soil to maintain water in the surface layer, where the energy is available for evaporation.Transpiration: loss of water from which the living cells of plant tissues to the atmosphere by vaporization is called transpiration. Water that is absorbed by roots from soil is translocated upward to the foliage in the xylem of the roots and stem. This uptake and translocation is driven by solar energy falling on the leaves and stems, which causes water to evaporate from the moist outside surfaces of mesophyll cells into air spaces within the leaf. The water vapor either diffuses out to the atmosphere through stomata or evaporates directly through the cuticle of leaves.。

Chapter 6 PopulationregulationWang LiContent6.1 Life history-6.1.1 Life history long VS short -6.1.2 Offspring number VS size-6.1.3 Adult survival and reproductive allocation -6.1.4 Life history classification6.2 Population regulationLife history long Vs short .The observed in the life history patterns of different species is vast. Some species live for hundreds or even thousands of years, some grow to vast sizes whilst other are minute.Offspring number Vs size.Some produce many ,tiny offspring whilst others have few,relatively large offspring.Life history :Series of events from birth through reproduction to death .6.1 Life historiesHow these differences evolve is a key question in ecology.--6.1.1 Life history long VS shortSeed size and number in plants A small sample of the greatdiversity of seed sizes and shapes.Relationship between seed mass andseed number6.1.2 Offspring number VS sizeData from Turner and Trexler 1998Egg size and number in fish6.1.2 Offspring number VS sizeQuestion1 Why the number of those larger (smaller) offspring is always to be fewer (larger)?Fecundity ( ): simply the number of eggs or seeds produced by an organism.Q1Answer:Because all organisms have access to limitedenergy and other resources, there is a trade-offbetween the number and size of offspring.(P273)---those that produce larger (smaller) offspringare constrained to produce fewer (larger).---Those spend more (less) energy to take careoffspring are constrained to produce fewer(larger).Energy distribution theory——Energy allocated to one aspect of life historycannot be spent in another, so ‘trade-offs’ betweendifferent traits are inevitable.Energy distribution theory6.1.3 Adult survival andreproductive allocationQuestion2Is there a relationship between adult survival and the beginning time of reproduction?Reproductive effort ( ): allocation of energy, time, and other resources to the production and care of offspring.Survivorship 114 11Survivorship 3Survival and maturityQ2Answer:--Where adult survival is lower , organisms beginreproducing at an earlier age and invest a greater production;--Where adult survival is higher , organisms defer reproduction to a later age and allocate a smaller proportion of their resources to reproduction.6.1.4 Life history classificationLife history strategiesr-selected vs. K-selectedCRS strategiesFew large -greater investment/offspring-longer gestation or incubation-tend to be longer-lived, perennial organismsr-selected vs. K-selectedMuch small -minimal investment of energy/offspring -little opportunity for parental care-tend to be shorter-lived, “annual” organisms 1954 Lack birdsTwo distinct life history strategies are described by -and -selection theory ,which states that -selected species are adapted to maximize the rate of increase of the population size, whilst -selected species are adapted to be competitive .-and -selection1976 MacArthur WilsonCharacteristicsr-selected species-rapid development,-small adults,-many & small offspring -short generation time -good dispersal ability -Disturbed habitat -selected species-slow development,-large adult size,-few& large offspring-long generation times-poor dispersal ability-not disturbed habitatLife History Examplesr-selected species:1.Garden weeds2.Insects3.Desert annualsK-selected species:1.Humans2.Oak trees3.ElephantsLarge sizeSeeddispersalgoodMany smallseedsSmall sizeShort life spanDandelionRapid growthSlow growthFewer, bigseedsPoor seed dispersalLong life span Oak treer-selected speciesLife history continuumK-selected speciesLife history strategies: r-and K-selected speciesr-KcontinuumAlthough some species fit this theoretical dichotomy( ), many do not, and this theory is now out-dated as better models have wider predictive powers.r-K continuum andbet-hedging strategySpecies can generally be placed somewherealong this continuum.However, not all species fall neatly ontothis continuum.A bet-hedging strategy combines elementsof r and K selection.If juvenile mortality is variable andoccasionally high , neither a classic r nora classic K strategy is optimal.§In addition to the concepts of r-and -selection,there a variety of schemes which classify habitatsin an attempt to discern a pattern linking habitatsand life histories.§Habitats may be classified on the basis of thebalance of benefits between growth andreproduction, into‘high-cost-of-reproduction’ and‘low-cost-of-reproduction’.Habitatclassification§An alternative approach, ‘bet-hedging’, considers the impact of the habitat on the relative variability of mortality or fecundity for different growth stages and uses this to predict optimal life history strategies.§Grime’s ‘CSR triangle’classifies habitats form a perspective of plant life history, using the degree of habitat disturbance (or stability) and its severity to plants.CRS strategies-Plant life historyRuderals, competitors, and stress tolerators(Grime 1977 and 1979)Ruderals (botanical term for weed)-Adapted to cope with habitat disturbancesCompetitors-Adapted to live in highly competitive but benignenvironments (e.g., tropics)Stress tolerators-Adapted to cope with severe environmentalconditions (e.g., salt marsh plants)Grime’s classification of plant life history strategies2550751001007550250100755025CSRCSSRCRGrime C-S-RCompetitor-stress tolerator-ruderal theoryCS RCS CRSRCSRGrime(1977) CSR Life history theory Emphases1. Using energy distribution theory explain1,22.Life history strategies--r-selected vs. K-selected--CRS strategiesKey terms: life history, fecundity,reproductive effortChapter 7 Intraspecific & InterspecificcompetitionWang Li ZNGI ZNGIX1234561.Intra-& inter-specific competition2. Intra-specific competition (regulation)3. Inter-specific competition4. Else interspecific relationContent2.1 plant-self-thinning2.2 Diapause & dormancy2.3 Migration3.1 Classification3.2 Some basic theoryIntraspecific competition-competition with numbers of their ownspecies.Interspecific competition-competition between individuals of twospecies that reduces the fitness of both.1. intra-& inter-specific competition6.2 Intra-specific competition 6.2.1 Plant -self thinning6.2.2 Animals -Migration6.2.1 Plant -self thinningSelf-thinning( ) Yoda 1963 P300:reductionin population density as a stand of plant increase inbiomass,due to intraspecific competition.Self-thinning rule(-3/2):a rule resulting from theobservation that plotting the average weight of individualplants in a stand against density often produces a linewith a average slope of approximately-3/2.W=C*d-3/2w-mean weight;d-survival densityThe Law of FinalConstant Yield( ):when density issufficiently high andresources becomelimited,the effects ofcompetition will resultin a constant biomassdue to a proportionaldecrease in the size ofthe individuals.Organisms may also avoid local harsh conditions by moving to another location.Migration is directional movement ,such as the autumn flight of swallows from Europe toAfrica.Dispersal , in contrast, is a nondirectional movement away from the birth or breeding site.There are three categories of migration:(i)repeated return trips (ii)a single return trip,(iii)a one-way trip.6.2.2 Migrationrepeated return tripsa single return tripLemming•• 7~8 6 6a one-way tripCompetitionExploitation competitionInterference competitionIndirect action through resources competitionDirect influence, or indirect-——allelopathy3. Inter-specific competition-ClassificationExploitation competitionAction through resources competitionApparent competitionAction through natural enemyConsumer 1Consumer 2ResourcesPredatorprey 1prey 2Holt,1977,1984ClassificationCompetitionSymmetrical competitionNonsymmetrical competitionAmensalismClassification3.1 Gause ’s principle of competitive exclusion3.2 Lotka-Volterra model3.Inter-specific competition-Basic theoriesG.F. Gause 1934Competitiveexclusion principle ( )The principle that two species with identical niches cannot coexist indefinitely.3.1Gause’s principle of competitive exclusionFig.1 Population of Paramecium aurelia and P . caudatum grown separately (a) and together (b)separately)(111111K N K N r dt dN Carrying capacity of species 1Carrying capacity of species 2)(222222K N K N r dt dN 3. 2 Lotka-Volterra (1932, 1926) model P305N 2N 1N 2N 1K 1/K1N 2N 1K2/K2Isoclines of zero population growthCompetition coefficient : express the competitive effects of thecompeting species (P310).K KK KBK K K K AN 1N 2Species1 Wins Po size =K1Species2 Wins Po size =K2Sp1 win Sp2 absent 211K K 121K K Sp2 win Sp1 absent211K K 121K K 3. 2 Lotka-Volterra modelKK K K DKKK K CN 2N 1Eventually Sp 1 or 2 win211K K 121K K Sp 1 & 2 coexist at the crossover point of the isoclines211K K 121K K 3. 2 Lotka-Volterra modelK 2 K 1K 2K 1K 1=K 2, = =1Eventually Sp 1 or 2 winLotka-Volterra1. 2. 3.r33. 2 Lotka-Volterra model Tilman 1982“K ”“K ” YX3. 3 Tilman’s ModelXYZNGIML K JZNGI BZNGI AXY123ZNGI AZNGI BXY123456A BZNGI AA BZNGI A ZNGI B3. 3 Tilman’s ModelTilmanLotka-VolterraComparison TilmanLotka-VolterraPredationPrey and predator4. Else interspecific relationPlant defenseFeeding behaviorPrey and predator90Feeding behaviorPlant defense4.Else interspecific relationparasitismand symbiosismutualismCommensalism Parasitism Cooperation parasitism20parasitismparasitoid : an insect whose larva consumers its host and kills it in the process; parasitoids are functionally equivalent to predators.parasitism : an organism lives in or on host, deriving benefit from it. Parasites typically reduce fitness of the host, but do not generally kill it.Commensalismcooperationmutualismmutualism : interactions between individuals of different species that benefit both partners.Advantageous, detrimental , no interest effect : + - 0Interaction types S 1S 2traitsneutral interaction no effect from each other Interference competition one inhibits the other directly Exploitation competitionindirect inhibition under limited sourcesamensalism s1 inhibited, s2 no effect.parasitism + infestor s1, usually smaller than host s2predation + predator s1, usually larger than prey s2commensalism + beneficial to s1, no effect for host s2originalcooperaction ++beneficial to both, but not necessary mutualism++necessarily beneficial to bothKey PointsLotka-Volterra model。