Ecological Communities And Ecosystems Lecture Slides PDF

Module 1.2 Ecological Communities and Ecosystems Interspecific Interactions between populations in Interactions a biological community  +: the interacting individual benefits  : the interacting individual is harmed  0: no effect...

Module 1.2 Ecological Communities and Ecosystems Interspecific Interactions between populations in Interactions a biological community  +: the interacting individual benefits  : the interacting individual is harmed  0: no effect on the interacting individual  Interspecific Any -/- interspecific interaction in which different species compete for competition the same limited resources ? Limited resources can be biotic or abiotic (biotic; abiotic) The interspecific competition between two closed ? than that related species is typically more intense between two unrelated species (as intense as; more intense than; less intense than) Figure 41.3 Resource partitioning among Dominican Republic lizards  The specific set of biotic and abiotic Ecological resources used by an organism and Niche its role within its ecosystem  Physical home or habitat  Physical and chemical environmental factors necessary for survival and reproduction  Energy and materials Figure 41.3 Resource partitioning among Dominican Republic lizards  The specific set of biotic and abiotic Ecological resources used by an organism and Niche its role within its ecosystem Do different species of Anolis lizards shown in Figure 41.3 share aspects of their ecological niche? Yes? Do A. distichus and A. insolitus shown in Figure 41.3 have the same ecological niche? No ? Figure 41.3 Resource partitioning among Dominican Republic lizards  If two species occupy exactly the same Competitive niche, strong competition should lead Exclusion to local elimination of an inferior competitor  Have different niches — can coexist  Have identical niches — one excludes the other Figure 41.3 Resource partitioning among Dominican Republic lizards  One or more significant differences that Resource ecologically similar species develop in Partitioning their niches to reduce interspecific competition Resource partitioning by occupying a different ? area of the habitat allows seven species of Anolis lizards to coexist in a community in close proximity since competition for food ? is reduced Figure 41.3 Resource partitioning among Dominican Republic lizards  Character differences between two similar Character species are greater when populations are Displacement sympatric than allopatric  There is more overlap in the traits of A the allopatric, or geographically separate, populations B  Interspecific competition drives character displacement by causing C natural selection for characters that compete less Figure 41.5 Character displacement: indirect evidence of past competition.  Character differences between two similar Character species are greater when populations are Displacement sympatric than allopatric The character being displaced in this A ? example is beak depth On Floreana and San Cristobal islands, B G. fuliginosa individuals with shallower ? beaks and G. fortis C individuals with deeper ?beaks probably had less competition for food Figure 41.5 Character displacement: indirect evidence of past competition. Competitive Exclusion ? Intraspecific competition is usually a more intense form of competition controlling population size (intraspecific; interspecific) ? Intraspecific competition exerts strong density-dependent environmental resistance, limiting population size (density-dependent; density-independent)  Any +/- interspecific interaction in which Exploitation individual of one species benefit by feeding on living individuals of another species  Predation  Herbivory  Parasitism  An exploitative interaction in which an individual Predation of one species, the predator, kills and eats an individual of the other species, the prey Any predatory ? species can be a predator A. animals B. plants C. fungi D. bacteria E. protists  One species resemble the appearance, Mimicry sound, smell, or behavior of other species to deter predators or to entice prey  Batesian mimicry: a palatable or harmless prey species resemble an unpalatable or harmful model  Predators also use aggressive mimicry to attract or sneak up on prey Figure 41.6c Batesian mimicry https://www.youtube.com/watch?v=_5CRKTgFal0 https://www.youtube.com/watch?v=DDwwTE-P-WU  An exploitative interaction in which an Herbivory individual of one species, an herbivore, eats parts of a plant or alga In herbivory, herbivores ? kill plants or alga usually don’t A. kill B. don’t kill A West Indian manatee Figure 41.7 A marine herbivore.  An exploitative interaction in which an Parasitism individual of one species, the parasite, derives its nourishment from another organism, its host  Parasites do not kill their hosts immediately  Many parasites have complex life cycles In Figure 41.8, cocoons of the parasitoid wasp are ectoparasites ? of the tobacco hornworm A. endoparasites B. ectoparasites Figure 41.8 A parasitoid invasion.  An exploitative interaction in which an Parasitism individual of one species, the parasite, derives its nourishment from another organism, its host  Many parasites have multiple host species What is the interspecific relationship between the two hosts of the malaria parasite of humans? Parasitism: Anopheles ? mosquitos are ectoparasites of humans https://www.cdc.gov/malaria/about/  Any +/+ interspecific interaction in which Mutualism members of both interacting species benefit  In some mutualisms, one or both species cannot survive without the other  In other mutualisms, both species can survive alone ? not all, mutualistic Many, but relationships are symbiotic (Few; Many; All) Clownfish and anemone fish Figure 41.9 Mutualism between acacia trees and ants.  Any +/0 interspecific interaction that benefits Commensalism individuals of one species without harming or helping individuals of the other species  Commensalism: an interaction that benefits individuals of one species without harming or helping individuals of the other species  A commensal relationship may become mutualistic How can the commensal relationship between cattle egrets and the African buffalo shown in Figure 41.10 become mutualistic? Figure 41.10 Commensalism between cattle egrets and an African buffalo Interspecific Interactions between populations in Interactions a biological community  Interspecific competition: ?  Predation: +/ ?  Herbivory: +/ ?  Parasitism: +/ ?  Commensalism: +/ ?  Mutualism: +/+?  The species richness and relative Species Diversity abundance of species in a biological community  Species diversity increases with the species richness and evenness Community 1 and community 2 have the same tree species ? richness (tree species diversity; tree species richness; relative abundance of tree species; all three) Community 1 ? has greater tree species diversity (1; 2) Figure 41.12  The species richness and relative Species Diversity abundance of species in a biological community  Communities with higher diversity usually able to produce more biomass and resist invasive species Typically, only ? a few species have an especially large impact on community’s diversity and structure A. all B. most C. a few D. no Figure 41.12  The feeding relationships between Trophic Structure species in a community  Food chains: linear feeding relationship from producers to top carnivores  A food web: non-linear complex trophic interactions from producers to top carnivores Figure 41.15 An Antarctic Figure 41.14 Examples of terrestrial and Marine Food Web marine food chains.  The feeding relationships between Trophic Structure species in a community In the Antarctic ocean, phytoplankton are primary producers ? A. producers B. primary consumers C. secondary consumers D. tertiary consumers Figure 41.15 An Antarctic Figure 41.14 Examples of terrestrial and Marine Food Web marine food chains.  The position of a species in the Trophic Level trophic structure of a community  Primary producers (autotrophs): build organic molecules from inorganic sources  Primary consumers (herbivores): feed directly and exclusively on producers  Higher-level consumers: feed on herbivores or other carnivores  Decomposers: consumers that derive their energy from detritus Figure 42.4 An overview of energy and nutrient dynamics in an ecosystem.  The position of a species in the Trophic Level trophic structure of a community Squids can be C, D, or E? in this Antarctic Marine food wed A. producers B. primary consumers C. secondary consumers D. tertiary consumers E. quaternary consumers Figure 41.15 An Antarctic Marine Food Web  Foundation A species that provides food/habitats or exploit key resources due to their Species high abundance or large size  Foundation species dominates an ecosystem in abundance and influence ? Corals are dominant consumers in a coral reef A. producers B. consumers A coral reef. "Community ecology: Figure 13," by OpenStax College, Biology, CC BY 4.0. Original work by Jim E. Maragos, USFWS.  A species that exerts a disproportionately Keystone large effect on community structure relative Species to its abundance In this classic experiment of community ecology conducted in 1963, Dr. Robert ? Paine discovered a sharp reduction in species diversity of the intertidal zone occurred within 1 and half year after the sea stars were removed (no change; a Figure 41. 16 A sea star Pisaster ochraceus reduction; an increase) The sea stars were a keystone species in the intertidal zone because they kept the mussels ? in check  A species that modify their environment in a Ecosystem significant manner, creating new habitats or Engineers modifying existing ones Ecosystem engineers such as beavers change the distribution and abundance of many other ? species mostly by indirect interactions A. direct B. indirect Figure 14.17 Beavers as ecosystem engineers Species with a Large Impact on Community Structure Most keystone?species have been recognized only after their loss has had dramatic, unforeseen consequences ? species are more likely to be top predators Keystone A. foundation species B. keystone species; C. ecosystem engineers  Pathogens Disease-causing agents  Pathogens can affect communities locally and globally  Zoonotic pathogens: infect and cause disease in both animals and humans  Vectors: organisms that can transmit infectious pathogens between humans SARS-CoV-2  Pathogens Disease-causing agents SARS-CoV-2 is a zoonotic pathogen primarily spread among humans though direct? contact (a vector; direct contact) Lyme ? disease is a vector-borne zoonotic pathogen (Malaria; Lyme disease) SARS-CoV-2  Disturbances New Zealand ecologists recorded New Zealand streams the numbers of invertebrate species in streambeds that experienced different intensities and frequencies of flooding. The largest numbers of species were present in streambeds with intermediate ? disturbances. Figure 41.19 Testing the intermediate disturbance hypothesis. A. no B. mild C. intermediate D. intense  Disturbances New Zealand streams Low ? levels of disturbance allow competitively dominant species to exclude less competitive ones (high; low; intermediate) High ? levels of disturbance exclude many slow-growing or slow- Figure 41.19 Testing the intermediate disturbance hypothesis. colonizing species (high; low; intermediate)  Ecological The sequential change in community composition during colonization Succession following a major disturbance  Primary succession occurs “from scratch,” where there is no trace of a previous community  Secondary succession begins with some remains of a Figure 41. 21 Glacier retreat and succession at Glacier disrupted community Bay, Alaska  Ecological The sequential change in community composition during colonization Succession following a major disturbance The succession at Glacial Bay, Alaska after retreat of the glacier since 1760 provides a valuable field research opportunity for observing primary ? succession (primary; secondary) Figure 41. 21 Glacier retreat and succession at Glacier Bay, Alaska  Ecosystems  Law of conservation of mass: matter cannot be created or destroyed An entire ecosystem can? be affected by changes in a single component (can; can’t) The mass of a given ecosystem isn’t ? a constant (is; isn’t) Figure 42.4 An overview of energy and nutrient dynamics in an ecosystem. Biogeochemical The pathways nutrients follow between Cycles communities and reservoirs  Limiting nutrients regulate community’s structure and composition of ecosystems Figure 42.14 Visualizing Biogeochemical Cycles Biogeochemical The pathways nutrients follow between Cycles communities and reservoirs Carbon, oxygen, nitrogen, water, and sulfur ? cycle globally (phosphorus; sulfur; potassium; calcium) Nutrient cycles involve both biotic?and abiotic components (biotic; abiotic; both) Phosphorus?and nitrogen are usually the limiting nutrients in photic zones of aquatic ecosystems (phosphorus; carbon, oxygen, nitrogen, water)  Hydrologic Cycle Figure 42.15 The water cycling  The major reservoir: the oceans  Key processes: evaporation, transpiration, condensation, precipitation, and movement through surface and groundwater Movement over land by wind  Forms available to life: water liquid or Precipitation Evaporation Precipitation over land vapor over ocean from ocean Evapotranspiration from land The hydrologic cycle is primarily driven by solar heat ?energy Percolation through (solar energy; photosynthesis; Runoff and soil cellular respiration) groundwater  Carbon Cycle Figure 42.15 the carbon cycle  The major reservoirs: sedimentary rocks, fossil fuels, the atmosphere, the oceans, biomass  Kay processes: photosynthesis, cellular respiration, volcanic activity and burning fossil fuels and wood  Forms available to life: CO2 and solute  Carbon Cycle Figure 42.15 the carbon cycle ? rocks are the largest Sedimentary reservoir for carbon (sedimentary rocks, fossil fuels, the atmosphere, the oceans, biomass) The atmosphere ? and the oceans are the major short-term reservoirs (sedimentary rocks, fossil fuels, the atmosphere, the oceans, biomass)  Nitrogen Cycle  The major reservoir: the atmosphere  Key processes  nitrogen fixation of N2 to ammonia (NH3) by nitrogen-fixing bacteria  nitrification of NH4+ to nitrate (NO3–) by nitrifying bacteria  incorporation of nitrogen from NO3– , NH4+ and amino acids into biological molecules by producers  denitrification of NO3– back to N2 by denitrifying bacteria  the fixing of nitrogen for fertilizer and burning fossil fuels by humans  Phosphorus Cycle  The major reservoir: rocks  Key processes: weathering of rocks, incorporation of PO43+ into biological molecules by plants, decomposition and excretion , human production of phosphate fertilizers  Almost all phosphorus remains as PO43+ throughout its cycles   List three types of ecological interaction and predict how these interactions will affect a species  Link the concept of resource partitioning to the phenomenon of competitive exclusion  Diagram a trophic structure or food web  Contrast foundation species, keystone species, and ecosystem engineers Learning  List three types of disturbances and predict how the Objectives effects on an ecosystem over time  Predict how a change in the number of decomposers would affect a biogeochemical cycle  Diagram the water, carbon, phosphorous or nitrogen cycle  Relate the concepts of community ecology, ecological disturbances, and zoonotic pathogens to predict the emergence of pandemics  Review Question 1 Which best describes resource partitioning? A. avoiding direct competition. B. encouraging mutualistic interactions. C. enabling prey to hide from predators. D. creating new resources. E. allowing abiotic factors, such as climate or nutrient availability, to influence the community  Review Question 2 Niche partitioning enables species to coexist by _________. A. Two species can coevolve to share identical niches. B. Competitive exclusion results in the success of the superior species. C. A climax community is reached when no new niches are available. D. Slight variations in niches allow similar species to coexist. E. Differential resource utilization results in the decrease in community species diversity.  Review Question 3 Sympatric populations of closely related species, which could compete for resources, show more differences in body structures and the resources they use than do allopatric populations. The term that describes this is __________. A. exploitation B. parasitism C. character displacement D. competitive exclusion E. mutualism  Review Question 4 Robert Paine removed Pisaster, an uncommon sea star, from some communities and measured species diversity. Species diversity dropped dramatically when Pisaster was not present. From this, one can conclude that ___________ A. uncommon species are more vital to the community than common species. B. predators are more vital to the community than prey. C. Pisaster likely consumed dominant organisms. D. Robert Paine’s experiment was poorly designed. E. removing one species always hurts the community.  Review Question 5 Why does a natural disturbance favor the process of succession? A. It kills off all of the invasive species, leaving only native species. B. It allows for secondary succession to occur because the seeds that are left behind colonize quickly. C. It often leaves behind favorable conditions that allow for the rapid growth of new species. D. It saves the climax community and destroys the less-evolved species.  Review Question 6 A species that exerts control over community structure by dramatically altering the physical environment is called a(n) ___________ A. foundation species. B. keystone species. C. dominant species. D. ecosystem engineer.  Review Question 7 Which of the following communities would have a higher diversity value? A. A community with 12 species where all species have roughly equal abundance. B. A community with 12 species that has two species with high abundance and 10 species with relatively low abundance. C. Neither community A nor B is equally diverse because they have the same number of species.  Review Question 8 Unlike energy, matter cycles within an ecosystem. This means that ___________. A. chemicals cannot be lost from an ecosystem B. a continuous input of matter from outside the system is required to maintain an ecosystem C. elements can be passed between living and nonliving components of the ecosystem indefinitely D. matter is being continually converted into heat and back into matter  Review Question 9 The biogeochemical cycle that excludes gases is _________ A. phosphorus. B. nitrogen. C. carbon. D. water.  Review Question 10 Most of the atmosphere is nitrogen gas (N2). _____________________ can convert nitrogen gas into a form accessible to life. A. plants B. primary producers C. nitrogen-fixing bacteria D. decomposers