CHAPTER 19 Communities and Ecosystems Figures 19 1 19 4 PowerPoint Lecture Slides for Essential Biology Second Edition Essential Biology with Physiology Neil Campbell Jane Reece and Eric Simon Presentation prepared by Chris C Romero Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Some plants recruit parasitic wasps that lay their eggs in caterpillars that eat the plants The oceans cover about 75 of Earth s surface Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Only a tiny fraction of the sunlight that shines on Earth is converted to chemical energy Sunken ships army tanks and subway cars are being used as artificial reefs Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 1 BIOLOGY AND SOCIETY REEFS CORAL AND ARTIFICIAL Coral reefs Are distinctive and complex ecosystems Support a diversity of organisms Figure 19 1 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Pollution and development Can easily degrade coral reefs Artificial reefs Are being created by humans to help replace those that have been destroyed Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings KEY PROPERTIES OF COMMUNITIES A community Is an assemblage of species living close enough together for potential interaction Figure 19 2 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 2 Diversity The diversity of a community Is the variety of different kinds of organisms that make up the community Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings The diversity of a community has two components Species richness the total number of different species in the community Relative abundance of the different species Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Community 1 Community 2 Figure 19 3 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 3 Prevalent Form of Vegetation The prevalent form of vegetation mainly depends on the terrestrial situation The types and structural features of plants in a community largely determine the kinds of animals that live in the community Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Stability Community stability Refers to the community s ability to resist change and return to its original species combination after being disturbed Depends on both the type of community and the nature of disturbances Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Trophic Structure The trophic structure of a community concerns the feeding relationships among the various species making up the community Figure 19 4 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 4 INTERSPECIFIC INTERACTIONS IN COMMUNITIES Interspecific interactions are interactions between species Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Competition Between Species Interspecific competition May occur when two or more species in a community rely on similar limiting resources May limit population growth of the competing species Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Competitive Exclusion Principle Russian ecologist G F Gause studied the effects of interspecific competition in two closely related species of protists Separate cultures Combined cultures P aurelia P caudatum Figure 19 5 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 5 From his research Gause concluded that two species so similar that they compete for the same limiting resources cannot coexist in the same place Ecologists called this concept the competitive exclusion principle Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Testing the competitive exclusion principle High tide Chthamalus Balanus Ocean Low tide Figure 19 6 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings The Ecological Niche A species ecological niche Is the sum total of a species use of the biotic and abiotic resources in its environment Is the species ecological role Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 6 We can now restate the competitive exclusion principle as follows Two species cannot coexist in a community if their niches are identical Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Resource Partitioning There are two possible outcomes of competition between species with identical niches Extinction of one species Evolution of one species to use a different set of resources Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Resource partitioning Is the differentiation of niches that enables similar species to coexist in a community Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 7 A ricordii A ricordii A distichus A insolitus A aliniger A christophei A distichus A distichus A christophei A cybotes A cybotes A etheridgei A etheridgei A insolitus Figure 19 7 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Predation Predation Is when organisms eat other organisms Identifies the predator as the consumer and the food species as the prey Includes herbivory the consumption of plants by animals Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Predator Adaptations Most predators have acute senses Many predators Have adaptations such as claws teeth fangs stingers or poison to help catch and subdue prey Are fast and agile Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 8 Plant Defenses Against Herbivores Plants have various types of defenses against herbivores Chemical toxins Spines and thorns Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Animal Defenses Against Predators Animals can avoid being eaten By using passive defenses such as hiding By using active defenses such as escaping or defending themselves Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Behavioral defenses include Alarm calls Mobbing Figure 19 8 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 9 Distraction displays Direct the attention of the predator away from a vulnerable prey to another prey that is more likely to escape Figure 19 9 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Camouflage or cryptic coloration Is a passive defense that makes a potential prey difficult to spot against its background Figure 19 10 Copyright 2003 Pearson Education Inc publishing as