CHAPTER 18 The Ecology of Organisms and Populations Figures 18 1 18 3 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 Every four years the world s population increases by the population equivalent of the United States Some ecological communities depend on periodic fires Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings The biosphere is currently undergoing a mass extinction After several days at high altitude your body will begin to produce more red blood cells Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 1 BIOLOGY AND SOCIETY THE HUMAN POPULATION EXPLOSION Humans Are by far the most abundant large animals Have a disproportionately high impact on the environment Figure 18 1 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings The human species Requires vast amounts of materials and space Has devastated the environment for many other species Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings AN OVERVIEW OF ECOLOGY Ecology Is the scientific study of the interactions between organisms and their environments The environment Can be divided into two major components Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 2 The abiotic component Consists of nonliving chemical and physical factors The biotic component Includes the living factors Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Ecology as Scientific Study Natural history as a discovery science remains fundamental to ecology Figure 18 2 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings An example of an ecological experiment Testing a hypothesis regarding growth of algae in lakes Figure 18 3 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 3 A Hierarchy of Interactions Ecology can be divided into four increasingly comprehensive levels Organismal ecology Population ecology Community ecology Ecosystem ecology Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Organismal ecology Is concerned with the evolutionary adaptations that enable individual organisms to meet the challenges posed by their abiotic environments Figure 18 4a Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Population ecology Is concerned with populations groups of individuals of the same species living in the same area Concentrates mainly on factors that affect population density and growth Figure 18 4b Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 4 Community ecology Is concerned with communities assemblages of populations of different species Focuses on how interactions between species affect community structure and organization Figure 18 4c Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Ecosystem ecology Is concerned with ecosystems which include all the abiotic factors in addition to the community of species in a certain area Focuses on energy flow and the cycling of chemicals among the various abiotic and biotic factors Figure 18 4d Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings The biosphere Is the global ecosystem Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 5 Ecology and Environmentalism Our current awareness of the biosphere s limits stems mainly from the 1960s a time of growing disillusionment with environmental practices of the past Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings The pesticide DDT which improved agricultural production Was developed in the 1950s Was determined to have harmful side effects Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Rachel Carson Was one of the first ecologists to perceive the global dangers of pesticide abuse Helped initiate our current environmental awareness with her book Silent Spring Figure 18 5 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 6 The modern environmental movement was catalyzed by Rachel Carson Figure 18 6 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Analyzing environmental issues should be part of every student s education Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Abiotic Factors of the Biosphere On a global scale ecologists have recognized striking regional patterns in the distribution of terrestrial and aquatic life Figure 18 7 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 7 Global distribution patterns Reflect regional differences in climate and other abiotic factors Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Patchiness of the environment on a local scale reveals a mixture of characteristics Figure 18 8 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Habitats Are environmental situations in which organisms live Reveal patchiness on an even smaller scale Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 8 Sunlight Solar energy powers nearly all ecosystems Availability of sunlight affects aquatic and terrestrial environments Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Water Aquatic organisms may face problems with water balance For terrestrial organisms the main water problem is drying out Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Temperature Environmental temperature Is an important abiotic factor because of its effect on metabolism Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 9 Some extraordinary adaptations enable some species to live in extreme temperatures Figure 18 9 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Wind Some organisms depend on nutrients blown to them by wind Organisms such as plants depend on wind to disperse pollen and seeds Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Wind Can also affect the pattern of a plant s growth Figure 18 10 Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings 10 Rocks and Soil Soil variation contributes to the patchiness we see in terrestrial landscapes In streams and rivers the composition of the soil can affect water chemistry Copyright 2003 Pearson Education Inc publishing as Benjamin Cummings Periodic Disturbances Catastrophic