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Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential.

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Presentation on theme: "Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential."— Presentation transcript:

1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 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 CHAPTER 18 The Ecology of Organisms and Populations

2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ecology AN OVERVIEW OF ECOLOGY –Is the scientific study of the interactions between organisms and their environments The Environment –Can be divided into two major components The abiotic component Consists of nonliving chemical and physical factors The biotic component Includes the living factors

3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Natural history as a “discovery science” remains fundamental to ecology Ecology as Scientific Study Figure 18.2

4 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

5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ecology can be divided into four increasingly comprehensive levels –Organismal ecology –Population ecology –Community ecology –Ecosystem ecology A Hierarchy of Interactions

6 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

7 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

8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 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

9 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

10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Biosphere –Is the global ecosystem

11 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings On a global scale, ecologists have recognized striking regional patterns in the distribution of terrestrial and aquatic life Abiotic Factors of the Biosphere Figure 18.7

12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Global distribution patterns –Reflect regional differences in climate and other abiotic factors

13 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

14 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Habitats –Are environmental situations in which organisms live –Reveal patchiness on an even smaller scale

15 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Solar energy powers nearly all ecosystems Sunlight Availability of sunlight affects aquatic and terrestrial environments

16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Aquatic organisms may face problems with water balance Water For terrestrial organisms, the main water problem is drying out

17 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Environmental temperature Temperature –Is an important abiotic factor because of its effect on metabolism

18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Some extraordinary adaptations enable some species to live in extreme temperatures Figure 18.9

19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Some organisms depend on nutrients blown to them by wind Wind Organisms such as plants depend on wind to disperse pollen and seeds

20 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Wind –Can also affect the pattern of a plant’s growth Figure 18.10

21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Soil variation contributes to the patchiness we see in terrestrial landscapes Rocks and Soil In streams and rivers, the composition of the soil can affect water chemistry

22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Catastrophic disturbances Periodic Disturbances –Can devastate biological communities

23 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings After a disturbance –An area is recolonized by organisms or repopulated by survivors –The structure of the community undergoes a succession of changes during the rebound Figure 18.11

24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The fields of ecology and evolutionary biology are tightly linked THE EVOLUTIONARY ADAPTATIONS OF ORGANISMS Evolutionary adaptation through natural selection results from the interaction of organisms with their environments

25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Three types of adaptations that enable organisms to adjust to changes in their environments will be analyzed –Physiological –Anatomical –Behavioral

26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In mechanisms of temperature regulation, responses by organisms occur quickly Physiological Responses

27 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Acclimation –Is a physiological response that is longer term The ability to acclimate –Is related to the range of environmental conditions a species naturally experiences

28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Among Vertebrates –Birds and mammals can tolerate the greatest temperature extremes because they are endotherms –Reptiles are more limited in the climates they can tolerate because they are ectotherms

29 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure The number of lizard species in different regions in the contiguous United States

30 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Many organisms respond to environmental challenge with some type of change in body shape or anatomy Anatomical Responses

31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In contrast to plants, most animals can respond to an unfavorable change in the environment by moving to a new location Behavioral Responses

32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Population ecology WHAT IS POPULATION ECOLOGY? –Is the study of how members of a population interact with their environment

33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Population density –Is the number of individuals of a species per unit of area or volume Population Density

34 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings How do we measure population density? –In most cases, it is impractical or impossible to count all individuals in a population –In some cases, population densities are estimated by indirect indicators, such as number of bird nests or rodent burrows Figure 18.14

35 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Another sampling technique is the mark-recapture method –Animals are trapped, marked, and then recaptured after a period of time Figure 18.15

36 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The dispersion pattern of a population is the way individuals are spaced within the population’s geographic range Patterns of Dispersion

37 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In a clumped pattern of dispersion, individuals aggregate in patches Figure 18.16a (a) Clumped

38 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A uniform pattern of dispersion results from interactions among the individuals of a population Figure 18.16b (b) Uniform

39 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In a random pattern of dispersion, individuals are spaced in a patternless, unpredictable way Figure 18.16c (c) Random

40 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Some populations exhibit both clumped and uniform dispersion patterns, but on different scales Figure 18.17

41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Two models, the exponential growth model and the logistic growth model, will help us understand population growth.. Population Growth Models

42 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The exponential growth model The Exponential Growth Model: The Ideal of an Unlimited Environment –Describes the rate of expansion of a population under ideal, unregulated conditions.. Figure 18.18

43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A key feature of the exponential growth model is that the rate at which a population grows depends on the number of individuals already in the population..

44 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In nature, a population may grow exponentially for a while, but eventually one or more environmental factors will limit its growth The Logistic Growth Model: The Reality of a Limited Environment Population-limiting factors restrict population growth..

45 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The logistic growth model –Describes growth of an idealized population that is slowed by limiting factors.. Figure 18.19

46 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A comparison of the logistic growth model and the exponential growth model.. Figure Carrying capacity Exponential growth Logistic growth

47 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Carrying capacity –Is the number of individuals in a population that the environment can just maintain with no net increase or decrease..


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