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Ecology - Study of interactions among organisms and their environment Conservation biology, environmentalism: preservation of natural world

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Biosphere Ecosystems Community Population ECOSYSTEM LEVEL Eucalyptus forest COMMUNITY LEVEL All organisms in eucalyptus forest POPULATION LEVEL Group of flying foxes ORGANISM LEVEL Flying fox ORGAN SYSTEM LEVEL Nervous system ORGAN LEVEL Brain Brain Spinal cord Nerve TISSUE LEVEL Nervous tissue CELLULAR LEVEL Nerve cell MOLECULAR LEVEL Molecule of DNA Figure 1.1

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Population Ecology Population- how to measure? Growth rates: J shaped, S shaped K, r, and reproductive strategies Human population

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Population density = number of individuals in a given area or volume count all the individuals in a population estimate by sampling How are populations measured?

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings mark-recapture method depends on likelihood of recapturing the same individual Figure 35.2A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The dispersion pattern of a population refers to the way individuals are spaced within their area –Clumped - –Uniform: –Random: no pattern

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 35.2C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Idealized models describe two kinds of population growth 1. exponential growth 2. logistic growth How do populations grow?

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings King’s chess game A J-shaped growth curve, described by the equation G = rN, is typical of exponential growth –G = the population growth rate –r = the intrinsic rate of increase, or an organism's maximum capacity to reproduce –N = the population size

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 35.3A

Time (years) Population size r = 0.06 r = 0.02 r = 0 r = high intrinsic rate of increase low intrinsic rate of increase zero population growth negative intrinsic rate of increase

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 2. Logistic growth is slowed by population- limiting factors K = Carrying capacity is the maximum population size that an environment can support Figure 35.3B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings logistic growth curve –K = carrying capacity –The term (K - N)/K accounts for the leveling off of the curve Figure 35.3C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings declining birth rate or increasing death rate The regulation of growth in a natural population is determined by several factors –limited food supply –the buildup of toxic wastes –increased disease –predation Multiple factors may limit population growth

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –About every 10 years, both hare and lynx populations have a rapid increase (a "boom") followed by a sharp decline (a "bust") Figure 35.5

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Survivorship curves plot the proportion of individuals alive at each age Three types of survivorship curves reflect important species differences in life history Figure 35.6

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings An organism's life history is the series of events from birth through reproduction to death Life history traits include –the age at which reproduction first occurs –the frequency of reproduction –the number of offspring –the amount of parental care given –the energy cost of reproduction Evolution shapes life histories

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Principles of population ecology may be used to –manage wildlife, fisheries, and forests for sustainable yield –reverse the decline of threatened or endangered species –reduce pest populations –IPM = Integrated Pest Management

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Integrated pest management (IPM) uses a combination of biological, chemical, and cultural methods to control agricultural pests IPM relies on knowledge of –the population ecology of the pest –its associated predators and parasites –crop growth dynamics

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In 1890, a group of Shakespeare enthusiasts released about 120 starlings in New York's Central Park The Spread of Shakespeare's Starlings

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Today: over 100 million starlings, spread over N. Amer. Current Current

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

The starling population in North America has some features in common with the global human population –Both are expanding and are virtually uncontrolled –Both are harming other species

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings doubled three times in the last three centuries about 6.1 billion and may reach 9.3 billion by the year 2050 improved health and technology have lowered death rates THE HUMAN POPULATION

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The history of human population growth Figure 35.8A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 35.9B RAPID GROWTH Kenya MaleFemale Percent of population SLOW GROWTH United States MaleFemale ZERO GROWTH/DECREASE Italy MaleFemale Ages 45+ Ages 15–44 Under 15 Ages 45+ Ages 15–44 Also reveals social conditions, status of women The age structure of a population is the proportion of individuals in different age-groups

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The ecological footprint represents the amount of productive land needed to support a nation’s resource needs The ecological capacity of the world may already be smaller than its ecological footprint

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ecological footprint in relation to ecological capacity Figure 35.8B

U.S. China India Russia Japan U.S. China India Russia Japan Per capita CO 2 emissions (metric tons of carbon) Total CO 2 emissions (billion metric tons of carbon)

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings What next? Figure 35.8C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 2.10x