Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 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 ECOSYSTEM LEVEL Eucalyptus forest COMMUNITY LEVEL All organisms in eucalyptus forest • Community • Population POPULATION LEVEL Group of flying foxes ORGANISM LEVEL Flying fox Brain ORGAN SYSTEM LEVEL Nervous system ORGAN LEVEL Brain Spinal cord Nerve TISSUE LEVEL Nervous tissue CELLULAR LEVEL Nerve cell MOLECULAR LEVEL Molecule of DNA Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 1.1 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 How are populations measured? • Population density = number of individuals in a given area or volume • count all the individuals in a population • estimate by sampling 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 - often correlates with resources – Uniform: interactions among individuals – Random: no pattern Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 35.2C Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings How do populations grow? • Idealized models describe two kinds of population growth 1. exponential growth 2. logistic growth 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 growth rate in an ideal environment (births-deaths) – N = the population size Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 35.3A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings high intrinsic rate of increase 1500 Population size 1000 low intrinsic rate of increase 500 r=0 zero population growth negative intrinsic rate of increase r = -0.05 0 0 5 10 Time (years) 15 20 2. Logistic growth is slowed by populationlimiting 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 Multiple factors may limit population growth 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 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 Evolution shapes life histories • 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 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 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 The Spread of Shakespeare's Starlings • In 1890, a group of Shakespeare enthusiasts released about 120 starlings in New York's Central Park Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings • Today: over 100 million starlings, spread over N. America Current 1955 Current 1955 1945 1935 1925 1945 1905 1915 1935 1925 1925 1935 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings – Population is expanding, virtually uncontrolled – Population is harming other species • The starling population in North America or the global human population? Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings THE HUMAN POPULATION • 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 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 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fig. 28.14a, p.500 Age structure diagrams by country, 1997 What affects the fertility rate? Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fig. 28.14b, p.500 Demographic transition model based on economic development Stage 1 Preindustrial Stage 2 Transitional Stage 3 Industrial Stage 4 Postindustrial relative population size births deaths Factor: Social status, education of women Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fig. 28.15b, p.501 • The ecological footprint represents the amount of productive land needed to support a nation’s resource needs –Crops, forests, pasture, dwellings, energy –CO2 production • Is the ecological capacity of the world smaller than its ecological footprint? Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings • Ecological footprint in relation to ecological capacity Figure 35.8B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Per capita CO2 emissions (metric tons of carbon) 0 1 2 3 U.S. China 5 6 5.48 2.65 Japan 2.51 0.29 0 0.5 1 U.S. Russia Japan India 1.5 1.49 China 0.75 Russia India 4 Total CO2 emissions (billion metric tons of carbon) 0.91 0.39 0.32 0.28 • What next? Figure 35.8C Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 2.10x Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings