Copyright 2003 Pearson Education Inc publishing as Benjamin
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 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. 2 A 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. 2 C 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 = r. N, 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. 3 A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
high intrinsic rate of increase 1500 r= Population size 1000 06 0. 02 r = 0. 500 r=0 low intrinsic rate of increase 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. 3 B 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. 3 C 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 – 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
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. Amer. Current 1955 1945 1935 1925 1945 1905 1915 1935 1925 1935 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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
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. 8 A Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The age structure of a population is the proportion of individuals in different age-groups RAPID GROWTH SLOW GROWTH ZERO GROWTH/DECREASE Kenya United States Italy Male Female Ages 45+ Ages 15– 44 Under 15 Percent of population Male Female Under 15 Percent of population Also reveals social conditions, status of women Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 35. 9 B
• 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. 8 B Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Per capita CO 2 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 CO 2 emissions (billion metric tons of carbon) 0. 91 0. 39 0. 32 0. 28
• What next? Figure 35. 8 C Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 2. 10 x Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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