Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition Solomon Berg Martin Population Ecology

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Population DensityNumber of individuals of a species per unit at a given time Population dispersion (spacing) Clumped dispersion Uniform dispersion Random dispersion

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Dispersion of individuals with a population

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Dispersion in a sand pine population in Florida

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Four factors that produce changes in population size: 1.Natality: Birth Rate 2.Mortality: Death Rate 3.Immigration: Entering a territory 4.Emigration: Leaving a territory

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Carrying capacity (K) is the largest population that can be maintained –Exponential population growth (J-shaped curve) –Logistic population curve (S-shaped curve)

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Exponential population growth

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Carrying capacity and population growth

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Density-dependent factors: Factors that regulate population growth by affecting a large proportion of the population as population rises Examples include predation, disease, and competition

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Density-dependent factors and negative feedback

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Density-independent factors: Factors that limit population growth but are not influenced by changes in population density Examples include hurricanes, blizzards, floods, volcanic eruptions, drought, etc

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Human Population Growth World population reached 6.3 billion in Today is almost 7.0 billion Per capita growth rate has declined from peak in 1965 of about 2% per year to 1.3% Scientists predict zero population growth by the end of the 21st century

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Human population growth

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Population characteristics Highly developed countries –Low birth rate, low infant mortality, low fertility rate, long life expectancies, and high GPP Developing countries –High birth rate, high infant mortality, high fertility rate, short life expectancies, and low GNI PPP

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Comparison of 2003 population data in developed and developing countries

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Birth and death rates in Mexico, 1900–2000

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Age structure influences dynamics Young age structure causes a positive population growth momentum as large pre- reproductive age group matures

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Age structure diagrams

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 51 Introduction to Ecology: Population Ecology Developing countries tend to have over-population which degrades the environment. (Mexico, Brazil, India, China etc) Developed countries tend to have over-consumption which degrades the environment. (USA, Germany, France, Britain, etc)