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
Landscape ecology wikipedia , lookup
Restoration ecology wikipedia , lookup
Agroecology wikipedia , lookup
Reconciliation ecology wikipedia , lookup
Soundscape ecology wikipedia , lookup
Maximum sustainable yield wikipedia , lookup
Human population planning wikipedia , lookup
Molecular ecology wikipedia , lookup
Deep ecology wikipedia , lookup
Biology, Seventh Edition Solomon • Berg • Martin Chapter 51 Introduction to Ecology: Population Ecology Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Population density • Number 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 Edition CHAPTER 51 Introduction to Ecology: Population Ecology Dispersion of individuals with a population Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Dispersion in a sand pine population in Florida Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Four factors that produce changes in population size • Natality • Mortality • Immigration • Emigration Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Intrinsic rate of increase (rmax) • Maximum rate at which species or population can increase under ideal conditions • Carrying capacity (K) is the largest population that can be maintained –Exponential population growth (Jshaped curve) –Logistic population curve (S-shaped curve) Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Exponential population growth Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Carrying capacity and logistic population growth Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Density-dependent factors • 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 Edition CHAPTER 51 Introduction to Ecology: Population Ecology Density-dependent factors and negative feedback Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Density-independent factors • Limit population growth but are not influenced by changes in population density • Examples include hurricanes and blizzards Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Semelparous reproduction • Expend their energy in a single, immense reproductive effort • Iteroparous reproduction • Exhibit repeated reproductive cycles throughout their lifetimes Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Semelparity Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Species exhibiting an r strategy • Emphasizes a high growth rate • Organisms typically have small body size, high reproductive rates, short life spans, and they inhabit variable environments Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Species exhibiting a K strategy • Maintains a population near the carrying capacity of the environment • Species often have large body size, low reproductive rates, long life spans, and they inhabit stable environments Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Survivorship curves • Type I –Mortality is greatest in old age • Type II –Mortality is spread evenly across all ages • Type III –Mortality is greatest among the young Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Survivorship curves Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Survivorship curve for a herring gull population Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Source habitats • Preferred habitats • Local reproductive success is greater than local mortality • Local individuals disperse from source habitats Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Sink habitats • Lower-quality habitats • Individuals may suffer death or poor reproductive success Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Source and sink populations in a hypothetical metapopulation Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Human population growth • World population reached 6.3 billion in 2003 • 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 Edition CHAPTER 51 Introduction to Ecology: Population Ecology Human population growth Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 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 GNI PPP • 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 Edition CHAPTER 51 Introduction to Ecology: Population Ecology Comparison of 2003 population data in developed and developing countries Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Birth and death rates in Mexico, 1900–2000 Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Age structure influences dynamics • Possible for country to have replacement-level fertility and still experience population growth • Young age structure causes a positive population growth momentum as large prereproductive age group matures Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology Age structure diagrams Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition CHAPTER 51 Introduction to Ecology: Population Ecology • Developing countries tend to have people overpopulation that degrades the environment • Developed countries have consumption overpopulation that degrades the environment Copyright © 2005 Brooks/Cole — Thomson Learning