Chapter 36 Population Ecology PowerPoint Lectures Campbell Biology: Concepts & Connections, Eighth Edition REECE TAYLOR SIMON DICKEY HOGAN 2015 Pearson Education, Inc. Lecture by Edward J. Zalisko Figure 36.0-2 Chapter 36: Big Ideas 1989 Male
Population Structure and Dynamics 2015 Pearson Education, Inc. Female The Human Population THE HUMAN POPULATION 1. Explain how the structure of the worlds human population has changed and continues to change. 2. Explain how the age structure of a population
can be used to predict changes in population size and social conditions. 3. Explain the concept of an ecological footprint. 2015 Pearson Education, Inc. 36.9 The human population continues to increase, but the growth rate is slowing The human population grew rapidly during the 20th century and currently stands at about 7 billion. An imbalance between births and deaths is the cause of population growth (or decline). The human population is expected to continue increasing for at least the next several decades.
2015 Pearson Education, Inc. 10 100 Population increase 80 8 60 6
40 4 Total population size 20 2 1500 1550 1600 1650 1700 1750 1800 1850 1900 1950 2000 2050 Year Adapted from The World at Six Billion, United Nations Publications (1999). 2015 Pearson Education, Inc.
0 Total population (in billions) Annual increase (in millions) Figure 36.9a 36.9 The human population continues to increase, but the growth rate is slowing The demographic transition is a shift from zero population growth, in which birth rates and death rates are high but roughly equal, to zero population growth, due to low but roughly equal birth and death rates. Ex: Mexico
2015 Pearson Education, Inc. 36.9 The human population continues to increase, but the growth rate is slowing In the developing world death rates have dropped, but high birth rates persist, and these populations are growing rapidly.
2015 Pearson Education, Inc. 36.9 The human population continues to increase, but the growth rate is slowing The age structure of a population is the number of individuals in different age-groups affects the future growth of the population. 2015 Pearson Education, Inc. 36.9 The human population continues to increase, but the growth rate is slowing The fertility rate is the average number of children produced by a woman over her lifetime. Population momentum is the continued growth that occurs
despite reduction of the fertility rate to replacement level result of girls in the 014 age-group of a previously expanding population reaching their childbearing years. 2015 Pearson Education, Inc. 36.10 CONNECTION: Age structures reveal social and economic trends Age-structure diagrams reveal a populations future growth trends and social conditions. For instance, an expanding population has an increasing need for schools, employment, and
infrastructure, and a large elderly population requires that extensive resources be allotted to health care. 2015 Pearson Education, Inc. 36.11 CONNECTION: An ecological footprint is a measure of resource consumption The U.S. Census Bureau projects a global population of 8 billion people within the next 20 years and 9.5 billion by the mid-21st century. Do we have sufficient resources to sustain 8 or 9 billion people?
To accommodate all the people expected to live on our planet by 2025, the world will have to double food production. 2015 Pearson Education, Inc. History of Human Population Growth http://www.npr.org/2011/10/31/141816460/visualizin g-how-a-population-grows-to-7-billion?ps=cprs 2015 Pearson Education, Inc. 36.11 CONNECTION: An ecological footprint is a measure of resource consumption An ecological footprint is an estimate of the amount of land required to provide the raw
materials an individual or a nation consumes, including food, fuel, and housing. 2015 Pearson Education, Inc. 36.11 CONNECTION: An ecological footprint is a measure of resource consumption Comparing our demand for resources with Earths capacity to renew these resources, or biocapacity, gives us a broad view of the sustainability of human activities. 2015 Pearson Education, Inc.
Earths Overshoot http://www.footprintnetwork.org/en/index.php/GFN/ page/video_overshoot_explained/ 2015 Pearson Education, Inc. 2015 Pearson Education, Inc. You should now be able to 1. Define a population and population ecology. 2.
Define population density and describe different types of dispersion patterns. 3. Explain how life tables are used to track mortality and survivorship in populations. 4. Compare Type I, Type II, and Type III survivorship curves. 5.
Describe and compare the exponential and logistic population growth models, illustrating both with examples. 2015 Pearson Education, Inc. You should now be able to 6. Explain the concept of carrying capacity. 7. Describe the factors that regulate growth in
natural populations. 8. Define boom-and-bust cycles, explain why they occur, and provide examples. 9. Explain how life history traits vary with environmental conditions and with population density. 10. Compare r-selection and K-selection and indicate examples of each.
2015 Pearson Education, Inc. You should now be able to 11. Describe the major challenges inherent in managing populations. 12. Explain how the structure of the worlds human population has changed and continues to change. 13. Explain how the age structure of a population can be used to predict changes in population size and social conditions. 14. Explain the concept of an ecological footprint. Describe the uneven reliance upon natural resources in the world. 2015 Pearson Education, Inc.
Percentage of survivors Figure 36.UN01 Few large offspring, low mortality I until old age Many small offspring, high mortality II III
Percentage of maximum life span 2015 Pearson Education, Inc. Age Figure 36.UN02 80+ 7579 7074 6569 6064 5559 5054
4549 4044 3539 3034 2529 2024 1519 1014 59 04 1989 Male 6 5 4
2012 Female Male Female 3 2 1 0 1 2 3 4 5 6 5 4 3 2 1 0 1 2 3 4 5 Population in millions Estimated population in millions Total population size = 83,366,836 Total population size = 114,975,406 2015 Pearson Education, Inc.
Figure 36.UN03 (K N) G = rN K 2015 Pearson Education, Inc. Figure 36.UN04 II Birth or death rate I
Time 2015 Pearson Education, Inc. III IV Figure 36.UN05 2015 Pearson Education, Inc.
