Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show.” To advance through the presentation, click the right-arrow key or the space bar. From the resources slide, click on any resource to see a presentation for that resource. From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation. You may exit the slide show at any time by pressing the Esc key. How to Use This Presentation

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter Presentation TransparenciesStandardized Test Prep Visual Concepts Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Populations Chapter 19 Table of Contents Section 1 Understanding Populations Section 2 Measuring Populations Section 3 Human Population Growth

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Objectives Describe the main properties that scientists measure when they study populations. Compare the three general patterns of population dispersion. Identify the measurements used to describe changing populations. Compare the three general types of survivorship curves. Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Properties of Populations A population is a group of organisms that belong to the same species and live in a particular place at the same time. Populations can be measured in terms of size, density, dispersion, growth rate, age structure, and survivorship. Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Properties of Populations, continued Population Size –A population’s size is the number of individuals that the population contains. Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Properties of Populations, continued Population Density –Density is a measure of how crowded the population is. Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Properties of Populations, continued Dispersion –Dispersion describes the distribution of individuals within the population and may be random, uniform, or clumped. Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Three Patterns of Population Dispersion Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Characteristics of Populations Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Dynamics Age Structure –A population’s age structure indicates the percentage of individuals at each age. Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Dynamics, continued Patterns of Mortality –Populations show three patterns of mortality or survivorship curves: Type I (low mortality until late in life) Type II (constant mortality throughout life) Type III (high mortality early in life followed by low mortality for the remaining life span). Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Survivorship Curves Section 1 Understanding Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Objectives Identify the four processes that determine population growth. Compare the exponential model and the logistic model of population growth. Differentiate between density-dependent and density- independent regulation of populations. Explain why small populations are more vulnerable to extinction. Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Growth Rate Demographers, scientists who study population dynamics, define the growth rate of a population as the amount by which a population’s size changes in a given time. Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Growth Rate, continued Population Size –Birth rate - death rate = growth rate Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 The Exponential Model The exponential model describes perpetual growth at a steady rate in a population. The model assumes constant birth and death rates and no immigration or emigration. Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Exponential Growth Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 The Logistic Model In the logistic model, birth rates fall and death rates climb as the population grows. When the carrying capacity is reached, the number of individuals the environment can support is reached and population growth becomes stable. Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Logistic Model Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Two Population Growth Models Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Regulation Population-limiting factors, such as competition, are density-dependent because the effect on each individual depends on the number of other individuals present in the same area. Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Regulation, continued Population-limiting factors, such as bad weather and fires, are density-independent because the effect on each individual does not depend on the number of other individuals present in the same area. Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Comparing Density-Dependent and Density- Independent Factors Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Regulation, continued Population Fluctuations –All populations fluctuate in size. Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Population Regulation, continued Perils of Small Populations –Small populations have low genetic diversity and are subject to inbreeding, so they are less likely to adapt to environmental changes. Section 2 Measuring Populations

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Objectives Explain how the development of agriculture changed the pattern of human population growth. Describe changes in human population size in the past 10,000 years. Compare observed patterns of population growth in developed and developing countries. Section 3 Human Population Growth

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 History of Human Population Growth The Development of Agriculture –About 10,000 to 12,000 years ago, the development of agriculture increased the growth rate of the human population. Section 3 Human Population Growth

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 History of Human Population Growth, continued The Population Explosion –Around 1650, improvements in hygiene, diet, and economic conditions further accelerated population growth. –After World War II, the human population grew at the fastest rate in history, largely because of better sanitation and medical care in poorer countries. Section 3 Human Population Growth

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 History of Human Population Growth, continued Population Growth Today –Today, developing countries have faster human population growth and lower standards of living than developed countries do. Section 3 Human Population Growth

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Human Population Growth Section 3 Human Population Growth

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Demographic Transition Human populations have undergone rapid growth, yet in some developed countries, populations have stopped growing. The demographic transition model shows how these population changes happen. Section 3 Human Population Growth

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 19 Demographic Transition Model Section 3 Human Population Growth

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice 1. Which of the following is a population? A. all the fish in a pond B. all the birds in New York City C. all the members of a family of humans D. all the fish of the same species in a lake Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 1. Which of the following is a population? A. all the fish in a pond B. all the birds in New York City C. all the members of a family of humans D. all the fish of the same species in a lake Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 2. Which of the following is true in the exponential model of population growth? F. Population growth continues indefinitely. G. Population growth stops at the carrying capacity. H. Population growth increases and then decreases. J. The immigration rate falls with increasing population size. Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 2. Which of the following is true in the exponential model of population growth? F. Population growth continues indefinitely. G. Population growth stops at the carrying capacity. H. Population growth increases and then decreases. J. The immigration rate falls with increasing population size. Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 3. Which of the following refers to the population size that can be sustained by an environment over time? A. bell curve B. allele frequency C. carrying capacity D. exponential growth Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 3. Which of the following refers to the population size that can be sustained by an environment over time? A. bell curve B. allele frequency C. carrying capacity D. exponential growth Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 4. Which of the following is a density-dependent factor for a population of deer in a forest? F. a drought G. a landslide H. a period of freezing weather J. the number of cougars in the forest Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued 4. Which of the following is a density-dependent factor for a population of deer in a forest? F. a drought G. a landslide H. a period of freezing weather J. the number of cougars in the forest Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued Use the graph below to answer question 5. The graph shows the size of a particular population over time. Standardized Test Prep Chapter In the graph, which time period shows negative growth of the population? A. phase 1 B. phase 2 C. phase 3 D. phase 4

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued Standardized Test Prep Chapter In the graph, which time period shows negative growth of the population? A. phase 1 B. phase 2 C. phase 3 D. phase 4 Use the graph below to answer question 5. The graph shows the size of a particular population over time.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued Complete the following analogy: 6. birth rate : death rate :: immigration : F. mortality G. migration H. emigration J. growth rate Standardized Test Prep Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued Complete the following analogy: 6. birth rate : death rate :: immigration : F. mortality G. migration H. emigration J. growth rate Standardized Test Prep Chapter 24

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued Use the graph below to answer question 7. The graph shows the growth of a population of fruit flies over time. Standardized Test Prep Chapter At which point would a density- dependent limiting factor have a greater impact on the population? A. 1 B. 2 C. 3 D. Both 1 and 3

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Multiple Choice, continued Standardized Test Prep Chapter At which point would a density- dependent limiting factor have a greater impact on the population? A. 1 B. 2 C. 3 D. Both 1 and 3 Use the graph below to answer question 7. The graph shows the growth of a population of fruit flies over time.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Short Response Study the graph of fruit fly population growth on the previous slide. Explain why the population stops increasing after it reaches the point labeled 3 on the curve. Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Short Response, continued Study the graph of fruit fly population growth on the previous slide. Explain why the population stops increasing after it reaches the point labeled 3 on the curve. Answer: At point 3, the population has stopped exponential growth and has reached its carrying capacity. Limiting factors usually slow population growth down. Standardized Test Prep Chapter 19

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Prep Chapter 19 Extended Response Base your answers to parts A & B on the information below. Study the graph of fruit fly population growth again. Use the graph to support your answers to the following questions. Part A Name one limiting factor that could affect this population of fruit flies. Part B At which point on the curve would this limiting factor have the greatest effect on the population? Explain your reasoning.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Standardized Test Prep Chapter 19 Extended Response, continued Answer: Part A Food availability is one limiting factor that could affect population growth. Part B Food availability will affect the population at every point along the growth curve. Without food, the population could not experience unlimited growth as shown in area 2. However, food availability has its greatest effect at the carrying capacity, or area 3 on the curve. At the carrying capacity, the environment is supporting the maximum number of individuals based on available resources. Less food will lead to a sudden decrease in population.