What are the characteristics that define populations? What causes populations to grow or decline? In the following video you will learn how a population is a group of individuals of the same species living within a designated area at one time. Three important structural aspects of a population are: dispersion pattern, population density and growth rate. [14:24]

Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Describe how ecologists measure population size and density
Describe three different patterns of population distribution
Use life tables to calculate mortality rates
Describe the three types of survivorship curves and relate them to specific populations

Overview of population size, density, and distribution.

A free CK-12 account is required to view all materials.

[Free Registration/Login Required] This is a formative assessment task where students are asked to estimate the population of Utah based on information given about its population density and the perimeter of its state boundaries. Samples of student responses and possible misconceptions are provided along with questions to help students clarify their thinking and deepen their understanding.

In this lesson, students are asked to examine a model for a space station on Mars that will house six researchers studying the possibility of establishing a colony. Given the dimensions of the station and the minimum amount of space needed for each person, students are asked to determine whether each researcher has sufficient living space.

Rate

Type of Unit: Concept

Prior Knowledge

Students should be able to:

Solve problems involving all four operations with rational numbers.
Understand quantity as a number used with a unit of measurement.
Solve problems involving quantities such as distances, intervals of time, liquid volumes, masses of objects, and money, and with the units of measurement for these quantities.
Understand that a ratio is a comparison of two quantities.
Write ratios for problem situations.
Make and interpret tables, graphs, and diagrams.
Write and solve equations to represent problem situations.

Lesson Flow

In this unit, students will explore the concept of rate in a variety of contexts: beats per minute, unit prices, fuel efficiency of a car, population density, speed, and conversion factors. Students will write and refine their own definition for rate and then use it to recognize rates in different situations. Students will learn that every rate is paired with an inverse rate that is a measure of the same relationship. Students will figure out the logic of how units are used with rates. Then students will represent quantitative relationships involving rates, using tables, graphs, double number lines, and formulas, and they will see how to create one such representation when given another.

In this lesson, students use an interactive map to compare the crowdedness of three countries of their choice. They learn that to compare countries with different areas and populations, they need to calculate population density—a rate that compares the population of a region to its area.Key ConceptsA ratio is a comparison of two quantities by division. It can be expressed in the forms a to b, a:b, or ab, where b ≠ 0. The value of a ratio is found by dividing the two quantities. A ratio provides a relative comparison of two quantities. A rate is a ratio that compares two quantities measured in different units. Population density is a rate that compares the population of a region to its area. The value is given in number of people per unit of area.ELL: Identifying key words are crucial for students. Spend some time discussing the key vocabulary in this unit.Goals and Learning ObjectivesExplore rate in the context of population density.Compare three countries to see which is most crowded—that is, which has the greatest population density.

A companion site to Nova's film that examines "human populations and environments." Find some fascinating facts in the interactive slide shows "Human Numbers Through Time," and "Global Trends Quiz."

Students learn about population density within environments and ecosystems. They determine the density of a population and think about why population density and distribution information is useful to engineers for city planning and design as well as for resource allocation.

In the following video, Evan Seimann, PhD, defines key terms and concepts of ecology, basic characteristics of populations, population age structures and densities, and explains the dynamics of growth models within a population. [22:59]