Ch 20: Praxis Biology: Species, Populations and Evolution

About This Chapter

Turn to this biology chapter when it's time to review for the Praxis II Biology Content Knowledge exam. The engaging video lessons and self-assessing quizzes can help you learn all about the theory of evolution, natural selection, speciation and equilibrium.

Praxis Biology: Species, Populations and Evolution - Chapter Summary

You can find out why the equilibrium equation developed by Hardy and Weinberg is important, and learn how a species develops through the lessons in this chapter. This preparation for the Praxis II Biology Content Knowledge exam includes the study of natural selection, adaptation, sexual selection and artificial selection. All of the following topics are included to assist you:

  • Movement of alleles between populations
  • Evolutionary theory and supporting evidence
  • The Hardy-Weinberg equilibrium equation
  • Types of natural selection
  • Speciation types and barriers

You can watch the informative video lessons as many times as you wish, and you might want to read the accompanying transcripts. Many of the lessons provide additional links, which lead to text lessons offering even more information about select terms and topics. A multiple-choice quiz appears at the end of each lesson, to give you immediate feedback on your progress.

Praxis Biology: Species, Populations and Evolution Objectives

You can demonstrate an understanding of the concepts included in this chapter through your success in the classical genetics and evolution content area, which represents about 15% of the Praxis II Biology Content Knowledge exam. That portion addresses the equilibrium equation formed by Hardy and Weinberg, in addition to speciation concepts. You should also be prepared to answer questions about evolution, along with the pertinent support of the theory. All of the test questions are multiple-choice, for which practice gained with our quizzes can be an asset.

15 Lessons in Chapter 20: Praxis Biology: Species, Populations and Evolution
Test your knowledge with a 30-question chapter practice test
Genetic Drift: Definition, Examples & Types

1. Genetic Drift: Definition, Examples & Types

Genetic drift reduces genetic variability of a population by decreasing the size of the population. The change in population size and variability often leads to new species and unique populations.

Theories of Evolution: Lamarck vs. Darwin

2. Theories of Evolution: Lamarck vs. Darwin

We'll look at the interplay between population genetics and environment. Are traits individually acquired or do entire populations evolve? The flying hamsters and a few other notable experiments will provide the answers.

Hardy-Weinberg Equilibrium I: Overview

3. Hardy-Weinberg Equilibrium I: Overview

In this lesson, we'll examine population genetics in greater detail. We'll also explore notions of Hardy-Weinberg equilibrium for large, stable populations. Is the genetic makeup of our flying hamster population changing? The Hardy-Weinberg equilibrium can serve as a reference point as we try to answer population genetics questions.

Hardy-Weinberg Equilibrium II: The Equation

4. Hardy-Weinberg Equilibrium II: The Equation

The Hardy-Weinberg equilibrium equation is represented by a polynomial, so we'll have to do some calculations. Don't be intimidated; a few coin tosses can help us make sense of allelic frequencies in a given gene pool.

Hardy-Weinberg Equilibrium III: Evolutionary Agents

5. Hardy-Weinberg Equilibrium III: Evolutionary Agents

In this lesson, you'll learn how the Hardy-Weinberg equation relates to different evolutionary agents and population changes. Discover how the equation may be used to discover populations that are not in equilibrium.

Natural Selection & Adaptation: Definition, Theory & Examples

6. Natural Selection & Adaptation: Definition, Theory & Examples

How does natural selection help shape the amazing types of animals we witness around us? In this lesson, we'll explore adaptations and what they can tell us about a species' past evolution.

Natural Selection: Definition, Types & Examples

7. Natural Selection: Definition, Types & Examples

We'll take a look at the types of natural selection that can occur. From flying hamsters to moths, you'll start to grasp the different paths organisms can take as they respond to their changing environments over time.

Sexual Selection & Mate Choice in Animals

8. Sexual Selection & Mate Choice in Animals

In this lesson we describe sexual selection and its role in evolution. Sexual selection, both within sexes (intrasexual selection) and between sexes (mate choice), is defined with examples from the animal kingdom.

Artificial Selection in Evolution

9. Artificial Selection in Evolution

Humans have been selectively breeding for desirable traits in plants and animals for a long time. This artificial selection allows for a lot of control in the breeding process but can also lead to unintended mutations within a population of organisms.

Speciation: Allopatric and Sympatric Speciation

10. Speciation: Allopatric and Sympatric Speciation

Discover the definition of a species and learn more about how species split. Find out common terms related to the splitting of species and study what role polyploidy plays in the development of a species.

Prezygotic Reproductive Barriers & Speciation: Definition & Examples

11. Prezygotic Reproductive Barriers & Speciation: Definition & Examples

We may take for granted why animals choose to mate with other animals of similar appearance, but it's not that simple. There are actually biological barriers to reproduction that can prevent even seemingly closely related species from reproducing. This lesson looks at one such category of hindrances, prezygotic barriers, which make fertilization impossible.

Postzygotic Reproductive Barriers: Definition & Examples

12. Postzygotic Reproductive Barriers: Definition & Examples

Do flying hamsters represent a separate species from your run-of-the-mill hamsters? We'll get to the bottom of this by performing crosses between the two hamster types. You'll explore postzygotic reproductive barriers and their possibly tragic consequences.

Adaptive Radiation: Definition & Example

13. Adaptive Radiation: Definition & Example

Adaptive radiation is when members of a single group or lineage evolutionarily diverge into a variety of different forms. These forms are dictated by selection pressures and the use of habitats or resources.

Forms & Patterns of Evolutionary Change

14. Forms & Patterns of Evolutionary Change

Since Charles Darwin introduced natural selection, scientists have come up with different ideas on how evolution proceeds, and how living things evolve over time. This lesson will focus on different patterns of evolution.

Evidence for Evolution: Paleontology, Biogeography, Embryology, Comparative Anatomy & Molecular Biology

15. Evidence for Evolution: Paleontology, Biogeography, Embryology, Comparative Anatomy & Molecular Biology

There is much support for the theory of evolution. This evidence comes from a variety of scientific fields and provides information that helps us trace changes in species over time. In this lesson, we'll look at this evidence and explore how it supports the theory of evolution.

Chapter Practice Exam
Test your knowledge of this chapter with a 30 question practice chapter exam.
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Practice Final Exam
Test your knowledge of the entire course with a 50 question practice final exam.
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