About This Chapter
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- Identify the lessons in the Holt McDougal Evolution of Populations chapter with which you need help.
- Find the corresponding video lessons with this companion course chapter.
- Watch fun videos that cover topics on the evolution of populations you need to learn or review.
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Students will learn:
- Genetic variation types
- Kinds of natural selection
- The definition for sexual selection
- Hardy-Weinberg equilibrium
- Differences between temporal and mechanical isolation
- Descriptions of convergent and divergent evolution
- Adaptive radiation and punctuated equilibrium
- What coevolution is
- Basics of extinction
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1. What Is Genetic Variation? - Sources, Definition & Types
Natural selection is the process that drives evolution, but what drives natural selection? Genetic variation increases the genetic diversity in and among populations, allowing for new traits to become more or less prominent in the gene pool.
2. 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.
3. Gene Flow: Definition & Examples
Chances are you've probably witnessed gene flow today! This lesson will define gene flow and give examples. It will also explain why gene flow creates genetic diversity.
4. 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.
5. Sexual Selection: Definition & Forms
Why are you attracted to someone? One reason may be due to the forces of sexual selection. This lesson will explain sexual selection and will investigate types of sexual selection.
6. 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.
7. 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.
8. 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.
9. Mechanical Isolation: Definition & Example
What prevents species that are closely related from mating with each other? Sometimes it's just a matter of having the right equipment - mechanical isolation is one evolutionary mechanism that prevents different species from interbreeding.
10. Temporal Isolation: Example & Definition
What prevents species that are closely related from mating with each other? Temporal isolation is an evolutionary mechanism that keeps individuals of different species from interbreeding, even if they live in the same environment.
11. Convergent & Divergent Evolution: Definition & Examples
Ever wonder why birds and bees both have wings, even if they aren't related? This lesson will examine that question. In addition, it will define and explain convergent and divergent evolution and will give examples of each.
12. Coevolution: Examples & Definition
Can you imagine having a tongue three times the length of your body? There actually exists a moth with such a tongue, and it evolved due to the features of a flower that it feeds on. Learn about this and other examples of organisms that have evolved together.
13. What Is Extinction? - Defining Background and Mass Extinction
In this lesson you'll discover what the term 'extinction' means as well as learn the two different types of extinction: mass extinction and background extinction. You will also discover how humans contribute to extinction events.
14. Punctuated Equilibrium: Definition, Theory & Examples
In this lesson, we'll take a look at the theory of punctuated equilibrium developed by the notable paleontologists Niles Eldredge and Stephen Jay Gould. We'll define punctuated equilibrium, explain its basic tenets and see some simple examples.
15. 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.
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Other chapters within the Holt McDougal Biology: Online Textbook Help course
- Holt McDougal Biology Chapter 1: Biology in the 21st Century
- Holt McDougal Biology Chapter 2: Chemistry of Life
- Holt McDougal Biology Chapter 3: Cell Structure & Function
- Holt McDougal Biology Chapter 4: Cells & Energy
- Holt McDougal Biology Chapter 5: Cell Growth & Division
- Holt McDougal Biology Chapter 6: Meiosis & Mendel
- Holt McDougal Biology Chapter 7: Extending Mendelian Genetics
- Holt McDougal Biology Chapter 8: From DNA to Proteins
- Holt McDougal Biology Chapter 9: Frontiers of Biotechnology
- Holt McDougal Biology Chapter 10: Principles of Evolution
- Holt McDougal Biology Chapter 12: The History of Life
- Holt McDougal Biology Chapter 13: Principles of Ecology
- Holt McDougal Biology Chapter 14: Interactions in Ecosystems
- Holt McDougal Biology Chapter 15: The Biosphere
- Holt McDougal Biology Chapter 16: Human Impact on Ecosystems
- Holt McDougal Biology Chapter 17: The Tree of Life
- Holt McDougal Biology Chapter 18: Viruses & Prokaryotes
- Holt McDougal Biology Chapter 19: Protists & Fungi
- Holt McDougal Biology Chapter 20: Plant Diversity
- Holt McDougal Biology Chapter 21: Plant Structure & Function
- Holt McDougal Biology Chapter 22: Plant Growth, Reproduction & Response
- Holt McDougal Biology Chapter 23: Invertebrate Diversity
- Holt McDougal Biology Chapter 24: A Closer Look at Arthropods
- Holt McDougal Biology Chapter 25: Vertebrate Diversity
- Holt McDougal Biology Chapter 26: A Closer Look at Amniotes
- Holt McDougal Biology Chapter 27: Animal Behavior
- Holt McDougal Biology Chapter 28: Human Systems & Homeostasis
- Holt McDougal Biology Chapter 29: Nervous & Endocrine Systems
- Holt McDougal Biology Chapter 30: Respiratory & Circulatory Systems
- Holt McDougal Biology Chapter 31: Immune System & Disease
- Holt McDougal Biology Chapter 32: Digestive & Excretory Systems
- Holt McDougal Biology Chapter 33: Protection, Support & Movement
- Holt McDougal Biology Chapter 34: Reproduction & Development