About This Chapter
Ecology, Organism Populations & the Environment - Chapter Summary
Review this collection of science lessons to strengthen or refresh your understanding of ecological, population and environmental concepts. This comprehensive chapter covers topics such as biodiversity, ecological succession, population density, habitats and more. You'll examine the factors that affect population sizes and ecosystems and define terms like extinction, migration and dispersion. After watching/reading the lessons in this chapter, you'll be able to:
- Describe the environment, levels of ecology and ecosystems
- Explain biodiversity and its relation to an ecosystem's stability
- Define habitats and ecological niches
- Understand an ecosystem's food chains, trophic levels and energy flow
- Summarize population density, survivorship and life histories
- Assess population change in trophic levels and its effects on ecosystems
- Analyze environmental effects on population size
- Identify examples of carrying capacity, migration and dispersion
- Recognize examples of mass extinction
- Know what ecological succession is
This study resource contains bite-sized lessons that focus on the most important ecology and environment topics. These lessons are taught by expert science instructors who have a straightforward and engaging teaching style. After you complete each lesson, try the accompanying self-assessment quiz to make sure you've fully grasped the material. Lesson transcripts are available to print and you can quickly find topics using your convenient course Dashboard. To make your studying experience flexible, the lessons are available at any time and accessible on any computer or mobile device.
1. The Environment, Levels of Ecology and Ecosystems
Do you know the difference between an environment and an ecosystem? In this lesson, you'll find out what makes an environment, and what makes an ecosystem. You'll also learn what ecology is and some of the ways that scientists study ecology using organisms, populations, communities, ecosystems and even the entire biosphere.
2. What is Biodiversity? - Definition and Relation to Ecosystem Stability
Imagine making a list of all of the species you have ever heard of; it would be an enormous list! There are many different species on this planet. This lesson will explore the diversity of species, as well as the different types of diversity and how diversity of life is essential for maintaining healthy ecosystems.
3. Ecosystems, Habitats and Ecological Niches
Check out this video lesson to understand the many complex aspects of an ecosystem. See how animals live in habitats and survive amongst their surroundings.
4. Food Chains, Trophic Levels and Energy Flow in an Ecosystem
In this lesson, you'll learn about food chains, food webs, and the different roles that organisms play in an ecosystem. You'll also learn about how energy flows through an ecosystem.
5. Populations: Density, Survivorship and Life Histories
Have you ever wondered how biologists determine the populations of animals in a particular geographic area? Watch this video lesson to find out, and discover how scientists look at the survivorship and life histories of many different species.
6. Population Change in Trophic Levels & Effects on Ecosystems
One small effect can ripple throughout an ecosystem. We'll look at three examples where different trophic levels experience population changes that lead to changes in the rest of the ecosystem.
7. Population Ecology: Environmental Effects on Population Size
Populations can range from the very small to the very large, but the size and prosperity of all populations are influenced by a few basic things. In this lesson we'll discuss the important factors that cause a population to grow or decline in size.
8. Carrying Capacity, Migration & Dispersion
Have you ever wondered why some types of birds fly south in the winter or why some animals form territories? Watch this video to learn about a species' maximum growth capabilities, the way its members group themselves and why they might migrate to new locations every year.
9. 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.
10. Ecological Succession: From Pioneer to Climax Communities
Just as people grow and change so, too, do ecosystems. Watch this lesson to learn about ecological succession from the beginning stages of development to a community's ultimate destination, or climax.
11. What Is Succession in Biology? - Definition & Examples
This lesson covers succession in biology. You'll learn the difference between primary and secondary succession and look at some specific examples of succession in different ecosystems.
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