Ch 12: Ecosystems, Populations & Communities

About This Chapter

Expand on your knowledge of ecosystems, communities and populations by watching the videos and reading the lessons in this chapter. Factors that affect these biology systems are a focal point.

Ecosystems, Populations & Communities - Chapter Summary

Using this chapter, you will get to review different factors like biotic and abiotic factors. Density-dependent factors are also covered as well as some examples. Different types of communities and populations are addressed, giving you the chance to see some of their attributes. After you watch all of the videos, you will know more about:

  • Factors of ecosystems
  • Carrying capacity and biotic potential
  • Characteristics of populations
  • Social behavior
  • Different types of communities and the ecology of communities
  • Ecological niche

Our instructors use video and text lessons to quickly teach you about ecosystems and their makeup. After watching a video, take a quiz to see how much you remember. If you feel like you need to revisit a certain topic, just click on the video tags down at the bottom of the video. The instructors also can answer any questions you may have about topics from this chapter.

10 Lessons in Chapter 12: Ecosystems, Populations & Communities
Test your knowledge with a 30-question chapter practice test
Biotic Factor: Definition & Examples

1. Biotic Factor: Definition & Examples

This lesson focuses on the meaning of the term 'biotic factor.' It also introduces other terminology such as the words 'abiotic' and 'ecosystem'. There are real-world examples embedded in the lesson, and a brief quiz follows.

Abiotic Factors of an Ecosystem: Definition & Examples

2. Abiotic Factors of an Ecosystem: Definition & Examples

When it comes to ecosystems, a mountain, a river, and a cloud have more in common than you might think. Abiotic factors have specific and important roles in nature because they help shape and define ecosystems.

Biotic Potential and Carrying Capacity of a Population

3. Biotic Potential and Carrying Capacity of a Population

When you look around, you can see a number of different individuals and species. In this lesson, we will explore the factors that control and define how many organisms can really inhabit a particular ecosystem or habitat.

Density-Dependent Factors: Examples & Definition

4. Density-Dependent Factors: Examples & Definition

Populations cannot grow indefinitely because they are limited by resources. When there are too many individuals in a given area, the population may become too dense. However, nature has ways of helping the population return to a more appropriate size.

Social Behavior: Agonistic, Dominance Hierarchies, & Territoriality

5. Social Behavior: Agonistic, Dominance Hierarchies, & Territoriality

Instead of using words, animals communicate with each other through social behaviors. These actions between individuals may be used to establish rank, defend home and breeding sites, and compete for resources.

Populations: Density, Survivorship and Life Histories

6. 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.

Community Ecology: Definition & Types

7. Community Ecology: Definition & Types

Community ecology looks at the interactions between populations of organisms. Here we explore a polar ecosystem in Greenland to describe what community ecology entails and what it really means to be at the top of the food chain.

Pioneer Community: Definition & Explanation

8. Pioneer Community: Definition & Explanation

In this lesson, we'll be explaining what ecological succession is and the role that pioneer species play in it. We'll explain the pioneer community and look at an example of volcanic rock.

Climax Community: Definition & Example

9. Climax Community: Definition & Example

In this lesson, you will learn about ecological communities that have reached a point of equilibrium. Though rare in nature, these communities are unique because they are so well established that they exhibit very little change.

Ecological Niche: Definition & Importance

10. Ecological Niche: Definition & Importance

Most people want to feel like they belong and have an important role in society. This is also true in a biological aspect. In this lesson, we will learn about ecological niches as well as the roles of organisms and the various aspects of their lives.

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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