Ch 22: Living Organisms & Ecosystems

About This Chapter

Use these fun video lessons to review vertebrate characteristics, primate origins, animal body plans and the human musculoskeletal system. You'll also take another look at various ecosystems and the levels of ecology.

Living Organisms & Ecosystems - Chapter Summary

Get a quick refresher on the basic needs of living organisms before delving into lessons on the evolutionary history of vertebrates and the characteristics of primate groups, such as lemurs, tarsiers and anthropoids. You'll also rediscover components of the human muscular and skeletal systems.

The second half of the chapter can help you review the differences between environments, ecosystems, habitats and ecological niches. Lessons also cover the various levels of ecology and factors affecting an ecosystem's population density. Round out your study by re-examining the features used to define an organism's body plan. This chapter covers the following topics:

  • Living organisms' basic needs
  • Vertebrate characteristics and origins
  • Primate groups and human origin
  • The human muscular and skeletal systems
  • Ecosystems and habitats
  • Levels of ecology
  • Classifications of animal body plans

This chapter's illustrated videos feature an engaging instructional style that can help you commit key science terms and concepts to memory. Self-checking quizzes are also included to help you develop a solid understanding of what's being covered in the lessons. Plus, you can submit a question to one of our instructors if you need help at any point during your studies.

8 Lessons in Chapter 22: Living Organisms & Ecosystems
Test your knowledge with a 30-question chapter practice test
The Defining Characteristics of Living Organisms

1. The Defining Characteristics of Living Organisms

A house is not a living thing, but the people, animals, and plants living inside it are. So how do we define 'life'? Learn about seven characteristics that all living organisms have in common, no matter how different they may look on the outside.

Living Organisms: Basic Needs

2. Living Organisms: Basic Needs

There are many types of living organisms on Earth. But what makes us all the same is our basic needs for survival, which is a shorter list than you might think!

Vertebrates: Origin, Characteristics & Diversity

3. Vertebrates: Origin, Characteristics & Diversity

Vertebrates are diverse and widespread across Earth, but this was not always the case. In this lesson you'll learn about the origins and evolution of these animals, as well as explore their vast diversity.

Primates and Human Origin

4. Primates and Human Origin

You probably know that you are a primate, just like gorillas and monkeys. But you may be surprised to find out how long primates have been around and how many of them are still living on Earth, which are covered in this lesson.

Skeletal System and Muscular System

5. Skeletal System and Muscular System

Do you know how many bones are in the human body? Check out this video lesson to uncover the answer, as well as understand the role and importance of the skeletal and muscular systems.

Ecosystems, Habitats and Ecological Niches

6. 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.

The Environment, Levels of Ecology and Ecosystems

7. 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.

Animal Body Plans: Classifications and Features

8. Animal Body Plans: Classifications and Features

The Animal Kingdom is diverse and complex. How do we make sense of it all? Scientists use body plans to classify and organize the animals of Earth, making it much easier to differentiate between them.

Chapter Practice Exam
Test your knowledge of this chapter with a 30 question practice chapter exam.
Not Taken
Practice Final Exam
Test your knowledge of the entire course with a 50 question practice final exam.
Not Taken

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.