About This Chapter
How It Works:
- Identify the lessons in the Holt McDougal Biology in the 21st Century chapter with which you need help.
- Find the corresponding video lessons with this companion course chapter.
- Watch fun videos that cover the 21st century biology topics you need to learn or review.
- Complete the quizzes to test your understanding.
- If you need additional help, rewatch the videos until you've mastered the material or submit a question for one of our instructors.
Students will learn:
- What biosphere, biodiversity and ecosystems are
- Energy transformation in living organisms
- The definition for homeostasis
- Evolutionary theory
- Steps and terms of the scientific method
- How scientific hypotheses are developed
- Alternative vs. null hypothesis
- Dependent vs. independent variables
- The uses of electron and compound microscopes
- The relationship between biology and technology
- Applications, safety and ethics of DNA technology
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1. Biosphere: Definition & Explanation
All organisms, from the tiniest bacterium to the largest blue whale, need a place to live. The 'place on Earth's surface where life dwells' is called the biosphere. But what does this really mean? In this lesson, we'll look at the definition of the biosphere and examine how human activity is changing this important part of our planet.
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. Energy and Life: The Transformation of Energy in Living Organisms
While the sun is an excellent source of energy, not all forms of life can utilize the sun's energy directly. This lesson describes how plants transform the sun's energy into potential energy stored in sugar, how living organisms utilize energy in sugar to perform work, and how the relationship between photosynthesis and cellular respiration is necessary for life.
4. What Is an Ecosystem? - Definition & Explanation
Similar to a car engine that is made up of multiple parts working together, an ecosystem has interacting parts that support a whole. But how do we define an ecosystem and what are the components they consist of?
5. What Is Homeostasis? - Definition & Examples
Homeostasis can be defined as a property of an organism or system that helps it maintain its parameters within a normal range of values. It is key to life, and failures in homeostasis can lead to diseases like hypertension and diabetes.
6. 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.
7. The Scientific Method: Steps, Terms & Examples
The scientific method is more than just hypotheses and experiments. In this lesson, we'll explore the themes and variations that make up the world of science.
8. Developing a Scientific Hypothesis
This video describes how to create a hypothesis and includes the three main things needed to create a strong hypothesis. You'll learn how to make a clear statement that can be both tested and measured.
9. Hypothesis Testing: Comparing the Null & Alternative Hypothesis
This lesson explores the process of comparing the null and the alternative hypothesis, as well as how to differentiate between the two after your testing is done.
10. Identifying & Interpreting Independent & Dependent Variables
Scientists answer questions by performing experiments that have an independent variable, a dependent variable and at least one control variable. By controlling, adjusting and measuring these variables, scientists find answers to their questions.
11. What is an Electron Microscope? - Definition, Types & Uses
Find out how we can observe the arrangement of atoms in a crystal, or the small features on the antenna of a wasp. In this lesson you will understand how electron microscopes work and their applications in science and technology.
12. Introduction to the Compound Microscope: Parts & Uses
The compound light microscope is a useful tool in any biology laboratory. In this lesson, you'll be introduced to the parts of a compound microscope, as well as understand the function of each of those parts.
13. How Computer-Based Technologies Influence the Study of Biology
Through the digital revolution, computers have spread into every home and workplace. Science is no exception. Learn about how computers have impacted the study of biology.
14. Practical Applications of DNA Technology
DNA technology is a field that has many applications for our everyday lives. In this video lesson, you will learn about some of the important contributions of DNA technology to industries such as medicine, agriculture and criminal investigation.
15. Ethical and Safety Concerns for DNA Technology
DNA technology is very powerful and has had positive influences on many fields and industries. However, DNA technology is not perfect. In this lesson, you will explore some of the safety and ethical concerns that people have regarding this field of study.
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Other chapters within the Holt McDougal Biology: Online Textbook Help course
- 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 11: The Evolution of Populations
- 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