Intro to Biology
About this free Intro to Biology course
Intro to Biology is a free introductory biology course that explores the wonders of life, from the tiniest cells to entire ecosystems. Across eight units, students uncover how living things are organized, how they grow, adapt, and reproduce, how they change over time, and how scientists can now edit genes.
Topics include genetics, ecosystems, human biology, and the diversity of life on Earth. Hands-on activities, such as examining cells, modeling DNA, and investigating food chains, make abstract ideas concrete. The course sparks curiosity and gives students the skills to think like biologists, a strong foundation for high school biology.
Who this course is for
This course is designed for students in grades 6 through 9 who are new to biology or about to take their first high school biology class. No prior science background is required.
Course outline
- Unit 1: Biodiversity. The variety of life on Earth, how organisms are classified, and why biodiversity matters.
- Unit 2: Cells. Cell theory, plant and animal cells, and the organelles that keep cells alive.
- Unit 3: Cell replication. How cells divide through mitosis and why cell division matters for growth and repair.
- Unit 4: Evolution. Natural selection, adaptation, and the evidence for evolution.
- Unit 5: Plant reproduction. Flowers, pollination, seeds, and how plants reproduce.
- Unit 6: Chemistry of life. Water, carbohydrates, lipids, proteins, and nucleic acids.
- Unit 7: Organ systems. How cells, tissues, and organs work together in the human body.
- Unit 8: Genetic engineering. DNA, genes, and how technologies like CRISPR are changing medicine and agriculture.
What you'll learn
- Explain cell theory and identify the parts of plant and animal cells
- Describe how cells divide and why it matters
- Explain natural selection and how species adapt over time
- Identify the major molecules of life and their jobs
- Describe what genetic engineering is and discuss its benefits and risks
How long it takes
Plan on about 12 hours, or roughly 90 minutes per unit. Units work well as weekly lessons over a school term.
Frequently asked questions about Intro to Biology
Is Intro to Biology really free?
Yes. Intro to Biology is completely free, with no fees, subscriptions, or account required. STEM for Others is a 501(c)(3) nonprofit, and every course in our curriculum library is free for students, families, and teachers.
What should I take after Intro to Biology?
Continue with Intermediate Biology for a deeper, AP-style look at cells and genetics. You can also branch out with Intro to Human Anatomy or Intro to Ecology.
How do I start the course?
Click Begin Course at the top of this page to open the full slide deck in a new tab. You can also flip through the slides embedded above. Work through one unit at a time and try the practice questions before moving on.
Do I get a certificate?
The self-paced Intro to Biology materials don't include an official certificate. If you're taking the course through a STEM for Others chapter program, ask your chapter leader about recognizing your completion.
Can teachers and clubs use this curriculum?
Yes. Teachers, homeschool families, libraries, and after-school clubs are welcome to use the Intro to Biology materials with their students at no cost. STEM for Others volunteers also teach our curriculum in partner schools and libraries. You can find a chapter near you or start one at your school.
