This two-day lesson helps students understand abiotic and biotic factors. Once the concept has been grasped, they can trace the interactions of these factors within a system.

This lesson describes how amino acids build proteins in a person's body. Amino acids are the chemical building blocks for the structure of an organism. A link to a quiz is provided at the end of the lesson to check comprehension.

This one-day activity challenges students to understand the ecological concept of carrying capacity through the physically-active process of role playing. Upon completion, students will be able to formulate and test hypotheses related to ecosystems and carrying capacity as well as describe the significance of carrying capacity.

This presentation from Bruce Coulter covers the basics of how cells contribute to the process of homeostasis. Sixteen slides are included and cover the transport of materials into and out of the cell, the process of homeostasis, what tissues are, plasma membranes, the fluid mosaic model, membrane proteins, cholesterol molecules, and passive and active transport. The slides also include a number of links to useful animations depicting these processes. A transcript is provided, and Flash is required to view the slides.

This 28 minute presentation provides basic information on DNA. The structure of DNA as well as the four bases are discussed in detail. The process of creating proteins is also explained.

This presentation from Hippocampus introduces the concept of biodiversity via a series of narrated animations. The material is broken down into five sections: Animal Fundamentals, Body Plans, Protostomes and Deuterostomes and a conclusion. Students will learn both how species are different from one another and the common bonds all living things share. Students may choose to skip between sections, or explore other related concepts on the biology portion of the Hippocampus site.

This lesson explains how energy is used to keep the structure of an organism maintained. Otherwise, systems naturally progress from order to disorder according to the second law of thermodynamics. Key terms are hyperlinked to provide more detailed explanations.

This lesson explains how energy travels through an ecosystem. This flow can be diagrammed in food chains and food webs as shown in the lesson's illustrations. Key terms are hyperlinked so students can easily view definitions of new concepts.

This multimedia lesson from Baylor College of Medicine's BioEd Online project introduces the systems of the human body. Deanne Erdmann covers the levels of organization in the body, the types of tissue, organ systems, and the skeletal system. The total running time for the program is one hour three minutes. Real player is required to view the content.

This lesson plan from PBS covers a variety of biology topics related to the human as an animal. Students will view and discuss segments from the PBS program The Human Spark. In the first learning activity, the class will explore how human thought differs from that of other species. In the second learning activity, students will examine different traits and abilities, how these abilities have evolved to help humans deal with their environment, and how they distinguish humans from other animals.

This lesson explains the two laws of thermodynamics that govern the relationship between energy and natural systems. These are the Law of Conservation of Energy and Law of Entropy. Key terms are hyperlinked so that students can easily find definitions to unfamiliar words.

This lesson describes how meiosis makes sexual reproduction possible. Specifically, meiosis produces haploid cells and allows for genetic variation. Key terms in this lesson are hyperlinked so students can easily find definitions to new words.

This 17 minute lecture explains photorespiration in detail. All chemical equations are explained so viewers gain a thorough understanding of the chemicals involved and how they react.

This 13 minute lecture discusses how plants convert sunlight into carbohydrates through photosynthesis. The chemical equations and reactions involved in this process are explained in depth including light and dark reactions.

This lesson describes meiosis and its purpose. Diagrams illustrate each stage in the preparation of the cells. Key terms are hyperlinked so students can easily find definitions to new words.

This lesson provides an introduction to Punnett Squares. Key terms are hyperlinked so that students can easily bring up definitions to unfamiliar words. Graphics further explain the concepts in the lesson.

In this lesson, students will gain experience using Punnett Squares. The case study determines the probability of children having freckles from a freckled father and non-freckled mother. Illustrations guide each step of the case study.

Students work in pairs to compare five aspects of an organism that reproduces sexually with one that reproduces asexually. A variety of organisms are profiled including sand scorpions, red kangaroos, and meadow garlic. As a class, students share their comparisons and generate a list of general characteristics for each mode of reproduction, and discuss the advantages and disadvantages of both. References are included for information on reproduction of various organisms.

This short lesson explains why energy is required for all living things. Types of energy are discussed and an illustration shows examples of the different types of energy. Key terms are hyperlinked so students can easily view definitions to unfamiliar words.

This short lesson explains that matter is required for all living things. An accompanying illustration shows how a peanut butter and jelly sandwich is made of matter. Key terms are hyperlinked so students can easily view definitions of unfamiliar terms.