Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Discuss exponential human population growth
Explain how humans have expanded the carrying capacity of their habitat
Relate population growth and age structure to the level of economic development in different countries
Discuss the long-term implications of unchecked human population growth

A companion site to Nova's film that examines "human populations and environments." Find some fascinating facts in the interactive slide shows "Human Numbers Through Time," and "Global Trends Quiz."

Many factors influence the success and survival rate of a population of living things. Explore several factors that can determine the survival of a population of sheep in this NetLogo model. Start with a model of unlimited grass available to the sheep and watch what happens to the sheep population! Next try to keep the population under control by removing sheep periodically. Change the birthrate, grass regrowth rate, and the amount of energy rabbits get from the grass to keep a stable population.

Have we used up all our resources? Have we filled up all the livable space on Earth? Paul Gilding suggests we have, and the possibility of devastating consequences, in a talk that's equal parts terrifying and, oddly, hopeful. [16:47]