A screencast tutorial which describes the major characteristics of animals with backbones called vertebrates. [1:38]
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:
Describe the various types of body plans that occur in animals
Describe limits on animal size and shape
Relate bioenergetics to body size, levels of activity, and the environment
By the end of this section, you will be able to do the following:
List the features that distinguish the kingdom Animalia from other kingdoms
Explain the processes of animal reproduction and embryonic development
Describe the roles that Hox genes play in development
Homeobox genes are important because they determine the overall body plan for most animals. This article explains the experiments that helped scientists discover these master genes. Article includes animations, pictures, video, biographical information, and quiz questions that are accessed by clicking on buttons along the bottom of the page.
If you draw a line down the middle of the body, both sides are mirror images of each other. With a head and stereo senses leading the way, this body plan is ideal for active hunters. [2:49]
The flatworm's bilateral body plan has a head with a brain and stereo eyes that enable it to actively hunt. Its mouth and pharynx are in the center of its underside. With no circulatory system, the gut distributes food to all parts of the body. [2:49]
The squid's body plan has developed for fast action. The shell is reduced to a thin "pen." The mantle wall has elastic fibers that intensify the jet propulsion. Giant nerves allow a fast reflex and three hearts pump oxygen to the gills. [1:34]
