Dolphins, manatees, and sea lions are all aquatic mammals but are not closely related taxonomically. All three species are marine mammals, meaning they spend part or all of their lives in the sea and contiguous bodies of water. Dolphins belong to the taxonomic order Cetacea, which includes whales, dolphins, and porpoises. Manatees (sea cows), however, belong to the order Sirenia, which also includes the dugong. Sea lions were once placed in the order Pinnipedia, with seals, but now belong to the order Carnivora with bears, dogs, and raccoons. Even though these species at first glance may seem similar, the way they are classified shows that each has very different characteristics and abilities.
Students can learn about the convergent and divergent characteristics of these animals by examining their physical, physiological, and behavioral traits, along with their ecological niches. The Marine Mammal Brain Game (MMBG) described in this article introduces students to the intricate relationships between form and function, movement and behavior, and the role of each animal in the ecosystem. Students compare and contrast dolphins, manatees, and sea lions, discover the structure and function of these animals and their various adaptations, and learn how the marine mammals' brains, behaviors, and habits differ. Students also have the chance to practice oral communication and chart-reading skills.
Although marine mammals are used as the example in this game, educators may also develop similar games and activities comparing other animals: lions and zebras can be used to compare carnivores and herbivores, or domesticated goats and white-tailed deer can demonstrate similar types of animals that differ in their human interactions. Students can also use the MMBG as a model to develop their own games, which can compare everything from moles and bats to camels, elephants, and humans.
The content of this game meets requirements set by the National Science Education Standards (see "Addressing the Standards," p. 29) and covers topics ranging from taxonomy and diversity to anatomy and physiology. The game can be used in classes studying environmental science, natural history, life science, and even psychology. The content can be modified to expand instruction in a specific area such as environmental biology or to cover a broader range of topics such as evolution, biodiversity, and oceanography.
The primary focus of the MMBG is, as the title suggests, learning about the animals' brains. Just as different animals have unique external characteristics, they also have different adaptations of the brain. One of the more obvious adaptations is brain size. Larger animals have larger brains in order to control a greater number of muscles and bigger, more complex systems. However, overall brain size is less important than the relative brain size--the brain size adjusted for body weight. If two species of animals have the same brain weight, for example, it is likely that the species with the lower body weight is more intelligent.
Neurons are packed in more densely in the brains of some advanced animals (which results in an increased brain weight but not brain size) through convolutions (foldings) in the cerebral cortex. More advanced animals tend to have more complicated cerebral cortexes. An animal with a relatively smooth cerebral cortex is called lissencephalic, while an animal with a very convoluted cerebral cortex is called gyrencephalic. One clear example of this is a comparison of the brains of the lissencephalic manatee to the gyrencephalic bottlenose dolphin (see brain images on p. 24).
Additionally, the cerebral cortex comprises a greater proportion of the overall brain in more complex animals. Another obvious external feature of the brain is the relative size of the cerebellum, which is important for balance and coordination. …