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:

Explain in what way smell and taste stimuli differ from other sensory stimuli
Identify the five primary tastes that can be distinguished by humans
Explain in anatomical terms why a dog’s sense of smell is more acute than a human’s

This course serves as an introduction to the structure and function of the nervous system. Emphasis is placed on the cellular properties of neurons and other excitable cells. Topics covered include the structure and biophysical properties of excitable cells, synaptic transmission, neurochemistry, neurodevelopment, and the integration of information in simple systems and the visual system.

The course will start with an overview of the central and peripheral nervous systems (CNS and PNS), the development of their structure and major divisions. The major functional components of the CNS will then be reviewed individually. Topography, functional distribution of nerve cell bodies, ascending and descending tracts in the spinal cord. Brainstem organization and functional components, including cranial nerve nuclei, ascending/descending pathways, amine-containing cells, structure and information flow in the cerebellar and vestibular systems. Distribution of the cranial nerves, resolution of their skeletal and branchial arch components. Functional divisions of the Diencephalon and Telencephalon. The course will then continue with how these various CNS pieces and parts work together. Motor systems, motor neurons and motor units, medial and lateral pathways, cortical versus cerebellar systems and their functional integration. The sensory systems, visual, auditory and somatosensory. Olfaction will be covered in the context of the limbic system, which will also include autonomic control and the Papez circuit. To conclude, functional organization and information flow in the neocortex will be discussed.

Olfaction is the sense of smell, which is the ability to perceive and distinguish odours. Most mammals have a good sense of smell, but most birds generally do not. The sense of smell is well-developed in carnivores (predators) and ungulates (prey). Fish also have a fairly well-developed sense of smell. Olfactory and gustatory receptors can combine to contribute to flavour.