Biology is designed for multi-semester biology courses for science majors. It is grounded on an evolutionary basis and includes exciting features that highlight careers in the biological sciences and everyday applications of the concepts at hand. To meet the needs of today’s instructors and students, some content has been strategically condensed while maintaining the overall scope and coverage of traditional texts for this course. Instructors can customize the book, adapting it to the approach that works best in their classroom. Biology also includes an innovative art program that incorporates critical thinking and clicker questions to help students understand—and apply—key concepts.

By the end of this section, you will be able to:Describe prions and their basic propertiesDefine viroids and their targets of infection

The US pork industry has long believed in “continuous process improvement” for all aspects of pork production, and the search for better nutrition, genetics, facilities, welfare, and health has driven the evolution of the industry over the decades. As a result, today’s US pork industry is a world leader in production efficiency, product quality, and competitiveness. However, recent events have exposed two threats to this leadership position:

pathogens endemic to the US that resist traditional control strategies and
pathogens (trade impacting diseases) whose detection within our borders would immediately cause a ban of US pork from global markets and result in a seismic shift and economic hardship across the entire US pork industry.
Benjamin Franklin’s words seem written for these circumstances: “By failing to prepare, you are preparing to fail.” That is, it is our responsibility to prepare for the risks that threaten our future. But how should the industry move forward? Initiated in 1935, the National Poultry Improvement Plan (NPIP) is a poultry industry-driven entity designed to promote health and control targeted diseases among participating US poultry producers and slaughter facilities, and presents a possible model for the pork industry to learn from and consider. A study was commissioned by the Swine Health Information Center in 2018 with the aim of understanding the NPIP and assessing the potential for an NPIP like program to support the US pork industry. While there are many species- and industry-specific considerations, in the opinion of these authors, the findings of this study suggest that a “US Swine Health Improvement Plan,” modeled after the NPIP, could provide an effective platform for addressing the major swine health related challenges, opportunities, and risks confronting the 21st century US pork industry.