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:Explain how electromagnetic waves differs from sound wavesTrace the path of light through the eye to the point of the optic nerveExplain tonic activity as it is manifested in photoreceptors in the retina

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Changes in day length, or photoperiod, help regulate seasonal breeding in some mammals by altering hormone levels and aggression. Photoperiod changes can also affect the gut microbiota, and gut microbes can influence hormone secretion and sperm production. However, it’s unclear if the gut microbiota participates in photoperiod-mediated regulation of seasonal breeding. To find out, researchers recently examined the reproductive parameters and microbiomes of male Brandt’s voles exposed to short- or long-day conditions. They found that changing the photoperiod altered the voles’ reproductive hormone and gene expression levels. as well as their gut microbiome compositions. In addition, specific microbes were associated with the reproductive changes that occurred during acclimation to a new photoperiod. Transplantation of gut microbes from short- or long-day-exposed voles into recipient voles induced hormonal and genetic changes (dashed arrows)..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"Over billions of years of evolution, the rhythm of Earth’s day and night – the diurnal cycle – has remained one of very few constants. As a result, all kingdoms of life have evolved internal time-keeping mechanisms. Organisms with the ability to maintain a circadian clock have an evolutionary advantage in both survival and reproductive rates, and disruption of circadian rhythms has been linked to disease states, including obesity, heart disease, diabetes, depression, and cancer. As shift work, stress, digital devices, and health conditions can disrupt our internal clocks, better understanding of how they function is needed. A new review of the circadian circuit examines the role of protein disorder in maintaining clock function. In animals and fungi, the circadian clock functions as a protein-directed feedback loop, with the positive arm stimulating the negative arm..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.

This resource is a video abstract of a research paper created by Research Square on behalf of its authors. It provides a synopsis that's easy to understand, and can be used to introduce the topics it covers to students, researchers, and the general public. The video's transcript is also provided in full, with a portion provided below for preview:

"As we go about our daily lives, we aren’t generally aware of the forces generated by solar activity or the earth’s magnetic field. While these planetary changes are well documented, precisely how they affect human beings is less clear. To answer this question, researchers have turned to the autonomic nervous system – the subconscious control system that regulates bodily functions such as breathing and digestion. Their findings suggest that our nervous systems are well attuned to the energetic fluctuations that ripple through our solar system. The work builds on observations made by the famed astronomer Alexander Chizhevsky during World War I. He noted that battles intensify during peak solar flare periods and that major human events and behaviors closely follow the cycle of the sun – which led to the hypothesis that some unknown solar forces affect human health and behavior, providing a provocative link between events occurring in our solar system and life on Earth..."

The rest of the transcript, along with a link to the research itself, is available on the resource itself.