Middle and High School
Canis familiaris, the domestic dog.
The evolution of dogs from wild wolves to domesticated pets (aka fur babies) is well documented. Now, scientists at Duke University say the term that may best describe the canines’ evolutionary success is survival of the friendliest! Awww (insert your adorable pooch photo here)! Science shows that a population of wolves became attracted to humans and ate garbage people left around the home.1 These wolves gained an evolutionary advantage by giving up on being aggressive hunters and becoming friendly toward humans instead. Today, these four-legged creatures are our helpers, hunters, guardians, and friends; it’s no wonder we cherish this unique inter-species relationship like no other.
The dog lovers in your class may be surprised to learn that studying dogs’ evolution, genetics, and behaviors also helps humans. So, unleash students’ curiosity by sharing some of the fascinating aspects of dog science.
How dog genetics are influencing human medicine.
Researchers are increasingly using dogs to study aspects of human biology. The benefit of using the dog for genetic studies is that dogs age and get many of the same diseases as humans, with similar frequency and genetic factors. We can get sick as a dog!
Over the centuries, dog breeders created many different phenotypes (observable characteristics or traits) and the 400-plus dog breeds we know today. However, undesired genetic variants were also inadvertently enriched in specific breeds, which has made different breeds more protected or more vulnerable to specific diseases.2 As genetic researchers look to improve veterinary care for our canine friends, there may be discoveries that help advance work in the human equivalent diseases.
Dogs are good for human health and well-being!
The National Institutes of Health describes how researchers continue to investigate how pets, like dogs, may decrease stress, improve heart health, and even help children with their emotional and social skills.3 The NIH shows how dogs may also aid in the classroom. The study found that dogs can help children with ADHD focus their attention. Researchers enrolled two groups of children diagnosed with ADHD into 12-week group therapy sessions. The first group of kids read to a therapy dog once a week for 30 minutes. The second group read to puppets that looked like dogs. Kids who read to the real animals showed better social skills and more sharing, cooperation, and volunteering. They also had fewer behavioral problems.
Any dog lover knows that dogs are a great source of comfort and support, especially those trained for service. Even some hospitals and nursing homes bring in dogs to help reduce patients’ stress and anxiety.
Smells like a dog!
Throughout the world, dogs are used to detect substances like food, drugs, or human scents. After a century, scientists haven’t developed a machine that can replicate a dog’s powerful olfactory skills. A dog’s nose is 10,000 to 100,000 times more acute than a human nose. So, if humans can detect the smell of one teaspoon of sugar in a cup of coffee, the dog equivalent would be one teaspoon of sugar in two Olympic-sized pools.4
There are three main reasons why dogs can detect odors better than humans.
- Dogs have 300 million scent receptors in their nose (humans only have 6 million)
- 14% of the air that dogs breathe in passes through a series of boney turbinate structures that spread it out over millions of receptors. When humans inhale, all the air passes straight into the lungs.
- Dogs have slits on either side of their nose (and floppy ears) that circulate air so that additional odors are funneled into their snout. Resulting in a constant whiff of whatever they are interested in smelling.
The benefits to humans are right under our noses! For example, studies have shown that seizures in humans are associated with olfactory-specific characteristics and can be easily detected with high accuracy by trained dogs.5 Trained dogs can detect narcolepsy and type-1 hypoglycemic episodes! Dogs are also trained to recognize diseases in exhaled air, urine, feces, and cancer tissue samples.
These canine superpowers make dogs the reigning biosensor champions!
Activity: Edvotek Scents and Sense-Ability
Use this activity in your lab so students can pass the smell test!
Thin-layer chromatography teaches students about olfactory receptors; it’s NGSS-aligned with MS-LS8. The objective of this experiment is for students to understand that olfactory receptors respond to smells and transmit them as signals to the brain. Students will also be able to understand the principles of thin-layer chromatography and how they apply to the separation of olfactory compounds.
Researchers are interested in learning how the human nose and brain sense complex smells. Specifically, they want to understand how combinations of odors—rather than single odor molecules at a time—are sensed and processed. The nose can detect individual odors very well but identifying the components of a complex odor can still be challenging. Scientists can use other methods, such as thin-layer chromatography (TLC), to visualize the different components in a mixture of odorants. TLC is an analytical method used in chemistry and biochemistry to separate and analyze various molecular mixtures. TLC methods can separate mixtures of inorganic ions, organic molecules, and bioorganic compounds such as pigments, lipids, amino acids, nucleotides, and sugars. In this way, TLC methods can be used to separate odorants.
Plan ahead! This kit contains perishable materials; please request materials two weeks before your lab.
1. American Psychological Association, Speaking of Psychology: Survival of the friendliest with Brian Hare, Ph.D. 2. UW School of Veterinary Medicine: Canine Solution: How Dog Genetics Is Influencing Human Medicine 3. NIH: Health Benefits of Human-Animal Interactions 4. Alexandra Horowitz, Inside Of a Dog 5. National Center for Biotechnology Information: Canine Olfaction: Physiology, Behavior, and Possibilities for Practical Applications
Ward's® AP Biology Investigation 1: Evolution: Artificial Selection
Students simulate the process of natural selection, differential reproduction, and the underlying process of evolution to explore how external factors impact the prevalence of a phenotype in the next generation.
Vectors of Diseases Affecting Man and Domestic Animals Slide Set
Demonstration of important arthropod vectors. Identifying features clearly distinguishable. Rigorous quality control standards. All slides are prepared as whole mounts.