Category Archives: Biological Sciences

A Model for Predicting Population Abundance of Species

Vancouver Island as seen from North Shore Mountain. The phytoplankton used in the experiment were sampled from Vancouver Island. (Source: Morgan Strohan)

As the environment changes with time and climate, the ability for a species to survive is dependent on the resources available to support body functions. The process by which nutrients from the environment are converted into the energy needed to support an organism is called metabolism. As temperatures increase, the metabolic rate of species increases; this means that resources in the environment are used up faster to produce energy. While previous studies looked at the effects of temperature on a species’ population growth rate, Dr. Joey Bernhardt and her colleagues decided to look at how temperature affects a species’ population carrying capacity, and how the metabolic theory of ecology (MTE) can explain these effects.

Background of the experiment

Phytoplankton were sampled in areas around Vancouver Island, from the Pacific Ocean.

Several populations of phytoplankton were kept under a fixed supply of resources between 5-38°C for forty-three days. As the phytoplankton’s ideal temperature is 25°C, the researchers measured their oxygen production between 8-24°C so as to see the rates of photosynthesis and respiration (their metabolic functions). It was found that carrying capacity declined with increasing temperature.

Phytoplankton is a simple organism relative to multicellular organisms so it provides a good model within the lab. (Source: Dr. Joey Bernhardt)

The stability of the environment

Carrying capacity describes the maximum size of a species population in a certain environment as a function of time, which is related to the amount of resources available. As resources are limited, the environment can only support a certain number of organisms. Carrying capacity is reached over time as resources are used up and the population growth rate naturally reaches zero.

[The phytoplankton] grow from almost no cells, through an exponential phase, and then eventually they plateau out; upon plateauing, they’ve reached carrying capacity. (Source: Wikimedia Commons)

Of course, an environment is not stable forever – natural disasters occur, other species evolve and dominate, etc. – thus the carrying capacity of a species population is subject to change. The metabolic theory of ecology can be used to explain the phenomenon of population decline with increasing temperatures.

Listen to the podcast below to hear why!


Why does this all matter?

Given all this information on theories and phytoplankton, what does this really mean as a big picture and why is it important? We know that along with climate change comes warming waters in our oceans. As stated above, warming temperatures have obvious effects on populations, specifically phytoplankton in this case. But just because phytoplankton may seem boring and meaningless to most people doesn’t mean these results don’t have a much bigger meaning to all other species on Earth!

Watch the video below to find out just what phytoplankton have in common with every other species on this planet, and what warming temperatures could really mean…

As we can see, the factors of temperature, metabolism and the surrounding environment all have significant effects on a population. Climate change is currently happening and we are already starting to see the effects on ecosystems around the world, both in oceans and on land. We are not able to predict all outcomes – as there are many unknowns associated with climate change – but Dr. Joey Bernhardt said it best: “One thing we can say for sure is that warming temperatures will undoubtedly accelerate metabolic rate, and this will have predictable effects on abundance.”

By Gabi Rosu, Morgan Strohan, Dan Choi, and Olivia Wong

Raw Meat-Based Pet Foods – Are They Really Good for Your Pets?

Puppy eating kibble pet food (Source: Wikimedia Commons)

We all love our pets dearly, and there is nothing wrong with that. So wouldn’t you want what’s best for your pet’s health? Recently, many cat and dog owners are switching over from dry kibbles and wet-canned foods to a raw pet food diet. The raw pet food diet usually consists of uncooked animal meats, organs, bones, fruits, and vegetables. Many have claimed that they see an increase in their pet’s poop quality, shinier coats, cleaner teeth, and just an overall improvement in their health.  Yet, veterinarians, the FDA (U.S. Food and Drug Administration), and CVMA (Canadian Veterinary Medical Association)  don’t agree at all with these claims, and they have a really good reason why.

Many studies have been conducted to analyze raw meat-based pet foods, and show some pretty interesting results. Studies have found bacteria like Salmonella and E.coli in raw meat pet foods, as well as large amounts of these bacteria in the poop of pets being fed raw meat. Salmonella can affect humans and animals, and is known to cause diarrhea (a condition where stool or poop is watery) and are often dehydrated (a condition where there is more water leaving the body, rather than entering). E.coli can also affect both humans and animals, and is similar to Salmonella, except it can cause strong cramps, and bloody vomit and diarrhea. The craziest part is that certain studies have also found that the bacteria in the these types of pet food can resist many kinds of drugs that are meant to kill it. So we know that there’s an insane amount of bacteria found in the raw meat pet foods, and studies show that they can be resistant to drugs. But how does this affect humans and our pets?

There are a lot of health risks that come with eating a raw meat-based diet. Aside from what bacteria like Salmonella and E.coli can cause in humans and pets, pets can fracture their teeth upon eating large bones, become constipated, and rupture their gastro-intestinal tract. The gastro-intestinal tract is the part of the body that deals with digestion, absorption, and excretion of food. Animal and human bodies work similarly by breaking down food to absorb the nutrients and be used for various biological processes. Unfortunately, certain substances are left in the meat products if not cooked and when consumed they can prevent the break down process within the gastro-intestinal tract. Thus, pets that consume these raw meat-based foods can become nutrient deficient. Upon eating raw meat-based foods, pets can also pass on bacteria like salmonella and E.coli from their poop and also from their mouths via licking. To make matters worse, if indeed bacteria is passed on from pets, there is an increase risk of infection in young children, kittens, and puppies, the elderly, and those that are pregnant or have a weak immune system.

To sum everything up, studies can’t conclude the benefits and one should consult with their Veterinarian for diet changes.

Link to the study: 

Why Are There So Few Blue Fruits?

Speaking of fruits, how many kinds of blue fruits can you come up with? A recent research conducted in Xishuangbanna Tropical Botanical Garden located in Yunnan, China has shown that, amongst the over 600 species of fruits growing in the garden, only 6 types of fruits are blue. How did this come about? There are a variety of aspects that we need to look at in order to answer this question.


Where do colours in fruits come from?

Fruits get their colours from three main types of plant pigments: carotenoids for colours red, orange and yellow, flavonoids for blue and red, as well as chlorophyll for green colour. Due to the fact that colour red is the most common hue among the three chemicals, most fruits are red.

Colours of fruits and their reproduction

The reason why we are able to identify different colours is that the wavelengths of these colours can be perceived by a specific type of cells called cones in our eyes. Some animals see more colours than we do because they can detect a wider range of wavelengths in the nature. However, when reacting to different colours, cone cells show different levels of sensitivity to their wavelengths, and the colour blue is, unfortunately, not as visible as other colours to most animals.


Lower visibility of blue fruits leads to lower probabilities that they get spotted and eaten by animals and consequently have their seeds spread, which is an important method of reproduction for most plants. As a consequence, blue fruits can not be spread as easily and frequently as fruits with other colours such as red and orange.

However, while the colour blue gives these fruits a hard time to reproduce, there also exist some animals that are inherently colourblind. These animals spot and eat fruits randomly instead of by identifying colours, and this is also the reason why there is still a small amount of blue fruits we can find in our everyday life nowadays.

Additionally, another factor that should be taken into account is that, because it is always connected with characteristics such as danger, the colour blue can result in a loss of appetite in animals.

(video credit:

Overall, the shortage of blue fruits is due to a number of reasons. Specifically, the uneven distribution of pigments in different species of fruits and some special characteristics of the colour blue are the two main factors that account for this phenomenon to a great extend.


– Siqi Tao


Are You Sure You Are Allergic to That?

Imagine you have been allergic to something for most of your life. But now you’re told that it may not be true. Do you trust it? Recent studies show that there is a substantial number of patients incorrectly labelled as having an allergy to penicillin. Some even call this unverified allergy an epidemic. An estimated 32 million people in the United States are documented to be allergic to penicillin. That would mean that 1 out of 10 people reading this are allergic. Yet, over 90% of these patients are not actually allergic to penicillin.

Penicillin is one of the oldest antibiotics for bacterial infections. Alternatives to this drug raise concerns as they are less effective, more expensive and sometimes more toxic. Therefore, doctors only choose to prescribe alternatives when options are limited.

Penicillin is often termed the wonder drug for it’s ability to fight infections. Source: Flickr Commons

If a patient is labelled with an allergy to penicillin, doctors, with good reason, choose to err on the side of caution and prescribe an alternative medication to fight the infection. A misdiagnosis may occur when symptoms are thought to appear when penicillin was taken, i.e. when penicillin is prescribed to a sick child. If a viral infection is mistaken for a bacterial one then the symptom that is developed from the virus may be attributed to the drug instead. Thus incorrectly concluding the child is allergic.

A skin test is the definitive tool to determine if an allergy exists. The procedure involves pricking the skin and  observing the reaction. Doctors can then determine if the patient is actually allergic to the drug in question.

Allergy skin test. See how allergies are identified by the appearance of red and inflamed areas. Source: Wikimedia Commons

A study published in 2017 created an approach for testing and challenging the penicillin allergy label. Patients who were admitted to the hospital underwent an investigation of their allergy history with a pharmacist. Then, if appropriate, the patient would undergo a penicillin skin test. If the test was negative, the allergy would be challenged and the patient would be given a penicillin-like drug. Results showed that one-third of the patients were switched to penicillin successfully leading to less days spent in the hospital and lower hospital bills.

Another paper developed a similar way to evaluate reported penicillin allergies. First, the history of the allergy is researched to determine the risk. Those with mild symptoms would be low-risk while those that develop breathing problems would be moderate to high-risk. Low-risk patients would be given a course of a penicillin-like drug and observed for symptoms of a reaction. Moderate-risk patients would first undergo a penicillin skin test and then given a round of the drug if the skin test was negative. High-risk patients were not challenged and referred to a specialist. Those who tolerated the drug administration then had the allergy removed from their health records.

Both papers emphasize the necessity that penicillin allergy testing  become part of the admission process to a hospital. This test saves money and reduces the chance for patients to get further infections from less effective drugs. Plans for allocating funds in hospitals may need to incorporate this information to better treat patients in the future. 

  • Katie Donohoe

Products marketed as “Organic” vs “Synthetic”… What is truly better for your skin?

When we hear the words “natural”, “organic” and “green” we automatically believe this means something is good for us because it comes from nature, compared to a product that is advertised as “synthetic” or containing “chemical” ingredients. But the truth is, not all products advertised as natural are necessarily good for you, and not all synthetic and chemical products are bad for you… especially when it comes to talking about skincare!

Face Mask Application Source: Flickr Commons


What’s the difference?

One of the main differences between products advertised as “organic” and “synthetic” is that many of the ingredients that are made up from organic molecules in these products are much bigger due to the structure of the molecule and they tend to be less refined. This can be bad because the ingredients then sit on top of your skin and can cause irritation. Whereas in synthetic ingredients, the molecules tend to be smaller and more refined so they can easily absorb into your skin. However, the synthetic products that are more easily absorbed into your skin are only any better than the organic products if they don’t irritate your own skin, but this can vary from person to person. Still, the synthetic ingredients overall have less of a chance of irritating your skin because it can absorb.

In order to decide what kind of products are good or bad for your skin regardless of what they are advertised as, you should always look at the ingredients list to discover the truth of what is in these products. For example, a lot of “organic” skin care products contain essential oils, which may be pleasant to smell but it can actually really irritate your skin as with many fragrances in skin care- these molecules are quite large as well.

Aloe Plant, a common ingredient found in Skincare products Source: Flickr Commons

A recent study was done investigating two forms of sunscreen – a chemical based synthetic sunscreen and an organic physical block. Researchers compared the two and found that the chemical sunscreen absorbed better into skin and people experienced less irritation compared to the organic physical block sunscreen where dermatitis (inflammation of the skin) was common.


So what should you use?

It’s true that some natural and organic skincare products can be harmful for your skin especially if you’re not aware of what ingredients are contained in the product, but the same is true for synthetic. I believe that synthetic products are a safer option for your skin due to the easy absorption. At the end of the day regardless of what the product is marketed as I will always be reading the ingredient list to determine what products are best for my skin and I suggest you do the same as well!

Ingredients List for skincare product Source: Flickr Commons


If you’re curious as to what are some examples of common irritants are in skincare, check out this blog post by skin care specialist and author Paula Beguon.

-Morgan Strohan

Spicy foods: Do we eat them because we like the way they taste?

Trick question. While there are five different classes of taste, spicy isn’t one of them. Sweet, salty, bitter, sour and umami are the five basic qualities that stimulate taste receptors on our tongue and all other taste sensations arise from the different combinations. So what about spicy?

(Source: Flickr Commons)

Spicy is not a taste

We experience the sensation of spiciness not because it’s a taste but because it’s pain-inducing. Spicy foods make you feel as though your mouth is on fire even though there is no real heat in spices. The searing pain occurs because of a chemical called capsaicin present in spicy foods that activate nociceptors (pain receptors) called TRPV1 on the tongue.

Interestingly, the description of heat is more accurate than most people realize. TRPV1 normally respond to heat to alert the body for heat damage, thereby warning us when we consume literally hot drinks or foods. They respond to extreme temperatures, intense mechanical stimulation, as well as certain chemicals like capsaicin.

(Source: Wikimedia Commons (modified))

So why do we eat spicy foods?

Some of our taste preferences are innate, such as our tendencies to crave sweet and salty foods and avoid bitter and sour foods. We’re inclined to consume sugar and salt because they’re biologically useful to us and we have an aversion towards concentrated bitter and sour foods because they can be poisonous or can damage our body tissues. When it comes to spicy foods, it seems that our preferences depend on social influences.

Some people dread the runny-nosed, sweaty-faced experience while others indulge in the burn. In places like India and South America, hot peppers are an integral part of their culture and is often incorporated in daily cuisine. For example, Mexican children are introduced to chili early on through spicy candies, and by the time they’re 5-6 years old, they eat chili peppers on their own accord.

Internationally famous spicy instant noodle from Korea. The cartoon says “스트레스 해소에 직빵이닭”, which means it’ll relieve your stress. (Source: my picture)

In Korea, it’s part of their culture to eat spicy foods in an attempt to relieve stress. The rationale? The pain of eating scorchingly spicy foods distracts someone from their anxieties. Unsurprisingly, a study at the Pusan National University found that Koreans who love spicy food are more prone to stress.

In the Western world, the interest in spicy foods as demonstrated by the fire noodle challenge, Carolina Reaper challenge, etc. may have more to do with masochism than an appreciation of a burn that accompanies a meal. The love for spicy food could be an indicator of personality; a study at the University of Pennsylvania found a relationship between chili-liking and thrill/sensation-seeking in Americans.


Author: Olivia Wong