5 Cool Facts I Learned as a Biology Student

Recently, I graduated with degrees in biology and comparative literature. Although literature is pretty cool, nothing gets my nerd gears going more than biology factoids. Biology is the study of life; anything that is composed of cells, respires, or metabolizes is lumped into biology. It took me five years to complete my degree, and I learned a decent amount in this time. Here are 5 random biology facts I remember.

1. Bacteria rule

Bacteria are cool, yes. But bacteria also rule… everything. There are 50 million bacterial cells per gram of soil, and some scientists estimate that there are more than 70 billion tons of carbon stored in bacteria on Earth. That comes out to roughly 15% of Earths overall biomass. Although there is some debate over this number, the fact remains that there are a lot of bacteria. In contrast, all the humans on Earth only store 105 million tons of carbon (about 0.02% of Earths total biomass).

Photo by Anna Shvets from Pexels

Speaking of humans, bacteria rule us too. There are roughly an equal number of bacterial cells living inside of you as there are human cells (a ratio of about 1.3:1 bacterial to human cells). Your gut is teaming with bacteria, which are essential for digestion. This bacteria is so important, in fact, that a lot of research has been done on gut microbe transplants in recent years. Called Fecal Microbiota Transplants, or FMT, this procedure would involve collecting a small amount of diluted feces from a donor and placing it into the colon of a recipient (yuck). Such a procedure would help protect your gut from unwanted bad bacteria such as C. difficile. Like a bacterial war!

2. Coral are animals

That’s right… animals, not plants. Even though they look like plants, and photosynthesize like plants, they are still technically animals. Coral consist of colonies of tiny polys that come in many varieties. Some have hard, calcium carbonate skeletons while others are soft and squishy. All coral have mouths and many feed on plankton regularly using stinging cells called cnidocytes. All coral have these cells, and it’s actually where their phylum name, cnidaria, comes from.

Photo by James Lee from Pexels

But, didn’t I just say they also photosynthesize? That’s right, corals are so kick-butt they can eat both food and light. Coral have a symbiotic relationship with photosynthetic unicellular dinoflagellates called “zooxanthellae” that allows them to use sunlight as an energy source.

Unfortunately, as global temperatures increase due to climate change, more and more bleaching events are killing these amazing animals. Bleaching occurs when zooxanthellae evacuate polyps, leading to a bleached-white appearance. Because many coral rely heavily on photosynthesis for survival, when zooxanthellae jump ship the coral is often left to die. What can you do? Below is a list of organizations that are here to help our reefs

3. You are part Virus

Remember how I said there are billions of bacteria living inside you? Well, viruses have taken this a step further… some viruses have literally become a part of you. Endogenous Retroviruses (ERV) are bits of DNA in your genome that originate from viruses. DNA is the foundation of all life, it is the instruction book that makes you who you are. From your hair and eye color to how your brain is wired, DNA provides the instruction manual for everything that makes you, you. Some scientists estimate that as much as 5-8% is ERV.

CDC/ Dr. Terrence Tumpey/ Cynthia Goldsmith

Viruses are weird because they are not really living- they are like microscopic zombies that depend entirely on their hosts cellular machinery. This usually involves inserting their DNA or RNA into the host cell so that they can produce viral proteins. Retroviruses are a type of virus that insert their genetic code into their hosts genome. Over the course of our evolution, some of these insertions have stuck around, making you who you are today.

4. Your Appendix Does Something

Perhaps sometime in elementary school you were told that your appendix can be removed because… well… it doesn’t do anything, right? Well, recent research on the topic suggests otherwise. Hanging off the colon like a tiny visceral worm, the appendix may actually act as a safe house for beneficial bacteria in your gut. During certain gastrointestinal illnesses, the normal gut flora of the intestines is wiped out due to diarrhea. As I explained earlier bacteria in your gut is essential for digestion, and without it other bad bacteria, like C. difficile, can take hold and make you very ill. The appendix, however, is full of good, healthy bacteria that are unaffected by gastrointestinal illnesses and subsequent bacterial evacuation.

5. Trees are Dead on the Indside

That’s right, you’re not the only one. Most mature trees are actually dead on the inside, with the inner-most wood providing nothing more than structural support. This wood is called the “heart wood” and is surrounded by living “sap wood” that transports water and other nutrients. In fact, if you took a cross-section of a tree you would most likely find that heart wood takes us the majority of the inside of a tree, though this varies from species to species. Heart wood can be identified by its darker coloration compared to light sap wood. The fact that I never knew this until college (along with many other people, I assume) shows how little most people learn about plant anatomy in high school… a real shame in my opinion. Plants are complex, and insanely cool organisms!



Living things can get pretty wild, and its a topic definitely worth exploring. Even though science is not everyone’s cup of tea (which I respect), I hope you found these facts as cool and interesting as I did, and I hope you learned something! If not enlighten me with your own cool facts in the comments!

No content on this site should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician, please see the disclaimer page

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