Welcome, to your introductory article on Biology. This article is going to be tackling the concepts and the lens through which we study biology. What is biology and why does it matter? As always, it’s important to keep in mind that the reason that science exists is to understand the world around us, but it’s also so that we understand our connection to that world. More so than any other subject, biology shows us that we are connected to every other organism and every process on Earth, that is what makes it so exciting!
The Study of Life
Most of you reading this have taken a biology class or two. You might even be a biology major, getting ready to start down the exciting road that is biology. Wherever you’re at I’m going to ask you to read the heading for this section. Now read it again, and again and again and again… until you want to rip off your clothes in frustration and run down the street butt ass naked, screaming “I AM STUDYING LIFE.” I’m sorry but the standard definition for biology (the scientific study of life) is ridiculously boring.
There’s nothing inherently wrong with the definition it just leaves out all of the good parts! Life is full of all sorts of excitement; there’s death, birth, and of course a fan favorite, sex! There is a never ending race between all life on earth just to see who can pass on a little genetic material. All of it spanning billions of years until we reach a point where a bunch of apes decide that they’re curious as to how their surroundings work. They make observations, venture a guess as to how those observations work, TRY TO CONTROL THE SITUATIONS that they’re observing, write down what they see, and argue about it endlessly. All so they can take a small glance in to how the world works around them! Sorry I had to get that off my chest.
So you see my point? Biology is a field that can branch off infinitely into the deepest darkest corners of space-time, there’s even a branch of physics called biophysics. Of course there isn’t enough time in a human life span to tell this whole story (especially since we probably only know 10-100 percent (a 1 with 100 zeros in front of it. the opposite of a googol) of the whole story (using conservative estimates). So for now we are going to focus on the Earth, the place where those apes, are hard at work, trying to understand the story.
Life had to have a beginning. No we’re not talking about a supernatural beginning. We support peoples right to believe what they want, but if you want to know how the world works, you’re going to need real observable data and a theory that can help you predict natural phenomena (yes this is part of the actual definition of a scientific theory). Enter evolution, which is the very well established scientific theory, that states that there is a change in the genetic composition of a population from generation to generation. These changes have made it so that every species living today came from a species that has lived in the past but is no longer alive today.
We haven’t gotten in to genetics yet, but I’m sure you’ve heard of DNA (Deoxyribonucleic Acid). Well that DNA actually makes you who you are through something called gene expression. Genes give you your body type, hair color, blood type and just about everything else about you. All living things on this planet use DNA as their basic blueprint (there are some things that use RNA, but we’ll get to that!). So if we’re all using the same basic genetic code, then why do we have different species? Even among people there are small variations!
You see, if a certain variation persists and allows an individual to breed more successfully, and if that variation is passed on to its offspring and it allows them to breed more successfully, then you have the beginnings of evolution. It takes a really long time, and a whole lot of things have to go right, but eventually you might see that the individual where the genetic variation originated might look and act very different from what you see in present and future generations.
What is Life?
Understanding isn’t something that just happens. Scientists don’t just telepathically communicate their ideas to the world. That’s why they come up with definitions. In my opinion a definition is the most useful tool that a student has at their disposal. It allows you to work within the construct of the definition without having to rely on if’s and but’s. When it comes to studying life we need a set of parameters that allow us to actually know what life is. As with all things in science there’s bound to be controversy regarding definitions. The definition of life is no exception, especially since it carries with it a lot of weight.
1. Life Has Order (Organization)
Even the smallest bacteria have a defined structure. When it comes to life it isn’t just a random set of variables thrown together in hopes of getting something usable. Even when we get to the smallest components of living systems we see that seemingly random events can build up to complex systems. Remember a living organism is composed of one or more cells, the basic unit of life.
Maintaining a constant internal environment is crucial to the survival of an organism. Different organisms use different methods to regulate their internal environment, but the one constant is the need to regulate their internal system. You can think of homeostasis as an organism maintaining a balance (equilibrium) between their internal and external environment, such that their body is kept at a relatively constant state.
It is worth noting that not all methods of creating a homeostatic environment are created equal. A reptile is cold blooded, meaning that it can’t maintain it’s body temperature without a little help from an external source. For example a snake uses the sun as a source of warmth. Whereas humans can generate their own heat. Both of these examples are fairly straight forward, but they both leave out an important aspect of biology, and that is the need for compromise. As you continue your study of biology, ALWAYS keep in mind that when an organism utilizes a system (a system being anything that allows it to function in it’s normal way), that nature has made a compromise when using that system. A reptile’s metabolism is slower, and it can’t survive once temperature gets a little too extreme, and a human (or any mammal really) must consume an ungodly amount of energy to keep their heat up. It’s all about compromise.
*Note: In the next section we’re going to be talking about metabolism, this is different than maintaining homeostasis. Homeostasis is about more than just body temperature. Sure, energy processing can be used to maintain homeostasis, but think about your blood pH levels, this isn’t just maintained by what you eat.
3. Energy Processing (Metabolism)
All living things must take in energy to build their bodies and survive. There’s actually a law in physics that states that a system will move towards a more disordered state just by existing (second law of thermodynamics: entropy). A living system (organism) is about as complex as it gets. So then, how do we prevent the inevitable breakdown of the system known as our bodies?
Well the bad news is we can’t. As we all know (some more than others) aging is the inevitable breakdown of the system. The good news is that, for most of us, we can postpone it. We do this every time we take a drink and every time we eat something. The break down of the food is our bodies way of obtaining the energy needed to prevent a break down in the system, but remember the whole compromise thing? While our bodies are more efficient than any man made methods of capturing energy, it is still worth noting that cellular respiration (how our bodies make energy) is only about 39% efficient. 61% of the energy which you take in is lost as heat! What this means is that the “net-entropy” of the universe is going up even though your body is maintaining a relative state of order.
4. Response to Stimuli
When you smell something bad you reel, when you feel an ice cube on your skin you get goosebumps, when you see a car about to slam in to you you move out of the way. These are just some examples of how you and I would respond to the environment around us given a certain stimulus (a thing or event that evokes a certain reaction). Of course these examples are highly simplified, but you get the gist.
In order to be considered a living organism there has to be response to stimuli. Think about a plant. Have you ever noticed that some trees grow sideways, or that a house plants’ leaves are oriented in a certain direction? Well this is due to a very specific process called photosynthesis.
Photosynthesis is how a plant creates its food using light. The plant’s cells have structures known as chloroplasts, and it is those that respond to light. Now there is a hormone in plants called auxin that actually causes elongation, as the light moves, so does the concentration of auxin in a specific region of the plant. It’s meant to maximize the amount of light that the plant is exposed to. See the picture above.
Try not to think about this in terms of organisms that we can see with our naked eye. It’s easy to see that an insect grows and matures in to an adult form, or that a fetus grows in the womb. Instead try to conceptualize a single cell organism like an amoeba and you’ll start to see that all organisms experience some form of growth during their life cycle. Though this growth might change based on different environmental conditions.
Without reproduction there would be no life. Period. As a higher thinking species we are often plagued by what the meaning of life is. To other organisms the answer is quite simple. To get it on. Well actually it’s a little bit more complicated than that, as there are two types of reproduction: sexual and asexual reproduction. Some species forego the intimacy of having sex by basically cloning themselves.
Spreading genetic material and propagating the survival of the species is highly important. It’s one of the most basic driving forces in nature. Those species with low reproductive drives will cease to exist. While it should go without saying, an organism reproduce their own kind (species). A dog will not give birth to a cat, and a person will not give birth to an alien, unless of course it is parasitized by Alien, but then it isn’t really birth is it?
We’ve come full circle to the basis of modern biology. Every organism on the planet has the potential to develop in to a different species over the course of time. There are many factors that may cause this and still even more that can end a species before they have a chance to adapt to new circumstances.
It is estimated that out of all of the species that have ever existed, about 99% of them are extinct. While humans appear to be a largely successful species it is important to keep in mind that modern humans have probably only existed for about 200,000 years in Earth’s 4.5 billion years. Needless to say we haven’t been around for that long, and unless we start to come up with solutions to some of the big problems that face us today, it is unlikely that we will be around long enough to evolve in to the next level of species.
I believe that Neil DeGrasse Tyson gave us one of the best senses of scale when it comes to the cosmic calendar.
As you start your quest in to the study of Biology, it is important to remember that you are a biological organism. You are connected to the universe and what’s more exciting is that you are able to perceive how you are connected. While other animals are content to live life, grow and reproduce. Humans have inherited a curiosity about the world around them. It is this curiosity that makes us scientists; constantly attempting to understand our place in the universe.
[BIO 211 Concept 1.1]