THE LIVING WORLD
0. Studying Biology
This puzzled leopard, seemingly poised to jump, faces an uncertain future, a future it cannot escape by leaping off the cover of this book. Sadly, it literally has no place to go. Once distributed across Africa and southern Asia, the leopard’s range has decreased radically in the last century due to hunting and loss of habitat. Now, except for a few relict populations in Asia, it is found only in sub-Saharan Africa, and is considered a “Near Threatened” species. The leopard’s fate, and that of all other creatures of the living world, will depend critically on the steps we humans take to protect and preserve our world’s climate and resources. Your study of biology will provide you with a key tool to help. You are about to leap into the study of molecules, cells, and intricate body processes, of evolution and ecology. Rich with new ideas unknown to many of you, biology is a science course full of promise. This short “Chapter Zero” is intended to provide you with the tools to make the leap more strongly, and with greater confidence. Good luck.
0.1. How to Study
Some students will do well in this course, others poorly. One of the best predictors of how well you will do is how well you are prepared to learn. Entering an introductory science course like this one, do you know how to take lecture notes? Do you know how to use these notes effectively with your textbook? Can you read a graph? This edition of The Living World tackles this problem head-on by providing you with this “Chapter Zero” at the beginning of the text. It is intended to help you master these very basic but essential learning tools.
Listening to lectures and reading the text are only the first steps in learning enough to do well in a biology course. The key to mastering the mountain of information and concepts you are about to encounter is to take careful notes. Studying from poor-quality notes that are sparse, disorganized, and barely intelligible is not a productive way to approach preparing for an exam.
There are three simple ways to improve the quality of your notes:
1. Take many notes. Always attempt to take the most complete notes possible during class. If you miss class, take notes yourself from a tape of the lecture, if at all possible. It is the process of taking notes that promotes learning. Using someone else’s notes is but a poor substitute. When someone else takes the notes, that person tends to do most of the learning as well.
2. Take paraphrased notes. Develop a legible style of abbreviated note taking. Obviously, there are some things that cannot be easily paraphrased (referred to in a simpler way), but using abbreviations and paraphrasing will permit more comprehensive notes. Attempting to write complete organized sentences in note taking is frustrating and too time consuming— people just talk too fast!
3. Revise your notes. As soon as possible after lecture, you should decipher and revise your notes. Nothing else in the learning process is more important, because this is where most of your learning will take place. By revising your notes, you meld the information together and put it into a context that is understandable to you. As you revise your notes, organize the material into major blocks of information with simple “heads” to identify each block. Add ideas from your reading of the text and note links to material in other lectures. Clarify terms and concepts that might be confusing with short notes and definitions. Thinking through the ideas of the lecture in this organized way will crystallize them for you, which is the key step in learning.
Figure 0.1. A learning timeline.
Remembering and Forgetting
Learning is the process of placing information in your memory. Just as in your computer, there are two sorts of memory. The first, short-term memory, is analogous to the RAM (random access memory) of a computer, holding information for only a short period of time. Just as in your computer, this memory is constantly being “written over” as new information comes in. The second kind of memory, long-term memory, consists of information that you have stored in your memory banks for future retrieval, like storing files on your computer’s hard drive. In its simplest context, learning is the process of transferring information to your hard drive.
Forgetting is the loss of information stored in memory. Most of what we forget when taking exams is the natural consequence of short-term memories not being effectively transferred to long-term memory. Forgetting occurs very rapidly, dropping to below 50% retention within one hour after learning and leveling off at about 20% retention after 24 hours.
There are many things you can do to slow down the forgetting process (figure 0.1). Here are two important ones:
1. Recopy your notes as soon as possible after lecture. Remember, there is about a 50% memory loss in the first hours. Optimally, you should use your textbook as well while recopying your notes.
2. Establish a purpose for reading. When you sit down to study your textbook, have a definite goal to learn a particular concept. Each chapter begins with a preview of its key concepts—let them be your guides. Do not try and learn the entire contents of a chapter in one session; break it up into small pieces that are “easily digested.”
Learning may be viewed as the efficient transfer of information from your short-term memory to your long-term memory. This transfer is referred to as rehearsal by learning strategists. As its name implies, rehearsal always involves some form of repetition. There are three general means of rehearsal in the jargon of education called “critical thinking skills” (figure 0.2).
Repeating. The most obvious form of rehearsal is repetition. To learn facts, the sequence of events in a process, or the names of a group of things, you write them down, say them aloud, and mentally repeat them over and over until you have “memorized” them. This often is a first step on the road to learning. Many students mistake this as the only step. It is not, as it involves only rote memory instead of understanding. If all you do in this course is memorize facts, you will not succeed.
Organizing. It is important to organize the information you are attempting to learn because the process of sorting and ordering increases retention. For example, if you place a sequence of events in order, like the stages of mitosis, the entire sequence can be recalled if you can remember what gets the sequence started.
Connecting. You will learn biology much more effectively if you relate what you are learning to the world about you. The many challenges of living in today’s world are often related to the information presented in this course, and understanding these relationships will help you learn. In each chapter of this textbook you will encounter full-page Connection essays that allow you to briefly explore a “real-world” topic related to what you are learning. One appears on page 5. Read these essays. You may not be tested on these essays, but reading them will provide you with another “hook” to help you learn the material on which you will be tested.
Figure 0.2. Learning requires work.
Learning is something you do, not something that happens to you.
Studying to Learn
If I have heard it once, I have heard it a thousand times, “Gee, Professor Johnson, I studied for 20 hours straight and I still got a D.” By now, you should be getting the idea that just throwing time at the material does not necessarily ensure a favorable outcome.
Studying, said simply, is putting your learning skills to work. It should come as no surprise to you that how you set about doing this matters. Three simple strategies can make your study sessions more effective:
1. Study at intervals. The length of time you spend studying and the spacing between study or reading sessions directly affects how much you learn. If you had 10 hours to spend studying, you would be better off if you broke it up into 10 one-hour sessions than to spend it all in one or two sessions. There are two reasons for this:
First, we know from formal cognition research (as well as from our everyday life experiences) that we remember “beginnings” and “endings” but tend to forget “middles.” Thus, the learning process can benefit from many “beginnings” and “endings.”
Second, unless you are unusual, after 30 minutes or an hour your ability to concentrate is diminished. Concentration is a critical component of studying to learn. Many short, topic-focused study sessions maximize your ability to concentrate effectively.
2. Avoid distractions. It makes a surprising amount of difference where you study. Why? Because effective studying requires concentration. For most of us, effective concentration requires a comfortable, quiet environment with no outside distractions like loud music or conversations.
It is for this reason that studying in front of a loudly playing television or stereo, or at a table in a busy cafeteria, is a recipe for failure. A quiet room, a desk in the library, outside on a sunny day—all these study locations are quiet, offering few distractions and allowing you to focus your concentration on what you are trying to learn. Keep your mobile phone off— texting while studying is as distracting as it is while driving, and as much to be avoided.
3. Reward yourself. At the end of every study interval, schedule something fun, if only to get away from studying for a bit. This “carrot and stick” approach tends to make the next study interval more palatable.
Learning Is an Active Process
It is important to realize that learning biology is not something you can do passively. Many students think that simply possessing a lecture video or a set of class notes will get them through. In and of themselves, videos and notes are no more important than the Nautilus machine an athlete works out on. It is not the machine per se, but what happens when you use it effectively that is of importance.
Common sense will have a great deal to do with your success in learning biology, as it does in most of life’s endeavors. Your success in this biology course will depend on doing some simple, obvious things (figure 0.3):
• Attend class. Go to all the lectures and be on time.
• Read the assigned readings before lecture. If you have done so, you will hear things in lecture that will be familiar to you, a recognition that is a vital form of learning reinforcement. Later you can go back to the text to check details.
• Take comprehensive notes. Recognizing and writing down lecture points is another form of recognition and reinforcement. Later, studying for an exam, you will have already forgotten lecture material you did not record, and so even if you study hard, you will miss exam questions on this material.
• Revise your notes soon after lecture. Actively interacting with your class notes while you still hold much of the lecture in short-term memory provides perhaps the most powerful form of reinforcement, and will be a key to your success.
The process of revising your lecture notes can and should be a powerful learning tool. For the best results, don’t simply transcribe more legibly what you scribbled down so rapidly in class. Instead, focus on how the lecture was organized, and use that framework to organize your revised notes. Most lectures are organized much like each chapter is in this textbook, with three or four main topics, each covered in a series of steps. To revise your class lecture notes most effectively, you should try to outline what was said in lecture: First write down the three or four main headings, and then under each heading place the block of lecture material that addressed that topic.
Perhaps more than you have realized, a lecture in a biology course is a network of ideas. Going through your class lecture notes and identifying the main topics is a powerful first step in sorting these ideas out in your mind. The second step, laying out the material devoted to each topic in a logical order (which is, hopefully, the order in which it was presented), will make clearer to you the ideas that link the material together— and this is, in the final analysis, much of what you are trying to learn.
As you proceed through this textbook, you will encounter a blizzard of terms and concepts. Biology is a field rich with ideas and the technical jargon needed to describe them. What you discover reading this textbook is intended to support the lectures that provide the core of your biology course. Integrating what you learn here with what you learn in lecture will provide you with the strongest possible tool for successfully mastering the basics of biology. The rest is just hard work.
Figure 0.3. Critical learning occurs in the classroom.
Learning occurs in at least four distinct stages: attending class; doing assigned textbook readings before lecture; listening and taking notes during lecture; and recopying notes shortly after lecture. If you are diligent in these steps, then studying lecture notes and text assignments before exams is much more effective. Skipping any of these stages makes successful learning far less likely.
Key Learning Outcome 0.1. Studying biology successfully is an active process. To do well, you should attend lectures, do assigned readings before lecture, take complete class notes, rewrite those notes soon after class, and study for exams in short, focused sessions.
Pulling an All-Nighter
At some point in the next months you will face that scary rite, the first exam in this course. As a university professor, I get to give the exams rather than take them, but I can remember with crystal clarity when the shoe was on the other foot. I didn't like exams a bit as a student—what student does? But in my case I was often practically paralyzed with fear. What scared me about exams was the possibility of unanticipated questions. No matter how much I learned, there was always something I didn't know, some direction from which my teacher could lob a question that I had no chance of answering.
I lived and died by the all-nighter. Black coffee was my closest friend in final exam week, and sleep seemed a luxury I couldn't afford. My parents urged me to sleep more, but I was trying to cram enough in to meet any possible question, and couldn't waste time sleeping.
Now I find I did it all wrong. In work published over the last few years, researchers at Harvard Medical School have demonstrated that our memory of newly learned information improves only after sleeping at least six hours. If I wanted to do well on final exams, I could not have chosen a poorer way to prepare. The gods must look after the ignorant, as I usually passed.
Learning is, in its most basic sense, a matter of forming memories. The Harvard researchers' experiments showed that a person trying to learn something does not improve his or her knowledge until after he or she has had more than six hours of sleep (preferably eight). It seems the brain needs time to file new information and skills away in the proper slots so they can be retrieved later. Without enough sleep to do all this filing, new information does not get properly encoded into the brain's memory circuits.
To sort out the role of sleep in learning, the Harvard Medical School researchers used Harvard undergrads as guinea pigs. The undergraduates were trained to look for particular visual targets on a computer screen, and to push a button as soon as they were sure they had seen one. At first, responses were relatively sluggish—it typically took 400 milliseconds for a target to reach a student's conscious awareness. With an hour's training, however, many students were hitting the button correctly in 75 milliseconds.
How well had they learned? When retested from 3 to 12 hours later on the same day, there was no further improvement past a student's best time in the training session. If the researchers let a student get a little sleep, but less than six hours, then retested the next day, the student still showed no improvement. For students who slept more than six hours, the story was very different. Sleep greatly improved performance. Students who achieved 75 milliseconds in the training session would reliably perform the target identification in 62 milliseconds after a good night's sleep! After several nights of ample sleep, they often got even more proficient.
Why six or eight hours, and not four or five? The sort of sleeping you do at the beginning of a night's sleep and the sort you do at the end are different, and both, it appears, are required for efficient learning.
The first two hours of sleeping are spent in deep sleep, what psychiatrists call slow wave sleep. During this time, certain brain chemicals become used up, which allows information that has been gathered during the day to flow out of the memory center of the brain, the hippocampus, and into the cortex, the outer covering of the brain, where long-term memories are stored. Like moving information in a computer from active memory to the hard drive, this process preserves experience for future reference. Without it, long-term learning cannot occur.
Over the next hours, the cortex sorts through the information it has received, distributing it to various locations and networks. Particular connections between nerve cells become strengthened as memories are preserved, a process that is thought to require the time-consuming manufacture of new proteins.
If you halt this process before it is complete, the day's memories do not get fully "transcribed,” and you don't remember all that you would have, had you allowed the process to continue to completion. A few hours are just not enough time to get the job done. Four hours, the Harvard researchers estimate, is a minimum requirement.
The last two hours of a night's uninterrupted sleep are spent in rapid-eye-movement (rem) sleep. This is when dreams occur. The brain shuts down the connection to the hippocampus and runs through the data it has stored over the previous hours. This process is also important to learning, as it reinforces and strengthens the many connections between nerve cells that make up the new memory. Like a child repeating a refrain to memorize it, the brain goes over things until practice makes perfect.
That's why my college system of getting by on three or four hours of sleep during exam week and crashing for 12 hours on weekends didn't work. After a few days, all of the facts I had memorized during one of my "all-nighters” faded away. Of course they did. I had never given them a chance to integrate properly into my memory circuits.
As I look back, I see now that how well I did on my exams probably had far less to do with how hard I studied than with how much I slept. It doesn't seem fair.