The concept of “free energy” is an important part of Big Idea 2. As a phrase, “free energy” is mentioned 55 times, more than twice as often as any other phrase. As a term the word “energy” far surpasses all other words, appearing in the text 81 times. The most common phrases to include “free energy” are “capture free energy” (8 times), “changes free energy” (6 times), and “use free energy” (5 times). It is easy to see why the authors included the term “free energy” in the title of Big Idea 2.
Other words from the title appear in the outline less frequently. The word “molecules” appears 34 times, while the similar terms “matter” and “material(s)” appear 7 and 5 times respectively. The term “growth” is mentioned 10 times and the word “grow” appears 8 times. Taken together, the terms “reproduce”, “reproduction”, and “reproductive” appear a total of 21 times. The similar terms “maintains”, “maintained”, and “maintain” appear a collective 33 times. It is also important to note that the word “maintain” and its variants are always used in ways that indicate the need for energy, i.e. maintain homeostasis, maintain order, maintain organization, maintain internal environment. The phrase “dynamic homeostasis” is mentioned 21 times and the phrase “biological systems” appears 9 times.
In addition to the key words in the title of Big Idea 2, there are a couple of other phrases that should be examined.
The phrase “feedback mechanisms” appears 14 times. As discussed in the text, feedback mechanisms play an important role in the maintenance of homeostasis. The concept is mentioned most frequently in the phrases “positive feedback mechanisms amplify” (5 times) and “negative feedback mechanisms maintain” (3 times).
The concept of the timing and coordination of biological events is given special attention in Big Idea 2. Together, “timing” and “coordination” appear 13 times within the text. The terms are used to illustrate how the regulation of developmental, physiological, and behavioral events are essential to the “normal” development of an organism.
The phrase “biological systems” appears 9 times and usually refers to the various system levels (molecules, cells, organisms, populations, communities, and ecosystems.)
Big Idea 2 Word Cloud
The word cloud in Figure 2 offers a graphical representation of the most frequently occurring words from Big Idea 2. There is a positive correlation between word size and the number of times the term appears in the text. The word color is arbitrary.