</span>Evolution is an important theme in biology. If you go looking for it, you will be able to find an aspect of every living creature out there that is in fact a product of evolution. How did life get to be the way that it is? Evolution, that's how.
2. Levels of organization
How do systems, processes, and events at one level of organization affect other levels? Are units at one level just the sum of units at other levels, or are there emergent properties unique to certain levels? As you may have guessed by our strategic bolding, the latter choice is the answer.
3. Regulation
Let’s face it: Life is a control freak. Everything is regulated, and when regulation fails, the results are generally not good. How does regulation work at the different levels of organization, such as molecules, organs, and ecosystems?
4. Structure and function
How do biological structures relate to the functions they perform? Is a specific structure ideal or optimal for that function? If not, how might this less-than-optimal structure be explained by evolution?
5. Unity and diversity
Certain structures and processes may be common to many or all life forms, but Nature has modified them in diverse ways, resulting in a tremendous range of variation.
This list of themes isn’t complete yet, and as you bask in your newfound, undying love of biology, you will no doubt come up with themes of your own. Try to keep these ideas in the back of your mind…preferably forever, but if that’s not possible, then at least as long as you’re learning biology. They will enable you to keep everything you learn in perspective so that you can see how all the little tidbits of information fit into the big picture. That’s what biology is all about: little, teensy tiny tidbits and how they fit into a bigger picture. Oh, and organization, organization, and more organization.
Sulfur is an essential element for the macromolecules of living things. As a part of the amino acid cysteine, it is involved in the formation of disulfide bonds within proteins, which help to determine their 3-D folding patterns, and hence their functions.
Moonlight is no longer thought of as the cause. In the 16th century, moonmilk, a soft white limestone precipitate found in caves, was thought to be caused by the rays of the Moon.
