Themes in Biology

Biology is a vast subject, and with it come a variety of themes. Three of these themes are evolution, relationship of structure to function and interdependence in nature.

Evolution is the core of biology and relates to the change of populations over the generations. It occurs in all animals and plants on Earth and allows species to adapt and change as the  environment around them does, allowing them a chance at survival. Through studying evolution, scientists hypothesize that all organisms alive today share a common ancestor. Although this may sound bizarre and unlikely, scientists have already proven that animals as different as spiders and monkeys belong to the same family trees. Furthermore, when DNA strands from different animals are examined, it becomes clear that there are many similarities. It seems likely that a very, VERY long time ago, all living organisms were the same single-celled organisms.

http://www.dailymail.co.uk/sciencetech/article-1070671/Evolution-stops-Future-Man-look-says-scientist.html

Many people have seen pictures such as the one above, depicting the evolution of men, from monkeys.

http://afterhardship.blogspot.ca/2012/01/pledge-under-tree.html

However, evolution is not the only large concept in biology. Everyday, we see examples of how the way an object functions is directly related to the structure of that object. The structural levels from molecules to organisms ensure successful functioning in all living organisms and systems. For example, DNA is composed of a double helix. Each step in the strand of DNA is a base-pair, consisting of a base in one chain attracted to an opposite base by a hydrogen bond. This hydrogen bond allows the DNA to be easily separated and put back together, allowing the creation of new DNA to form new life to be simple. An even easier example is looking at giraffes. Giraffes with longer necks will find it easier to reach high branches to get at food, whereas giraffes with shorter necks will have a harder time. Therefore, giraffes with structurally longer necks can function better and have a better chance at survival.

Finally, many animals living in an ecosystem are strongly dependent on one another.  There are many different reasons organisms may depend on each other, but one thing that is common is that their lives are so strongly interlocked that, without one, the other would not survive. Examples of interdependence can be seen in plants that need insects or animals to pollenate them to carnivores that need the meat and sustenance provided by prey. In the end, all living things are connected to each other in a cycle of dependencies.