By learning about evolution and natural selection, Cristina could begin to see the different evolutionary reasons behind the extreme features some animals have. For example, the aye-aye, a mammal native to Madagascar, has evolved to have an extra long middle finger, which it can use to dig grubs out of trees. Throughout the course we’ll learn about different organisms and how their unique features allow them to survive and thrive in different environments.

While our scientific understanding is much broader than it once was, our understanding is always expanding—we are always learning more things.

Clarifications of the mesenteric anatomy have facilitated a clearer understanding of diseases involving the mesentery—which include malrotation and Crohn’s disease (CD). In CD, the mesentery is frequently thickened, rendering haemostasis challenging. Some authors say that CD is mainly a mesenteric disorder that secondarily affects the GIT and systemic circulation.^[1]

As scientists researched the mesentery more and more, they found that it should be reclassified as an organ. As we will see in the chapter “Body Systems,” having a better understanding of bodies can dramatically improve our ability to detect and prevent illness.