“Some marine birds, such as the guillemot, which lives in northern seas, lay their pear-shaped eggs without the shelter of a nest directly onto the bare windy rock ledge of the rookery. The center of gravity is far from the center of the egg. When the egg starts to roll on the sloping rock, it goes into a curved course and returns all by itself to a position of equilibrium. By its own dynamics, the egg protects itself from falling off. Presumably, all those guillemot eggs that did not have this property were destroyed.” (Tributsch 1984:22)
Image: Christophe Schindler / Pixabay / Free non-commercial use
Modify Position
Many resources that living systems require for survival and reproduction constantly change in quantity, quality, and location. The same is true of the threats that face living systems. As a result, living systems have strategies to maintain access to shifting resources and to avoid changing threats by adjusting their location or orientation. Some living systems modify their position by moving from one location to another. For those that can’t change location, such as trees, they modify position by shifting in place. An example of an organism that does both is the chameleon. This creature can move from place to place to find food or escape predators. But it also can stay in one place and rotate its eyes to provide a 360-degree view so that it can hunt without frightening its prey.
Birds
Class Aves (“bird”): Eagles, hawks, sparrows, parrots
Birds are evolutionary engineering marvels. They are descended from dinosaurs, but are far from our idea of heavy, scaly reptiles. Of the specific adaptions that set them apart, most notable is flight—although some mammals can fly, birds take the prize for abundance in the skies. Many birds have hollow, lightweight skeletons and specially-designed wings to help them stay aloft. They also have feathers made of keratin that help them stay warm, attract mates, and improve navigation and aerodynamics in flight. In contrast to their dinosaur ancestors, they lack true teeth and have replaced them with specialized beaks and bills.
