Organs or skeletal elements of animals and organisms
Birds and animals and maybe the bony fish.
Through phosphorylation, Cdks signal the cell that it is ready to pass into the next stage of the cell cycle. As their name suggests, Cyclin-Dependent Protein Kinases are dependent on cyclins, another class of regulatory proteins. Cyclins bind to Cdks, activating the Cdks to phosphorylate other molecules.
Predators and prey are both in a constant struggle for survival, foxes with bigger ears tend to catch more mice, and live longer, because of this, foxes with smaller ears don't live as long, pretty soon all foxes have larger ears. The same goes for prey, Mice with padded feet live longer due to the foxes having more trouble hearing them, pretty soon all mice have padded feet, and the cycle continues.
