<span>Lipid
bilayers go through a self assembly process in the formation of
membranes. The cell membrane consists primarily of a thin layer of
amphipathic phospholipids which spontaneously arrange so that the
hydrophobic "tail" regions are shielded from the surrounding polar
fluid, causing the more hydrophilic "head" regions to associate with the
cytosolic and extracellular faces of the resulting bilayer. This forms a
continuous, spherical lipid bilayer. Forces such as Van der Waal,
electrostatic, hyrdogen bonds, and noncovalent interactions, are all
forces that contribute to the formation of the lipid bilayer. Overall,
hydrophobic interactions are the major driving force in the formation of
lipid bilayers. </span>
This allows for humans to breed in the same genes and have the same characteristics as the people in their geographic location for example how Asian people share common characteristics with Asian people. But they differ from European people.
In evolutionary theory, the relationship between the rough-skinned newt and the common garter snake is considered an example of co-evolution. The mutations in the snake's genes that conferred resistance to the toxin have resulted in a selective pressure that favors newts which produce more potent levels of toxin.
