Eyes with lenses are believed to have evolved independently multiple times, but all evolutionary scenarios face insurmountable barriers.
If lateral gene transfer is rampant throughout life, the universal tree of life becomes a matter of philosophical preference, not empirical demonstration.
The evolution of many complex traits, such as echo location in whales, requires the modification or creation of numerous proteins, physical structures, and neural connections.
One of the central pillars of the standard evolutionary model is the belief that all living species evolved from a common ancestor through a gradually unfolding tree of life.
Douglas Axe is a protein scientist who has published work on the rarity of new protein folds by doing research on beta-lactamase enzymes.