Keratin Keratin Keratin () is one of a family of fibrous structural proteins. It is the key structural material making up hair, horns, claws, hooves, and the outer layer of human skin. Keratin is also the protein that protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. The only other biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin derives from Greek ' from '
The Origin of Species (The Outer Limits) next sentient species to arise could suffer the same fate, they built the ship to save a sample of that race before it wiped itself out, and protect it until it could repopulate the Earth. The ship extracted genetic material from the group students (and Hope) during the journey and created babies (modifying their genetics to avoid the dangers of inbreeding), creating a sufficient number of humans with enough genetic variation to repopulate the Earth. The Origin of Species (The Outer Limits) "The Origin of Species" is an episode of "The Outer Limits" television show. It was first broadcast on