It is a single layer of cube-shaped cells. New epidermal skin cells, called keratinocytes, are formed in this layer through cell division to replace those shed continuously from the upper layers of the epidermis. This regenerative process is called skin cell renewal. As we age, the rate of cell renewal decreases.
Primates - marmosets, monkeys, apes, lemurs, humans. There are about 233 species in this order. Primates range in size from the tiny pygmy marmoset that weighs less than 3 ounces to the large mountain gorilla that weighs close to 400 pounds.Most species of primates are found in subtropical or tropical forests and many species live in trees. Primates have five fingers on their hand and five toes on their feet.
The most primitive living primates are called prosimians. They are primitive in the sense that they retain characteristics of the very first primates from millions of years ago. Prosimians include lemurs, lorises, galagos and tarsiers.Within simians, the next most primitive group is the new world monkeys.These monkeys are native to North and South America.he most primitive living primates are called prosimians. They are primitive in the sense that they retain characteristics of the very first primates from millions of years ago. Prosimians include lemurs, lorises, galagos and tarsiers.