Primates - what kind of family? The order of primates and their evolution

Primates are a group entering the mammal class, a type of chordates (subtype vertebrates). The class of mammals is characterized by live birth, feeding the baby with milk, bearing it in the uterus. All representatives of this class are homeothermic, that is, their body temperature is constant. In addition, the level of metabolism they have high. In addition to the middle and inner, all mammals also have an external ear. The females have mammary glands.

Primates (semi-monkeys and monkeys) from all mammals differ, perhaps, the greatest wealth and variety of forms. However, despite the differences between them, many of the features of their body structure are similar. They were developed in a long process of evolution as a result of the tree way of life.

Limbs of primates

Primates are animals that have a five-fingered grasping limb, well developed. It is adapted to lasagna representatives of this detachment through the branches of trees. They all have a clavicle, and also completely divided the ulna and radius, which provides a variety of movements and mobility of the forelimb. The thumb is also moved. It can be contrasted in many species to the rest. Nails end with phalanges of fingers. In forms of primates with clawed nails, or those that have claws only on some fingers, the thumb is characterized by the presence of a flat nail.

The structure of primates

When traveling on the surface of the earth, they rely on the entire foot. In primates with arboreal life, the reduction of smell is associated, as well as the good development of the organs of hearing and sight. They have 3-4 nasal conchas. Primates are mammals whose eyes are directed forward, orbits (lemur, tupayi), or bone septum (monkeys, tarsiers) are separated from the temporal pit by a circumglobular ring. In the lower primates on the muzzle there are 4-5 groups of vibrissae (tactile hair), in the higher - 2-3. In monkeys, as well as in humans, cutaneous scallops are developed on the entire plantar and palmar surface. However, they have only half-pawns on the cushions. The variety of functions that front limbs have, as well as the active life of primates, have led to a strong development in their brain. And this means an increase in the volume of these skulls in these animals. However, large, well-developed hemispheres of the brain with a lot of gyri and furrows have only higher primates. In the lower ones, the brain is smooth, with few convolutions and furrows.

Hair and tail

In the species of this order, the scalp is thick. The half-breeder has an undercoat, but in most primates it is poorly developed. Wool and skin in many species are brightly colored, eyes are yellow or brown. The tail is long, but there are also tailless and short-tailed forms.

Food

Primates are animals that feed mainly on mixed food, in which the vegetable predominates. Some species are insectivorous. Stomach in primates, due to mixed type of food, simple. They have 4 types of teeth - fangs, incisors, large (molars) and small (premolars), as well as molars, having 3-5 tubercles. Complete replacement of teeth occurs in primates, it affects both permanent and dairy.

Body Dimensions

In the size of the body of representatives of this detachment there are significant variations. The smallest primates are mouse lemurs, while the growth of gorillas reaches 180 cm and above. The body weight of males and females varies - males are usually larger, although there are many exceptions to this rule. The family of some monkeys consists of several females and a male. Since body weight is an advantage for the latter, natural selection occurs, associated with its increase. For example, a male Hanuman can collect a whole harem consisting of 20 females, a very large family. Primates are forced to guard their harem from other males. At the same time in the host family the body weight reaches 160% of the mass of the female. In other species, in which males usually mate only with one female (for example, gibbons), the representatives of different sex do not differ in size. Sexual dimorphism is very weakly expressed in lemurs.

In the struggle for paternity, an important role is played not only by the size of the body of such a detachment as the primates. These are animals whose fangs serve as a powerful weapon. Males use them in aggressive demonstrations and battles.

Propagation of primates and litters

Primates reproduce all year round. Usually one cub is born (in lower forms there may be 2-3). Large species of primates reproduce less often, but live longer than their smaller relatives.

Already at the age of the year, mouse lemurs can reproduce. Each year, two cubs appear in the light. The body weight of each of them is about 6.5 g. Pregnancy lasts 2 months. 15 years is a record of longevity of this species. Female gorilla, in contrast, sexually mature only by age 10 years. A single calf is born whose body weight is 2.1 kg. Pregnancy lasts 9 months, after it, repeated pregnancy can occur only after 4 years. Usually gorillas live up to 40 years.

Common for various species of monkeys, with significant species differences, is a small offspring. The rate of growth of young animals in the members of this order is very low, much lower than that observed in other mammals with similar body weight. It is difficult to say what the reason for this is. Perhaps it should be sought in the size of the brain. The fact is that the most energy intensive in the body are precisely the brain tissue. In large primates, a high level of metabolism is observed in it, which reduces the rate of development of the reproductive organs, as well as the growth of the body.

Propensity to infanticide

In primates, due to low rates of reproduction, a tendency to infanticide is expressed. Often males kill cubs, which the female gave birth from other males, since the feeding individual can not conceive again. Males, which are at the peak of physical development, in their attempts at reproduction are limited. Therefore, they do their best to preserve their genotype. A male monkey, for example, Hanuman, for the continuation of the genus, there are only 800 days of 20 years of life.

Lifestyle

The order of primates, as a rule, lives on trees, however there are semi-terrestrial and terrestrial species. The representatives of this detachment have a daily life style. Usually it is herd, more rarely single or pair. Mostly they live in the subtropical and tropical forests of Asia, Africa and America, and also occur in highland areas.

Classification of primates

About 200 species of modern primates are known. There are 2 suborders (monkeys and semi-ovaries), 12 families and 57 genera. According to the classification, the most widespread at the present time, the tupayis enter the primates' detachment, forming an independent family. These primates, together with tarsiers and lemurs, constitute the sub-order of the semi-poor. They connect insectivorous animals through lemurs with modern primates, recalling what ancestors were in antiquity in the latter.

Primates: evolution

It is believed that the ancestors of modern primates were insectivorous primitive mammals, similar to tupayem, existing in our day. Their remains were found in Mongolia, in the Upper Cretaceous sediments. Apparently, these ancient species lived in Asia, from which settled to other places in North America and the Old World. Here these primates developed to long-lions and lemurs. Evolution of the original forms of the monkeys of the Old and New World, apparently, was from primitive long-lagged ones (the ancestors of monkeys some authors consider ancient lemurs). Regardless of the monkeys that met in the Old World, American primates arose. Their ancestors from North America penetrated into the South. Here they specialized and developed, adapting to an exceptionally arboreal way of life. In many biological and anatomical traits, people are the highest primates. We are a separate family of people with the genus of man and only one species - modern reasonable.

The practical importance of primates

Modern primates are of very great practical importance. They have for a long time drawn the attention of man as funny living beings. Monkeys were the subject of hunting. In addition, they were put up for sale for home entertainment or in a zoo these mammals. Primates are even used today for food! Today, the aborigines eat the meat of many monkeys. Meat semi-ovine is also considered very tasty. Skins of certain species are used today for the manufacture of various things.

The order of primates in recent years has become increasingly important in medical and biological experiments. These animals show a great similarity with man in terms of a variety of anatomical and physiological features. And not only anthropoid primates have this similarity, but also the lower ones. Representatives of this unit are even susceptible to the same diseases as we (tuberculosis, dysentery, diphtheria, poliomyelitis, angina, measles, etc.), which proceed in general in the same way as we do. That is why some of their organs are used today in the treatment of people (in particular, kidneys of green monkeys, macaques and other monkeys - a breeding ground for the growth of viruses, which after appropriate treatment are then turned into a polio vaccine).