What is Primate evolution?

Primates are a relatively new species and first appeared in the fossil record nearly 55 million years ago. They may have originated as far back as the cretaceous period. Their fossils were observed in North America, Asia, and Europe. Long before the first monkeys and their prosimian relatives developed, most animal species thrived and died. The first primates did not exist until about 50-55 million years ago, even though the planet is 4.54 billion years old and the first life goes back at least 3.5 billion years. Dinosaurs had been extinct for 10 to 15 million years when this happened.

Characteristics of primate

Primates are an order of mammals. The characteristics of mammals are they have constant body temperature, well-formed and differentiated teeth. The females give birth to offspring. Mammals have multiple developed life stages. Primates include prosimians that are apes, monkeys, etc. The characteristics of primates are:

• Finger and toes: All primates, except spider monkeys, have five fingers and toes on their hands and feet, respectively. The mobility of the fingers and thumb helps to grasp easily. All primates, other than humans, also have prehensile feet.

• Shoulder and hips: Many mammals, including primates, have flexible shoulder and hip joints.

• Improved vision: It has large eye sockets placed forward and overlapping visual fields such as binocular vision. 

Phylogeny

The study of the relationships between various groups of species and their evolutionary development is called phylogeny. Phylogeny is a branch of biology that studies the evolution of all living things on earth. The phylogenetic theory states that all living organisms have a common ancestor. A phylogenetic tree is a diagram that depicts the relationships between species. Shared traits define relationships, as evidenced by comparisons of genetic and anatomical similarities.

Classification of primate

 In primate evolution, the primate is classified into two types. They are prosimians and anthropoids. The prosimians are small and nocturnal. They are the oldest living things. Anthropoids are human-like primates.

Prosimians

Prosimians are a group of primates. Prosimians are small in size and nocturnal. The prosimians are characterized morphologically by having large ears and eyes. They lack vision, but they have enhanced vision under low-light conditions. Lemurs, lorises, and tarsiers are examples of prosimians. Lemurs and lorises are nocturnal primates with large eyes adapted for night vision. Many have long noses. As primates evolved, their olfactory sensations were reduced, and the brain mainly focused on cognitive ability.

Anthropoids

Anthropoids are similar to human primates. They are human-like primates, and they include monkeys, great apes, and humans. They are divided into three groups: new world monkeys, old world monkeys, and hominoids. The new world monkey from the new world can be found throughout central and South America. Members of this tribe spend virtually all of their time in trees. They can swing from branches with the help of their long, flexible arms. New world monkeys also have a long, prehensile tail that may be used as a fifth hand by coiling firmly around a branch. The old-world monkey and big apes belong to the other anthropoid branch, which developed in Africa and Asia. Old World monkeys spend a lot of time in trees, yet they don't have prehensile tails. Hominoids are divided into great apes and lesser apes. The majority of hominids belong to the Australopithecus or homo genus. Australopithecine was a popular genus. Homo sapiens appeared 2.4 million years ago.

Hominine evolution

Gibbons, orangutans, gorillas, chimps, and humans are great apes, sometimes known as hominoids. Chimpanzees are closely related to humans among the great apes, according to deoxyribonucleic acid (DNA) analysis. Hominins are habitually bipedal primates. Modern humans are the only living species of hominins. Hominins have considerably bigger brains than other mammals. Australopithecus species evolved into the Homo genus in Africa around 2 million years ago. Australopithecus was the first of the hominins to show the existence of a gene whose expression led to the increase in the number and length of neurons in the brain, which was crucial in human evolution.

Genus-homo

The emergence of the genus homo in Africa happened around 2 million years ago. Homo is a primate genus in the Hominidae family, characterized by a relatively large cranial capacity and limb structure adapted to a habitual erect posture and a bipedal gait, well-developed and fully opposable thumbs, and hands capable of power and precision grips. It has a more complex culture and the ability to use stone tools. Homo habilis is a member of the genus homo.

Primate-evolutionary trend

In monkeys, the development of the brain has been the primary evolutionary pattern. From prosimians through new world monkeys to old world monkeys to apes, and eventually to humans, comparative findings indicate a consistent tendency toward increased intellect. The brain, which is responsible for sensory perception, motor command production, spatial thinking, and conscious cognition, is the part of the brain that has grown the most. In the fossil record, the neocortex plays an important role in the language of human primates. The arboreal existence of primates has resulted in touch and a visually dominant sensory system, whereas other animals rely primarily on their sense of smell. As primates evolved, their olfactory sensations were reduced, and the brain mainly focused on cognitive ability.

Humans-Homo sapiens

From a biological point of view, humans are animal species whose scientific name is Homo sapiens. They evolved 200,000 years ago. Homo sapiens is the only genus of homo species that still exist. Homo sapiens is a primate and hominoid lineage. Homo sapiens first appeared in Asia and spread throughout the world. Earlier, homo sapiens spent their lives on earth as hunter-gatherers. In scientific records, modern behavior appeared about 50,000 years ago, with the first sign of prehistoric art. The man survived by hunting and creating manufactured tools.  

Characteristics of Homo sapiens

• Humans are social animals, able to conceive and learn fully to convey abstract concepts. 

• Human beings have the mental ability to invent, learn and use complex linguistic structures, logic, writing, science, and technology.

• They have long limbs and short and slender trunkAbility of handling. 

• The modern human is on average 160 cm and 175cm for females and males.

• A large brain, which makes up 2.2% of our body weight. 

Context and Applications

This topic is essential in the professional exams for both school level, undergraduate and postgraduate courses, mainly for Bachelors and Masters in Anthropology and Human biology.

Practice problems

Question 1: Which of the following is true about homo sapiens?

1. Omnivorous
2. Protruded mouth
3. Developed Chin

Answer: Option 3 is correct.

Explanation: Homo-sapiens have a well-developed chin.

Question 2: Bipedal movement has a number of advantages that is ____________.

1. Increased speed
2. Release the limbs for other purposes
3. Reduced body weight

Answer: Option 2 is correct.

Explanation: The bipedal movement helps to release the limbs for other activities. Bipedalism is terrestrial locomotion where an organism moves through its two rear limbs or legs.

Question 3: The evolution theory indicates that___________________.

1. Man originated from a monkey
2. Monkey originated from man
3. Man, and apes have a common ancestor.

Answer: Option 3 is the correct answer.

Explanation: The man and apes had a common ancestor, because based on the fossil record, the human and chimpanzees had the same ancestor.

Question 4: The characteristics of apes are________.

1. Absence of tail
2. Large cranial cavity
3. All of the above.

Answer: Option 1 is correct.

Explanation: The apes have no tail. Apes are found in the tropical forests of western and central Africa and Southern Asia. Apes are distinguished from monkeys by the complete absence of a tail and presence of an appendix and by their more complex brain.

Question 5: Homo belongs to class of ______________.

1. Primate
2. Prosimian
3. Mammalian

Answer: Option 3 is correct.

Explanation:  Homo is classified as mammalian. Humans are classified as mammals because they share the same distinguishing characteristics as the rest of this large group. Humans are also classified as primates, as well as apes, specifically the 'great apes' subgroup of primates.