i. During Eocene epoch Primates came into existence about 65 million years ago. The first primates were somewhat arboreal form like present day tree shrews. The have short nose with flat snouts, grasping hands and feet. These are insectivorous and have large eyes facing more in front than lateral sides. The long bushy tails help them to balance the body while leaping from branch to branch and have shown progress in using vision more than the smell.
ii. About 60 million years ago during Eocene epoch the prosimians diverged much easier from main stock.
iii. About 50 millions years ago the new world monkeys branched from the ancient primates than after the separation of new world monkeys is called anthropoids line. The anthropoids are the ancestors of old world monkeys,apes,humans. Their fossils were discovered from Oligocene rocks about 36-40 million years old.
iv. In Oligocene epoch about 25-30 million years ago the old world monkeys probably diverged from that anthropoids.
v. The lineage remaining after the separation of the world monkeys is called hominoid line.
vi. The hominids (Dryopithecus or proconsul) are the ancestors of apes and humans.It has been discovered in a rock of Miocene epoch about 20-25 millions years in Asia and Africa. The new world monkeys are native to South America. They possess flat nose, wideb)ly separated and outwardly directed nostrils and long prehensile tail. They lacks opposable thumb and their teeth consists of 3 premolars and 3 molars in each half of jaw. Example- marmosets and spider monkey. The old world monkeys have a narrow nose with closely placed and downwardly directly nose, it is named as Catarrhines , thumb is opposable , have two premolars, show better developed and specialized brain, smaller pinnae and are capable of expressing their emotions by facial gestures. Examples baboons and proboscis.
vii. During the middle of Miocene epoch the subsequent separation of apes and human ancestors occurred between 5 to 10 millions years ago.
The apes evolved on two families they are
a) Hylobatidae : This includes small sized arboreal Gibbons restricted to Asia only.
b) Pongidae : This includes Orangutan, Gorilla, Chimpanzee.
The human evolved on one family Hominidae :
The apes mainly remained on trees and walked on two feet. The main changes in the evolution of human were as follows:
a) The development of an upright postures and bipedal locomotion.
b) The size of body has been increase.
c) The size of canine,incisor teeth and eyebrow ridges reduced.
d) The size of brain have gradually increase for higher intelligency and coordination.
e) The binocular (stereoscopic) vision developed due to shifting of eyes on front size.
f) The development of grasping power in hands i.e thumb opposable to fingers.
g) The arms becomes shorter than legs during the gradual evolution.
h) The chin become distinct and snout absent.
i) Flattering of face have occured.
- Gibbons diverged from the main line about 10 million years ago.
- Orangutans diverged about 8 millions years ago.
- Amcestors of gorilla and chimpanzee separated about 2.3 millions years ago.
viii. During the Miocene epoch about 14 millions years ago the earliest known direct ancestor of man is genus Ramapithecus was found . Its fossils have been found in Aftica , Europe and Asia. The first fossil of Ramapithecus was found in the mid 1930 which included a curved Jaw with an arched palate in northern siwalink hills of India. Similarly, a fragment Jaw of Ramapithicus was recorded in kenya in 1960 about 14 millions years ago. In 1980 Munthe etal was found i.e one of the most important fossils yet collected in Nepal was hominoid tooth on the bank. New fossils discover from the Miocene of Nepal include a hominoid in 1983. The hominoid specimen was a well preserved left upper first molar 10mm long and 10.9mm wide. The tooth was 9-9.5 million years old. It's age was determined by palaemkagnetic studies conducted by the university of Wisconsin-Milliwaukee, USA. Mow it is preserved in the Natural History Museum, Swayambhu, Kathmandu of Nepal.
- They were partially upright and ground dwelling in savannah.
- They were arborial having man like feeding habits.
- They resembled man in having erect posture and small canines.
- Jaw fragments suggest that they chewed from side to side and had fairly short muzzles.
ix. Australopithecus : This is the first human like forms. The name means "Southern ape from Africa" They were live in the dry open grasslands of afeica about 5 million years ago during
Pliocene epoch because of a good fossil record, it provides a lot of information about the evolution of man. The features show that Australopithecus was the connecting link between apes and man (clark 1960). It shows following features :
a) They walked erect and had long sized canines and incirors.
b) The brain box was about 600cc in size.
c) They are about 4feet tall.
d) they used weapons of bones.
Fossil evidences shows that there were two species. Australopithecus africanus and Australopithecus robustus. A. robustus remained unchanged and becomes extinct while A. africanus continued to change and evolved to form modern man.
ii. About 60 million years ago during Eocene epoch the prosimians diverged much easier from main stock.
iii. About 50 millions years ago the new world monkeys branched from the ancient primates than after the separation of new world monkeys is called anthropoids line. The anthropoids are the ancestors of old world monkeys,apes,humans. Their fossils were discovered from Oligocene rocks about 36-40 million years old.
iv. In Oligocene epoch about 25-30 million years ago the old world monkeys probably diverged from that anthropoids.
v. The lineage remaining after the separation of the world monkeys is called hominoid line.
vi. The hominids (Dryopithecus or proconsul) are the ancestors of apes and humans.It has been discovered in a rock of Miocene epoch about 20-25 millions years in Asia and Africa. The new world monkeys are native to South America. They possess flat nose, wideb)ly separated and outwardly directed nostrils and long prehensile tail. They lacks opposable thumb and their teeth consists of 3 premolars and 3 molars in each half of jaw. Example- marmosets and spider monkey. The old world monkeys have a narrow nose with closely placed and downwardly directly nose, it is named as Catarrhines , thumb is opposable , have two premolars, show better developed and specialized brain, smaller pinnae and are capable of expressing their emotions by facial gestures. Examples baboons and proboscis.
vii. During the middle of Miocene epoch the subsequent separation of apes and human ancestors occurred between 5 to 10 millions years ago.
The apes evolved on two families they are
a) Hylobatidae : This includes small sized arboreal Gibbons restricted to Asia only.
b) Pongidae : This includes Orangutan, Gorilla, Chimpanzee.
The human evolved on one family Hominidae :
The apes mainly remained on trees and walked on two feet. The main changes in the evolution of human were as follows:
a) The development of an upright postures and bipedal locomotion.
b) The size of body has been increase.
c) The size of canine,incisor teeth and eyebrow ridges reduced.
d) The size of brain have gradually increase for higher intelligency and coordination.
e) The binocular (stereoscopic) vision developed due to shifting of eyes on front size.
f) The development of grasping power in hands i.e thumb opposable to fingers.
g) The arms becomes shorter than legs during the gradual evolution.
h) The chin become distinct and snout absent.
i) Flattering of face have occured.
- Gibbons diverged from the main line about 10 million years ago.
- Orangutans diverged about 8 millions years ago.
- Amcestors of gorilla and chimpanzee separated about 2.3 millions years ago.
viii. During the Miocene epoch about 14 millions years ago the earliest known direct ancestor of man is genus Ramapithecus was found . Its fossils have been found in Aftica , Europe and Asia. The first fossil of Ramapithecus was found in the mid 1930 which included a curved Jaw with an arched palate in northern siwalink hills of India. Similarly, a fragment Jaw of Ramapithicus was recorded in kenya in 1960 about 14 millions years ago. In 1980 Munthe etal was found i.e one of the most important fossils yet collected in Nepal was hominoid tooth on the bank. New fossils discover from the Miocene of Nepal include a hominoid in 1983. The hominoid specimen was a well preserved left upper first molar 10mm long and 10.9mm wide. The tooth was 9-9.5 million years old. It's age was determined by palaemkagnetic studies conducted by the university of Wisconsin-Milliwaukee, USA. Mow it is preserved in the Natural History Museum, Swayambhu, Kathmandu of Nepal.
- They were partially upright and ground dwelling in savannah.
- They were arborial having man like feeding habits.
- They resembled man in having erect posture and small canines.
- Jaw fragments suggest that they chewed from side to side and had fairly short muzzles.
ix. Australopithecus : This is the first human like forms. The name means "Southern ape from Africa" They were live in the dry open grasslands of afeica about 5 million years ago during
Pliocene epoch because of a good fossil record, it provides a lot of information about the evolution of man. The features show that Australopithecus was the connecting link between apes and man (clark 1960). It shows following features :
a) They walked erect and had long sized canines and incirors.
b) The brain box was about 600cc in size.
c) They are about 4feet tall.
d) they used weapons of bones.
Fossil evidences shows that there were two species. Australopithecus africanus and Australopithecus robustus. A. robustus remained unchanged and becomes extinct while A. africanus continued to change and evolved to form modern man.
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