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.
The process of change of simpler organisms into complex living organisms due to the gradual changes is called organic evolution. This is almost universally accepted that the present day organisms are evolved by progressive development of simpler organisms to the complex organisms by gradual modifications with time. Life began on the earth after the solidification from molten form and had sufficiently cooled down. During the course of evolution simple form changed into complex form, unicellular forms changed into colonial forms and than multi cellular forms of different tissues. The development of sexuality and alternation of diploid as well as haploid stages of life cycle started. Reduction of haploid gametophytic phase in the life cycle take place. Evolution of new group of plants and animals advances very slowly and it requires millions of years to produced new plants and animals. Evolution proceeds either on progressive or on retrogressive lines, both of these processes of evolution are proceeding simultaneously in nature.
First living organism :
1. They were heterotrophic nature.
2.They were prokaryotic like bacteria and were single celled.
3. They were anaerobic in nature.
4. DNA was naked i.e lacks histone protein.
5. Enzymes were present.
6. Soup like sea water was the source of chemoheterotrophic nutrition.
7. The atmosphere was reducing.
8. The respiration was anaerobic and carbon dioxide was evolved.
b) Formation of organic compounds : As the temperature cooled down to 100 degree centigrade or even lower, molecules mineral undergoes condensation, Polymerization, Oxidation and reduction to form simple organic compound eg- alcols, Aldehydes, Amino acids, glycerol, Fattyacids, Simple sugars, Purine and pyrimidines etc. These reaction were operated under the infulence of ultraviolent rays, radiation, electricity of thunderstomes and volancanic activities.
c) Formation of complex organic compounds : simple molecules combined to form complex compounds like polysaccharides, fats, proteins, nucleotides, nucleic acids etc.
BIOGENY (BIOLOGICAL EVOLUTION)
a)Formation of coacervates : The complex organic compounds of oceanic soup were accumulated due to intermolecular attraction and forms large and highly organised collidal system. These were named as coacervates. The coacervates aquired the ability to exchange energy and could grow.
b) Formation of primative life : The coacervates contains biologically important macro molecules such as proteins, lipids, nucleic acids, nucleic proteins and other organic and inorganic substance. The prokaryotes evolved about 3.8 billions year ago. They were chemoheterotrops and anaerobes.
c) Origin of Autotrops :Primitive autotrops were developed from heterotrops. The primitive autotrops used chemical energy for synthesis of carbohydrates. They are chemoautotrops. The first aerobic photosynthetic organisms probably were cyanobacteria evolve organic 3300-3500 millions years ago. They were the earliest oxygen producing photoautotrops.
d) Origin of Eukaryotic cell ( true nucleus cell) : After the evolution of free oxygen in the environment conditions, suitable for aerobic respiration established upon the earth about 2.7 billion years ago. The prokaryotic modified gradually to adapt the aerobic mode of respiration. They developed a true nucleus, mitochondria and other cell organelles. Thus, free living eukaryotes originated in the ocen probably about 1.6 billions years ago. these eukaryotes were like unicellular organisms of today.
The Greek philosphers of Prechristian era Thales (640-546BC), Anaximender (611-547BC), Empedocles(495_435BC), Plato and Aristoles (384-322BC) followed the theory of Spontaneous generation(Abiogenesis) . According to this theory life originated from non-living materials automatically from time to time. It was belived that frogs, mice, toads, snakes arose from the mud, parisites, beetles and flies arose from the sweat and manure, aplids and others insects arose under the influences of heat and moisture and micro organism arose from air or water.
Later on the theory of Biogenesis i.e Living beings only was forwarded by different scientists due to which the theory of Abiogenesis fails. Francesco Redii (1626-1698) had experimentally proved the theory of Biogenesis. He had taken three jars with meat. First jar was kept open, second jar was covered by net and third one was covered by a piece of paper. He observed little white worms and larvae (maggots). opened jar. In other two jar worms and larvae developed outside the net and paper. He concluded that maggotswere borne due to contamination of meat by flies. Another scientist Lazaaro Spallanzani (1729-1799) performed experiment to conclude that even primatives, unicellular oeganisms lso cannot aeises from non-living matters. Louis Pasture (1822-1895) a french microbiologists disproved the theory of Abiogenesis of microbes. He had proved that self generation of organism is impossible.
CHEMICAL EVOLUTION OF LIFE
chemical is the most modern and convincing theory of origin of life. Russian Biochemist Alexander Ivanovich Oparin (1923) and englishman J.B.S Haldine(1928) independently gave the "Biochemical theory of origin of life" This theory purposed the origin of life occured along the origin and evolution of earth and its atmosphere. This theory is called "oparin-Haldane Theory" . Accordindg to this theory life on the earth was originated by non-living molecules throughout the series of chemical reactions.The inorganic molecules formed simal organic compound, simple compound forms more complex compound which finally formed first living being, cell. Oparin have rxplain about this theory in a book called "The origin of life on earth" which was published in 1936. yhis theoty can be explained in two ways
1. Chemical Evolution (Chemogeny)
2. Biological Evolution(Biogeny)
Technology is derived from the Greek word Tekhnologyia which means skills. Technology is the art of science of applying scientific knowledge to the practicle problems and also the application of science for commercial and industrial objectives. Due to the development of technology we are able to use various type of technological factors such as computers, electricity, communication facilities, auto mobiles, telephone, artificial satellites, space ships, aeroplanes etc. Technology and science are related to each other. After the research in science, technology come into exsistence.