First Life

Theory of special creation
This theory explains that all the life on the earth have been created by god. The various types of organism are believes to exist in the same form and have not change since their creation. This theory is based on religious believe which do not required obserption and experimentation to find out the truth. The scientific at axidences do not support this theory.

Theory of Abiougenisis
This theory was purpose by von-Helmont(1577-1644). He stated that; life is originated from non-living substances spontaneously. He proposed that mice will be developed when human sweat and wheat floor kept together for 21 days. Similarly, Aristole told that, worms, insects, fish, frogs developed from filts and soil. This theory also propose the formation of maggots(larva of fly) from decaying meat. But this theory is discarved the theory of Biogenetic.

Biogenetic theory
This theory state that, life is originated from preexisting life. This theory is just opposite to theory of Abiogenesis. But it does explain the origin of first life. This theory is proposed by Louis Pasture (1864AD) and spallanzani (1865AD).

Cosmozoan theory
It was propose by Sichter in 1865 AD. It state that, life on earth came from another planate in the form of seed or spore, called panspermia. But this theory couldn’t explain that who would come to the earth.

Modern theory of origin of life or
Naturatistic theory of origin of life
This theory was given by AI Oparin(1923) and later supported by JBS Haldane (1923). This theory is also called Oparin-Haldane theory. They explained life was originated from non-living chemicals. Here the chemical evolution took place from simple chemical compound to complex chemical compound and simple life was originated after a long span of time.
Modern theory of origin of life is divided into the following heading:
Formation of simple inorganic chemical compound
Formation of simple organic compound
Formation of complex organic compound
Formation of molecular aggregate or coecervate
Formation of first life
Development of chemosynthesis
Development of photosynthesis



Formation of simple inorganic chemical compound
At the beginning, the earth was very hot containing gases substance. At that time the substances are present in ionic form- cation & anion with the passes of time, earth was getting cooler slowly and gases ionic substances combine with each other to form element, light elements form gases atmosphere and remain in the upper part while heavier element settle in the form of hard crust of earth.
The atmosphere contains different gases like Hydrogen, Oxygen, Nitrogen, Sulphur etc. This element reacts or combine with each other forming simple inorganic compounds like water, carbon dioxide, carbon mono oxide, NO2, H2S etc. with the decreasing of earth temperature moisture or vapor condains and came as heavy rain which made depletion and elevation in the hot crust.
Rain water was collected in the depreation giving birth to sea and ocean. Water contain different inorganic chemical in dissolve state.
Formation of simple organic compound
With the decrease of earth temperature gradually, the simple inorganic compounds dissolve in sea water reactate with each other to form simple organic compound.
The heat required for the reaction provided by sun light with ultra violet rays, lighting & heat of the earth. The formation of simple organic compounds from inorganic compound was experimentally demonstrated by 2 scientist Urey and Miller. Their experiment is later called Urey-Miller experiment. This experiment was done in laboratory taking sterilized glass apparatus. They kept different chemicals like H, O, N, NH3, CO2, CO, H2S. In this apparatus, the apparatus was provided with rays from electrode and the apparatus also have heating and cooling system. This experiment was kept for 7 days. At the end they analysis the product and found simple organic compound like C6H12O6, ammonia acid, fatty acid, etc.
Formation of complex organic compound
When the earth was gradually cooling, the simple organic compounds present in the water of ocean react with each other ot form complex organic compound. The energy for the reaction is provided by heat of the earth and sunlight. Another scientist S.W. fox experimentally proved the formation of complex organic compound like carbohydrate, protein, fat, etc. from simple chemical compound C6H12O6, ammonia acid, fatty, etc.
Formation of molecular aggregate or coecercate
The complex organic compound present in the water were attracted each other with the help of molecular attraction force and formed a large unit. The unit thus form moves together and shows the increase in size and divisible into small unit. The unit containing large number of complex organic compound, molecular aggregate or coecercate. The water is thicken and also called organic shup. This coecercate started to achieve like living organism so, they were also called pre-cell or protobiont.
Formation of origin of first life

Coervate or prebiont, later developed into first life by evolution. First life was unicellular, microscopic and anaerobic. It took organic substances present in water as food. Therefore, they were also called ‘chemo-heterotrophs’. These organisms increased in number. They reproduce asexually by mitosis like cell division and exploited organic food present in water. Still anaerobic bacteria are found in the bottom of deep water bodies.
Development of chemosynthesis
When the population of chemo-heterotrophs was increase in large number, organic food present in water might have decrease and ocarsity of food occurred for them. Chemo-heterotrophs were later evolved into new type of unicellular organisms. These organisms could take simple organic and inorganic substances present in water and organized or synthesized their food inside the body. They were called ‘chemo-autotrophs’. Nitrogen fixing bacteria, iron bacteria, sulphur bacteria, nitritying bacteria are still found in earth.
Development of photosynthesis
When the population of ‘chemo-autotrophs’ was increased in large number, inorganic & simple organic substances present in the water might have decreases and ocarcity of food occurred for them. Chemo-autotrophs were later, evolved into new type of unicellular organisms. These organisms could make their food from the energy of sunlight and simple inorganic substance (that is CO2 & H2O). these could occur as they developed green chlorophyll in the body. These organisms was called ‘photo-autotrophs’. They proliferated in large numer as a raw material of food was never decreased. From it, advanced type of plant and animals developed later.

THEORY OF EVOLUTION
Lamarckism
Darwinism
Neo-darwinism (Modern theory of origin of species) or (Modern synthesis theory of origin of species) or (Evolution)
Lamarckism
It is the pioneer theory of evolution given by Jean Baptiste Lamarck. Lamarck is also regarded as the father of evolution. This theory is named after Lamarck, who was a French naturalist. He did an extensive study of nature and nature phenomenon and came to conclusion that the varieties of plants, animals and micro-organisms found in nature, is due to evolution or adaptation to diversified habitat.
He gave the theory of evolution in 1809 AD and published a book ‘Philosophy of Nature’ in 1911AD, which included all his views explanations.
In Lamarckism, the change occurred in the life is the basis or fundamental factor for origin of species. Lamarck has three basic assumptions.
1. Change is brought by use and disuse.
2. Change is brought by environment.
3. Inheritance of acquired characters.
Acquired characters:-
Acquired character is the change developed during life time. This change is in herited to next generation and established by reproduction. Lamarckism is therefore also called ‘Theory of Inheritance of acquired character.’
Evidences in support of Lamarckism:-
Development of bicep and triceps muscles in arms and body of wrestler’s and blacksmith by continuous use.
Elongation of neck of giraffe by continuous stretching to take leaves of tree.
Loss of limbs in snake or the formation of different vestigial organ in human is due to disuse for long time.
Development fish like body with fins in whale and dolphins (Mammal) to live in aquatic condition.
Cave dwellers have non-functional eyes.
Desert animal have anatomical features and physiology suited for water conservation.
Flying animals have wings, light body, stream-lined shaped for flying purpose.
Criticisms of Lamarckism
Wrestler’s children are not burned with well developed bicep and triceps muscles.
Woman bore ear nose for ornaments but their daughter are born without pores in ear and nose. Their children have to bore again.
Chinese woman prefer small legs and this is managed by tight shoes. Still this fashion has to be continued.
The children of learned man are not necessarily intelligent but they may be dull also.
Weiss man did an experiment of cutting tail of rat and breeding. This experiment repeated for 50 generation, but still was burned with tail.
Conclusion:- Lamarckism is an such not wrong but it is incomplete because Lamarck was unaware of genetic factor is responsible for the inheritance of acquired character. Genetics was developed only after 1900AD, which was long after the Lamarkism (1809-1811) AD.
Darwinism
This theory is given by English naturalist Sir Charles Darwin. He did extensive study of nature for more than 25 years and developed a theory known as ‘Theory of natural selection’. This theory was later called ‘Darwinism’ in his honor. Charles Darwin wrote a book ‘Origin of species’ in 1859 AD, in which all his observation explanations are included. His theory gives 7 different assumptions. They are:-
Assumption Consequences
Over production
Survival number constant
Struggle for existence Natural selection or survival of the fittest
Variations and heredity
Natural selection
Environmental change
Origin of species
1. Over production
Any organism have very high capacity to produce large number of off springs, this capacity is called ‘Biotic potential.’ Example:-
Male house fly Female house fly
120 eggs -7batches
60m 60f
More than 50 trillion

Example:-
Elephant (70 to 80 years longevity)
30 years (start giving birth)
5-7 young
After 900 years, the number of elephant will be 150 million
2. Survival number constant:-
However the number of survival is not increase but remaining same or constant.
3. Struggle for existence
Though large number of off springs produced by all the living organisms most of them will die due to starvation, lack of space. As food supply is limited and space is constant, there will be tough competition among the numbers of same or different species to exploit limited resources. So there is two type of competition.
Intraspecific competition:- It is the competition among the number of same species.
Inter specific competition:- It is the competition among the number of different species.
Besides competition, members of living organisms also die due to predation, parasitism, diseases etc. Predation is a common feature toward among animals. Predation also, controls the population. Different ecto and endo parasites and different micro-organisms like virus, bacteria, fungi cause different dieses in poor fed population to control their number.
4. Heredity and variation
Variation:- Though most of organisms will dies; some members will surve who have good variations (charge or qualities),
Variations are three types
Meristic and substantiative
Continuous and discontinuous
Somatic and germinal
Meristic and substatiative
Meristic:- It is the change in number of parts of body. For example:- change in number of toes arms etc.
Substantiative:- It is the change in morphological feature like coloration, shape and size etc.
Continuous and discontinuous:-
Continuous:- It is slow, gradual but continuous change. The slow change shown by living organism with the change in environment and habit is continuous change.
Discontinuous:- It is fast or abrupt change occurring occasionally just like mutation.
Somatic and germinal:-
Somatic:- It is the change in somatic cell which does not take part in reproduction. So this change is not inherited to next generation. Example:- development muscle of wrestler. Small feet of Chinese woman etc.
Germinal:- It is the change in reproductive cells which is inherited to next generation. Somatic change may influence the germinal and the change is inherited to next generation.
Heredity:- All the variation should influence the germinal cell or chromosome (DNA) and it inherited the change in next generation, it is called heredity.
5. Natural selection
The organisms with good qualities; change/variations are selected by natural. This is called ‘Natural selection’. Here, organism must have best variations. So that it can complete or struggle for existence. Therefore, natural selection is in other word also called ‘Survival of the fitted’. The theory of Darwinsm is based on ‘Natural selection’. Therefore darwinsm is also called ‘Theory of natural selection’
Environmental change
Evolution is a phenomenon of long time during which, condition of earth is also changes. There was a great ‘Tethis sea’ in the place of ‘Great Himalays’. Forest land, grass land, deserts are continently changed in the course of long run. Similarly, earth was covered completely by ice during glacial period, Earthquake, volcanoes, strums change the geography of earth that is Tsunami.
Origin of species
Constant struggle for survival along with struggle to adjust in the changing environment of earth, the living organisms have developed many changes in then the established as new species. This is called ‘Origin of Species.’
The earth was earlier 2 great continents which collided with each other and form present 7 different continents and this is explained by ‘Drief continental change’.
Neo-Darwinism (Modern Theory of Origin of Species)
Neo-Darwinism is a modern theory of evolution. This theory is the combination of mutation theory given by De-Vries and theory of natural selection given by Charles Darwin. This theory consists of three assumptions:-
Mutation
Natural selection
Isolation
Mutation
Mutation is the sudden change expressed by the development of new characters. This sudden change is due to the change in chromosome or genes. Therefore mutation is two types:-
Chromosomal mutation
Gene mutation
Gene mutation
De Vries belived the evolution is series of change and these change are not due to slow variation, but due to sudden changes by mutation. Mutation is the main factor responsible for the changes. He studied a wild prime rose plant (Oenothera lamarckiana). He found the number of chromosome from 14-30 or more. All this difference in chromosome is due to mutation. The varied chromosome number is associated with varied characters;
 Difference in flower size.
 Difference in flower color.
 Difference in leaf size and shape.
 Difference in nature of stem.
 Difference in bud characters.
 Difference in development.
 Difference in ecological growth habitat.
These different plants are called ‘Elementory species’. Such different plants will add new changes after series of mutation and develop into new species.
Natural selection:-
The change occurred due to mutation may be harmful or beneficial. If the change suit the individual to flight in the struggle for existence, which variation/ change is selected by nature known as ‘Natural selection’. Natural selection gives the validity to the changes and stabilizes towards more development and evolution.