(i) All the organisms that we see today were created as such. 
(ii) The diversity was always the same since creation and will be same in future. 
(iii) Earth is about 4000 years old.
The Miller-Urey experiment provided the first evidence that organic molecules needed for life could be formed from inorganic components. Some scientists support the RNA world hypothesis, which suggests that the first life was self-replicating RNA.

1.Charles Darwin observed an amazing variety of small black birds called Darwin's finches in the same island. All the varieties evolved on the island itself from ancestral stock and have radiated to different habitats where they have undergone adaptive changes. Darwin interpseted the formation of a number of divergent species from a common ancestral stock with new species adapting different habitats as adaptive radiation resulting into the divergent evolution.
2.According to Darwin this evolution was also based on available resonances of food and space and on this basis therefore by observing their characteristics on the Galapagos islands, he proposed his famous theory known as the 'theory of natural selection'. The main postulates of this theory are as follows:
1. All organisms possess an enormous power of fertility.
2. There is a struggle for the existence within a species as well as between two different species for Food, space and resources.
3. Nature will favour the survival of the fittest.
4. Darwin believed that variations ultimately lead to the formation of new species.

(a) Adaptive radiation is the process of evolution of different species in a given geographical area from a point and spreading or radiating to other geographical area or habitats. For example Drawin's finches / black birds (on Galapagos islands), evolved from original seed eating features, into insectivorous & vegeterian features in different habitat / islands.
(b)A number Australian marsupials and placental mammals each different from the other have evolved from an ancestral stock with in Australian island continent. This is a type of convergent evolution, because more than one adaptive radiation occurred in isolated geographical area.

Evolution of marsupial mammals has resulted in flying phalanger, through adaptive radiation.
Evolution of placental mammals' has led to the evolution of a flying squirrel (independently).
The resemblance between the two, proves convergent evolution.

New about Neo-Darwinism: Dodson (1960) mentions, "Slow accumulation of small mutations, the screening out of combination and these by ecological factors comprise natural selection to form subspecies and finally the formation of food species by the same processes aided by isolating mechanisms, which prevent the sub-species from merging with the general population from which it came."
The Neo-Darwinism is considered to be explanatory theory as modified by new research as a highly probable and the best explanation, which we have had so far. Recently, some evidences in favour of natural selection have come up. Extensive use of D.D.T. against mosquitoes have been responsible for mutant forms which are resistant to the insecticides. These mutant species reproduced quickly and survived due to extinction of original forms. This experiment together with several other proved effectiveness of the Darwin's theory.

Continental Drift is the process in which it is supposed that the continental land masses have not always occupied their present position on the globe and that, powered by processes within the Earth itself, they are slowly by processes within the Earth itself, they are slowly and continuously on the move. In this way new land masses are created and destroyed, split apart and joined, over geological time.
Significance: Continental Drift is one of the processes that can lead to the geographical isolation of a breeding population and so to speciation.

If the embryonic stages of reptiles, birds and mammals are studied, they represent a series of common characters.
All have notochord, pharynx perforated by gill slits and presence of dorsal hollow nerve tube. Even tail is present in the embryos of all the representative types. It indicates that birds and mammals have evolved from common ancestor reptiles.

Formation of first living cell: The fluid substances in colloidal substances formed small globules called coacervates. They got enveloped by lipid membrane. A coacervate having nucleoproteins in the middle surrounded by various nutritive substances ensheathed by a protective membrane was fore-runner of a simple type of call. It was called eobiont or protocell. Gradually inclusion and organelles were formed by combination of various macromolecules. Finnaly a cell was formed.

(i) Branching descent:
1. The members of a population show variations in their characteristics, though they look superficially similar.
2. Some individuals/organisms are better adapted to survive in the given environment.
3. This adaptive ability is inherited and has a genetic basis.
4. Accumulation of variations over a period of time through a number of generations leads to a change in the population characteristics, i.e. descent with modification.
(ii) Natural Selection:
1. Natural selects those individuals who are fit in the environment.
2. Fitness, according to Darwin, refers to ultimately and only - reproductive fitness.
3. Those individuals who are better adapted, reproduce in large number and the progeny consists of more fit individuals, who are selected by nature, i.e. natural selection.