Explain how natural selection has worked on population of peppered moth in industrial area of England.
However, with the replacement of coal and petroleum by gas and electricity the situation has changed. Thus the white moth has become abundant with a sharp decline in the number of black. The reason being the decrease in pollution and restoration of grey colour on the trees because of the growth of the lichens on the tree trunk.
Thus industrial melanism is an interesting example of evidence in favour of natural selection.
G. Araduiana developed the first geological time scale. In the geological time scale, the duration of earth's history has been divided as follows :
Era Periods -
Palaeozoic era has 6 Periods. They are : Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.
Mesozoic era has 3 Periods. They are Triassic, Jurassic and Cretaceous.
Coenozoic era has 2 Periods. Tertiary and Quarternary.
Some of the periods are further divided into still smaller time spans called epochs. Tertiary period 5 epochs namely Palaeocene, Eocene, Oligocene, Miocene and Pliocene.
Quarternary has 2 epochs called Pleistocene and Recent.
1. Cranium expanded, maximum brain size 750 cc.
2. Less erect posture.
3. Strong jaws and without well marked
4. Incisor and canine teeth large.
5. Limited use and no manufacture of tools.
6. Not able to speak.
1. Cranium expanded, maximum brain size 2,250 cc.
2. Fully erect posture.
4. Incisor and canine teeth reduced.
5. Extensive use and manufacture of tools.
6. Able to use spoken and written language.
1. Survival of the fittest. Darwinism can explain the survival of fittest but is unable to account for arrival of the fittest. It is difficult to suppose that small variations could have formed organs like wings and mimicry colouration which are useful only in their fully developed state.
Certain organs can be helpful to the organism only in fully developed state and what about their presence in early stages.
2. Over specialization. Tusks of elephants and the antlers of some deer have overgrown their usefulness.
3. Vestigial organs. A number of vestigial organs persisting generation after generation has no explanation according to Darwinism.
4. Darwin did not differentiate between somatic and germinal variations.