Long Answer Type(a) Name the primates that lived about 15 million years ago. List their characteristic features.
(b) (i) Where was the first man-like animal found?
(ii) Write the order in which Neanderthals, Homo habilis and Homo erectusappeared on earth.
State the brain capacity of each one of them.
(iii) When did modern Homo sapiens appear on this planet?
Short Answer Type(a) Select the homologous structures from the combinations given below :
(i) Forelimbs of whales and bats
(ii) Tuber of potato and sweet potato
(iii) Eyes of octopus and mammals
(iv) Thorns of Bougainvillea and tendrils of Cucurbita
(b) State the kind of evolution they represent.
Since the origin of life on the earth, there were five episodes of mass extinction of species.
(i)How is the 'Sixth Extinction', presently in progress, different from the previous episodes?
(ii)Who is mainly responsible for the 'Sixth Extinction''?
(iii)List any four points that can help to overcome this disaster.
Darwin's theory of natural selection is a process in which the organisms which have favourable variations in order to survive in the changed environment are selected by the nature to continue their generations and the rest fail to survive. Industrial melanism also showed the same case as was explained by Darwin’s theory of natural selection.
Industrial melanism - In England, it was noted that before industrial revolution, the number of white-winged moths was much more than that of dark melanised moth. However, after industrialisation, the number of dark moths increased. This happened because; the industrialization caused the tree trunks to become darker with deposits of soot and smoke. Hence, the dark moths increased as they escaped the predators as they were not easily visible while the white-winged ones were easily picked up. Thus, dark ones were selected by nature (natural selection) and light ones failed to survive.How do homologous organs represent divergent evolution ? Explain with the help of a suitable example.
Switch
