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The kind of evolution in which two species of different geneology come to resemble one another closely, is termed as
Progressive evolution is development of organisms with more elaborate and specialized structures from those having less elaborate features e.g. amphibians from reptiles .Retrogressive or degenerative evolution is development of simpler forms from more complex ones. Such evolution has occurred in case of vestigial organs, parasitic forms, and in reduction of overspecialized structures such as wings in flightless birds. Parallel evolution is formation of similar traits in related groups of organisms independently due to similar requirement e.g. running of two toed deer and one toed Horse. Evolution of wings in insects and birds serve as example of convergent evolution
Identify the correct sequence in which the following substances have appeared during the course of evolution of life on earth
Elements present on the surface of the earth as well as in the early atmosphere combined to produce simple and compound molecules. Atmospheric elements produced molecules of Hydrogen, Nitrogen, Water, CO, CO2, Ammonia, methane etc. UV-radiations, cosmic rays, lightening and heat made these to react amongst themselves and produce organ compounds like sugars, fatty acid, glycerol and amino acids.
Which one of the following sets includes only the vestigial structures in man?
Vestigial organs are those organs which are non-functional in the possessor but were functional in their ancestors and in related animals. Human beings possess many vestigial organs like nictitating membrane in the eye, vermiform appendix at the end of caecum, coccyx and tail muscles, non-functional muscles of the pinna, wisdom teeth, segmental muscle of abdomen and nipples in males.
Extremities, tail and ear are relatively shorter in animals living in cooler regions as compared to those inhabiting warmer zones. This is
This is known as Allen's rule.
In the evolution of man, several changes occured in the ancestral characters. Which one of the following changes is irrelevant in this context ?
Change of diet from fruits, hard nuts and roots to softer food encouraged settled human life.
Which one of the following is regarded as the direct ancestor of modern man ?
Australopithecus appeared in early Pleistocene. Homo habilis had a cranial capacity of 700–800 cc.
Common origin of man and chimpanzee is best shown by
Cranial capacity shows an increase form apes to man which indicates increase in intelligence.
Which one of the following statements about fossil human species is correct?
Homo erectus was a large hominid. It had a length of about 150 to 170 cm (5 to 5.5 feet) with a low but distinct forehead strong browridge and a brain capacity of about 1000 cc. Homo erectus was social and living in tribes of 20 to 50 people and thus had a successful and complex culture. It became widespread throughout the tropical and temperate old world.
Which one of the following includes all homologous organs ?
Homologous organs are theorgans having similar structural plan and origin but performing different functions. Analogous organs perform similar function but have different structural and developmental origin e.g. wings of birds, wings of bat and wings of insects are analogous organs.
In general, in the developmental history of a mammalian heart, it is observed that it passes through a two-chambered fish-like heart, three-chambered frog-like heart and finally to four-chambered stage. To which hypothesis can this above cited statement be approximated?
Hardy - Weinberg law is the principle of genetic equilibrium according to which in the absence of external environmental disturbances, a randomly mating population remains in genetic equilibrium. Lamarck postulated the theory of inheritance of acquired characters. Mendelian principles explained the inheritance of genetic characters from one generation to another.
Genetic drift operates only in
Genetic drift can operate only on smaller populations where its fluctuation can be observed in the proportion of allele distribution in the presence of external disturbances. Genetic drift is the random change in allele number and frequency in a gene pool.
The age of the fossil of Dryopithecus on the geological time scale is
Dryopiihecus lived about 20-25 million years ago. Dryopithecus had the combined characters of great apes, old world monkeys and maa. The main structuracharacteristics of Dryopithecus are broad jaws, large canines, semi-erect walking, 5 cusped molars and absence of brow ridges.
Life cannot originate from inorganic materials at present because of
Synthesis of organic molecules from simple molecules is no longer possible because of the oxidizing atmosphere.
Diversity in the type of beaks of finches adapted to different feeding habits on the Galapagos Islands, as observed by Darwin, provides evidence for
Nature select those set of characters that are best adapted to the environment. This has resulted in the great diversity seen in the population of finches.
Which one of the following statements is correct?
Cro-Magnon fossils have been found in Europe. Neanderthal man is a transitional stage. Australopithecus appeared in early Pleistocene.
Which is not a vestigial part in humans?
Human body contains about 180 vestigial organs coccyx, third molars (wisdom teeth) and muscles of abdomen etc.
During organ differentiation in Drosophila an organ is often modified to another organ such as wings could be replaced by legs. Genes responsible for such metamorphosis are called
Homeotic genes are the group of genes involved in the embryonic development and control the pattern of body formation. Alleination in these gene found in flies like Drosophila result in development of legs in place of wings.
Homo sapiens evolved during
Oligocene is masked by the rise of monkeys and apes. Miocene is masked by appearance of man like apes. Pliocene is characterized by origin of man.
Which of the following primate is the closest relative of humans?
Chimpanzees and gorillas are our closest relatives among the living primates
Which one of the following features is closely related with the evolution of humans?
Loss of a prehensile tail is associated with the gradual development of errect posture and bipedal gait.
Darwin’s finches provide an excellent evidence in favour of evolution. This evidence comes from the field of
Biogeography is the study of geographical distribution of organisms. Paleontology is the study of past life based on fossils and fossil impressions. Anatomy is the study of internal structure. Embryology is the study of development of embryo from zygote till it becomes an offspring.
Similarities in organism with different genotype indicates
Microevolution is a series of changes within a species due to gene mutations and accumulation of variations.
Macroevolution is evolution in which taxa higher than the level of species are formed due to morphological and cytological changes. Formation of different functional forms of a basically similar structure is called divergent evolution.
Which of following is closest relative of man?
Chimpanzee is the closest relative of man. Banding pattern of human chromosome number 3 and 6 are remarkably similar to that of chimpanzee indicating common origin for both.
Which of the following is correct order of evolutionary history of man?
Peking man had a cranial capacity of about 1000cc. Heidelberg man is regarded as ancestor of Neanderthal man. Cro-Magnon is the form of modern man living in Europe.
Darwin’s theory of pangenesis shows similarity with theory of inheritance of acquired characters then what shall be correct according to it?
According to both the views, 'something' is passed from parent to offspring which causes development of specific characters.