Occur rence of endemic species in South America and Australia is due to
These areas are geographically isolated from other continents by the oceanic barrier which has prevented uniform distribution of fauna.
Half life period of C is about
In 5000 years a given amount of radioactive carbon would decay to half initial concentration.
Which of the following are homologous organs?
Homologous organs are those organs, which have the same origin and similar basic structure but may differ in external appearance and function. Wings of birds and pectoral fins of fishes are an example of the homologous organs.
There is no life on moon due to the absence of
Water is an essential constituent of cytoplasm of all living organisms it helps in distribution of substances within the organism elimination of waste products, body temperature maintenance etc. It is absent on moon. Anaerobic organisms can live in the absence of O2. Light and temperature are already known to exist on moon.
Sequence of which of the followings is used to know the phylogeny?
rRNA occurs in side ribosomes and involved in protein synthesis, mRNA brings coded information from DNA to form polypeptides. tRNA takes part in transferring amino acids from cellular pool to episomes for polymerization to form polypeptides.
Carl Woese gave the theory of life based on his discovery that the genes encoding ribosomal RNA are ancient and distributed over all lineages of life with little or no gene transfer. Therefore rRNA are commonly used to infer phylogeny.
In which era reptiles were dominant?
The Mesozoic era is the era during which reptiles were dominant. It includes three periods: Triassic (240 million years ago), Jurassic (195 million years ago) and Cretaceous (135 million years ago). Origin of dinosaurs occurred during the triassic period. During the Jurassic period, lizards, crocodiles and alligators originated. Dinosaurs became large and reptiles were dominant during this period. During the cretaceous period, dinosaurs got extinct.
Two different species can not live for long duration in the same niche or habitat. This law is
Gause's hypothesis states that two different competing species cannot coexist together for a long in the same niche, one has to get eliminated by the other competing species, if they do coexist, then they do so as a result of niche differentiation, i.e. differentiation of then realized niches.
Which of the following is most important for speciation ?
The phenomenon of development of a new species from pre-existing one is called speciation. Reproductive isolation is the prevention of interbreeding between the populations of two different species. It maintains the characters of the species but can lead to the origin of new species.
According to fossils discovered up to present time origin and evolution of man was started from
Africa is often called as the cradle of man.
In which condition the gene ratio remains constant for any species?
Mutation is any random sudden heritable change occurring in the genetic material. Sexual selection refers to selection of a mate by an organism.
In recent years, DNA sequences (nucleotide sequence) of mt-DNA and Y chromosomes were considered for the study of human evolution, because
In human cells, chromosomes are present in both nucleus as well as mitochondria. Most of the proteins in humans are encoded by the nuclear genome but mitochondrial DNA plays a significant role too. Mitochondria contain their own DNA that is separate from the nuclear DNA. mtDNA shows maternal inheritance. The nuclear DNA which is equally inherited from both the mother and the father, mitochondrial DNA (mtDNA) is inherited only from the mother. This makes mitochondrial DNA particularly interesting and useful for human evolutionary studies. Normally, mtDNA is identical to that of the mother. But like all DNA molecules, mtDNA molecules also undergo mutations that change the sequence slightly. Thus, mtDNA of a daughter cell would be different from the mtDNA of its mother and this difference is proportional to the amount of time that has passed and therefore proves to be very useful for studying human evolution. Similar is the case with Y chromosome that is inherited from the father and, therefore, follows a similar evolutionary pattern like mtDNA.
So, the correct answer is option C.
Which one of the following sequences was proposed by Darwin and Wallace for organic evolution ?
According to Darwinism there is differential reproduction, followed by struggle for existence, suitable variations are selected by nature-natural selection.
Industrial melanism is an example of
The replacement of grey coloured moth by dark coloured melanic species due to industrial smoke is called industrial melanism. Initially on the lichen covered tree trunks, the mutant moths was more conspicuous due to its black colouration and was therefore more susceptible to predation by birds. The large scale burning of coal during industrial revolution resulted in the deposition of sooty particulate matter on tree trunks. Hence the grey coloured moths became more conspicuous to predatory birds. Thus the population of black moths increased considerably.
In a random mating population in equilibrium, which of the following brings about a change in gene frequency in a non-directional manner? 
Migration refers to the movement of individuals into and out of population. Mutation refers to random and sudden heritable variations or changes arising in the genetic constitution.
Convergent evolution is illustrated by
Independent formation of functionally similar structures by unrelated organism is called convergent evolution.
Which one of the following describes correctly the homologous structures ?
Those organs which have a common origin and are built on the same anatomical pattern, but perform different functions and are modified accordingly.
Darwin in his 'Natural Selection Theory' did not believe in any role of which one of the following in organic evolution ?
In any population , there is always competition for space and food resources.
Random genetic drift in a population probably results from
Genetic drifts occurs only in small isolated population.
Presence of gills in the tadpole of frog indicates that
Amphibians have moved onto terrestrial habitat but they still need to go back to water for reproduction. The presence of gills in tadpole indicate that amphibians have evolved from fishes. Fishes are completely aquatic so the other three options are incorrect.
What kind of evidence suggested that man is more closely related with chimpanzee than with other hominoid apes?
DNA from sex chromosomes, autosomes and mitochondria reflect the entire genomic limit. Chromosome morphology is only partial.
Age of fossils in the past was generally determined by radio-carbon method and other methods involving radioactive elements found in the rocks. More precise methods, which were used recently and led to the revision of the evolutionary periods for different groups of organisms, includes
ESR, Electron Spin Resonance measures number of charges occupying deep traps in crystal band gap.
Electron Paramagnetic Resonance (EPR) or Electron Spin Resonance (ESR) is a spectroscopic technique which detects species that have unpaired electrons, generally meaning that the molecule in question is a free radical if it is an organic molecule, or that it has transition metal ions if it is an inorganic complex. Because most stable molecules have a closed-shell configuration without a suitable unpaired spin, the technique is less widely used than nuclear magnetic resonance (NMR). The EPR was first discovered in Kazan State University by Soviet physicist Yevgeniy Zavoyskiy in 1944
According to Oparin, which one of the following was not present in the primitive atmosphere of the earth
According to Oparin, the atmosphere of calmative earth was reducing because its atoms were most numerous and most reactive. Free oxygen was not present in significant amount.
Large quantities of H2, N2, water vapour, CO2, CH4 and NH3 were present.
Which of the following is the relatively most accurate method for dating of fossils?
Electron Spin Resonance method is the most accurate method for dating of fossils.
Animals have the innate ability to escape from predation. Examples for the same are given below. Select the incorrect example.
Animals resist predation by cryptic coloration deceptive marking, behavioural defenses and possession of mechanical or chemical defenses. Examples are colour change in Chameleon Enlargement of body size by swallowing air in potter fish, Melanism in moths.
There are two opposing views about origin of modern man. According to one view Homo erectus in Asia were the ancestors of modern man. A study of variation of DNA however suggested African origin of modern man. What kind of observation on DNA, variation could suggest this?
According to Neodarwinism variation is the root cause of evolution.