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Published on: 28/05/2021
QB365 Provides the HOT Question Papers for Class 12 Biology, and also provide the detail solution for each and every HOT Questions. HOT Questions will help to get more idea about question pattern in every exams and also will help to get more marks in Exams
Download CBSE Class 12th Standard CBSE Biology question papers, sample papers, important questions, and previous year solved papers in PDF format. Get free study materials, NCERT solutions, and exam preparation resources for Class 12th Standard CBSE Biology
Questions + Answers key
Take MCQ Biology Test1.
When and where did Neanderthal man live? What was his brain capacity? Mention the advancements he showed over Homo erectus?
2.
Evolution is a change in gene frequencies in a population in response to changes in the environment in a time scale of years and not centuries. Justify this statement with references to DDT. How does the theory of Hugo de Vries support this?
3.
A population is exhibiting genetic equilibrium answer the following with regard to this statements.
(i)Explain the above statements
(ii)Name the underlying principle.
(iii)Name any two factors which could upset the genetic equilibrium(i.e allele frequency) of the population.
4.
Give reasons for the following statements:
(a) Placental wolf and Tasmanian wolf exist sharing the same habitat.
(b) Special kind of evolution has brought the similarity as seen in fins of fishes and flippers of dolphins Name the kind of evolution also.
(c) Study of fossils provide us direct and most reliable evidences of evolution.
5.
Name the specific term being used for the following statements:
(a) The chance elimination of the genes of certain traits when a section of population migrates or dies of natural calamity is referred to as ____________.
(b) Change in the morphology and number of chromosomes at times is referred to as____________.
(c) A small group of human being leave their homes to find a new settlement. This results in the formation of a different genotype in the settlement. It is called____________.
6.
Can the host-parasite relationship provide evidence for evolution? Explain.
7.
State in what ways Stanely Miller simulated the conditions of:
(i) primitive atmosphere on earth.
(ii) energy source at the time of origin of life, and
(iii) formation of organic molecules of life to prove the theory of chemical evolution?
8.
The study of
(i) fossils of dinosaurs
(ii) forelimbs of Cheeta, bat and human
(ii) thorns of Bougainvillea and tendril of Cucurbita shows that evolution of life forms has indeed taken place on earth. Explain.
9.
Anthropogenic action can hasten evolution. Explain with the help of a suitable example.
1.
1. Near east and central Asia between 1, 00,000 - 40,000 years back.
2. Brain capacity is around 1400 cc.
3.buried their dead & used hides to protect their body.
2.
1.The use of DDT for the first time resulted in the death of maximum number of mosqutoes but a few survived. Later on it was found that mosqutoes continue to servive and reproduce even in the presence of DDT. It is because the sustained use of DDT made the mosquitoes resistant to DDT within a few years due to variation and change in gene frequencies in their population inrelation to changes in environment within a time span of few years only.
2. According to Hugo de Vries the evolution is caused by a single step large mutation arising out suddenly in a population.
3.
(i)The relative frequency of allels of sexually reporting organisms in a given populations remains constant from generation to generation.
(ii)Hardy-Weinberg equilibrium
(iii)Gene mutations, recombination , gene flow, genetic drift and natural selection.
4.
(a) Placental wolf and Tasmanian wolf exist sharing the same habitat in different continents (former in Asia and the latter in Australia) because these species show parallel evolution. These have shown independent development of similar characters in two animal groups of common ancestory living in similar habitats of different continents.
(b) Convergent evolution has brought the similarity in the fins of fishes and flippers of dolphins because these are analogous structures. These are quite different in fundamental structure and embryonic origin but have been modified to perform same function in aquatic habitats.
(c) Study of fossils (palaeontology) deals with the actual organisms or their parts that lived in the past. Therefore, it provides us direct and most reliable evidence of evolution.
5.
(a) Genetic drift
(b) Chromosomal aberrations
(c) Founder effect.
6.
Yes. Ostrich and rhea, two flightless birds placed in separate orders, are parasitised by an identical species of tapeworm and two identical species of feather mites. These parasites do not occur in any other bird. This similarity of parasites shows that the ostrich and rhea birds have evolved from a common ancestor.
7.
(i) Stanley Miller designed a glass apparatus (Fig. 7.11) comprising a gas flask, a condenser, and a liquid flask interconnected with tubes and fitted with sources of energy. This apparatus simulated the conditions on the primitive earth, including a reducing atmosphere and an ocean.
(ii) He provided energy, for the interaction of gases present as mixture in the apparatus, in the form of electric sparks of 75,000 volts from electrodes in the gas flask.
(iii) Miller circulated, in this apparatus, a mixture of methane, ammonia and hydrogen gases in the ratio of 2 : 2 : 1 and water vapour at 800\(^{o}\)C. After electric spark, the gas were condensed in a narrow tube and passed through a liquid flask. Here, energy was provided as heat with an electric heater. This resulted in mixture of small organic molecules in the gas flask (atmosphere) and were carried by condensation (rain) to the liquid flask (ocean).
8.
(i) Fossils of dinosaurs provide palaeontological evidences for evolution.
They represent extinct organisms.
A study of fossils indicates the geological time period in which these organisms existed and that life forms varied over time.
(ii) Forelimbs of cheetah, bat, whale and humans provide evidences of evolution from comparative anatomy and morphology.
The similarity in the anatomy of these organs indicates that the same structure has developed along different directions as adaptations to different needs; homology indicates common ancestry.
(iii) Thorns of Bougainvillea and tendril of Cucurbita also provide evidences from comparative anatomy and morphology.
They represent homology (both are stem modifications) and homology represents common ancestry and divergent evolution.
9.
1.Anthropogenic actions, i.e. human activities have been found to enhance evolution.
e,g. 1.Use of DDT has resulted in evolution of DDT-resistant mosquitoes.
2.Evolution of antibiotic or drug-resistant microbes.
3. When DDT was used fo the first time, many mosquitoes died, but a few survived.
4. These few mosquitoes showed resistance to DDT and reproduced in the presence of DDT.
5. Most of the offspring were also resistant to DDT.
6. Hence, the mosquito populations of today consist mainly of DDT-resistant mosquitoes and hence, DDT is not effective.
7. In the absence of DDT, these DDT-resistant mosquitoes had no advantage over those mosquitoes, which were sensitive to DDT.
8. This is an example of evolution due to anthropogenic activities.
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