Chapter 1
Evolution
1) Choose the correct answer-
(I ) Name the process through which modern breed of pet dog was acquired-
(a) Natural selection (c) Juvenile selection
(b) Artificial selection (d) Work selection.
Ans: – a.) Natural selection
(ii) Forelimbs of dog and sheep are for walking, whale for swimming and that of bat for flying. All these are examples of-
(a) Analogous (c) Undeveloped organ
(b) Homologous (d) all above.
Ans: – c. Homologous.
(iii) Which of the following are analogous structures-
(a) Wings of bat and butterfly
(b) Gills of prawn and fish
(c) Thorns of bougainvillea and tendrils of bottle gourd
(d) Wings of bat and legs of horse.
Ans: – a. Wings of bat and butterfly.
(iv) While proposing his theory, Darwin was influenced by-
(a) The observations of his voyage. (b) Cell theory
(c) Law of genetics of Mendel (d) None of the above.
Ans: – a. The observation of his voyage.
2) Fill in the blanks
(i) A group of organisms which can interbreed sexually producing viable off-springs is known as …….a species…………………..
(ii) Difference among beaks of finches show the ……. evolution……………. among them.
(iii) Some bacteria can grow in the medium containing streptomycin (antibiotic). The reason behind this is ……. resistance developed in bacteria…………..
3) There are different types of bacteria growing in our intestines. They are capable of reproducing mainly asexually (without involvement of sex cells) very fast about once every 20 minutes. During reproduction variations emerge and some of these variations are heritable, that is, they pass from one generation to the next. Due to this, we find variations in populations of bacteria growing in our intestines. This is how they evolve very fast. We often consumeantibiotics that kill most of these bacteria but some always remain on which the antibiotics may have no effect. This is simply because of the variations present among the bacteria. Bacterial types on which antibiotics have no effect are said to be antibiotic resistant.
Answer the following on the basis of this information.
a) Justify that natural selection is responsible for evolution among bacterial population.
Ans: – Different types of bacteria present in our body participate in asexual reproduction by which any bacteria can reproduce once in 20 minutes. As a result of this reproduction variation are seen in them.
b) During which process does variation arise in bacteria?
Ans: – By reproduction variation are arise in bacteria. Its passes from one generation to the other generation by this process.
c) What is the role of variation in the process of evolution? Use the example of reproduction of bacterial population to elaborate your answer.
Ans: – As a result of reproduction variation are emerged in bacteria and this variation are transfer from one generation to the other generation. In spite of taking some antibiotics sometimes bacteria remain in our body which are mutated according to the situation.
d) “Evolution can be slow or very fast”. Give an example each of slow and fast process of evolution.
Ans: – Evolution can be slow or very fast sometimes. But most of the case evolution happened through out the generation. In case of human, we have read there are various changes happened throughout the generation which was proved by scientists.
e) Does a better adapted population of bacteria become antibiotic resistant? Give reasons for your answer.
Ans: – Sometimes a better adapted population of bacteria become antibiotics resistance as by reproduction variation are emerged and this transfer from one generation to other generation. And for this reason, this variation makes it more resistance from antibiotics.
4) Write two differences between natural and artificial selection.
Ans: – The natural selection is seen for all population. While the artificial are not which are seen specifically selected species. And the artificial selection doesn’t make huge impact but natural selection does.
5) What do we come to know from the theory of evolution as proposed by Darwin and Wallace?
Ans: – The theory of evolution proposed by Darwin and Wallacehad make an important evolution in the science field in this they stated that the natural selection is responsible for the evolution. This natural selection is seen almost every specie’s which are present throughout the generation.
6) What are the main points of the theory of evolution of organisms?
Ans: – The main things of the theory of evolution of organisms is the natural selection. In which Darwin described that which are capable of staying in changing situation will be remain throughout the generation otherwise it will be stopped.
7) What is the role of selection and adaptation in the process of evolution?
Ans: – Selection and adaptation are the main process by which all the creatures as we seen in this changing world are able to survive. Selection is process by which any substance is capable of living throughout the generation and the difference resistance are adapted in their body by which they can remain.
8) Observe the figure and say whether it represents homologous or analogous structures? Justify your answer.
Ans: – From the images of this plant we can say analogous structure are observed.
9) (i) Observe the branched tree of evolution given in the figure and find out the closest relative of humans.
Ans: – The closest relative of humans is Chimpanzee.
(ii) Write the names of two organisms, by observing the figure, that show maximum similarity. Also write the names of two organisms that show maximum differences.
Ans: – The maximum similarities that are seen between the organism’s human and Chimpanzee. And the maximum difference is seen in the organisms are cow and platypus.
(iii) What do you understand from the figure about evolution of organisms shown there? Write a brief description to elaborate your answer.
Ans: – From the tree we can understand that all the organisms are from the similar group that are mammals. As we all know the mammals are fed from their mother from birth for sometimes. In this there are some similarities are also be seen between the like human and chimpanzee which show’s some similar property. And the dogs and horse have four legs. The rats and mouse seen same characteristics. So, in this tree’s we seen that there are some similar in some case and differ also.