Variations in a Population
Variations in a Population
Variation refers to the changes observed in phenotype, and genotype, the individuals in a population or between parents and their offspring. Suppose, twelve red beetles live in bushes with green leaves, their population grows by sexual reproduction and generates variations. In a population of beetles, variation may occur through the following means:
Case I
During reproduction, a colour variation may arise, which may lead to the production of a green beetle. It passes the green colour to its progeny. Crows cannot see green coloured beetles on green leaves, so they cannot eat them. Hence, the grey ones continues to be eaten and number of green beetles increases in the population. In this case, variation gives a survival advantage. The natural selection exerted by the crows will lead to the survival of green beetles.
Case II
In another situation, a colour variation arising during reproduction may result in a blue beetle instead of grey and all its progeny will be blue. Crows can see both blue and grey coloured beetles and therefore, can eat them. At the outset, there are a few blue beetles and more of grey beetles. Suddenly, an elephant stumps on the bushes and kills most of the beetles. By chance, the few beetles that survived were mostly blue, which gradually increase in number. This change in the frequency of some genes in a population which provides diversity without any survival disadvantage is called genetic drift.
In a forest ________________ cannot see green coloured beetles on green leaves, so they cannot eat them. | |||
| Right Option : A | |||
| View Explanation | |||
This change in the frequency of some genes in a population which provides diversity without any survival disadvantage is called _________________ . | |||
| Right Option : B | |||
| View Explanation | |||
Which of the following are correct ? (a) Variation refers to the changes observed in phenotype, and genotype, of the individuals in a population or between parents and their offspring. (b) During reproduction variation of colour may arise, which may lead to the production of a green beetle. | |||
| Right Option : C | |||
| View Explanation | |||
Students / Parents Reviews [10]
My experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Ayan Ghosh
8thAbhyas is a complete education Institute. Here extreme care is taken by teacher with the help of regular exam. Extra classes also conducted by the institute, if the student is weak.
Om Umang
10thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
8thBeing a parent, I saw my daughter improvement in her studies by seeing a good result in all day to day compititive exam TMO, NSO, IEO etc and as well as studies. I have got a fruitful result from my daughter.
Prisha Gupta
8thI have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
Yatharthi Sharma
10thMy experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.
Shivam Rana
7thAbout Abhyas metholodology the teachers are very nice and hardworking toward students.The Centre Head Mrs Anu Sethi is also a brilliant teacher.Abhyas has taught me how to overcome problems and has always taken my doubts and suppoeted me.
Shreya Shrivastava
8thIt has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
Barkha Arora
10thIt was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Cheshta
10thAbhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
