Home
Class 12
BIOLOGY
Excessive and continous use of pesticide...

Excessive and continous use of pesticides has resulted in evolution of some new species of pests. Explain what must have led to this. What is this type of evolution called ?

Text Solution

Verified by Experts

Farmers spray higher doses of pesticides and excess use of herbicides which resulted in selection of resistant varieties in a much lesser time scale.
Evolution is not a directed process ir the sense of determinism. It is a stochastic process based on chance events in nature and chance mutation in the organisms. This type of evolution is called 'ntural selection'.
Promotional Banner

Topper's Solved these Questions

  • XII BOARDS

    XII BOARD PREVIOUS YEAR PAPER ENGLISH|Exercise SECTION-E|6 Videos

  • XII BOARDS

    XII BOARD PREVIOUS YEAR PAPER ENGLISH|Exercise [OUTSIDE DELHI : SET-II] SECTION -A|2 Videos

  • XII BOARDS

    XII BOARD PREVIOUS YEAR PAPER ENGLISH|Exercise OUTSIDE DELHI SET III|8 Videos

  • SAMPLE PAPER 2019

    XII BOARD PREVIOUS YEAR PAPER ENGLISH|Exercise Section E Part B|3 Videos

Similar Questions

Explore conceptually related problems

Name and explain the phenomenon that has resulted in the evolution of such diverse species in the region.

Mention the specific geographical region where these organisms are found. Name and explain the phenomenon that has resulted in the evolution of such diverse species in the region. Explain giving reason the existence of placental wolf and Tasmania wolf sharing the same habitat.

Study the figures below and answer the following : (a)Mention the specific geographical region where these organisms are found. (b)Name and explain the phenomenon that has resulted in the evolution of such diverse species in the region. (c )Explain giving reasons the existance of placental wolf and Tasmanian wolf sharing the same habitat.

(a) Define a universal indicator . Mention its one use. (b) Solution A gives pink colour when a drop of phenolphthalein indicator is added to it. Solution B gives red colour when a drop of methyl orange is added to it. What type of solutions are A and B which one of the solutions A and B will have a higher pH value ? (c) Name one salt whose solutions has pH more than 7 and one salt whose solution has pH less than 7.

Name the type of evolution that has resulted in the development of structures like wings of butterfly and bird. What are such structures called ?

A student is running at her top speed of 5.0 m s^(-1) , to catch a bus, which is stopped at the bus stop. When the student is still 40.0m from the bus, it starts to pull away, moving with a constant acceleration of 0.2 m s^(-2) . a For how much time and what distance does the student have to run at 5.0 m s^(-1) before she overtakes the bus? b. When she reached the bus, how fast was the bus travelling? c. Sketch an x-t graph for bothe the student and the bus. d. Teh equations uou used in part (a)to find the time have a second solution, corresponding to a later time for which the student and the bus are again at thesame place if they continue their specified motions. Explain the significance of this second solution. How fast is the bus travelling at this point? e. If the student s top speed is 3.5 m s^(-1), will she catch the bus? f. What is the minimum speed the student must have to just catch up with the bus?For what time and what distance dies she have to run in that case?

XII BOARD PREVIOUS YEAR PAPER ENGLISH-XII BOARDS-COMPTT
  1. What was the challenge for production of insulin using rDNA techniques...

    Text Solution

    |

  2. Name the organism from which the 'cry' genes are isolated. Mention wit...

    Text Solution

    |

  3. Excessive and continous use of pesticides has resulted in evolution of...

    Text Solution

    |

  4. Explain with the help of two examples how certain plants have evolved ...

    Text Solution

    |

  5. What type of organs eye of an Octopus and that of a human called? Give...

    Text Solution

    |

  6. With the revolution in information technology, now it has become an in...

    Text Solution

    |

  7. (a) Explain the steps involved in in-vitro fertilisation popularly kno...

    Text Solution

    |

  8. (a) State one difference and one similarity between geitonogamy and ...

    Text Solution

    |

  9. (a) Hershey and Chase carried their experiment in three steps : infect...

    Text Solution

    |

  10. Taking an example of white-winged moths and dark-winged moths of Engla...

    Text Solution

    |

  11. (a) Write the percentage of land area that was covered by forests by t...

    Text Solution

    |

  12. (a) Comment on the pattern in which all communities undergo a change i...

    Text Solution

    |

  13. Name the condition in vertebrates where the body attacks self-cells.

    Text Solution

    |

  14. Write the function of a Bioreactor.

    Text Solution

    |

  15. A colour blind boy is born to a couple with a normal colour vision. Wr...

    Text Solution

    |

  16. Mention any two conditons that enhance the chances of syngamy in organ...

    Text Solution

    |

  17. a) Write the conclusin drawn by Griffith at the end of his experiment ...

    Text Solution

    |

  18. Plants like potato, sugarcane do not require seeds for producing new p...

    Text Solution

    |

  19. Explain the role played by predators in a community.

    Text Solution

    |

  20. Name the first antibiotic discovered and by whom.

    Text Solution

    |