send mail to support@abhimanu.com mentioning your email id and mobileno registered with us! if details not recieved
Resend Opt after 60 Sec.
By Loging in you agree to Terms of Services and Privacy Policy
Claim your free MCQ
Please specify
Sorry for the inconvenience but we’re performing some maintenance at the moment. Website can be slow during this phase..
Please verify your mobile number
Login not allowed, Please logout from existing browser
Please update your name
Subscribe to Notifications
Stay updated with the latest Current affairs and other important updates regarding video Lectures, Test Schedules, live sessions etc..
Your Free user account at abhipedia has been created.
Remember, success is a journey, not a destination. Stay motivated and keep moving forward!
Refer & Earn
Enquire Now
My Abhipedia Earning
Kindly Login to view your earning
Support
Type your modal answer and submitt for approval
Read the passage and answer the following questions:
Three basic adaptive responses—regulatory, acclimatory, and developmental—may occur in organisms as they react to changing environmental conditions. In all three, adjustment of biological features (morphological adjustment) or of their use (functional adjustment) may occur. Regulatory responses involve rapid changes in the organism’s use of its physiological apparatus—increasing or decreasing the rates of various processes, for example. Acclimation involves morphological change—thickening of fur or red blood cell proliferation—which alters physiology itself. Such structural changes require more time than regulatory response changes. Regulatory and acclimatory responses are both reversible. Developmental responses, however, are usually permanent and irreversible: they become fixed in the course of the individual’s development in response to environmental conditions at the time the response occurs. One such response occurs in many kinds of water bugs. Most water-bug species inhabiting small lakes and ponds have two generations per year. The first hatches during the spring reproduce during the summer, then dies. The eggs laid in the summer hatch and develop into adults in late summer. They live over the winter before breeding in early spring. Individuals in the second (overwintering) generation have fully developed wings and leave the water in autumn to overwinter in forests, returning in spring to small bodies of water to lay eggs. Their wings are absolutely necessary for this seasonal dispersal. The summer (early) generation, in contrast, is usually dimorphic—some individuals have normal functional (macropterous) wings; others have much-reduced (macropterous) wings of no use for flight. The summer generation’s dimorphism is a compromise strategy, for these individuals usually do not leave the ponds and thus generally have no use for fully developed wings. But small ponds occasionally dry up during the summer, forcing the water bugs to search for new habitats, and eventuality that macropterous individuals are well adapted to meet. The dimorphism of micropterous and macropterous individuals in the summer generation expresses developmental flexibility; it is not genetically determined. The individual’s wing form is environmentally determined by the temperature to which developing eggs are exposed prior to their being laid. Eggs maintained in a warm environment always produce bugs with normal wing, but exposure to cold produces micropterous individuals. Eggs producing the overwintering brood are all formed during the late summer’s warm temperatures. Hence, all individuals in the overwintering brood have normal wings. Eggs laid by the overwintering adults in the spring, which develop into the summer generation of adults, are formed in early autumn and early spring. Those eggs formed in autumn are exposed to cold winter temperatures, and thus produce micropterous adults in the summer generation. Those formed during the spring are never exposed to cold temperatures, and thus yield individuals with a normal wing. Adult water bugs of the overwintering generation brought into the laboratory during the cold months and kept warm, produce only macropterous offspring.
The passage supplies information to suggest that which one of the following would happen if a pond inhabited by water bugs were to dry up in June?
The number of developmental responses among the water-bug population would decrease
Both micropterous and macropterous water bugs would show an acclimatory response
The generation of water bugs to be hatched during the subsequent spring would contain an unusually large number of macropterous individuals
The dimorphism of the summer generation would enable some individuals to survive
Correct answer is [d]. This indicates towards the answer ' But small ponds occasionally dry up during the summer, forcing the water bugs to search for new habitats, and eventuality that macropterous individuals are well adapted to meet.The dimorphism of micropterous and macropterous individuals in the summer generation expresses developmental flexibility'.
Report error
Please Wait..
Access to prime resources