aras82 Posted March 7, 2009 Share Posted March 7, 2009 Extinction is a process that can depend on a variety of ecological, geographical, and physiological variables. These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions. However, the fossil record shows that extinction occurs in a surprisingly definite pattern, with many species vanishing at the same time. Which of the following, if true, forms the best basis for at least a partial explanation of the patterned extinctions revealed by the fossil record? (A) Major episodes of extinction can result from widespread environmental disturbances that affect numerous different species. (B) Certain extinction episodes selectively affect organisms with particular sets of characteristics unique to their species. © Some species become extinct because of accumulated gradual changes in their local environments. (D) In geologically recent times, for which there is no fossil record, human intervention has changed the pattern of extinctions. (E) Species that are widely dispersed are the least likely to become extinct. Quote Link to comment Share on other sites More sharing options...
crazy800 Posted March 8, 2009 Share Posted March 8, 2009 Extinction is a process that can depend on a variety of ecological, geographical, and physiological variables. These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions. However, the fossil record shows that extinction occurs in a surprisingly definite pattern, with many species vanishing at the same time. Which of the following, if true, forms the best basis for at least a partial explanation of the patterned extinctions revealed by the fossil record? (A) Major episodes of extinction can result from widespread environmental disturbances that affect numerous different species.--> seems to be the correct answer (B) Certain extinction episodes selectively affect organisms with particular sets of characteristics unique to their species.--> no reason for many species to be vanished at the same time © Some species become extinct because of accumulated gradual changes in their local environments.--> some but not most of the species. no reason to follow definite pattern (D) In geologically recent times, for which there is no fossil record, human intervention has changed the pattern of extinctions.--> a factor is given but the extent to which it is changed and how it is changed is not given (E) Species that are widely dispersed are the least likely to become extinct.--->totally irrelevant IMO A Quote Link to comment Share on other sites More sharing options...
bmlaud Posted March 8, 2009 Share Posted March 8, 2009 Agree with A Quote Link to comment Share on other sites More sharing options...
rajatmeh Posted March 8, 2009 Share Posted March 8, 2009 Imo (a) Quote Link to comment Share on other sites More sharing options...
delhiboy1979 Posted March 9, 2009 Share Posted March 9, 2009 Extinction is a process that can depend on a variety of ecological, geographical, and physiological variables. These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions. However, the fossil record shows that extinction occurs in a surprisingly definite pattern, with many species vanishing at the same time. Which of the following, if true, forms the best basis for at least a partial explanation of the patterned extinctions revealed by the fossil record? (A) Major episodes of extinction can result from widespread environmental disturbances that affect numerous different species. (B) Certain extinction episodes selectively affect organisms with particular sets of characteristics unique to their species. © Some species become extinct because of accumulated gradual changes in their local environments. (D) In geologically recent times, for which there is no fossil record, human intervention has changed the pattern of extinctions. (E) Species that are widely dispersed are the least likely to become extinct. Between A and B (as both talk about extinction of different species at the same time) I will go with A as it includes 'major' episodes. Quote Link to comment Share on other sites More sharing options...
sushkan2008 Posted March 9, 2009 Share Posted March 9, 2009 A for me too... Quote Link to comment Share on other sites More sharing options...
ricks2 Posted March 9, 2009 Share Posted March 9, 2009 C,d and E are totally out. Left with A and B In B - the statement can hold good for 1 species as well as for multiple different species holding the similar unique characteristic. Thereofre by elimination- A Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.