1) A volcano erupted on an island. The ash released from the volcano changed the
ID: 151554 • Letter: 1
Question
1) A volcano erupted on an island. The ash released from the volcano changed the acidity (pH) of the soil from the level it had been for hundreds of years. This significant change resulted in new environmental pressures on species in the soil. Which of the following is a likely outcome of these pressures? a) Some species will disappear from the soil because they do not have individuals with traits that allow them to survive in more acidic soil b) Only some species will generate the needed mutations to adapt to the change in pH; other species will become extinct c) Most species gain additional genetically-based traits, and this increase in complexity allows them to live in the more acidic soil c) Inodhjidtuals in each species willevolve the traits necessary to survive under these new conditions 2) A ship that had been used for many years in arctic exploration was sold and moved to a harbor in the warm waters of the Caribbean. Worms that had lived on the ship bottom crawled off in the warm waters and attempted to attach to other ships in this tropical area where there were no similar worms. Some of the worms were able to survive and reproduce. What would you expect to happen to this group of worms over many generations in this new environment? a) The worms will mate and produce offspring just as they did in their previous b) The worms will gain new, more complex traits through natural selection that will help c) Worms possessing genetic variations that help them to survive and thrive in the new d) The mutation rate will increase in this group of worms in order to promote evolution. environment, and the group's traits will likely remain unchanged after many generations them better adapt to the warmer waters because natural selection leads to more complex and better adapted organisms environment will leave more offspring than others lacking those traits. Over time, the proportion of the worm population with these adaptive traits will likely increase. 3) Bacillus thuringienses bacteria produce a natural insecticide (Bt). Since Bt has beern commercialized and used widespread, Bt resistance among insects has increased. Why is this occurring? a) Individual insects that have mutations providing resistance to Bt can survive in the presence of Bt. The survivors pass this Bt resistance on to their offspring b) Bt-resistant insects increase in the population by chance. There are so many insects that some of them are resistant to each type of insecticide c) In the presence of Bt, individual insects evolve to become Bt resistant. d) Natural selection causes insects to generate genes providing resistance to BtExplanation / Answer
1) B
some species will adapt to the changes i.e acidic soil conditions while other who had not adapted will get extinct.
Those who have adapted to the new envronmental pressure because of the acquired mutations that was needed to survive in new acidic soil, those who were unable to do so got extinct.
2) c
Worms possesing genetic variations that helped them to survive and thrive well in new environmental conditions(warmer waters), these will inturn leave more offsprings than other who are lacking these traits. So their chances of selection is more than other worms, Over The time the proportion of worms possesing these traits will increase.
3) a
individual insects that are resistant to Bt can survive in presence of Bt and pass their genes to their offsrpings.
Chances of passing the resistant genes via gene transfer such as horizontal gene transfer is more,that will lead to spread of this gene in much more population making them resistant as well.
4) b
Some bacteria had the traits that allowed them to be selected by the application of the anti-microbials. They produced offsprings carrying the same trait.
But initially they took some time to adapt to the anti-microbial exposure, at that time their growth declines. once they acquired/developed the resistant traits then their population begin to rise again.
5) c
Bucks that were having smaller antlers were having less chances of getting hunted due to more hunting of longer antler deers, So they have more chances of reproducing . They passed their genes to their offsprings and therefore this trait has incresed in number , providing a survival advantage as well over the hunting.
6) a
The variations are random, the variation in mouth part will still remain the same, since flowering plants are also evolving, this is a type of cooevolution which will go hand in hand.
7) d
These traits evolve in response to environmental challenges, ensuring that the population will survive any changes in its habitat.
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