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Species interdependence in nature confers many benefits on the species [#permalink]
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EXPLANATION OF THE PASSAGE


Species interdependence in nature confers many benefits on the species involved, but it can also become a point of weakness when one species involved in the relationship is affected by a catastrophe.

Ok . Many species are intertwined with each other, and they have a lot of benefits from this mutual relationship. However, we do have also several drawbacks

Thus, flowering plant species dependent on insect pollination, as opposed to self-pollination or wind pollination, could be endangered when the population of insect-pollinators is depleted by the use of pesticides.

Plants depend on pollination from other animals or insects such as bees

In the forests of New Brunswick, for example, various pesticides have been sprayed in the past 25 years in efforts to control the spruce budworm, an economically significant pest.

We used pesticides to fight X but this had negative effects

Scientists have now investigated the effects of the spraying of Matacil, one of the anti-budworm agents that is least toxic to insect-pollinators.

A new compound could be be less harmful to pollinators than it was those we used 25 years ago


They studied Matacil’s effects on insect mortality in a wide variety of wild insect species and on plant fecundity, expressed as the percentage of the total flowers on an individual plant that actually developed fruit and bore seeds.


Ok Metacil was tested in the way you read above: in a certain ration. Do not need to remember in your mind. Just the location of the ratio in the passage just in case you need it to recall


They found that the most pronounced mortality after the spraying of Matacil occurred among the smaller bees and one family of flies, insects that were all important pollinators of numerous species of plants growing beneath the tree canopy of forests.

From the use of Matacil your bees and ONE family of flies were affected


The fecundity of plants in one common indigenous species, the red-osier dogwood, was significantly reduced in the sprayed areas as compared to that of plants in control plots where Matacil was not sprayed.

This specific plant if handled with the matacil had influenced the production if used


This species is highly dependent on the insect-pollinators most vulnerable to Matacil.

Red-osier heavenly depends on the pollinators that are affected a lot by Matacil

The creeping dogwood, a species similar to the red-osier dogwood, but which is pollinated by large bees, such as bumblebees, showed no significant decline in fecundity.

Another plant similar to the red osier- in the same scenario was not affected or at least in a minimum way nor the pollinators LARGE bees

Since large bees are not affected by the spraying of Matacil, these results add weight to the argument that spraying where the pollinators are sensitive to the pesticide used decreases plant fecundity.

The sentence above tell us that probably Matacil is dangerous for YOUNG bees but not Older or LARGE bees

The question of whether the decrease in plant fecundity caused by the spraying of pesticides actually causes a decline in the overall population of flowering plant species still remains unanswered.

regardless the first observations we do not have conclusive results to be certain

Plant species dependent solely on seeds for survival or dispersal are obviously more vulnerable to any decrease in plant fecundity that occurs, whatever its cause.

also plant that depends from the fecundity of other plant could be also affected. Not sure thought this is the real meaning of this portion. Kinda blurry

If, on the other hand, vegetative growth and dispersal (by means of shoots or runners) are available as alternative reproductive strategies for a species, then decreases in plant fecundity may be of little consequence.

In the scenario above, having an alternative, the fecundity could be the same

The fecundity effects described here are likely to have the most profound impact on plant species with all four of the following characteristics: a short life span, a narrow geographic range, an incapacity for vegetative propagation, and a dependence on a small number of insect-pollinator species.

The fecundity could be impacted for the reasons above


Perhaps we should give special attention to the conservation of such plant species since they lack key factors in their defenses against the environmental disruption caused by pesticide use.

Conclusion of the argument
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Re: Species interdependence in nature confers many benefits on the species [#permalink]
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EXPLANATION #1

1. Which of the following best summarizes the main point of the passage?

(A) Species interdependence is a point of weakness for some plants, but is generally beneficial to insects involved in pollination.

Not really

(B) Efforts to control the spruce budworm have had deleterious effects on the red-osier dogwood.

Just a fact and also is not related each other

(C) The used of pesticides may be endangering certain plant species dependent on insects for pollination.

Clearly the right answer. It is correct in 30 seconds once reading

(D) The spraying of pesticides can reduce the fecundity of a plant species, but probably does not affect its overall population stability.

Just a fact in details

(E) Plant species lacking key factors in their defenses against human environmental disruption will probably become extinct.

Totally out of scope
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Re: Species interdependence in nature confers many benefits on the species [#permalink]
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EXPLANATION #2


2. According to the author, a flowering plant species whose fecundity has declined due to pesticide spraying may not experience an overall population decline if the plant species can do which of the following?

(A) Reproduce itself by means of shoots and runners.

Yes true. See the portion of the passage where alternative ways of pollination can stabilize the fecundity of the plants

(B) Survive to the end of the growing season.

Out of scope

(C) Survive in harsh climates.

never mentioned the climate

(D) Respond to the fecundity decline by producing more flowers.

Never mentioned this detail about more flowers

(E) Attract large insects as pollinators.

Out of scope never mentioned
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Re: Species interdependence in nature confers many benefits on the species [#permalink]
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EXPLANATION #3


3. The passage suggests that the lack of an observed decline in the fecundity of the creeping dogwood strengthens the researchers conclusions regarding pesticide use because the

(A) creeping dogwood is a species that does not resemble other forest plants
(B) creeping dogwood is a species pollinated by a broader range of insect species than are most dogwood species
(C) creeping dogwood grows primarily in regions that were not sprayed with pesticide, and so served as a control for the experiment
(D) creeping dogwood is similar to the red-osier dogwood, but its insect pollinators are known to be insensitive to the pesticide used in the study
(E) geographical range of the creeping dogwood is similar to that of the red-osier dogwood, but the latter species relies less on seeds for reproduction

if you scan the option vertical the ONLY mentioned in the passage is that creeping dogwood is similar to the red-osier

D in 10 seconds is the right choice
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Re: Species interdependence in nature confers many benefits on the species [#permalink]
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EXPLANATION #4


4. The passage suggests that which of the following is true of the forest regions in New Brunswick sprayed with most anti-budworm pesticides other than Matacil?

(A) The fecundity of some flowering plants in those regions may have decreased to an even greater degree than in the regions where Matacil is used.

TRUE

(B) Insect mortality in those regions occurs mostly among the larger species of insects, such as bumblebees.

False

(C) The number of seeds produced by common plant species in those regions is probably comparable to the number produced where Matacil is sprayed.

Not mentioned

(D) Many more plant species have become extinct in those regions than in the regions where Matacil is used.

False

(E) The spruce budworm is under better control in those regions than in the regions where Matacil is sprayed.

Not mentioned in the passage. Matacil is the point of the argument as pollinator killer and NOT control of budworm
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Species interdependence in nature confers many benefits on the species [#permalink]
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EXPLANATION #5


5. It can be inferred that which of the following is true of plant fecundity as it is defined in the passage?

(A) A plant’s fecundity decreases as the percentage of unpollinated flowers on the plant increases.
(B) A plant’s fecundity decreases as the number of flowers produced by the plant decreases.
(C) A plant’s fecundity increases as the number of flowers produced by the plant increases.
(D) A plant’s fecundity is usually low if the plant relies on a small number of insect species for pollination.
(E) A plant’s fecundity is high if the plant can reproduce quickly by means of vegetative growth as well as by the production of seeds.

We said

They studied Matacil’s effects on insect mortality in a wide variety of wild insect species and on plant fecundity, expressed as the percentage of the total flowers on an individual plant that actually developed fruit and bore seeds.


Ok Metacil was tested in the way you read above: in a certain ratio. Do not need to remember in your mind. Just the location of the ratio in the passage just in case you need it to recall

The flowerS INCREASE due to pollination. If not, the will decrease and will not become a fruit

Therefore , the more we do not have pollination the more the fecundity DECREASE

A is correct
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Species interdependence in nature confers many benefits on the species [#permalink]
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EXPLANATION #6



6. It can be inferred from the passage that which of the following plant species would be LEAST likely to experience a decrease in fecundity as a result of the spraying of a pesticide not directly toxic to plants?

(A) A flowering tree pollinated by only a few insect species
(B) A kind of insect-pollinated vine producing few flowers
(C) A wind-pollinated flowering tree that is short-lived
(D) A flowering shrub pollinated by a large number of insect species
(E) A type of wildflower typically pollinated by larger insects


The fecundity effects described here are likely to have the most profound impact on plant species with all four of the following characteristics: a short life span, a narrow geographic range, an incapacity for vegetative propagation, and a dependence on a small number of insect-pollinator species.


The fecundity could be impacted for the reasons above

From the above clearly, C is the right choice. Remember the LEAST
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Species interdependence in nature confers many benefits on the species [#permalink]
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EXPLANATION #7


7. Which of the following assumptions most probably underlies the author’s tentative recommendation in lines 51-54?

(A) Human activities that result in environmental disruption should be abandoned.
(B) The use of pesticides is likely to continue into the future.
(C) It is economically beneficial to preserve endangered plant species.
(D) Preventing the endangerment of a species is less costly than trying to save an already endangered one.
(E) Conservation efforts aimed at preserving a few well-chosen species are more cost-effective than are broader-based efforts to improve the environment.


Perhaps we should give special attention to the conservation of such plant species since they lack key factors in their defenses against the environmental disruption caused by pesticide use.

They lack of key factors therefore if we will not act, the disruption will continue in the future

B is the correct choice
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