One of the questions of interest in the study of the evolution of spid

Question

New Project RC Butler 2019  -  Practice 2 RC Passages Everyday   
Passage # 338, Date : 18-Sep-2019
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One of the questions of interest in the study of the evolution of spiders is whether the weaving of orb webs evolved only once or several times. About half the 35,000 known kinds of spiders make webs; a third of the web weavers make orb webs. Since most orb weavers belong either to the Araneidae or the Uloboridae families, the origin of the orb web can be determined only by ascertaining whether the families are related.

Recent taxonomic analysis of individuals from both families indicates that the families evolved from different ancestors, thereby contradicting Wiehle’s theory. This theory postulates that the families must be related, based on the assumption that complex behavior, such as web building, could evolve only once. According to Kullman, web structure is the only characteristic that suggests a relationship between families. The families differ in appearance, structure of body hair, and arrangement of eyes. Only Uloborids lack venom glands. Further identification and study of characteristic features will undoubtedly answer the question of the evolution of the orb web.   1 
 B 
 1. The primary purpose of the passage is to

(A) settle the question of whether orb webs evolved once or more than once
(B) describe scientific speculation concerning an issue related to the evolution of orb webs
(C) analyze the differences between the characteristic features of spiders in the Araneidae and Uloboridae families
(D) question the methods used by earlier investigators of the habits of spiders
(E) demonstrate that Araneidae spiders are not related to Uloboridae spiders

2 
 D 
 2. It can be inferred from the passage that all orb-weaving spiders belong to types of spiders that

(A) lack venom glands
(B) are included either in the Uloboridae or Araneidae families
(C) share few characteristic features with other spider types
(D) comprise less than a third of all known types of spiders
(E) are more recently evolved than other types of spiders

3 
 B 
 3. According to the passage, members of the Araneidae family can be distinguished from members of the Uloboridae family by all of the following EXCEPT:

(A) the presence of venom glands
(B) the type of web they spin
(C) the structure of their body hair
(D) the arrangement of their eyes
(E) their appearance

4 
 D 
 4. Which of the following statements, if true, most weakens Wiehle’s theory that complex behavior could evolve only once?

(A) Horses, introduced to the New World by the Spaniards, thrived under diverse climatic conditions.
(B) Plants of the Palmaceae family, descendants of a common ancestor, evolved unique seed forms even though the plants occupy similar habitats throughout the world.
(C) All mammals are descended from a small, rodentlike animal whose physical characteristics in some form are found in all its descendants.
(D) Plants in the Cactaceae and Euphorbiaceae families, although they often look alike and have developed similar mechanisms to meet the rigors of the desert, evolved independently.
(E) The Cuban anole, which was recently introduced in the Florida wilds, is quickly replacing the native Florida chameleon because the anole has no competitors.

vannbj · Answer

kaptain · Answer

Correct. I overlooked the statement "descendants of a common ancestor," and instead concentrated on the statements "the plants occupy similar habitats throughout the world." Thought if the plants are found throughout the world then they must have evolved independently. However they can be spread across the world due to various factors such as wind, birds etc carrying pollens. Obviously, I was thinking beyond the context of the passage. Classic example that answers are easily inferred by closely studying the passage.

Gayatrimane · Answer

Please help me understand Q18

Why can't the answer be B?

Linhbiz · Answer

Gayatrimane

The passage only said "most" of orb-web belongs to 2 families, but in the question stem it's all - "all orb-weaving spiders belong to types of spiders that.."
Most is always smaller set than All, thereby, B is not correct.

KanishkM · Answer

Took 4 mins.

My answers are B D B B.

1) The primary purpose of the passage is to

(A) settle the question of whether orb webs evolved once or more than once 
There was no question asked.

(B) describe scientific speculation concerning an issue related to the evolution of orb webs 
Correct answer, Spoke about two theories, pertaining to different scientists.

(C) analyze the differences between the characteristic features of spiders in the Araneidae and Uloboridae families 
This was just a brief discussion

(D) question the methods used by earlier investigators of the habits of spiders 
habits of spiders-Broad scope

(E) demonstrate that Araneidae spiders are not related to Uloboridae spiders 
The passage spoke more on "study of the evolution of spiders is whether the weaving of orb webs evolved only once or several times."

Skywalker18 · Answer

All correct in 6 mins, including 2 mins 30 seconds to read.

1. The primary purpose of the passage is to

(A) settle the question of whether orb webs evolved once or more than once - incorrect, the passage does not settle the question; Further identification and study of characteristic features will undoubtedly answer the question of the evolution of the orb web.
(B) describe scientific speculation concerning an issue related to the evolution of orb webs - Correct
(C) analyze the differences between the characteristic features of spiders in the Araneidae and Uloboridae families - incorrect
(D) question the methods used by earlier investigators of the habits of spiders - incorrect- the methods of investigation used by earlier investigators is not questioned
(E) demonstrate that Araneidae spiders are not related to Uloboridae spiders - incorrect

2. It can be inferred from the passage that all orb-weaving spiders belong to types of spiders that 
(D) comprise less than a third of all known types of spiders - Correct
About half the 35,000 known kinds of spiders make webs; a third of the web weavers make orb webs.

3. According to the passage, members of the Araneidae family can be distinguished from members of the Uloboridae family by all of the following EXCEPT

(A) the presence of venom glands 
(B) the type of web they spin - Correct
(C) the structure of their body hair 
(D) the arrangement of their eyes 
(E) their appearance

The families differ in appearance, structure of body hair, and arrangement of eyes. Only Uloborids lack venom glands.

4. Which of the following statements, if true, most weakens Wiehle's theory that complex behavior could evolve only once? 
(D) Plants in the Cactaceae and Euphorbiaceae families, although they often look alike and have developed similar mechanisms to meet the rigors of the desert, evolved independently. - Correct,
In case of the Plants in the Cactaceae and Euphorbiaceae families, the complex behavior to meet the rigors of the desert evolved independently 
Wiehle's theory postulates that the families must be related, based on the assumption that complex behavior, such as web building, could evolve only once.

surbhisinha · Answer

Can someone please explain Q.2. 
Please correct my reasoning since I clearly got it wrong.

2. It can be inferred from the passage that all orb-weaving spiders belong to types of spiders that

(A) lack venom glands - incorrect; "Only Uloborids lack venom glands", not talking about the Araneidae families which is also part of the orb-weaving spiders
(B) are included either in the Uloboridae or Araneidae families - correct; "Since most orb weavers belong either to the Araneidae or the Uloboridae families"
(C) share few characteristic features with other spider types - incorrect; this was no stated anywhere in the passage
(D) comprise less than a third of all known types of spiders - incorrect; "a third of the web weavers make orb webs", doesn't mean less than a third.
(E) are more recently evolved than other types of spiders - incorrect; this was not stated anywhere in the passage.

4567845 · Answer

QUESTIONS no 3 why not 
A venom gland

Posted from my mobile device

Sajjad1994 · Answer

It is mentioned in the passage that Araneidae and Uloboridae family can be distinguishes by other option choices except the type of web they spin.

VerbalBot · Answer

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One of the questions of interest in the study of the evolution of spid

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One of the questions of interest in the study of the evolution of spid

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