An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the amount of life on earth. Such an event is identified by a sharp change in the diversity and abundance of macroscopic life. It occurs when the rate of extinction increases with respect to the rate of speciation. Because the majority of diversity and biomass on Earth is microbial, and thus difficult to measure, recorded extinction events affect the easily observed, biologically complex component of the biosphere rather than the total diversity and abundance of life. Over 98% of documented species are now extinct, but extinction occurs at a very uneven rate. Based on the fossil record, the background rate of extinctions on Earth is about two to five taxonomic families of marine invertebrates and vertebrates every million years. Marine fossils are mostly used to measure extinction rates because of their superior fossil record and stratigraphic range compared to land organism fossils. Since life began on Earth, the five major mass extinctions have significantly exceeded the background extinction rate for animal and plant species. The most recent, the Cretaceous–Paleocene extinction event, which occurred approximately 66 million years ago, was a large-scale mass extinction of animal and plant species in a geologically short period of time. In the past 540 million years, during each of these five major events, over 50% of animal and plant species died. Mass extinctions seem to be a Phanerozoic-era phenomenon, with extinction rates low before large complex organisms arose. 1 C (1) It can be inferred from the passage that: (A) in an extinction event, there is a dramatic decrease in microbial life on earth. (B) over 90% of easily observed, biologically complex species become extinct during a biotic crisis. (C) the background extinction rate of animal and plant species is well below 50%. (D) marine fossils are easier to find and thus more useful to those studying mass extinction events. (E) new species do not emerge during a mass extinction event. 2 D (2) It can be inferred from the passage that the Phanerozoic era was: (A) a time period that existed before 540 million years ago. (B) a time period during which few new species emerged. (C) a time period before the Cretaceous–Paleocene era. (D) a time period during which large, complex organisms existed. (E) a time period during which fewer than 50% of animal and plant species died. 3 D (3) The author would most probably agree with which of the following statements? (A) The diversity of microbial life has changed dramatically during mass extinction events. (B) The Cretaceous–Paleocene extinction event was the most significant in the past 540 million years. (C) There were many mass extinction events prior to 540 million years ago. (D) Extinction rates have varied widely over the past 540 million years. (E) Mass extinctions are less likely now than in the past 540 million years. 4 D (4) The primary purpose of the passage is to: (A) warn readers about the possible dangers of mass extinction events. (B) discuss the causes of a particular scientific phenomenon. (C) present new evidence to support the theory of mass extinction events. (D) describe an important scientific and historical occurrence (E) suggest that mass extinctions are likely to continue in the future.

Last visit was: 19 Nov 2025, 20:32

It is currently 19 Nov 2025, 20:32

Toolkit

Reading Comprehension (RC)

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Go to My Error Log Learn more

Request Expert Reply

Confirm Cancel

Nov 20
UCR MBA Impact - Live Q&A with UCR AdCom & Student
07:30 AM PST
-
08:30 AM PST
Learn what truly sets the UC Riverside MBA apart and how it helps in your professional growth
Nov 22
GMAT RC Masterclass
11:00 AM IST
-
01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment
Nov 23
Conquer Algebra on the GMAT Focus Edition
11:00 AM IST
-
01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease.
Nov 25
Try OnDemand GMAT Masterclass
10:00 AM EST
-
11:00 AM EST
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors.

Back to Forum

Create Topic

An extinction event (also known as a mass extinction or biotic crisis)

1 2

mSKR

Joined: 14 Aug 2019

Last visit: 10 Mar 2024

Posts: 1,290

Own Kudos:

938

Given Kudos: 381

Location: Hong Kong

Concentration: Strategy, Marketing

Schools: IE (A) IIML-IPMX '22 (A) HKUST '22

GMAT 1: 650 Q49 V29 Verified score

GPA: 3.81

Schools: IE (A) IIML-IPMX '22 (A) HKUST '22

GMAT 1: 650 Q49 V29 Verified score

Posts: 1,290

Kudos: 938

19 Jun 2020, 21:00

Kudos

Bookmarks

DiyaDutta

Can someone tell me how to figure out the primary purpose of this passage?

Q4: The primary purpose of the passage is to:

a) warn readers about the possible dangers of mass extinction events.
>> no message given to readers about warning /dangers

b ) discuss the causes of a particular scientific phenomenon.
>> why extinction happens is not discussed; observations are discussed.
A phenomenon is an observable thing that happens. Mass extinctions seem to be a Phanerozoic-era phenomenon

c) present new evidence to support the theory of mass extinction events.
>> no new evidence is discussed but only discussed based on what is available

d) describe an important scientific and historical occurrence
>> extinction event (also known as a mass extinction or biotic crisis)
Historical occurrence of mass extinctions is talked about
D is our answer

e) suggest that mass extinctions are likely to continue in the future.
>> not mentioned

Basshead

Joined: 09 Jan 2020

Last visit: 07 Feb 2024

Posts: 925

Own Kudos:

302

[1]

Given Kudos: 432

Location: United States

Posts: 925

Kudos: 302

[1]

22 Nov 2020, 03:58

Kudos

Bookmarks

This was a tricky passage.

One thing to note is background extinction refers to the normal extinction rate. These are species that go extinct simply because not all life can be sustained on Earth and some species simply cannot survive. Mass extinction, on the other hand, is a widespread event that wipes out the majority (over 50%) of living plants and animals.

Pranjal3107

Current Student

Joined: 13 Apr 2020

Last visit: 06 Jul 2022

Posts: 144

Own Kudos:

Given Kudos: 1,709

Location: India

Schools: NTU (A) ISB '23 (D)

GMAT 1: 710 Q45 V41 Verified score

GPA: 3

Schools: NTU (A) ISB '23 (D)

GMAT 1: 710 Q45 V41 Verified score

Posts: 144

Kudos: 18

05 Dec 2020, 05:19

Kudos

Bookmarks

VeritasKarishma

coreyander

Tanujm

In reference to Q3, the passage says that the Cretaceous–Paleocene extinction event was the most recent mass extinction event. Why can C not be inferred basis this?

VeritasKarishma SajjadAhmad I have the same doubt. Can you please clarify Q3, on what basis can C be eliminated?

"The most recent, the Cretaceous–Paleocene extinction event, which occurred approximately 66 million years ago, was a large-scale mass extinction of animal and plant species in a geologically short period of time."

"Mass extinctions seem to be a Phanerozoic-era phenomenon, with extinction rates low before large complex organisms arose."

Cretaceous-Paleocene is most recent. Hence, Phanerozoic-era should have occurred before. Hence, (C) a time period before the Cretaceous-Paleocene era could be valid.

Read these lines very carefully.

Since life began on Earth, the five major mass extinctions have significantly exceeded the background extinction rate for animal and plant species. - there have been 5 major mass extinctions.

In the past 540 million years, during each of these five major events, over 50% of animal and plant species died. - These 5 mass extinctions have taken place within the last 540 million years.

Mass extinctions seem to be a Phanerozoic-era phenomenon, with extinction rates low before large complex organisms arose. - Mass extinction is a phenomenon of Phanerozoic-era. Before this there were no large complex organisms and extinction rates were low.

This means the Phanerozoic-era is the 540 million years era in which large complex organisms arose.

Answer (D)

But doesn't it suggest that the large organisms arose ? How can we infer that they existed ? I got D using elimination. But D really does not seem right as well.

ricardorr04

Current Student

Joined: 05 Nov 2020

Last visit: 29 May 2021

Posts: 75

Own Kudos:

Given Kudos: 57

Location: Dominican Republic

Schools: Wharton '23 (A)

GMAT 1: 710 Q47 V40 Verified score

GPA: 3.91

Schools: Wharton '23 (A)

GMAT 1: 710 Q47 V40 Verified score

Posts: 75

Kudos: 11

14 Dec 2020, 18:04

Kudos

Bookmarks

9 mins (took a bit too long on the 3rd question) but got 4/4 correct.

This passage is great for practicing inference skills (identifying OOS arguments, and getting to the answer by process of elimination). Great read and challenging questions.

AnirudhaS

LBS Moderator

Joined: 30 Oct 2019

Last visit: 25 Jun 2024

Posts: 811

Own Kudos:

872

Given Kudos: 1,575

Posts: 811

Kudos: 872

17 Dec 2020, 01:01

Kudos

Bookmarks

Pranjal3107

But doesn't it suggest that the large organisms arose ? How can we infer that they existed ? I got D using elimination. But D really does not seem right as well.

this chart might help to visualise. Red is the inferred data.

On you specific question about how can you infer that they existed..
Well if they did not exist then whose extinction happened in the past 540 million years? We already know this from the passage - "Such an event is identified by a sharp change in the diversity and abundance of macroscopic life.". So we cannot detect small-simple organism's extinction. So large complex organism must exist for a period of time before they are deemed extinct.

Hope this helps.

Attachments

Veritas_RC_help.jpg [ 66.77 KiB | Viewed 2723 times ]

Saman2902

Joined: 22 Jun 2020

Last visit: 31 Dec 2020

Posts: 1

Given Kudos: 1

Posts: 1

Kudos: 0

18 Dec 2020, 23:35

Kudos

Bookmarks

11 mins and 3/4 correct. 1st one got wrong. I choose option D in the first question can someone explain why the answer is C ?

bM22

Retired Moderator

Joined: 05 May 2016

Last visit: 17 Jul 2025

Posts: 716

Own Kudos:

784

[2]

Given Kudos: 1,316

Location: India

Schools: IIM (A) IIM (A) IIM-A '24 (A) ISB '24 (A)

Products:

Schools: IIM (A) IIM (A) IIM-A '24 (A) ISB '24 (A)

Posts: 716

Kudos: 784

[2]

19 Dec 2020, 03:24

Kudos

Bookmarks

Saman2902

11 mins and 3/4 correct. 1st one got wrong. I choose option D in the first question can someone explain why the answer is C ?

Hi Saman2902,

Let me know if this helps.

Official Explanation

(1) It can be inferred from the passage that:

Explanation

In this example, as is the case with many hard inference problems, you must link several pieces of information to find the proper inference. Using process of elimination:

Evaluate the Answer Choices:

Choice (A) No. In the first paragraph you learn that mass extinction events are based on the extinctions of easily observed, biologically complex components. You therefore have no idea from this passage how the microbial organisms are affected during a mass extinction event and (A) is incorrect.

Choice (B) No. In the passage you learn that 98% of known species have become extinct but you only learn that over 50% were lost in each of the 5 major mass extinctions. You therefore cannot conclude that over 90% of complex species become extinct during a mass extinction event and (B) is also incorrect. Note: the testmakers are hoping you use the wrong data point to create this improper inference.

Answer Choice (C). CORRECT. (C), which is correct, requires that you link together two pieces of information. In the beginning of the 3rd paragraph you learn that “the five major mass extinctions have significantly exceeded the background extinction rate” and then you learn that the rate of those mass extinctions is well over 50%. This allows you to conclude that the background rate is far below 50%.

Choices(D) No. In (D), you learn that marine fossils are used because they provide a better fossil record and stratification but you do not know if they are easier or more difficult to find than other types.

Choices(E) No. In (E), no information is given about whether new species emerge during an extinction event so you cannot make that inference.

Answer: C

Thanks.

tinbq

Joined: 04 Nov 2016

Last visit: 26 May 2024

Posts: 119

Own Kudos:

Given Kudos: 599

Location: Viet Nam

Schools: Cornell '26 (WL)

GMAT 1: 710 Q50 V35 Verified score

GMAT 2: 720 Q49 V38 Verified score

GPA: 3.12

Schools: Cornell '26 (WL)

GMAT 2: 720 Q49 V38 Verified score

Posts: 119

Kudos: 24

03 Jun 2021, 07:55

Kudos

Bookmarks

sayantanc2k

kavish2000

For the Q-3, can you please explain as to how can we conclude the same about Phanerozoic era?

The passage mentions that Mass Extinctions were Phanerozoic era phenomenon with rates low before large organisms arose. Should not this sentence structure mean that phanero era was the one wherein the extinction rates were low and was the era devoid of large organisms?

Your misunderstanding of the last line of the passage seems to be a result of not being able to inerpret the function of the modifier "with extinction rates low before large complex organisms arose" properly. This modifier does not refer to "Phanerozoic-era phenomenon", but the entire previous clause. Shift the modifier at the beginning, and then probably the meaning would be clear:

With extinction rates low before large complex organisms arose, mass extinctions seem to be a Phanerozoic-era phenomenon.

The above sentence implies that extinction rates were low before large complex organisms arose. This also implies that mass extinctions were possible only AFTER large complex organisms arose. Since mass extinctions occured during the Phanerozoic-era, it can be inferred that there were large complex organisms during this era. Hence D is the correct option.

Hi sayantanc2k,

Thank for your explanation.
I missed this question because I cannot understand the word 'arise'. Sorry, I am not a native speaker, and I thought it means 'start'. However, in the sentence quoted above, does arise lean more to the meaning of rise up/develop/flourish (implying that existence happened before the action)?

Thanks,

VerbalBot

Non-Human User

Joined: 01 Oct 2013

Last visit: 04 Jan 2021

Posts: 18,831

Own Kudos:

986

Posts: 18,831

Kudos: 986

09 Jan 2025, 20:34

Kudos

Bookmarks

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.

1 2

Moderators:

GMATNinja

GMAT Club Verbal Expert

7443 posts

GMATNinjaTwo

GMAT Club Verbal Expert

231 posts

Sajjad1994

GRE Forum Moderator

17304 posts

miag