Biology · Geography

Fossils and Geological Eras

1,140 Questions

Fossils and geological eras provide a window into the history of the Earth. This topic covers prehistoric life, mass extinctions, and the geological time scale. It is an important part of the general science syllabus for many aptitude tests.

Geological time scaleTypes of fossilsPrehistoric lifeAncient climates

Fossils and Geological Eras Questions

Multiple choice geography rocks and rock cycle rock cycle and uses of rocks rocks - introduction and importance lithosphere and asthenosphere

The earth is said to be _________ million years old.

  1. 4700

  2. 5000

  3. 5015

  4. 5014
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • By dating the rocks in Earth's crust, as well as the rocks in Earth's neighbours, such as the moon and visiting meteorites, scientists have calculated that Earth is 4500 million years old.
  • Option A is closest, thus it is correct answer.
Multiple choice geography the earth and the graticule general idea about earth space around the earth is the earth round?

Most of the scientists are of the view that Earth began to form around _____ years ago.

  1. Two and a half billion

  2. Three and a half billion

  3. Four and a half billion

  4. Five and a half billion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  • Earth began to form over 4.6 billion years ago, from the same cloud of gas (mostly hydrogen and helium) and interstellar dust that formed our Sun, the rest of the solar system and even our galaxy.

Multiple choice geography the earth and the graticule general idea about earth space around the earth is the earth round?

Supercontinent Pangaea broke up to form ______.

  1. Laurensia

  2. Gondwana Land

  3. Both A & B

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Many earth scientists use the term "supercontinent" to mean "a clustering of nearly all continents".
  •  This definition leaves room for interpretation when labeling a continental body.
  • The landmass of   Pangaea is the collective name describing all of these continental masses when they were most recently in proximity to one another.
  • This would classify Pangaea as a supercontinent. According to modern definitions, a supercontinent does not exist today. Supercontinents have assembled and dispersed multiple times in the geologic past (see table). 
  • Laurasia was the more northern of two supercontinents (the other being Gondwana) that formed part of the Pangaea supercontinent around 335 to 175 million years ago (Mya).
  •  It separated from Gondwana 215 to 175 Mya (beginning in the late Triassic period) during the breakup of Pangaea, drifting farther north after the split. 
  • Gondwana also Gondwanaland, is the name given to an ancient supercontinent. 
  • It is believed to have sutured about 600 to 530 million years ago, joining East Gondwana to WestGondwana. 
  • Gondwana formed prior to Pangaea, and later became part of it.
Multiple choice geography the earth and the graticule general idea about earth space around the earth is the earth round?

What is the name of the supercontinent formed by all the continents millions of years ago?

  1. Eurasia

  2. Gondwanaland

  3. Pangaea

  4. Panthalassa
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In carboniferous period all the land masses were united together in the form of one land mass which was named as Pangaea. There were several smaller inland seas  scattered over Pangaea which was surrounded by a huge water body named as Panthalasa representing Pacific Ocean. Luratia consisting of present North America, Europe and Asia formed norther part of Pangaea while Gondwanaland consisting of South America, Africa, Madagascar, Peninsular India, Australia and Antarctica represented the southern part of Pangaea. South pole was located near present Durban.

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

Which of the following isotopes is used for finding the fossil age maximum about $35,0000$ years?

  1. $^{238}U$
  2. $^{14}C$
  3. $^{3}H$
  4. ${206}Pb$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Half life of carbon-14 is approx. 5730 years, hence it can be used to determine the age of fossil upto 70,000 years.
Half life of U-238 is 4.5 billion years .
So, the correct option is '238U'
Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

Read the following statements about fossilization:
(i) Animals and plants get fossilised and preserved in volcanic ash.

(ii) Replacement of organic parts by mineral decomposition is called Petrification which occurs only of hard parts, e.g. bones.

(iii) Casts are prints of leaves, stem, etc in soft mud which become fossilised.

(iv) Fossils present in the upper strata of earth are older than those present in lower strata. Of the above statements:

  1. (i) and (ii) are incorrect.

  2. (ii), (iii) and (iv) are incorrect.

  3. (ii) and (iv) are correct.

  4. (iii) and (iv) are incorrect.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Statement (iii) is incorrect because casts are impressions, not fossilized prints in mud. Statement (iv) is incorrect because fossils in lower strata are generally older than those in upper strata, not the other way around.

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

Which of these is not a living fossil?

  1. Archaeopteryx

  2. Duck-billed platypus

  3. Lungfish

  4. Frog
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Archaeopteryx is considered a transitional fossil (a link between reptiles and birds), not a living fossil. Living fossils are extant organisms that resemble ancient ancestors, such as the platypus or lungfish.

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

If the fossil of an organism is found in the deeper layers of earth, then we can predict that 

  1. The extinction of organism has occurred recently.

  2. The extinction of organism has occurred thousand years ago.

  3. The fossil position in the layers of Earth is not related to its time of extinction.

  4. Time of extinction cannot be determined.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If the fossil of an organism is found in the deeper layers of Earth then it can be predicted that the extinction of organism has occurred thousand years ago.

Fossils are a part of sedimentary layers which contains dead and decayed remains which contain the remains in each stratum.

When animals, plants and other organisms die, they typically decay completely. But sometimes, when the conditions are just right, they're preserved as fossils.
Several different physical and chemical processes create fossils.
Freezing, drying and encasement, such as in tar or resin, can create whole-body fossils that preserve bodily tissues. These fossils represent the organisms as they were when living, but they're very rare. Most organisms become fossils when they're changed through various other means.
The heat and pressure from being buried in sediment can sometimes cause the tissues of organisms including plant leaves and the soft body parts of fish, reptiles and marine invertebrates to release hydrogen and oxygen, leaving behind a residue of carbon. This process which is called as carbonization or distillation yields a detailed carbon impression of the dead organism in sedimentary rock. Thus, the correct answer is option B.

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

Age of fossils can be detected by

  1. Residual quantity of calcium

  2. Quantity of radioactive carbon compound

  3. Phylum of other mammals

  4. Structure of bones
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The dead and decomposing matter in the soil gets suppressed in the lower strata of the soil which turn into fossils due to pressure and temperature in the lower strata of the earth crust. Age of fossils can be detected by the quantity of radioactive carbon compound. Radiocarbon dating is used for determining the age of an object containing organic material by using the properties of radiocarbon (14C), a radioactive isotope of carbon. 

The radiocarbon dating method is based on the fact that radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting radiocarbon combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire 14C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and from that point onwards the amount of 14C it contains begins to reduce as the 14C undergoes radioactive decay. Measuring the amount of 14C in a sample from a dead plant or animal such as piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died. The older a sample is, the less 14C there is to be detected, and because the half-life of 14C (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by radiocarbon dating are around 50,000 years ago, although special preparation methods occasionally permit dating of older samples.
So, the correct answer is option B.

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

If the fossil of an organism is found in deep layers of earth, then we can predict that

  1. The organism became extinct recently

  2. The extinction of organism occurred years back

  3. The time of extinction is not related to layers of earth

  4. Cannot be determined
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Fossils are remains of dead plants and animals. When plants and animals die, their bodies are buried inside the soil. the older the fossils, earlier they must have been buried inside. Year after, many bodies must have got deposited over them. So deeper the fossil layer, older it must have been.

So, option B "The extinction of organism occurred years back" is the correct answer.

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

Age of fossils in the past was generally determined by radio-carbon method and other methods involving radioactive elements found in the rocks. More precise methods, which were used recently and led to the revision of the evolutionary periods for different groups of organisms, includes

  1. Electron spin resonance (ESA) and fossil DNA

  2. Study of carbohydrates/proteins in rocks

  3. Study of carbohydrates/proteins in fossils

  4. Study of conditions of fossilization
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

ESA is a more precise technique than previously used techniques for the dating of fossils. It is based on the principle of resonance due to electrons and electron deficient centres produced as a result of emission by naturally occurring radioactive elements in a sample. DNA is the information macromolecule in a living system and can be extracted from fossils or other ancient samples. The sequence information in such a DNA can be compared against sequence information of DNA in other samples or living plants and animals, leading to valuable information about the evolution of plants and animals.

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

Which of the following is the method to form fossils?

  1. Carbonization

  2. Recrystallization

  3. Replacement

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Fossils are formed in a number of different ways, but most are formed when a plant or animal dies in a watery environment and is buried in mud and silt. Soft tissues quickly decompose leaving the hard bones or shells behind. Over time sediment builds over the top and hardens into rock.

Types of fossils:- (a) insect preserved in amber, (b) petrified wood (permineralization), (c) cast and mold of a clam shell, (d) pyritized ammonite, and (e) compression fossil of a fern.
So, the correct answer is "All of the above".

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

Which of the following types of fossils are formed when mineral replaces all parts of the organism and entire animal transformed into stone?

  1. Petrified fossils

  2. Mould and cast

  3. Actuals remains

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Petrified fossils:- In geology, petrifaction or petrification is the process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with minerals.

Example:- Dinosaur bones, petrified wood and many trilobite fossils.
So, the correct answer is "Petrified fossils".

Multiple choice biology origin and evolution of life fossilization geological time scale, extinctions and fossils concepts of evolution

The oldest fossil record of blue-green alga is 2.9 billion years old. It is :

  1. Stromatolites

  2. Archaeopteryx

  3. Archaeospheroides

  4. Chlamydomonas
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Archaeospheroides is recognized as one of the oldest known microfossils, dating back to the Precambrian era, specifically associated with early blue-green algae.