Grade 12 : Biology | Evolution

Question 1

A population geneticist analyzes a diploid population in Hardy-Weinberg equilibrium. The frequency of the homozygous recessive genotype (aa) is determined to be 0.09.

What is the frequency of the heterozygous carriers (Aa) in this population?

Accepted Answer

C) 0.42

Answer

A) 0.21

Answer

B) 0.30

Answer

D) 0.49

Question 2

Assertion (A): Analogous structures are a result of convergent evolution.
Reason (R): Different structures evolve for the same function due to similar selection pressures in comparable habitats.

Select the correct choice from the options given below:

Accepted Answer

A) Both A and R are true and R is the correct explanation of A

Answer

B) Both A and R are true but R is not the correct explanation of A

Answer

C) A is true but R is false

Answer

D) A is false but R is true

Question 3

Which of the following pairs represents homologous organs demonstrating divergent evolution?

Accepted Answer

B) Forelimbs of whales and wings of bats

Answer

A) Eye of an octopus and eye of a mammal

Answer

C) Sweet potato root and potato tuber

Answer

D) Wings of a butterfly and wings of a pigeon

Question 4

In an industrial town in England before 1850, white-winged moths predominated. Following extensive coal-fueled industrialization by 1920, dark-melanic forms became overwhelmingly prevalent.

This historical shift exemplifies which type of natural selection?

Accepted Answer

C) Directional selection

Answer

A) Stabilizing selection

Answer

B) Disruptive selection

Answer

D) Balancing selection

Question 5

In S.L. Miller's classic 1953 experiment simulating primitive Earth conditions, which mixture of gases was sealed inside the closed spark-discharge flask at $800^\circ ext{C}$?

Accepted Answer

B) $	ext{CH}_4, 	ext{H}_2, 	ext{NH}_3, 	ext{H}_2	ext{O}$ vapor

Answer

A) $	ext{CH}_4, 	ext{O}_2, 	ext{NH}_3, 	ext{H}_2	ext{O}$

Answer

C) $	ext{CO}_2, 	ext{NH}_3, 	ext{H}_2, 	ext{N}_2$

Answer

D) $	ext{CH}_4, 	ext{CO}_2, 	ext{H}_2	ext{O}, 	ext{O}_2$

Question 6

The phenomenon whereby a small founding population carries an unrepresentative sample of parental alleles leading to speciation on an isolated island is termed:

Accepted Answer

D) Founder effect

Answer

A) Saltation

Answer

B) Gene conversion

Answer

C) Adaptive radiation

Question 7

A paleontologist studies early hominid fossils and notes cranial capacities across specimens. Specimen X has a cranial capacity of approximately $650 ext{--}800 ext{ cc}$ and was among the first known toolmakers.

Specimen X most likely belongs to which taxon?

Accepted Answer

A) Homo habilis

Answer

B) Homo erectus

Answer

C) Neanderthal man

Answer

D) Australopithecus

Question 8

Assertion (A): Hugo de Vries proposed that evolution occurs in single, sudden, large steps called saltation.
Reason (R): Mutations are directional and small, while Darwinian variations are random and directionless.

Select the correct choice from the options given below:

Accepted Answer

C) A is true but R is false

Answer

A) Both A and R are true and R is the correct explanation of A

Answer

B) Both A and R are true but R is not the correct explanation of A

Answer

D) A is false but R is true

Question 9

The process of evolution of different species in a given geographical area starting from a common ancestor and radiating to other habitats is called:

Accepted Answer

B) Adaptive radiation

Answer

A) Convergent evolution

Answer

C) Parallel evolution

Answer

D) Retrogressive evolution

Question 10

According to the modern synthetic theory of evolution, which of the following forces disturbs Hardy-Weinberg genetic equilibrium?

Accepted Answer

D) Non-random mating and persistent natural selection

Answer

A) Random mating in a large panmictic population

Answer

B) Complete absence of immigration and emigration

Answer

C) Absence of mutations over generations

Question 11

A group of researchers evaluated an isolated bird population where intermediate beak sizes survived best, while chicks with exceptionally large or small beaks had severe mortality.

Over multiple generations, this mode of selection will cause the bell-shaped trait distribution curve to:

Accepted Answer

A) Become narrower and taller around the mean phenotype

Answer

B) Shift entirely toward the right extreme

Answer

C) Develop two distinct peripheral peaks at both ends

Answer

D) Flatten out uniformly without any defined peak

Question 12

Fossils of the lobe-finned fish Coelacanth (Latimeria) caught in South Africa in 1938 are significant evolutionary evidence because:

Accepted Answer

C) They are transitional ancestors of the first amphibians that invaded land

Answer

A) They represent the direct ancestors of modern birds

Answer

B) They proved that all marine vertebrates evolved from freshwater mollusks

Answer

D) They provide direct proof of Lamarckian inheritance

Question 13

Assertion (A): Embryological support for evolution proposed by Ernst Haeckel was disapproved by Karl Ernst von Baer.
Reason (R): Von Baer noted that embryos never pass through the adult stages of other animals.

Choose the correct option:

Accepted Answer

B) Both A and R are true but R is not the correct explanation of A

Answer

A) Both A and R are true and R is the correct explanation of A

Answer

C) A is true but R is false

Answer

D) A is false but R is true

Question 14

About how many million years ago (mya) did cellular forms of life first originate on Earth?

Accepted Answer

D) 2000 mya

Answer

A) 4500 mya

Answer

B) 3000 mya

Answer

C) 500 mya

Question 15

Which of the following represents an accurate pairing of analogous organs in plants?

Accepted Answer

A) Sweet potato (root modification) and potato (stem modification)

Answer

B) Tendril of Passiflora and thorn of Bougainvillea

Answer

C) Thorn of Citrus and tendril of Cucurbita

Answer

D) Pitcher of Nepenthes and spine of Opuntia

Question 16

A newly discovered hominid fossil found in East Africa walked upright, hunted with stone weapons, but evidence shows that it essentially subsisted on fruit without eating meat.

This description matches which early human ancestor?

Accepted Answer

D) Australopithecus

Answer

A) Dryopithecus

Answer

B) Neanderthalensis

Answer

C) Homo erectus

Question 17

The sudden appearance of antibiotic-resistant bacteria upon the widespread introduction of penicillin is evidence of:

Accepted Answer

B) Selection of pre-existing advantageous mutations by anthropogenic action

Answer

A) Directed acquired inheritance due to bacterial need

Answer

C) Convergent evolution of bacterial plasmids

Answer

D) Saltation triggered directly by chemical toxicity

Question 18

In an equilibrium population, the dominant allele $A$ has a gene frequency of $p = 0.8$. The recessive allele $a$ has a frequency of $q = 0.2$.

What is the ratio of homozygous dominant individuals (AA) to heterozygous individuals (Aa) in this population?

Accepted Answer

C) $2 : 1$

Answer

A) $1 : 1$

Answer

B) $4 : 1$

Answer

D) $1 : 2$

Question 19

Marsupial mole, Tasmanian wolf, and Sugar glider sharing similarities with placental mole, Wolf, and Flying squirrel respectively exemplify:

Accepted Answer

A) Convergent evolution

Answer

B) Divergent evolution

Answer

C) Saltation

Answer

D) Sympatric speciation via genetic drift

Question 20

Which hominid ancestor possessed a brain size of roughly 1400 cc, buried their dead, and lived near central and east Asia between $100{,}000$ and $40{,}000$ years ago?

Accepted Answer

D) Neanderthal man

Answer

A) Homo habilis

Answer

B) Australopithecus afarensis

Answer

C) Ramapithecus

Set 5Grade 12 : Biology | Evolution