9. Heredity and Evolution

SEBA Class 10 Science Chapter 9. Heredity and Evolution

Chapter 9. Heredity and Evolution

Class 10 Science Chapter 9 Heredity and Evolution Multiple Choice Questions and Answers :

Question : A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white flowers. The progeny all bore violet flowers, but almost half of them were short. This suggests that the genetic make-up of the tall parent can be depicted as

(a) TTWW

(b) TTww

(d) TtWw

Answer : (c) TtWW

[ The given information indicates a typical Mendelian dihybrid cross involving two traits: plant height (tall or short) and flower color (violet or white). The fact that almost half of the progeny were short suggests that the tall parent must be heterozygous for the trait of plant height. The resulting progeny would have a genotype of Tt (heterozygous for height) and WW (heterozygous for flower color).]

Question : An example of homologous organs is

(a) our arm and a dog’s fore-leg.

(b) our teeth and an elephant’s tusks.

(d) all of the above.

Answer : (d) all of the above.

[ Homologous organs are organs that have a similar basic structure but may have different functions. ]

Question : In evolutionary terms, we have more in common with

(a) a Chinese school-boy.

(b) a chimpanzee.

(d) a bacterium.

Answer : (a) a Chinese school-boy.

Question : The organs having different origin, similar appearance and similar function are : [SEBA 2016]

(a) Homologous

(b) Analogous

(d) Vestigeal

Answer : (b) Analogous.

[ Analogous organs have different evolutionary origins but similar appearances and functions. They arise in different species as a result of convergent evolution, where organisms develop similar traits to adapt to similar environmental challenges. ]

Question : Human originated in – [SEBA 2017]

(a) Asia

(b) Africa

(d) Europe

Answer : (b) Africa.

Question : During the course of evolution, the process by which the characteristic features of the members of a species modify due to the influence of various factors and thus give rise to the organisms with new characteristic features is called : [SEBA2019]

(a) speciation

(b) evolution

(d) variation

Answer : (b) evolution.

[ Evolution is the process by which the characteristic features of a population of organisms change over successive generations. This change occurs through the mechanisms of natural selection, genetic drift, mutation, and other factors. ]

Question : If a cross is made between the plants having TT(tall) and tt (dwarf) genetic composition, which types of plants we will obtain in the next generation ? [SEBA 2020]

(a) Tall (TT) and Dwarf (tt) both

(b) Only tall

(d) None of the above

Answer : (a) Tall (TT) and Dwarf (tt) both .

[ If a cross is made between plants with the genetic composition TT (tall) and tt (dwarf), the resulting plants in the next generation will be Tall (TT) and Dwarf (tt) both. ]

Question : When two pea plants , one with yellow and round seeds and the other with green and wrinkled seeds are crossed, the plants of the generation will be obtained in the ratio of : [SEBA 2021]

(a) 1:1

(b) 3:1

(d) 1:1:1:1

Answer : (c) 9:3:3:1

[ When two pea plants, one with yellow and round seeds (genotype YYRR) and the other with green and wrinkled seeds , are crossed, the plants of the generation will exhibit a phenotypic ratio of (c) 9:3:3:1.]

Question : An example of homologous organs are [SEBA 2023]

(a) Wings of a birds and a bat

(b) Wings of a butterfly and a bat

(d) Wings of a parrot and a honey bee

Answer : (a) Wings of a bird and a bat.

[ Homologous organs are structures in different species that have a common evolutionary origin but may have different appearances and functions. Both birds and bats have wings that serve the same fundamental purpose of flight. ]

Question : Which of the following chromosome sets will determine the male sex in a human infant ? [SEBA 2023]

(a) XX

(b) XY

(d) YO

Answer : (b) XY.

[ In humans, sex determination is controlled by the presence of sex chromosomes. The typical sex chromosome combination for males is XY, and for females, it is XX. ]

Question : Exchange of genetic material takes place in
(a) vegetative reproduction
(b) asexual reproduction
(c) sexual reproduction
(d) budding

Answer : (c) Sexual reproduction.

[ Genetic material exchange occurs during the formation of gametes (sperm and egg), leading to genetic diversity in offspring. This process enhances adaptability and evolution within a population.]
Question : Two pink coloured flowers on crossing resulted in 1 red, 2 pink and 1 white flower progeny. The nature of the cross will be
(a) double fertilisation
(b) self pollination
(c) cross fertilisation
(d) no fertilisation
Answer : (b) self-pollination.

[ The consistent appearance of pink flowers indicates a stable trait, and the presence of red and white flowers suggests a genetic combination resulting from self-pollination.]

Question : A cross between a tall plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because
(a) tallness is the dominant trait
(b) shortness is the dominant trait
(c) tallness is the recessive trait
(d) height of pea plant is not governed by gene ‘T’ or ‘t’
Answer : (a) Tallness is the dominant trait.

[ In this case, the dominant allele (T) from the tall parent masks the expression of the recessive allele (t) from the short parent, resulting in all tall progeny.]

Question : Which of the following statement is incorrect?
(a) For every hormone there is a gene.
(b) For every protein there is a gene.
(c) For production of every enzyme there is a gene.
(d) For every molecule of fat there is a gene

Answer : (d) For every molecule of fat, there is a gene.

[ This statement is incorrect. The synthesis of molecules like fats is not directly controlled by individual genes; it involves complex interactions and multiple genes, not a one-to-one relationship.]
Question : If a round, green seeded pea plant (RR yy) is crossed with wrinkled,yellow seeded pea plant, (rr YY) the seeds produced in generation are
(a) round and yellow
(b) round and green
(c) wrinkled and green
(d) wrinkled and yellow
Answer : (a) Round and yellow.

[ The uppercase letters represent dominant alleles, and the lowercase letters represent recessive alleles. In this cross, the generation will be heterozygous for both traits (Rr Yy), resulting in round (dominant) and yellow (dominant) seeds. ]
Question : In human males all the chromosomes are paired perfectly except one. This/these unpaired chromosome is/are
(i) large chromosome
(ii) small chromosome
(iii) Y-chromosome
(iv) X-chromosome
(a) (i) and (ii) (b) (iii) only
(c) (iii) and (iv) (d) (ii) and (iv)

Answer : (c) (iii) Y-chromosome and (iv) X-chromosome.

[ In human males, the sex chromosomes are not perfectly paired; they consist of one X-chromosome and one Y-chromosome. ]
Question : The maleness of a child is determined by
(a) the X chromosome in the zygote
(b) the Y chromosome in zygote
(c) the cytoplasm of germ cell which determines the sex
(d) sex is determined by chance

Answer : (b) The Y chromosome in the zygote.

[ The presence of a Y chromosome in the fertilized egg determines maleness, while the absence of a Y chromosome results in femaleness. ]
Question : A zygote which has an X-chromosome inherited from the father will develop into a
(a) boy
(b) girl
(c) X- chromosome does not determine the sex of a child
(d) either boy or girl

Answer : (b) Girl.

[ In humans, females have two X chromosomes (XX), and if a zygote inherits an X chromosome from the father, it will develop into a girl.]
Question : Select the incorrect statement
(a) Frequency of certain genes in a population change over several generations resulting in evolution
(b) Reduction in weight of the organism due to starvation is genetically controlled
(c) Low weight parents can have heavy weight progeny
(d) Traits which are not inherited over generations do not cause evolution

Answer : (b) Reduction in weight of the organism due to starvation is genetically controlled.

[ This statement is incorrect. Weight reduction due to starvation is primarily influenced by environmental factors and not solely controlled by genetics.]
Question : New species may be formed if
(i) DNA undergoes significant changes in germ cells
(ii) chromosome number changes in the gamete
(iii) there is no change in the genetic material
(iv) mating does not take place
(a) (i) and (ii) (b) (i) and (iii)
(c) (ii), (iii) and (iv) (d) (i), (ii) and (iii)

Answer : (a) (i) and (ii).

[ New species may be formed if DNA undergoes significant changes in germ cells (genetic mutations) and if there are changes in chromosome number in the gametes (e.g., through chromosomal rearrangements or errors in meiosis). ]
Question : Two pea plants one with round green seeds (RRyy) and another with wrinkled yellow (rrYY) seeds produce progeny that have round, yellow (RrYy) seeds. When plants are selfed, the progeny will have new combination of characters. Choose the new combination from the following
(i) Round, yellow
(ii) Round, green
(iii) Wrinkled, yellow
(iv) Wrinkled, green
(a) (i) and (ii) (b) (i) and (iv)
(c) (ii) and (iii) (d) (i) and (iii)

Answer : (b) (i) and (iv).

[ The progeny can have new combinations of characters, including round green (RrYy) and wrinkled yellow (rrYy).]
Question : A basket of vegetables contains carrot, potato, radish and tomato. Which of them represent the correct homologous structures?
(a) Carrot and potato
(b) Carrot and tomato
(c) Radish and carrot
(d) Radish and potato

Answer: (c) Radish and carrot.

[ Radish and carrot are both taproots and represent homologous structures as they share a common evolutionary origin despite serving different functions in different plants.]
Question : Select the correct statement
(a) Tendril of a pea plant and phylloclade of Opuntia are homologous
(b) Tendril of a pea plant and phylloclade of Opuntia are analogous
(c) Wings of birds and limbs of lizards are analogous
(d) Wings of birds and wings of bat are homologous
Answer : (a) Tendril of a pea plant and phylloclade of Opuntia are homologous.

[ They both represent modified plant structures derived from the same ancestral form.]

Question : If the fossil of an organism is found in the deeper layers of earth, then we can predict that
(a) the extinction of organism has occurred recently
(b) the extinction of organism has occurred thousands of years ago
(c) the fossil position in the layers of earth is not related to its time of extinction
(d) time of extinction cannot be determined

Answer : (b) The extinction of the organism has occurred thousands of years ago.

[ Fossils found in deeper layers of the Earth's crust are generally older, indicating a longer period since the extinction of the organism. ]
Question : Which of the following statements is not true with respect to variation?
(a) All variations in a species have equal chance of survival
(b) Change in genetic composition results in variation
(c) Selection of variants by environmental factors forms the basis of evolutionary processes.
(d) Variation is minimum in asexual reproduction

Answer : (a) All variations in a species have an equal chance of survival.

[This statement is not true. Natural selection acts on variations, and not all variations have an equal chance of survival; the ones that provide a better adaptation to the environment are more likely to survive and reproduce.]
Question : A trait in an organism is influenced by
(a) paternal DNA only
(b) maternal DNA only
(c) both maternal and paternal DNA
(d) neither by paternal nor by maternal

Answer : (c) Both maternal and paternal DNA.

[ Traits in an organism are influenced by the combination of genetic material inherited from both the mother and the father, contributing to the organism's overall genetic makeup.]
Question : Select the group which shares maximum number of common characters
(a) two individuals of a species
(b) two species of a genus
(c) two genera of a family
(d) two genera of two families

Answer : (a) Two individuals of a species.

[ Individuals within the same species share the maximum number of common characters because they belong to the same biological species and have a common gene pool. ]
Question : According to the evolutionary theory, formation of a new species is generally due to
(a) sudden creation by nature
(b) accumulation of variations over several generations
(c) clones formed during asexual reproduction
(d) movement of individuals from one habitat to another

Answer : (b) Accumulation of variations over several generations.

[ According to the evolutionary theory, the formation of a new species is generally attributed to the gradual accumulation of variations over successive generations through the process of natural selection and adaptation.]
Question : From the list given below, select the character which can be acquired but not inherited
(a) colour of eye
(b) colour of skin
(c) size of body
(d) nature of hair

Answer : (c) Size of body.

[ The size of the body can be influenced by various environmental factors such as nutrition and health during an individual's lifetime, but it is not directly inherited through genetic material. ]
Question : The two versions of a trait (character) which are brought in by the male and female gametes are situated on
(a) copies of the same chromosome
(b) two different chromosomes
(c) sex chromosomes
(d) any chromosome

Answer : (a) Copies of the same chromosome.

[ The two versions of a trait, one from each parent, are typically located on homologous chromosomes, which are pairs of chromosomes that carry the same genes at corresponding loci. ]
Question : Select the statements that describe characteristics of genes
(i) genes are specific sequence of bases in a DNA molecule
(ii) a gene does not code for proteins
(iii) in individuals of a given species, a specific gene is located on a particular chromosome
(iv) each chromosome has only one gene
(a) (i) and (ii) (b) (i) and (iii)
(c) (i) and (iv) (d) (ii) and (iv)

Answer : (b) (i) and (iii).

[Genes are specific sequences of bases in a DNA molecule, and in individuals of a given species, a specific gene is located on a particular chromosome. The other statements are not accurate; genes generally code for proteins, and each chromosome can have multiple genes. ]
Question : In peas, a pure tall plant (TT) is crossed with a short plant (tt). The ratio of pure tall plants to short plants in is
(a) 1 : 3
(b) 3 : 1
(c) 1 : 1
(d) 2 : 1

Answer : (b) 3 : 1.

[ In the given cross, Tt (heterozygous tall) is formed in the generation, and when these individuals are self-pollinated, the genotype ratio in the generation is 1 TT : 2 Tt : 1 tt, resulting in a phenotypic ratio of 3 tall : 1 short. ]
Question : The number of pair (s) of sex chromosomes in the zygote of humans is
(a) one (b) two
(c) three (d) four

Answer : (a) One.

[ Humans have one pair of sex chromosomes in the zygote. Males have XY, and females have XX, making one pair of sex chromosomes in total. ]
Question : The theory of evolution of species by natural selection was given by
(a) Mendel

(b) Darwin
(c) Morgan

(d) Lamarck

Answer : (b) Darwin.

[ The theory of evolution by natural selection was proposed by Charles Darwin. ]
Question : Some dinosaurs had feathers although they could not fly but birds have feathers that help them to fly. In the context of evolution this means that
(a) reptiles have evolved from birds
(b) there is no evolutionary connection between reptiles and birds
(c) feathers are homologous structures in both the organisms
(d) birds have evolved from reptiles

Answer : (d) Birds have evolved from reptiles.

[The presence of feathers in some dinosaurs and their modified form in birds suggests an evolutionary connection between reptiles and birds, supporting the idea that birds evolved from certain groups of reptiles. ]