Case Based Questions Test: Heredity & Evolution


19 Questions MCQ Test Science Class 10 | Case Based Questions Test: Heredity & Evolution


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Attempt Case Based Questions Test: Heredity & Evolution | 19 questions in 38 minutes | Mock test for Class 10 preparation | Free important questions MCQ to study Science Class 10 for Class 10 Exam | Download free PDF with solutions
QUESTION: 1

Read the below passage and answer the following question:

Meena studied the forelimbs of three organisms and she found that organism X had long and short bones, covered with muscles, which are used for running. The organism Y had long and short bones, covered with feathers used for flying. The organism Z has a layer of a complex chemical with supporting framework which is not made of bones and which is used for flying.

Q. Analogous structures are

Solution: Analogous structures have the same function but are evolved from a common ancestor. They are the result of the convergent evolution that different organisms shared a common environment. Convergent evolution describes the independent evolution of similar features in species of different lineages. The two species came to the same function, flying, but did so separately from each other. They have "converged" on this useful trait.
QUESTION: 2

Read the below passage and answer the following question:

Meena studied the forelimbs of three organisms and she found that organism X had long and short bones, covered with muscles, which are used for running. The organism Y had long and short bones, covered with feathers used for flying. The organism Z has a layer of a complex chemical with supporting framework which is not made of bones and which is used for flying.

Q. The name given to the forelimbs of organisms X and Y?

Solution: Forelimbs of vertebrates are homologous organs, i.e., organs having the same fundamental structure but perform different functions.
QUESTION: 3

Read the below passage and answer the following question:

Meena studied the forelimbs of three organisms and she found that organism X had long and short bones, covered with muscles, which are used for running. The organism Y had long and short bones, covered with feathers used for flying. The organism Z has a layer of a complex chemical with supporting framework which is not made of bones and which is used for flying.

Q. The name is given to the forelimbs of organisms Y and Z is:

Solution: Wings of insects and wings of birds are analogous organs, i.e., organs having similar functions but different in their structural details and origin.
QUESTION: 4

Read the below passage and answer the following question:

Fossils are formed layer by layer in a sequence. It is a slow process that is totally dependent on where the organism dies. In the ocean, fossils are settled at the bottom in the soil or sand. In the course of time, these layers changed into rocks due to the presence of the water above and also due to chemical reactions. The distribution pattern of fossils shows that the ancient fossils present in the bottom rocks are simple, while the most recent fossils found in the upper strata are highly evolved. It means fossils form and become more and more complex as we proceed from earliest to recent rocks.

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

Solution: Fossils refer to the petrified remains of organisms that lived in the past and get preserved in rocks. The fossil position in the layer of earth relates to the time of extinction of organisms. If the fossil of an organism is found in the deeper layers of earth, then it is predicted that extinction of organisms occurred thousands of years ago. Whereas the fossils found closer to the surface are more recent
QUESTION: 5

Read the below passage and answer the following question:

Fossils are formed layer by layer in a sequence. It is a slow process that is totally dependent on where the organism dies. In the ocean, fossils are settled at the bottom in the soil or sand. In the course of time, these layers changed into rocks due to the presence of the water above and also due to chemical reactions. The distribution pattern of fossils shows that the ancient fossils present in the bottom rocks are simple, while the most recent fossils found in the upper strata are highly evolved. It means fossils form and become more and more complex as we proceed from earliest to recent rocks.

Q. 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

Solution: In the context of evolution, the use of feathers by birds for flying means that birds have evolved from reptiles. Dinosaurs had feathers but could not fly using them. Birds later adapted the feathers for flight. Since dinosaurs were reptiles, this means that birds have evolved from them.
QUESTION: 6

Read the below passage and answer the following question:

Fossils are formed layer by layer in a sequence. It is a slow process that is totally dependent on where the organism dies. In the ocean, fossils are settled at the bottom in the soil or sand. In the course of time, these layers changed into rocks due to the presence of the water above and also due to chemical reactions. The distribution pattern of fossils shows that the ancient fossils present in the bottom rocks are simple, while the most recent fossils found in the upper strata are highly evolved. It means fossils form and become more and more complex as we proceed from earliest to recent rocks.

Q. Which of these statements is correct about the importance of fossils in the study of organic evolution?

Solution: Role of Fossil: Provides missing link between the species/who has evolved from whom. They tell us about prehistoric organisms. Also, it helps in establishing the time period in which organisms lived.
QUESTION: 7

Read the below passage and answer the following question:

Fossils are formed layer by layer in a sequence. It is a slow process that is totally dependent on where the organism dies. In the ocean, fossils are settled at the bottom in the soil or sand. In the course of time, these layers changed into rocks due to the presence of the water above and also due to chemical reactions. The distribution pattern of fossils shows that the ancient fossils present in the bottom rocks are simple, while the most recent fossils found in the upper strata are highly evolved. It means fossils form and become more and more complex as we proceed from earliest to recent rocks.

Q. Which of the following constitutes a fossil?

Solution: Fossils are dead remains of animals and plants from the remote past.

Fossils are formed when dead organisms are not completely decomposed. The organisms may get trapped in resins of trees, lava of volcanoes or hot mud, which when hardened retains the animal’s parts thus forming fossils.

QUESTION: 8

Read the below passage and answer the following question:

Fossils are formed layer by layer in a sequence. It is a slow process that is totally dependent on where the organism dies. In the ocean, fossils are settled at the bottom in the soil or sand. In the course of time, these layers changed into rocks due to the presence of the water above and also due to chemical reactions. The distribution pattern of fossils shows that the ancient fossils present in the bottom rocks are simple, while the most recent fossils found in the upper strata are highly evolved. It means fossils form and become more and more complex as we proceed from earliest to recent rocks.

Q. Which of these organisms is fossilized?

Solution: Trilobite, any member of a group of extinct fossil arthropods easily recognized by their distinctive three-lobed, three-segmented form. For the animal to grow, the exoskeleton had to be shed, and shed trilobite exoskeletons, or portions of them, are fossils that are relatively common.
QUESTION: 9

Read the passage and answer the following questions:

There were three animals: A, B and C. Animal A can fly but animal B can only run on ground or walls. However, the forelimbs of animal A and B, both have the same basic design but they were used for different purposes such as flying and running respectively. The animal C became extinct a long time ago. The study of fossils of animal C tells us that it had some features like those of A and some like those of B. In fact, animal C is said to form a connecting link in the evolutionary chain of A and B.

Q. The animal C is

Solution: Archaeopteryx is an iconic fossil, often thought of as the 'missing-link' between dinosaurs and birds. It was first described in 1861 by the German palaeontology Hermann von Meyer (1801-1869). Since then Archaeopteryx has been the focus of controversy surrounding the origin of birds and their links with dinosaurs.
QUESTION: 10

Read the passage and answer the following questions:

There were three animals: A, B and C. Animal A can fly but animal B can only run on ground or walls. However, the forelimbs of animal A and B, both have the same basic design but they were used for different purposes such as flying and running respectively. The animal C became extinct a long time ago. The study of fossils of animal C tells us that it had some features like those of A and some like those of B. In fact, animal C is said to form a connecting link in the evolutionary chain of A and B.

Q. Which is the correct evolutionary chain involving A, B and C.

Solution:
QUESTION: 11

Read the passage and answer the following questions:

There were three animals: A, B and C. Animal A can fly but animal B can only run on ground or walls. However, the forelimbs of animal A and B, both have the same basic design but they were used for different purposes such as flying and running respectively. The animal C became extinct a long time ago. The study of fossils of animal C tells us that it had some features like those of A and some like those of B. In fact, animal C is said to form a connecting link in the evolutionary chain of A and B.

Q. A belongs to _______ and B belongs to _________ group respectively.

Solution:
QUESTION: 12

Read the passage and answer the following questions:

There were three animals: A, B and C. Animal A can fly but animal B can only run on ground or walls. However, the forelimbs of animal A and B, both have the same basic design but they were used for different purposes such as flying and running respectively. The animal C became extinct a long time ago. The study of fossils of animal C tells us that it had some features like those of A and some like those of B. In fact, animal C is said to form a connecting link in the evolutionary chain of A and B.

Q. Select the correct statement.

Solution: Wings of birds and wings of bats are homologous. Since they have the same basic design however their origin is different.
QUESTION: 13

Read the passage and answer the following questions:

There were three animals: A, B and C. Animal A can fly but animal B can only run on ground or walls. However, the forelimbs of animal A and B, both have the same basic design but they were used for different purposes such as flying and running respectively. The animal C became extinct a long time ago. The study of fossils of animal C tells us that it had some features like those of A and some like those of B. In fact, animal C is said to form a connecting link in the evolutionary chain of A and B.

Q. _____________ name is given to the forelimbs like those of A and B, which have the same basic design but different functions?

Solution: Homologous organs may be determined as the organs of animals which have some similar basic structure but their function is different to each other.
QUESTION: 14

Read the passage and answer the following questions:

Seema crossed purebred pea plants having round-yellow seeds with wrinkled green seeds and found that only A-B type of seeds were produced in the F1 generation. When F1 generation pea plants having A-B type of seeds were crossbreed by self pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties A-D and C-B types of seeds were also obtained.

Q. What are A-B types of seeds?

Solution: A-B type of seeds produced in the first generation (F1 generation) is round and yellow (RrYy).
QUESTION: 15

Read the passage and answer the following questions:

Seema crossed purebred pea plants having round-yellow seeds with wrinkled green seeds and found that only A-B type of seeds were produced in the F1 generation. When F1 generation pea plants having A-B type of seeds were crossbreed by self pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties A-D and C-B types of seeds were also obtained.

Q. A-D are __________ and C-B are _______ type of seeds.

Solution: A-D type of seeds produced are round and green (RRyy or Rryy) in nature.

C-B type of seeds produced are wrinkled and yellow (rrYY or rrYy) in nature.

QUESTION: 16

Read the passage and answer the following questions:

Seema crossed purebred pea plants having round-yellow seeds with wrinkled green seeds and found that only A-B type of seeds were produced in the F1 generation. When F1 generation pea plants having A-B type of seeds were crossbreed by self pollination, then in addition to the original round yellow and wrinkled green seeds, two new varieties A-D and C-B types of seeds were also obtained.

Q. The above cross is known as

Solution: Mendel’s experiment with peas is a classic example of a dihybrid cross. The experiment was done to highlight if any relationship exists between various pairs of alleles.
QUESTION: 17

Read the passage and answer the following questions:

In a cross between plants with purple flowers and plants with white flowers, the offspring of F1 generation all had white flowers. When the F1 generation was self-crossed, it was observed in the F2 generation that out of 100, 75 flowers were white. Make a cross and answer the following questions:

Q. The ratio of ‘White: Purple’ flowers in the F2 generation is

Solution: The F2 generation is 25% PP (homozygous dominant, purple flowers), 50% Pp (heterozygous, purple flowers), and 25% pp (homozygous recessive, white flowers). This is how the white characteristic reappears in the second generation. The phenotype is 3:1, purple to white.
QUESTION: 18

Study the given cross showing self pollination in F1 and answer the questions

RRYY × rryy Parents

(Round Yellow) (Wrinkled Green)

RrYy × ________ F1 generation

(Round Yellow)

Q. The missing black in the above cross is:

Solution: Mendel crossed pea plants having round green seeds (RRyy) with pea plants having wrinkled yellow seeds (rrYY).
QUESTION: 19

Study the given cross showing self pollination in F1 and answer the questions

RRYY × rryy Parents

(Round Yellow) (Wrinkled Green)

RrYy × ________ F1 generation

(Round Yellow)

Q. The ratio of the combination of characters in the F2 progeny is:

Solution: Mendel crossed pea plants having round green seeds (RRyy) with pea plants having wrinkled yellow seeds (rrYY).

An example of dihybrid cross: Since, the F1 plants are formed after crossing pea plants having green round seeds and pea plants having yellow wrinkled seeds. F1 generation will have both these characters in them. However, as we know that yellow seed colour and round seeds are dominant characters, therefore, the F1 plants will have yellow round seeds.

Then, this F1 progeny was self-pollinated and the F2 progeny was found to have yellow round seeds, green round seeds, yellow wrinkled seeds and green wrinkled seeds in the ratio 9:3:3:1.

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