Textbook Solutions: Heredity and Evolution | Science and Technology Class 10 (Maharashtra SSC Board) PDF Download

 Page 1


Heredity And Evolution 
 
Exercise 
Q. 1. Complete the following diagram 
 
 
Answer : 
 
Various evidences have been put forward to support of evolution theories, such as 
morphological evidence, embryological evidence, and anatomical evidence (similarities 
in bones) connecting links. 
Embryological evidence: 
The embryos of different vertebrates (examples are fish, salamander, tortoise chicken, 
cow human) show similarities in early stages of development and in the later stage of 
Page 2


Heredity And Evolution 
 
Exercise 
Q. 1. Complete the following diagram 
 
 
Answer : 
 
Various evidences have been put forward to support of evolution theories, such as 
morphological evidence, embryological evidence, and anatomical evidence (similarities 
in bones) connecting links. 
Embryological evidence: 
The embryos of different vertebrates (examples are fish, salamander, tortoise chicken, 
cow human) show similarities in early stages of development and in the later stage of 
development similarities decreases. Similarities in initial stages of embryo development 
shows the common origin of all these animals. 
 
Development of embryos in different vertebrates 
Connecting links: 
The animals or plants which possess the characteristics of two different groups of 
animals or plants. These plants or animals are ‘connecting links. For example, an 
animal duck billed platypus lays eggs like reptiles such as lizards, snakes, but share 
characters such as presence of mammary glands and hairs with mammals. Therefore, 
duck billed platypus shows link between reptiles and mammals. 
 
Page 3


Heredity And Evolution 
 
Exercise 
Q. 1. Complete the following diagram 
 
 
Answer : 
 
Various evidences have been put forward to support of evolution theories, such as 
morphological evidence, embryological evidence, and anatomical evidence (similarities 
in bones) connecting links. 
Embryological evidence: 
The embryos of different vertebrates (examples are fish, salamander, tortoise chicken, 
cow human) show similarities in early stages of development and in the later stage of 
development similarities decreases. Similarities in initial stages of embryo development 
shows the common origin of all these animals. 
 
Development of embryos in different vertebrates 
Connecting links: 
The animals or plants which possess the characteristics of two different groups of 
animals or plants. These plants or animals are ‘connecting links. For example, an 
animal duck billed platypus lays eggs like reptiles such as lizards, snakes, but share 
characters such as presence of mammary glands and hairs with mammals. Therefore, 
duck billed platypus shows link between reptiles and mammals. 
 
Q. 2. A. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
Human evolution began approximately 7 crore years ago. 
Answer : Approximately 7 crore years ago, the dinosaurs disappeared completely. At 
that time, monkey-like animals appeared from more or less similar to the modern 
lemurs. Tail of these monkey-like animals disappeared about 4 crore years ago. Due to 
enlargement of brain and improvement in their hands, ape-like animals were evolved 
and then later they evolved into gibbon and orangutan. Therefore, it is evident from the 
image that human evolution began approximately 7 crore years ago. 
 
Q. 2. B. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
Geographical and reproductive isolation of organisms gradually leads to 
speciation. 
Answer : Evolution leads to the formation of new species from an existing one is known 
as speciation. Species is the group of organisms that can reproduce among themselves 
and produce fertile offspring. The origin of many species is due to the separation of 
some individuals of one species by geographic barrier. It prevents the reproduction in 
separated groups. The separated groups can follow its own evolutionary course and 
evolved into two species. 
Page 4


Heredity And Evolution 
 
Exercise 
Q. 1. Complete the following diagram 
 
 
Answer : 
 
Various evidences have been put forward to support of evolution theories, such as 
morphological evidence, embryological evidence, and anatomical evidence (similarities 
in bones) connecting links. 
Embryological evidence: 
The embryos of different vertebrates (examples are fish, salamander, tortoise chicken, 
cow human) show similarities in early stages of development and in the later stage of 
development similarities decreases. Similarities in initial stages of embryo development 
shows the common origin of all these animals. 
 
Development of embryos in different vertebrates 
Connecting links: 
The animals or plants which possess the characteristics of two different groups of 
animals or plants. These plants or animals are ‘connecting links. For example, an 
animal duck billed platypus lays eggs like reptiles such as lizards, snakes, but share 
characters such as presence of mammary glands and hairs with mammals. Therefore, 
duck billed platypus shows link between reptiles and mammals. 
 
Q. 2. A. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
Human evolution began approximately 7 crore years ago. 
Answer : Approximately 7 crore years ago, the dinosaurs disappeared completely. At 
that time, monkey-like animals appeared from more or less similar to the modern 
lemurs. Tail of these monkey-like animals disappeared about 4 crore years ago. Due to 
enlargement of brain and improvement in their hands, ape-like animals were evolved 
and then later they evolved into gibbon and orangutan. Therefore, it is evident from the 
image that human evolution began approximately 7 crore years ago. 
 
Q. 2. B. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
Geographical and reproductive isolation of organisms gradually leads to 
speciation. 
Answer : Evolution leads to the formation of new species from an existing one is known 
as speciation. Species is the group of organisms that can reproduce among themselves 
and produce fertile offspring. The origin of many species is due to the separation of 
some individuals of one species by geographic barrier. It prevents the reproduction in 
separated groups. The separated groups can follow its own evolutionary course and 
evolved into two species. 
 
Q. 2. C. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
Study of fossils is an important aspect of study of evolution. 
Answer : Large number of plants and animals get buried in the earth due to natural 
calamity such as earthquake, volcano, and flood. Remains (parts of the body) and 
impressions of such organisms remain preserved underground are known as Fossils. 
Examples include bones, shells, exoskeletons, stone imprints of animals, etc. 
The time of death of a plant or animal can be calculated by measuring the radioactive 
carbon(C-14) in the fossil. By determining the age of the fossil, the information about 
other organisms can be gathered which helps in study of evolution. 
Page 5


Heredity And Evolution 
 
Exercise 
Q. 1. Complete the following diagram 
 
 
Answer : 
 
Various evidences have been put forward to support of evolution theories, such as 
morphological evidence, embryological evidence, and anatomical evidence (similarities 
in bones) connecting links. 
Embryological evidence: 
The embryos of different vertebrates (examples are fish, salamander, tortoise chicken, 
cow human) show similarities in early stages of development and in the later stage of 
development similarities decreases. Similarities in initial stages of embryo development 
shows the common origin of all these animals. 
 
Development of embryos in different vertebrates 
Connecting links: 
The animals or plants which possess the characteristics of two different groups of 
animals or plants. These plants or animals are ‘connecting links. For example, an 
animal duck billed platypus lays eggs like reptiles such as lizards, snakes, but share 
characters such as presence of mammary glands and hairs with mammals. Therefore, 
duck billed platypus shows link between reptiles and mammals. 
 
Q. 2. A. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
Human evolution began approximately 7 crore years ago. 
Answer : Approximately 7 crore years ago, the dinosaurs disappeared completely. At 
that time, monkey-like animals appeared from more or less similar to the modern 
lemurs. Tail of these monkey-like animals disappeared about 4 crore years ago. Due to 
enlargement of brain and improvement in their hands, ape-like animals were evolved 
and then later they evolved into gibbon and orangutan. Therefore, it is evident from the 
image that human evolution began approximately 7 crore years ago. 
 
Q. 2. B. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
Geographical and reproductive isolation of organisms gradually leads to 
speciation. 
Answer : Evolution leads to the formation of new species from an existing one is known 
as speciation. Species is the group of organisms that can reproduce among themselves 
and produce fertile offspring. The origin of many species is due to the separation of 
some individuals of one species by geographic barrier. It prevents the reproduction in 
separated groups. The separated groups can follow its own evolutionary course and 
evolved into two species. 
 
Q. 2. C. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
Study of fossils is an important aspect of study of evolution. 
Answer : Large number of plants and animals get buried in the earth due to natural 
calamity such as earthquake, volcano, and flood. Remains (parts of the body) and 
impressions of such organisms remain preserved underground are known as Fossils. 
Examples include bones, shells, exoskeletons, stone imprints of animals, etc. 
The time of death of a plant or animal can be calculated by measuring the radioactive 
carbon(C-14) in the fossil. By determining the age of the fossil, the information about 
other organisms can be gathered which helps in study of evolution. 
Q. 2. D. Read the following statements and justify same in your own words with 
the help of suitable examples. 
 
There is evidences of fatal science among chordates. 
Answer : Von Baer studies the embryo development in different vertebrates. The 
vertebrates include Fish, Frog, Tortoise, Pigeon, Chimpanzee and Man. The early 
stages of embryos development of above animals close are similarity with each other. It 
is difficult to separate them if the embryos were mixed. But the embryos differ in the 
final stages due to the formation of specialized characters. The similarity of early 
embryonic development indicate that the above animals have common ancestors. 
 
Q. 3. Complete the statements by choosing correct options from bracket. 
 
(Gene, Mutation, Translocation, Transcription, Gradual development, Appendix) 
a. The causality behind the sudden changes was understood due to -- -- principle 
of Hugo de Vries. 
b. The proof for the fact that protein synthesis occurs through -- --- was given by 
George Beadle and Edward Tatum. 
c. Transfer of information from molecule of DNA to mRNA is called as -- -- -- 
process. 
d. Evolution means -- -- -- --. 
e. Vestigial organ -- -- -- present in human body is proof of evolution.