Telangana SCERT Class 10 Biology Chapter 8 Solution – Heredity – Evolution. Here in this post we provides Class 10 Biology Heredity – Evolution Telangana State Board Solution. Telangana State Board English Class X Medium Students can download this Solution to Solve out Improve Your Learning Questions and Answers.
Telangana State Board Class 10 Biology Chapter 8 Heredity – Evolution Solution:
1.) What are variations? How do they help organisms?(AS1)
Ans: Variations are differences in characteristics among extremely closely related groups of organisms. A new character in a group frequently gives rise to variants that are passed down through the line. Variation can be can be seen in physical, metabolism, appearance etc.
Variation helps to adapt the necessary changes to survive in the changing environments .
2.) One student (researcher) wants to cross pure tall plant (TT) with pure dwarf (tt) plant, what would be the F1 and F2 generations? Explain.(AS1)
Ans: The F1 generation of a cross pure tall plant (TT) with pure dwarf (tt) plant is (Tt) and in the F2 generation it will be (TT) , (Tt) , (tt) in the ratio of 1:2:1 respectively.
3.) One experimenter cut the tails of parent rats , what could be the the traits in offsprings? Do the daughter rats contain tails or not? Explain your argument.(AS1)
Ans: After cutting the tails of the parent rats, the offspring will possess the tails on their body including the daughter rats. This is explained by August Weismann in which rats were used in experiment to test this notion. He cut off the parent rats’ tails. He saw that their progeny have tails and are healthy. Even after twenty-two generations of repeated actions on his part, his progeny continue to have tails. He established the non-heritability of the physical alterations. thus preventing them from being inherited by its progeny
4.) In a mango garden a farmer saw one mango tree with full of mango fruits but with a lot of pests. he also saw another mango tree without pests but with few mangoes. But the farmer wants the mango tree with full of mango fruits and pest free. Is it possible to create new mango tree which the farmer wants? Can you explain how it is possible?(AS1)
Ans: Yes it can be possible to create a mango tree with full of mangos with pest free.
The tree with more mango and pest can be crossed with tree having fewer mangos and without pest. In F1 generation there will be the combination of both the factors.
In F2 generation the trees are allowed to self pollinated and the desired tree which is more mangoes with no pest can be selected .
5.) Explain monohybrid experiment with an example, which law of inheritance can we understand? Explain.(AS1)
Ans: Cross between two elements in which only one character is passed in next generation which shows the dominant character is called monohybrid. Law of inheritance explains the monohybrid that explains that wo closely related “alleles,” or components for a character, are dominant over one another, thus only one of the alleles expresses itself in the first generation.
Eg.
6.) What is the law of independent assortment? Explain with an example?(AS1)
Ans: In the inheritance of more than one pair of characters (traits), the factors for each pair of characters assorted independently of the other pair. This is known as “Law of independent assortment”.
The parents of this dihybrid cross generate children with the characteristics (traits) of round (RR), yellow (YY), and wrinkled (rr), green (yy). These characters, which were created via self-pollination in the F1 generation, emerged separately and without interacting with one another in the F2 generation.
resulted from dihybrid cross.
1.) RRYY, 2. RRYy, 3. RrYY, 4. RrYy, 5. RRYy,
6.) RrYY, 7. RrYy, 8. RrYy, 9. RrYy are having Round and Yellow seeds.
1.) RRyy, 2. Rryy, 3. Rryy have Round and Green seeds
1.) rrYY, 2. rrYy, 3. rrYy have Wrinkled and Yellow seeds
1.) rryy have Wrinkled and Green seeds
From the above results it can be concluded that the factors for each character or trait remain independent and maintain their identity in the gametes. The factors are independent to each other and passes to the offsprings (through gametes).
7.) Explain the Darwin’s theory of evolution ‘Natural selection’ with an example?(AS1)
Ans: “Natural selection” refers to the process by which an organism is chosen or determined to survive or perish in the natural world. The phrase “survival of the fittest” refers to this. Beneficial characteristics will help an organism thrive. Features that are useless to organisms will either disappear from the environment or cease to exist.
Example : the Darwin noted that in the Galapagos islands, a small group of related birds were displaying structural diversity. These birds are known as finches. Each bird have different beak shapes to the food available there.
8.) What are variations? Explain with a suitable example.(AS1)
Ans: Variations are differences in characteristics among extremely closely related groups of organisms. A new character in a group frequently gives rise to variants that are passed down through the line. Variation helps to adapt the necessary changes to survive in the changing environments .
Variation in color of human eye, modification in the plant’s height and leaves.
9.) What variations generally have you observed in the species of cow?
Ans: Various breeds of cow, color, and cow who gives more milk are the variations generally observed in the species of cow.
10.) What are the characters Mendel selected for his experiments on pea plant?(AS1)
Ans:. Mendel selected color of flower, Position of flower, color and shape of seeds,color and shape of pods and length of stem for his experiments on pea plant.
11.) In what way Mendel used the word ‘Traits’- explain with an example.(AS1)
Ans: Mendel used the word Traits as the character which is passed from the parents to the offspring. He describe the character as trait in experiments of pea plant in which seeds have the traits of parent plants such as round or wrinkled seeds.
12.) What differences Mendel identified between parent and F2 generation.(AS1)
Ans: Parent generation have same type of traits while F2 generations had mixed type of traits into the offspring.
13.) Male is responsible for sex determination of baby – do you agree? If so write your answer with a flow chart.(AS1)
Ans: Yes, male is responsible for sex determination . In their cells, females contain two copies of the “X” chromosome (XX). One “X” and one “Y” chromosome (XY) are present in the cells of males. A woman’s gametes, or ova, are all made up of just one X chromosome. A male can generate two types of gametes, or sperm: one type has an X chromosome, while the other type has a Y chromosome. The newborn will have the XY condition if the sperm (which carries the Y chromosome) fertilises the ovum (which carries the X chromosome). Thus, the child will be male.
14.) Write a brief note on analogous organs.(AS1)
Ans: Analogous organs are the organs which are different in structure but have same functions in the organism. Insects can fly because of extensions of their exoskeleton on their wings. However, birds’ wings are covered in feathers all the way around. The two wings have different designs, as well as diverse components and structures. Despite having different origins, they share a common use for flying, which is the reasons they look same. This provides the ‘analogous’ traits .
15.) How do scientists utilise the information about fossils?(AS1)
Ans: The remains of extinct organisms or their former environments, preserved by organic processes, are known as fossils. Usually, sediments deposited beneath land and water have fossil remains. Scientists use the carbon dating method to estimate a fossil’s age. Certain elements, like carbon, uranium, and potassium, break down into their radioactive isotopes at a certain rate. Thus, the age of a mineral or rock that contains isotopes can be determined.
16.) Mendel selected a pea plant for his experiments. Mention the reasons in your point of view.(AS2)
Ans: Mendel conducted comprehensive studies on plants and concluded that pea plants would be the best characters for additional study due to their advantages such as
1.) Well defined characters
2.) Bisexual flowers
3.) Predominently self pollinating,
4.) Suitable for cross pollination
5.) It is an annual plant
17.) If the theory of inheritance of acquired characters proposed by Lamark was true how will the world be?(AS2)
Ans: If the theory of inheritance of acquired characters proposed by Lamark was true how will the world be totally different. The trait would have passed from the parent to the offspring which are acquired during the life time by the parents and which are not genetic. example if a parent is good in art the offspring is also an artist, this is not a compulsory trait which will be delivered to the child because it is an acquired trait not genetic.
18.) Collect information on the inherited traits in your family members and write a note on it.(AS4)
Ans: My father and sister have blue eyes which is the trait inherited through my grandmother
19.) Observe flowering plants in your surroundings? Write similarties and differences between them?
Ans: Similarities between the rose and sunflower plants are the flowering structure, they have petals and reproductive organs. The root systems of both the plants are same which are grown in soil.
The difference are the color of flowers and leave. Rose leafs have are small while sunflower leafs are large and wide.
20.) With the help of given information write your comment on evidences of evolution.(AS4)
Mammals have four limbs as do birds, reptiles and amphibians. The basic structure of the limbs is similar, though it has been modified to perform different functions.
Ans: They show a common pattern in the arrangement of bones, even though their external form and functions are different. It indicates that all the vertebrates have evolved from a common ancestor and these organs are called homologous organs. This type of evolution is called divergent evolution. They are evolved from same ancestor for different functions.
21.) Collect information about carbon dating method. Discuss with your physical science teacher.(AS4)
Ans: Utilising a technique called carbon dating method , the age of organic materials can be determined by tracking the rate at which the carbon-14 isotopes they contain decay. The underlying idea is that radioactive carbon-14 decays over time at a predictable rate. A sample’s age can be determined by scientists by calculating the ratio of carbon-14 to carbon-12 in the sample. This technique is frequently used to date organic objects and fossils in the fields of geology, anthropology, and archaeology.
22.) Draw a checker board show the law of independent assortment with a flow chart and explain the ratio.(AS5)
Ans: In the inheritance of more than one pair of characters (traits), the factors for each pair of characters assorted independently of the other pair. This is known as “Law of independent assortment”.
F2 generation
There is inheritance of two pairs of characters together. In this dihybrid cross, parents produce offsprings containing the factors for Characters (traits) of Round (RR), Yellow (YY), and wrinkled (rr), green (yy). which were produced by self pollination in F1 generation. These characters appeared independently without mixing with each other in F2 generation.
The different combinations of characters resulted from dihybrid cross are
1.) RRYY, 2. RRYy, 3. RrYY, 4. RrYy, 5. RRYy,
6.) RrYY, 7. RrYy, 8. RrYy, 9. RrYy are having Round and Yellow seeds.
1.) RRyy, 2. Rryy, 3. Rryy have Round and Green seeds
1.) rrYY, 2. rrYy, 3. rrYy have Wrinkled and Yellow seeds
- ) rryy have Wrinkled and Green seeds
This shows the ration as follow, 9:3:3:1
Fill in the blanks
1.) The process of acquiring character or traits is called Inheritance.
2.) Mendel’s experiment explains about Heridity.
3.) The four characters observed in the experiments on law of independent assossment are Round (RR), Yellow (YY), and wrinkled (rr), green (yy) pea.
4.) If we cross pollinate red flower plant with white flower we will get 25% percent of recessive trait plants.
5.) TT or YY, Tt or Yy are responsible for a dominant character.
6.) Humans have 22 pairs of autosomes and 1 pair of sex chromosomes.
7.) The population grows in geometrical progression where as food sources grow in arithmetic progression.
8.) A goat which can’t walk properly can’t live for a long time. According to Darwin this represents Natural Selection.
9) Forelimb of whale is for swimming where as in horse it is used for running.
10.) The study of fossils is called Palaeontology
Choose the correct answer
1.) Which of the following is not a variation in rose plant.
C) Tendrils
2.) According to Mendel alleles have the following character.
B) Responsible for character
3.) Natural selection means
A, B
4.) Palaeontologists deal with
B) Fossil evidences
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