TextBook Solutions
- Explain the terms analogous and homologous organs with examples. Homologus organs are those organs which have the same basic structural design and origin but have different functions. For Example: The fore... 1
- How are the areas of study - evolution and classification - interlinked? Classification involves grouping of organism into a formal system based on similarities in internal and external structure or evolutionary h... 1
- A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. This information is not sufficient. For considering a trait as dominant or recessive, we need data of at least three generations. This data... 1
- In evolutionary terms, we have more in common with (a) a Chinese school-boy. (b) a chimpanzee. (c) a spider. a) a Chinese school-boy. 2
- An example of homologous organs is (a) our arm and a dog's fore-leg. (b) our teeth and an elephant's tusks. Answer: (d) all of the above Homologous organs have the same basic structure and origin but may perform different functions. Our arm and a d... 1
- A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing white Correct option is c) TtWW 2
- In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a 'better' body Evolution cannot always be equated with progress or better body designs. Evolution simply creates more complex body designs. However, this d... 1
- Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same A species is a group of organisms that are capable of interbreeding to produce a fertile offspring. Skin colour, looks, and size are all var... 1
- What are fossils? What do they tell us about the process of evolution? Fossils are the remains of organisms that once existed on earth. They tell us about the development of the structures from simple structured... 1
- Can the wing of a butterfly and the wing of a bat be considered homologous organs? Why or why not? The wing of a butterfly and the wing of a bat are similar in function. They help the butterfly and the bat in flying. Since they perform sim... 1
- Give an example of characteristics being used to determine how close two species are in evolutionary terms. Feathers in some ancient reptiles like dinosaurs, as fossils indicate, evolved to provide insulation in cold weather. However, they cannot f... 1
- Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not No, because geographical isolation does not affect much in asexually reproducing organisms. Asexually reproducing organisms pass on the pare... 1
- Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Why or why not? Geographical isolation can prevent the transfer of pollens among different plants. However, since the plants are self-pollinating, which mea... 2
- What factors could lead to the rise of a new species? Natural selection, genetic drift and acquisition of traits during the life time of an individual can give rise to new species. 2
- Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics? The small number of members in a population of tigers do not allow large number of variation to occur which are essential to survival of the... 1
- Why are traits acquired during the life-time of an individual not inherited? This happens because an acquired trait involves change in non-reproductive tissues which cannot be passed on to germ cells or the progeny. T... 1
- What are the different ways in which individuals with a particular trait may increase in a population? Individuals with a particular trait may increase in a population as a result of the following: Natural selection: When that trait offers som... 2
- How is the sex of the child determined in human beings? In human beings, the females have two X chromosomes and the males have one X and one Y chromosome. Therefore, the females are XX and the mal... 1
- A man with blood group A marries a woman with blood group O and their daughter has blood group O. No. This information is not sufficient to determine which of the traits - blood group A or O - is dominant. This is because we do not know a... 1
- How do Mendel's experiments show that traits are inherited independently? Mendel crossed pure breeding tall plants having round seeds with pure breeding short plants having wrinkled seeds. The plants of F_(1 )gener... 1
- How do Mendel's experiments show that traits may be dominant or recessive? The trait which appears in all the members of F_(1 )generation and also in 75% numbers of F₂ generation obtained by self fertilization of F₁... 1
- How does the creation of variations in a species promote survival? Variations occur due to sexual reproduction and also due to inaccurate copying of DNA. Depending on the nature of variations, different indi... 1
- If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same Trait B because in asexual reproduction traits which are present in the previous generation are carried over to next generation with minimal... 1
- What could be the reasons for adopting contraceptive methods? Contraceptive methods are mainly adopted because of the following reasons: To prevent unwanted pregnancies. To control population rise or bi... 1