CBSE Class 10 Science Heredity And Evolution Notes Set D

HIGHER ORDER THINKING SKILLS (HOTS) QUESTIONS

1) Give two reasons for the appearance or variation among the progeny formed by sexual reproduction.

2) Colonies of yeast fail to multiply in water but multiply in sugar solution. Give one reason.

3) Malaria parasite divides into many daughter individual simultaneously through multiple fission. State an advantage the parasite gets because of this type of reproduction.

4) What is the importance of DNA copying in reproduction?

5) How does reproduction help in providing stability to population of species?

6) Why is vegetative propagation practised for growing some types of plants?

7) Why would be the reason for adopting contraceptive methods ?

8) Name those parts of flower , which serve the same function as the following do in the animals

a) testies       b) Eggs,              c) Ovary             ,d) Sperms.

*Activity- to grow rhizopus & prepare its temporary slide.

Aim: to show asexual reproduction in an organism.

App: slice of bread, water, box, slide, cover slip.

Procedure: children grow rhizopus on slice of bread and make a temporary slide.

*Project: 1.a) To study manner of vegetative reproduction in some commercially useful plants.

b) To study the seeds during sprouting period.

2. How do organisms reproduce.

1.Seprating the various parts of any 5 flowers displaying and comparing them.

2.Growing some plants by vegetative propagation.

*Seminars: reproductive health and sexually transmitted disease: children form groups and discuss.

*Symposium: gender related problems: female infanticide.

*Group discussion: if there was no sexual reproduction…..

*Debate: is it necessary to learn about reproductive health from class VII?

TOPIC 4: HEREDITY AND EVOLUTION

POINTS TO REMEMBER:

1.HEREDITY: Transmission of features or characters from one generation to another or from parents to offspring through their genes

2.VARIATION: It occurs due to sexual reproduction, inaccuracies during DNA replicating (mutation) and due to environmental factors.

3.GENETICS: Branch of biology dealing with the study of heredity and variations.

4.ALLELES :There is one pair of alleles which can express itself whether present in homozygous state or heterozygous state. Eg – T (tallness in pea plant), R(round seeds in pea plant)

5.GREGOR JOHANN MENDEL:- (1822-1884): He is known as the father of ‗genetics‘. He worked on Sweet pea plant(pisum sativum).

6.GENOTYPE: genetic composition of an individual, eg – pure tall-TT, hybrid tall-Tt

7.PHENOTYPE: Visible traits of an individual. Eg – Tallness or Dwarfness.

8.EVOLUTION: gradual changes in traits of organisms from pre existing organisms is called evolution.

9.SPECIATION: It may take place when variation is combined with geographical isolation. (Formation of new species)

FORMATIVE ASSESSMENT –III

TICK THE CORRECT OPTION:
1.The number of chromosomes in human ovum is

a.21


b.22

c.23

d.24

2. An example of homologous organs is

a.our arm and a dog‘s foreleg

b./our seethe and an elephant‘s tusk

c.potato and runners of glans.

d. all of these.

3. The hereditary units are:

a. Segments of RNA

b. Genes.

c. Chromosomes

f. Chromatin

4. The science dealing with biotechnology is called.

a.Heredity and variation

b. paleontology

c. genetics

HOTS

1.If a trait exists in 10% of a population of an asexually reproducing species and a trait B in 60% of the same population which trait is likely to have arisen earlier?

2.Which of the following is not the example of artificial selection ?

A)Colours of rose b.Flavours of mangoes 3.colours of beetle 4.Starch quality of wheat.

3. Explain how advantages variations like long neck help an organism like Giraffe to survive better?

4. Which of the following is the clearly acquiered trait in human beings?

a.Intelligence

b.Height

C.Swimming

d. Skin colour.

5. Why are human beings, who look different from each other size and colour belongs to the same species?

6. Acquiered characters are not inherited .Give reasons.

7. All the human races like Africans, Asians ,European and others might have from common ancestors provide few evidence in support of the view.

8. How is genetic drift different from natural selection? From the diagram given below which case shows natural selection?

FORMATIVE ASSESSMENT –IV

QUIZ

A. Decomposers are also called __________

B. Producers prepare their _____________

C. Ozone layer is destroyed by ___________

D. Ecology is the study of the interaction of_________ with each other and their surroundings.

SEMINAR

A. Mendel’s work

B. Sex determination in organisms

C. Role play

D. Student in act as Aristotle ,Darwin,Lemark and Mendel and present the work done by these great people.

GROUP DISCUSSION

If Mendel had met!

Projects: 1. Save Tiger….. Children collect information about the Tigers from various national Parks and Wild life sanctuaries. Perform the stage shows to develop the awareness about the forests and wild life.
3. To collect information on artificial selection carried out in some crops and animals . Visit to Vetenary college.

4. Visit to an agricultural research Institute to understand the various techniques involved in Hybridisation.

5. 1.Conducting a survey on

A. Evolution of wisdom teeth in parents.

B. Free and attached earlobes.

C. Rolling of tongue.

D. Finger prints.

Debate: Use of Biotechnology in Human Welfare .

Activity; To study vestigial organs in Human beings . Students define vestigial organs and discuss the use of every part of the body.Then come to the conclusion.

CHAPTER :5 REFLECTION AND REFRACTION

Key concepts and terms:

1) Light: light is a form of energy. It brings the sensation of sight. It is a form of electromagnetic radiation. It also provides us means of communication (fiber-optics).

2) Light wave: light wave travels with a speed of 3 x 108 ms-1 in free space. Its speed depends on the medium.

3) Ray and beam: the straight line indicating the path of the light (arrow- direction is called a ray. A bundle of rays originating from the same source of light in a particular direction is called a beam of light.

4) Reflection: when light falls on a surface and gets back the same medium, it is called reflection.

5) Image: the point of convergence or the point form where the light appears to diverge after reflection or refraction is called image.

6) Angle of incidence: the angle between the incident ray and the normal at the point of incidence is called angle of incidence.

7) Angle of reflection: the angle between the reflected ray and the normal at the point of reflection is called angle of reflection.

8) Laws of reflection: 1) the incidence ray the reflected ray and the normal at the point of incidence, all lie in the same plane.

2) The angle of reflection and the angle of incidence are equal.

9) Aperture: the width of the reflecting surface is called aperture.

10) Focus: the point on the principle axis where all parallel rays meet after reflection is called principle focus.

11) focal length: the length or separation between the pole and the focus is called focal length (PF = f)

12) In order to draw ray diagram, two rules are used:

1) The rays of light passing parallel to the principle axis will coverage at the focus after reflection.

2) The rays of light passing through the focus will emerge parallel to the principle axis after reflection.

3) The rays of light passing through the center of curvature will all retrace their both after reflection.(as it is normal at the point of incidence)

4) The rays of light falling at the pole get reflected at the same angle on the other side of principle axis.(Laws of reflection)

13) Relation between radius of curvature and focal length It is two times the focal length i.e. R=2f.

14) Mirror formula: 1/f= 1/v +1/u where f, v and u are the focal length, image distance and object distance.

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