CBSE ADDA

Q1)Define evolution. Ans-It a slow gradual process which occurs due to cumulative effects of adaptations and helps it to survive in a better way. Q2)How are fossils helpful in developing evolutionary relationships? Ans: Fossils forms a connecting link between groups of organisms. Q3)Cat’s paw ,human hand and horse’s legs-are these organs homologous or analogous? Give reason Ans- They are homologous organs as they are of same origin performing different functions.origin is forearm modified. Q4)Wings of bird and wings of insect-are these organs homologous or analogous?give one suitable season to support your answer. Ans-They are analogous organs as both have developed from different origin and perform same function of flying. Q5)Give one difference between eyes and eye spot.Which animal possesses eye spots? Ans-eyes are well developed organs helping to form an image, but eye spots just enable the animal to distinguish between day light and darkness.e.g. pl

  Chapter 9 Heredity and Evolution solved Questions for slow lerner        Very short answer type Question 1) Name the scientist who proposed the theory of natural selection. Ans- Charles Darwin. 2) What is micro-evolution? Ans-Evolution on a relatively small scale 3) Write the expended form of DNA. Ans-Doxyribo Nucleic Acid 4) Name two human traits which show variation. Ans- Colour of eyes and height of an individual. 5) What type of reproduction give rise to more number of successful variation? Ans- Sexual reproduction. 6) What is the basis of evolution? Ans-Selection of variants by environmental factors forms the basis of evolution. 7) Older fossils are found closer to the surface-True or False. Ans- False. 8) What will be the sex of a child who inherit Y Chromosome from his/her father? Ans- The sex of the child will be boy. 9) If a trait A exists in 10% of population of an asexually reproducing species and a trait B exists in 60%  of the sa

1 mark Questions 1 x 5 = 5 1. Questions: In a food chain consisting of snake, insect, grass and frog, assign an appropriate trophic level to frog. 2. Questions: Producers always occupy the first trophic level in any food chain. Why ? 3. Questions: Name the bacteria responsible for nitrification in nature. 4. Questions: Use of paper bags is more environment friendly than the use of polythene bags for packaging. Justify. 5. Questions: Name any two factors responsible for the formation of soil. 2 marks Questions 2 x 10 =20 6. Questions: Name those parts of a flower which serve the same function as the following do in the animal (i) Testis (ii) Ovary (iii) Eggs (iv) Sperms 7. Questions: What are fossil fuels ? How are they formed ? 8. Questions: What is ozone ? How does it protect the organisms on the Earth ? 9. Questions: What are sexually transmitted diseases ? Name an STD which damages the immune system of human body ? 10. Questions: Pre - natal sex determinat

Class 10 Heredity and Evolution – Gist of lesson Genetics : Branch of science that deals with Heredity and variation. Heredity : It means the transmission of features / characters/ traits from one generation to the next generation. Variation : The differences among the individuals of a species/population are called variations. Mendel and His Work on Inheritance Gregor Johann Mendel s tarted his experiments on plant breeding and hybridization. He proposed the laws of inheritance in living organisms. Mendel was known as Father of Genetics Plant selected by Mendel : Pisum sativum (garden pea). Mendel used a number of contrasting characters for garden pea. Following are the s even pairs of contrasting characters in Garden Pea (TABLE OF CONTRASTING CHARACTERS. SEVEN PARTS) CHARACTER DOMINANT TRAIT RECESSIVE TRAIT Flower colour Violet White Flower position Axial Terminal Seed colour Yellow