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 ...

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 ...