Heredity and evolution Worksheet-14

Heredity and evolution Worksheet-14


  1. Which of the two processes, sexual reproduction or asexual reproduction brings about marked variation in the offsprings?


  1. Name two human traits which show variation.


  1. Write down five inherited 'characters' or 'traits'.


  1. Which of the two — sperm or ovum (egg) decides the sex of the child?


  1. Which of the following combinations of sex chromosomes produces a male child, XX or XY?


  1. Name one reptile in each case where higher incubation temperature leads to the development of : (a) male progeny    (b) female progeny


  1. What name is given to the sequence of gradual changes over millions of years in which new species are produced?


  1. The forelimbs of frog, reptiles, birds and a man show the same basic design of bones. What name is given to such organs?


  1. Name the homologous organs of three animals.


  1. Name two animals having analogous organs.


  1. Name the unit of inheritance.


  1. How many types of sperms and ova are produced by a human male and female?


  1. Which type of sex chromosomes are carried by male gametes - sperms in human male? What is their percentage?


  1. What are fossils?


  1. What is the basis of sex determination in most plants and animals?


  1. Who was the first person to plan out the experiment on heredity?


  1. What did Mendel use to test his experiment?


  1. Why did Mendel choose pea plants for his experiment?


  1. Name any three different traits pea plant possess.


  1. What did Mendel's first experiment involved with?



  1. Sexual reproduction.


  1. Colour of eyes and height of an individual.


  1. Height, complexion, shape of head, colour of eyes and shape of nose.


  1. Sperm decides the sex of the child.


  1. XY.


  1. (a) Lizard          (b) Turtle.


  1. Evolution.


  1. Homologous organs.


  1. Forelimbs of a frog, a bird and a man.


  1. The wings of an insect and a bird.


  1. Gene is the unit of inheritance.


  1. Human male produces two types of sperms and human female produces one type of ova.


  1. X and Y chromosomes separately. 50% sperms carry X chromosomes and 50% carry Y chromosomes.


  1. Fossils are the preserved remains, impressions or traces of organisms that lived in the past.


  1. Genetic basis of sex determination is observed in most plants and animals.


  1. Gregor Mendel.


  1. Pea plant.


  1. Mendel choose pea plants for his experiment because they possess a number of inherited traits of contrasting visible characters.


  1. The three different traits pea plant possess are round and wrinkled seeds, tall and short plants, and white and violet flowers i.e., the seed shape, seed height and seed colour of the pea plant.


  1. Mendel’s first experiment involved with breeding varieties that differed in one characteristic.