Heredity and evolution Worksheet-17

Heredity and evolution Worksheet-17


  1. Explain why evolution cannot be said to progress from lower forms to higher forms.


  1. How environment determines sex of a new born in some organism?


  1. How do DNA help in defining evolutionary relationship?


  1. Give two examples of organisms in which environmental factors regulate sex determination.


  1. "Genes and chromosomes have similar behaviour." Justify.


  1. Name the scientific terms used to represent the following :

(a) The branch of biology which studies heredity and variation.

(b) The transmission of traits from parents to offsprings.

(c) Differences in a trait in human beings.

(d) A recognisable feature of an organism.


  1. Why are asexually reproducing organisms capable of showing the hereditary features more?


  1. What was the plant chosen by Mendel to work upon? What was his observation?


  1. What do genes have to do with evolution?


  1. How does the creation of variations in a species ensure survival?



  1. Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics?


  1. What factors could lead to the rise of a new species?


  1. Can the wing of a butterfly and the wing of a bat be considered homologous organs? Why or why not?


  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 species?


  1. Outline a project which aims to find the dominant coat colour in dogs.


  1. What evidence do we have for the origin of life from inanimate matter?


  1. How is the equal genetic contribution of male and female parents insured in the progeny?


  1. Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement? Why or why not?


  1. Define 'evolution'. Describe Darwin's theory of evolution.


  1. Explain the mechanism of sex determination in the zygote.


  1. Define fossils. Explain briefly any two ways in which the study of fossils helps in under-standing about the past life.


  1. Name any three organs homologous to human hand. Why are they considered homologous?


  1. What are homologous organs? How do they provide evidence in support of evolution?


  1. What is the significance of homologous and analogous organs in the process of evolution?


  1. Who was Mendel? Why was he called the 'Father of Genetics'?


  1. Define the term 'heredity'. In which types of organisms is heredity supposed to be better defined - in sexually reproducing or asexually reproducing kind? Why?


  1. Explain how a new species is generated.


  1. Explain with an example, how evolutionary relationship linked to classification.


  1. How are fossils formed?


  1. Explain various stages of evolution.