Worksheets › Class 12 › Evolution
Class 12 Evolution worksheet
CBSE Biology. Hardy–Weinberg frequencies, natural selection, homologous and analogous organs, human evolution. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
The theory of natural selection was put forward by:
- de Vries
- Mendel
- Lamarck
- Charles Darwin (with Alfred Wallace)
Answer
(d) Charles Darwin (with Alfred Wallace)
- 2.
In a population in Hardy–Weinberg equilibrium, the frequency of the recessive phenotype (aa) is 0.16. The frequency of heterozygotes (Aa) is:
- 0.48
- 0.4
- 0.6
- 0.36
Answer
(a) 0.48
q = √0.16 = 0.4, p = 0.6, 2pq = 0.48
- 3.
The wing of a bat and the arm of a human are:
- analogous (convergent evolution)
- vestigial organs
- homologous (divergent evolution)
- the result of genetic drift
Answer
(c) homologous (divergent evolution)
Section B · short answer
- 4.
Distinguish between homologous and analogous organs.
Answer
Homologous organs have the same basic structure and origin but may do different jobs (forelimbs of whale, bat and human): divergent evolution. Analogous organs do the same job but differ in structure and origin (wings of butterfly and bird): convergent evolution.
- 5.
In a population of 20,000 in Hardy–Weinberg equilibrium, 36% show the recessive trait. Find p, q, and the numbers of AA, Aa and aa individuals.
Answer
q = 0.6, p = 0.4; AA 3,200, Aa 9,600, aa 7,200
q² = recessive frequency; p + q = 1
Section C · long answer
- 6.
Explain Darwin's theory of natural selection.
Answer
Organisms produce more offspring than can survive; members of a population vary, and many variations are heritable. Resources are limited, so there is a struggle for existence. Those with variations suited to the environment survive and reproduce more (natural selection). Over many generations, these favourable variations accumulate, giving rise to new species.
Fresh sheets for your child
In the app, every Evolution sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
Coming soon for Android and iPhone.