5. EVOLUTION
2020
SAY
1. Which among the
following is an example for homology? (1)
(a)
The eye of the
Octopus and of Mammals
(b)
Sweet potato
and potato
(c)
Thorns and
tendrils of Bougainvillea and Cucurbita
(d)
Wings of butterfly
and of birds
ü Answer:
(c) Thorns and tendrils of Bougainvillea and Cucurbita.
2. (a) Define
Hardy – Weinberg principle.
(b) List out any two factors affecting Hardy – Weinberg
Equilibrium. (2)
ü Answer:
(a) Allele frequencies
in a population are stable and is constant from generation to generation.
(b) Gene migration,
Genetic drift, Mutation etc.
3. Diagrammatic
representation of the operation of natural selection on different traits is
shown below: (2)
I. Identify ‘a’,
‘b’ and ‘c’.
II. What is the evolutionary
significance of ‘b’?
ü Answer:
I. a. Stabilizing selection.
b. Directional selection.
c. Disruptive selection.
II. The
peak is shifted to one direction. i.e., more individuals acquire value other
than the mean character value.
2020
MARCH
1.
Which of the
following human ancestor is more ‘ape’ like? (1)
a.
Homo habilis
b.
Dryopithecus
c.
Australopithecines
d.
Homo erectus
ü Answer:
(b) Dryopithecus
2.
Fill the blanks
in Column A and B using appropriate terms. (2)
|
Theory |
Scientists |
|
(a)
Theory of
natural selection |
A |
|
(b)
Use and
disuse of organs |
B |
|
(c)
Theory of
mutation |
C |
|
(d)
Theory of
spontaneous generation |
D |
ü Answer:
A= Charles Darwin
B= Lamarck
C= de Vries
D= Aristotle / Louis Pasteur.
3.
p2 +
2pq + q2 = 1 denotes an evolutionary principle. (2)
a.
Name the
principle.
b.
Mention any
three factors affecting this.
ü Answer:
(a) Hardy – Weinberg Principle.
(b) Gene migration, Genetic drift, Mutation etc.
2019
SAY June
1. Based on
evolution in the geological period arrange the plants and animals in the
correct order in various million years ago. Choose the appropriate organisms
from the bracket. (2)
[Reptiles, Plants, Sea-weeds, Jawless fish, Fish with stout fin]
ü Answer:
(a) 500 mya: Plants.
(b) 350 mya: Jawless fishes, fish with stout fins.
(c) 320 mya: Sea-weeds. Plants.
(d) 200 mya: Reptiles
2. Make a flow
chart using the following terms: (2)
[Natural selection, Struggle for existence, Variation, Origin of
species, Over production, Survival of the fittest]
ü Answer:
Over production → Struggle for existence → Variation →
Survival of the fittest → Natural selection → Origin of species.
2019
MARCH
1. Prepare a flow
chart showing the evolution of modern man in the hierarchical order of their
evolution using the details given below: (2)
Homo erectus, Homo habilis, Dryopithecus, Australopithecines, Homo
sapiens, Ramapithecus, Neanderthal man
ü Answer:
Dryopithecus → Ramapithecus → Australopithecines →
Homo habilis → Homo erectus → Neanderthal man → Homo sapiens
2. Some examples
of evolutionary structures are given below. Classify them under suitable
headings: (2)
a.
Forelimb of
Man, Cheetah, Whale, Bat.
b.
Wings of
Butterfly, Bird.
c.
Thorns and
tendrils of Bougainvillea and Cucurbita.
d.
Vertebrate
hearts or brains.
e.
Eye of the
Octopus and Mammals.
f.
Flippers of
Penguins and Dolphins.
ü Answer:
Homologous organs:
a.
Forelimb
of Man, Cheetah, Whale, Bat.
b.
Thorns
and tendrils of Bougainvillea and Cucurbita.
c.
Vertebrate
hearts or brains.
Analogous organs:
· Wings of Butterfly, Bird.
· Eye of the Octopus and Mammals.
· Flippers of Penguins and Dolphins.
2018
SAY
1. p2 +
2pq + q2 = 1 is the gene frequency of a population showing an
evolutionary principle. (2)
a.
Name the
principle.
b.
Enlist any
three factors affecting this principle.
ü Answer:
(a) Hardy-Weinberg principle.
(b) Gene migration, Genetic drift, Natural selection
etc.
2. Above
homologous organs provide evidence for a particular type of evolution. (2)
a.
Identify the
type of evolution.
b.
What do you
mean by homologous organs?
ü Answer:
(a) Divergent evolution.
(b) Homologous organs are the organs having fundamentally
similar structure and origin but different functions.
3. Prepare a
flowchart of evolution of man in descending order by choosing the names given
below: (3)
Homo sapiens, Homo erectus. Homo habilis, Austrapithecines,
Ramapithicus, Neanderthal
ü Answer:
Ramapithecus → Austrapithecines
→ Homo habilis → Homo erectus → Neanderthal → Homo sapiens.
2018
MARCH
1. Complete the
boxes with the suitable words given below: (2)
[Analogues, Homologues, Convergent evolution, Divergent evolution]
ü Answer:
A=
Homologous organs.
B=
Divergent evolution.
C=
Analogous organs.
D=
Convergent evolution
2. Explain the
factors affecting the Hardy-Weinberg equilibrium. (2)
ü Answer:
Gene
migration, Genetic drift, Mutation, Genetic recombination, Natural selection.