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Biodiversity and Conservation — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYBiodiversity and Conservation4 Marks
Question
Explain in situ approach for conservation of biodiversity.
✓

Answer

→ In situ conservation faced with the conflict between development and conservation, many nations find it unrealistic and economically not feasible to conserve all their biological wealth.
→ Invariably, the number of species waiting to be saved from extinction far exceeds the conservation resources available.
→ On a global basis, this problem has been addressed by eminent conservationists.
→ They identified for maximum protection certain 'biodiversity hotspots' regions with very high levels of species richness and high degree of endemism (that is, species confined to that region and not found anywhere else).
→ Initially 25 biodiversity hotspots were identified but subsequently nine more have been added to the list, bringing the total number of biodiversity hotspots in the world to 34.
→ These hotspots are also regions of accelerated habitat loss.
→ Three of these hotspots - Western Ghats and Sri Lanka, Indo-Burma and Himalaya - cover our country's exceptionally high biodiversity regions.
→ Although all the biodiversity hotspots put together cover less than 2 per cent of the earth's land area, the number of species they collectively harbour is extremely high and strict protection of these hotspots could reduce the ongoing mass extinctions by almost 30 per cent.
→ In India, ecologically unique and biodiversity- rich regions are legally protected as biosphere reserves, national parks and sanctuaries.
→ India now has 14 biosphere reserves, 90 national parks and 448 wildlife sanctuaries.
→ India has also a history of religious and cultural traditions that emphasised protection of nature.
→ India has also a history of religious and cultural traditions that emphasized protection of nature.
→ In many cultures, tracts of forest were set aside, and all the trees and wildlife within were venerated and given total protection.
→ Sacred groves means conservation of plants and animals according to religious beliefs.
Some sacred groves in India :
→ Such sacred groves are found in Khasi and Jaintia Hills in Meghalaya.
→ Aravalli Hills of Rajasthan.
→ Western Ghat regions of Karnataka and Maharashtra.
→ Sarguja, Chanda and Bastar areas of Madhya Pradesh.
→In Meghalaya, the sacred groves are the last refuges for a large number of rare and threatened plants.

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Edward Wilson described diversity at all levels of biological organisation ranging from macromolecules inside the cells to biomes. It is of three inter-related hierarchial levels-genetic diversity, species diversity and conununity ecosystem diversity. Species diversity is the variety in the number and richness of the species of a region. For example, the Western ghats have a greater amphibian species diversity than the Eastern ghats.

  1. The number of species per unit area is called.
  1. Species evenness.
  2. Species richness.
  3. Species equitability.
  4. Both (a) and (c).
  1. The table below gives the population (in thousands) of ten species (A - J) in four areas (I - IV) consisting of the number of habitats given within brackets against each. Study the table and answer the question which follows:
Area and number of habitats
Species and their population (in thousands) in the area
A
B
C
D
E
F
G
H
I
J
I(11)
23
12
0.52
6.0
-
3.1
1.1
9.0
-
10.3
II(11)
10.2
-
0.62
-
1.5
3.0
-
8.2
1.1
11.2
III(13)
11.3
0.9
0.48
2.4
1.4
4.2
0.8
8.4
2.2
4.1
IV(12)
3.2
10.2
1.1
4.8
0.4
3.3
0.8
7.3
1.3
2.1
Which are out of I to IV shows maximum species diversity?

  1. II
  2. III
  3. IV
  4. I
  1. Study the given populations and choose the correct answer in relation to species diversity.
Population
Species
Species
Individuals
Population A
I
Mammals
3
II
Birds
2
III
Amphibians
2
Population B
I
Mammals
2
II
Mammals
2
III
Amphibians
1
Population C
I
Mammals
3
II
Mammals
2
III
Mammals
4

 

 
Maximum diversity
Minimum diversity
(a)
Population B
Population C
(b)
Population A
Population C
(c)
Population A
Population B
(d)
Population B
Population A
  1. The concept of species diversity has two components : evenness and richness. Evenness is based on the relative abundance of species. Richness is based on the total number of species present. Diversity indices combine a measure of richness and evenness. The Simpson index (D) is calculated from the following equations:

$\text{D}=\displaystyle\sum_{\text{i}=1}(\text{n}_\text{i}/\text{N})^2$

where, n = total number of organisms of particular species

N = total number of organisms of all species

Below are data collected in two terrestrial plant conununities that represent part of a successional chronosequence. ln this case the values were measured as percent cover.

Early Successional Community
Late Successional Community
Species
Percent Cover
Species
Percent Cover
A
83
F
24
B
5
G
20
C
9
H
18
D
2
I
23
E
1
J
15
The data indicate that, relative to the early successional community, the late successional community has which of the following characteristics?

 
Species Richness
Evenness
(a)
Higher
Higher
(b)
Higher
Lower
(c)
Same
Lower
(d)
Same
Higher
  1. Select the incorrect statement regarding species diversity.
  1. It results in polymorph formation and is useful in adaptation to changes in environmental conditions.
  2. Number of individuals of different species represent species evenness.
  3. It influences biotic interactions and stability of the community.
  4. It is a trait of the community.
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Rajat is a student of biotechnology. His professor tells him that for transformation with recombinant DNA the bacterial cells must be made capable of taking up DNA as DNA do not pass through membrane. While doing experiment in the lab, Rajat noticed that bacterial cells were not taking up the foreign DNA even after treating it with sodium ion. He asked his professor, the reason behind this. His professor explained that he should check the valency and charge of the ion that he is using for the treatment.

  1. It is difficult for DNA to pass through the membrane as
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  2. It is a hydrophobic molecule.
  3. It is a circular molecule.
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  4. Both (a) and (c)
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Reason: Transfer of DNA in a prokaryotic cell is called transfection.

  1. Both assertion and reason are true and reason is the correct explanation of assertion.
  2. Both assertion and reason are true but reason is not the correct explanation of assertion.
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Oogenesis is the process of formation of ovum in ovaries. It consists of three phases : multiplication, growth and maturation. Oogenesis is controlled by hormones GnRH, LH, FSH. GnRH secreted by the hypothalamus stimulates the anterior lobe of pituitary gland to secrete LH and FSH.

  1. What is the function of hormone FSH?
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  4. It causes ovulation.
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  4. Luteinising hormone.
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  4. Meiosis II.
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  1. (A) and (B) only.
  2. (B) and (C) only.
  3. (A), (C) and (D) only.
  4. (B) only.
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(b)
Rough surfaces
Non-pendulous
(c)
Light and sticky
Pendulous
(d)
Coarse and sticky
Protrude outside the flower
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A functional mammary gland is characteristic of all female mammals. Mammary glands are paired structures that contain glandular tissue and variable amount of fat. Refer to the given figure of a mammary gland and answer the following questions.

  1. Mammary glands are modified:
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  2. Sebaceous glands.
  3. Sudoriferous glands.
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