Question 1

Q1: Name the three important components of biodiversity.

Accepted Answer

The three important components (levels) of biodiversity are: 1.  Genetic diversity: This refers to the variation of genes within a single species. For example, the text mentions that the medicinal plant Rauwolfia vomitoria shows genetic variation in the potency and concentration of the chemical rese...

Question 2

Q10: Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

Accepted Answer

Yes, a situation where we might deliberately want to make a species extinct involves disease-causing microorganisms that are exclusively harmful to humans and have no known beneficial role in any ecosystem. Situation: The eradication of pathogens that cause devastating human diseases. A prime exampl...

Question 3

Q2: How do ecologists estimate the total number of species present in the world?

Accepted Answer

Ecologists estimate the total number of species on Earth using a method of statistical extrapolation. Since species inventories are more complete for temperate regions than for tropical regions, where most species are yet to be discovered, the following steps are taken: 1.  Select a well-studied gro...

Question 4

Q3: Give three hypotheses for explaining why tropics show greatest levels of species richness.

Accepted Answer

Ecologists and evolutionary biologists have proposed several hypotheses to explain the greater species richness in the tropics. Three important ones are: 1.  Longer Evolutionary Time: Tropical latitudes have remained relatively undisturbed by frequent glaciations for millions of years, unlike temper...

Question 5

Q4: What is the significance of the slope of regression in a species - area relationship?

Accepted Answer

The species-area relationship is described by the logarithmic equation: $\log S = \log C + Z \log A$, where: - $S$ = Species richness - $A$ = Area - $C$ = Y-intercept - $Z$ = slope of the line (regression coefficient) The significance of the slope of regression ($Z$) is that it indicates the rate at...

Question 6

Q5: What are the major causes of species losses in a geographical region?

Accepted Answer

The accelerated rates of species extinction are largely due to human activities. The four major causes, collectively known as 'The Evil Quartet', are: 1.  Habitat loss and fragmentation: This is the most significant cause of species extinction. It involves the destruction of natural habitats, such a...

Question 7

Q6: How is biodiversity important for ecosystem functioning?

Accepted Answer

Biodiversity is crucial for the health, stability, and proper functioning of an ecosystem. Its importance can be understood through the following points: 1.  Stability: Ecologists believe that communities with more species tend to be more stable. A stable community does not show excessive variations...

Question 8

Q7: What are sacred groves? What is their role in conservation?

Accepted Answer

Sacred groves are tracts of forest that are set aside and protected by local communities due to religious and cultural traditions. All the trees and wildlife within these groves are venerated and given total protection, making them a form of in situ (on-site) conservation. Role in conservation: Sacr...

Question 9

Q8: Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?

Accepted Answer

The biotic components of an ecosystem, primarily plants and soil microorganisms, play a crucial role in controlling floods and soil erosion through the following mechanisms: 1.  Role of Plants (Flora):        Binding Soil: The dense network of roots of trees, grasses, and other plants binds soil par...

Question 10

Q9: The species diversity of plants ( 22 per cent) is much less than that of animals ( 72 per cent). What could be the explanations to how animals achieve...

Accepted Answer

While the textbook does not provide a direct explanation, several evolutionary factors can account for the greater species diversification observed in animals compared to plants: 1.  Mobility: Most animals are mobile, whereas plants are largely sessile. Mobility allows animals to disperse to new are...

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