Introduction and Biodiversity Questions in English

(A) Out of the global biodiversity hotspots,two are found in India: the Western Ghats and the Eastern Himalayas. These regions extend into neighboring countries as well. These areas are characterized by a high degree of endemism and are inhabited by a wide variety of flowering plants,swallow-tailed butterflies,amphibians,reptiles,and mammals.

(C) biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is threatened with destruction.
Initially,$25$ biodiversity hotspots were identified.
Subsequently,nine more were added to the list,bringing the total number of biodiversity hotspots in the world to $34$.

(C) Alpha diversity refers to the diversity of organisms within a particular community or habitat.
It represents the number of species (richness) and their relative abundance (evenness) within that specific ecosystem.
Therefore,it is essentially a measure of species diversity within a single community.

(C) Species diversity is defined as the measure of the variety of species and their relative abundance within a specific region.
It accounts for both the number of different species (species richness) and the evenness of their distribution (relative abundance).
For example,the Western Ghats exhibit a higher amphibian species diversity compared to the Eastern Ghats.

(C) On Earth,$70 \;\%$ of all the species recorded are animals,while plants comprise no more than $22 \;\%$ of the total.
Among animals,insects are the most species-rich taxonomic group,making up more than $70 \;\%$ of the total. This means that out of every $10$ animals on this planet,at least $7$ are insects.

(B) The term 'biodiversity' was popularized by the sociobiologist Edward Wilson.
Immense diversity (heterogeneity) exists in our biosphere,not only at the species level but at all levels of biological organization ranging from macromolecules within cells to biomes.
Edward Wilson described the combined diversity at all levels of biological organization,which includes genetic diversity,species diversity,and ecological diversity.

(B) Biodiversity hot spots are regions characterized by high levels of species richness and high degree of endemism. There are $3$ such hot spots located in India:
$1$. Western Ghats and Sri Lanka
$2$. Indo-Burma (which includes North-Eastern Himalayas)
$3$. The Himalayas.
Therefore,among the given options,the Western Ghats and North Eastern Himalayas are recognized as biodiversity hot spots.

(D) India occupies a dominant position in South Asia. The country is quite rich in biodiversity with a sizable percentage of endemic flora and fauna.
India is divided into $10$ distinct biogeographical regions.
These regions are: Trans-Himalayan,Himalayan,Indian Desert,Semi-Arid,Western Ghats,Deccan Peninsula,Gangetic Plain,North-East India,Islands,and Coasts.
The Deccan Peninsula is the largest biogeographical region of India,occupying approximately $45 \; \%$ of the total land mass.

(D) Endemic species are those that are naturally restricted to a specific geographical area and are not found anywhere else.
Sibling species are species that are morphologically similar but reproductively isolated.
Sympatric species are species that inhabit the same geographical area.
Allopatric species are species that inhabit different geographical areas.

(B) India has more than $50,000$ genetically different strains of rice.
The diversity of rice in India is the highest in the world. It is estimated that there are more than $50,000$ genetically different strains of rice in India alone. Additionally,there are $27$ documented varieties of Basmati rice grown in India.

(B) The Amazon tropical rain forests,located primarily in South America,possess the greatest biodiversity on Earth.
They are home to more than $40,000$ species of plants,$3,000$ species of fishes,$1,300$ species of birds,$427$ species of mammals,$427$ species of amphibians,$378$ species of reptiles,and more than $125,000$ species of invertebrates.

(C) The World Summit on Sustainable Development was held in $2002$ in Johannesburg,South Africa.
During this summit,$190$ countries pledged their commitment to achieve a significant reduction in the current rate of biodiversity loss at global,regional,and local levels by the year $2010$.

(B) Genetic diversity refers to the variation in the genetic information contained within the organisms of a species.
It encompasses the diversity in the number and types of genes,as well as the chromosomes present in different species,and the variation in genes and their alleles within the same species.
This diversity is fundamental to the process of speciation and the evolution of new species,allowing populations to adapt to changing environments.

(A) The Amazon rain forest is a moist broadleaf forest that covers most of the Amazon basin of South America.
This region includes territory belonging to nine nations.
The majority of the forest is contained within Brazil,with $60\%$ of the rain forest,followed by Peru with $13\%$ and with minor amounts in Colombia,Venezuela,Ecuador,Bolivia,Guyana,Suriname,and French Guiana.
The Amazon represents over half of the planet's remaining rain forests and comprises the largest and most species-rich tract of tropical rain forest in the world.
According to the $NCERT$ textbook,the Amazon rain forest harbors the greatest biodiversity on Earth,with the specific species counts mentioned in the question.

(C) The reasons for conserving biodiversity are grouped into three main categories:
$1$. Narrowly utilitarian: Humans derive countless direct economic benefits from nature,such as food,firewood,fiber,industrial products,and medicinal substances.
$2$. Broadly utilitarian: Biodiversity plays a major role in many ecosystem services that nature provides,such as the production of oxygen,pollination of flowers,and aesthetic pleasure.
$3$. Ethical utilitarian: This argument relates to what we owe to millions of plant,animal,and microbe species with whom we share this planet. Every species has an intrinsic value,even if it may not be of current economic value to us.
Therefore,the correct categories are $I$,$II$,and $IV$.

(C) According to the $NCERT$ textbook,India has nearly $45,000$ species of plants and twice as many species of animals.

(A) India has a rich heritage of agricultural biodiversity. Among the given options,rice shows the maximum genetic diversity in India.
There are an estimated $2,00,000$ varieties of rice in India alone.
The diversity of rice in India is considered one of the richest in the world.
Additionally,there are $1,000$ varieties of mango in India.

(C) The $Great \ Indian \ bustard$ $(Ardeotis \ nigriceps)$ is a long-necked,long-legged,ground-dwelling bird.
It is recognized as the largest endangered bird species found in India.

(C) $5^{th}$ June is celebrated as World Environment Day.
$1^{st}$ December is celebrated as World $AIDS$ Day.
$22^{nd}$ May is celebrated as International Day for Biological Diversity (World Biodiversity Day).
$16^{th}$ September is celebrated as World Ozone Day for the preservation of the ozone layer.

(D) The $Rivet$ $popper$ $hypothesis$ suggests that ecosystems are like aeroplane wings, where the flight (ecosystem functioning) may or may not be compromised depending upon which species are being lost.
This hypothesis, proposed by $Paul$ $Ehrlich$, compares the ecosystem to an aeroplane and the species to the rivets joining all parts together.
If every passenger pops a rivet to take home (representing species extinction), it may not affect the flight safety initially (proper ecosystem functioning).
However, as more rivets are removed over time, the plane will become dangerously weak, eventually leading to a catastrophic failure of the ecosystem.

(C) Gamma $(\gamma)$ diversity represents the total species richness across all the different habitats found within a specific region,geographical area,or landscape. Since the question refers to the total diversity across multiple ecosystems (river,desert,forest,and lake) within the state of Gujarat,it refers to Gamma diversity.

(D) According to the $IUCN$ Red List of Threatened Species,the number of species facing the threat of extinction worldwide is $15,500$. This data highlights the critical need for biodiversity conservation efforts globally.

(C) Biodiversity hot spots are regions with high levels of species richness and high degree of endemism.
According to ecological studies,these hot spots collectively cover less than $2 \;\%$ of the Earth's land area.
Specifically,the approximate value is often cited as $1.5 \;\%$.
Therefore,the correct option is $C$.

(B) The Irrawady dolphin $(Orcaella \text{ } brevirostris)$ is the flagship species of Chilka lake.
Chilka is home to the only known population of Irrawady dolphins in India and is one of only two lagoons in the world that are home to this species.

(C) There are various hypotheses for higher biodiversity in tropical areas. One of the primary reasons is that the rate of extinction is low in the tropics compared to temperate regions,which have historically been subjected to frequent glaciations.

(B) The Rivet Popper hypothesis was proposed by Paul Ehrlich.
It assumes the ecosystem to be an aeroplane and the individual species to be the rivets that hold the aeroplane together.
If every passenger popping a rivet to take home as a souvenir (causing a species to go extinct),it may not affect flight safety initially,but as more rivets are removed,the plane becomes dangerously weak over a period of time.
Thus,$A$ refers to the ecosystem and $B$ refers to the species.

(B) Species diversity is a product of both species richness and evenness or equitability,i.e.,species richness weighted by species evenness.
Odum et al. $(1960)$ calculated species diversity $(d)$ as the number of species in relation to the square root of the total number of individuals.
In ecological studies,the diversity index most commonly used is the Shannon index (also known as the Shannon-Wiener index).

(B) Based on the standard $NCERT$ biodiversity pie charts:
$1$. In the pie diagram of invertebrates $(I)$,the section labeled $A$ represents Molluscs.
$2$. In the pie diagram of vertebrates $(II)$,the section labeled $B$ represents Amphibians.
$3$. In the pie diagram of plants $(III)$,the section labeled $C$ represents Fungi (which are often grouped with plants in these ecological charts) and $D$ represents Angiosperms.
Therefore,the correct labels are $A-$Molluscs,$B-$Amphibians,$C-$Fungi,and $D-$Angiosperms.

(D) According to ecological studies,a stable community exhibits the following characteristics:
$(i)$ Its productivity should not vary too much from year to year.
$(ii)$ It should be resistant to occasional natural and man-made disturbances.
$(iii)$ It should be resistant to invasions by alien species.
Therefore,all the given statements are correct.

(B) The Eastern Himalayas hotspot of our country extends to North Eastern India and Bhutan. The Indo-Burma region, which covers the Eastern Himalayas, is also known as the "Cradle of Speciation" because it serves as a significant center for the evolution and diversification of various species.

(B) Initially,$25$ biodiversity hot spots were identified globally. Subsequently,$9$ more were added,bringing the total number of biodiversity hot spots to $34$ $(A=25, B=34)$.
These regions are characterized by accelerated habitat loss.
Collectively,these hot spots cover less than $2 \%$ of the Earth's land area $(C=2)$.
Despite their small size,they harbour an extremely high number of species. Strict protection of these areas could reduce the ongoing mass extinctions by almost $30 \%$ $(D=30)$.

(D) $(i)$ Alpha diversity refers to the diversity within a particular area or ecosystem,often expressed by the number of species in a given habitat.
$(ii)$ Genetic diversity refers to the total genetic information contained in the genes of individuals of a species,including variations of genes within a species.
$(iii)$ Beta diversity refers to the diversity between communities,which appears due to the replacement of species along a gradient of habitats. It is not the diversity of the habitat in the whole region (which is Gamma diversity).
$(iv)$ Species diversity is a function of both species richness (number of species) and species evenness (relative abundance of species). Thus,it is considered a product of these two factors.
Therefore,statements $I$,$II$,and $IV$ are correctly matched.

(B) Among the given options,insects exhibit the highest species diversity on Earth. Specifically,within the insects,beetles $(Coleoptera)$ represent the largest group,showing the maximum species diversity.

(A) The medicinal plant $Rauwolfia \text{ } vomitoria$ grows in different Himalayan ranges.
This plant shows variation in the potency and concentration of the active chemical $Reserpine$ it produces.
Since this variation occurs within the same species due to different environmental conditions across its range, it is an example of genetic diversity.

(C) Insects are the most species-rich taxonomic group on Earth.
According to estimates,out of every $10$ animals on this planet,$7$ are insects.
Therefore,insects represent the most numerous group of animals.

(A) According to the global biodiversity data of plants,$Fungi$ represent the highest number of species,followed by $Angiosperms$. Therefore,among the given options,the statement that $Angiosperms$ represent the maximum number is often considered in the context of plant groups excluding $Fungi$ in some older textbooks,but strictly speaking,$Fungi$ have the highest diversity. However,based on standard multiple-choice question patterns where $Fungi$ is not the primary focus,$Angiosperms$ are often cited as the most diverse group of plants.

(D) The species-area relationship is described by the equation $S = CA^Z$.
For smaller areas,the value of the slope $Z$ generally lies in the range of $0.1$ to $0.2$.
However,for very large areas like entire continents,the slope of the line ($Z$ value) is much steeper,typically ranging from $0.6$ to $1.2$.

(D) The 'rivet popper' hypothesis was proposed by the ecologist Paul Ehrlich. This hypothesis compares an ecosystem to an airplane,where each species acts as a 'rivet' holding the plane together. As species go extinct,the ecosystem becomes weaker,similar to removing rivets from an airplane,eventually leading to a catastrophic failure.

(B) According to the $NCERT$ textbook,more than $25\;\%$ of the drugs currently sold in the market worldwide are derived from plants. This highlights the immense medicinal value of plant biodiversity.

(B) Bio-prospecting is the systematic search for new sources of chemical compounds,genes,microorganisms,macro-organisms,and other valuable products from nature. It involves exploring molecular,genetic,and species-level diversity specifically to identify products that provide economic benefits,such as pharmaceuticals,industrial chemicals,and agricultural resources.

(C) Biodiversity hot spots are regions with high levels of species richness and high degree of endemism.
Currently,there are $34$ biodiversity hot spots identified globally.

(C) In the World Summit on Sustainable Development held in $2002$ in Johannesburg,South Africa,$190$ countries pledged their commitment to achieve by $2010$,a significant reduction in the current rate of biodiversity loss at global,regional,and local levels.

(D) Genetic diversity refers to the variety of genes within a species. Higher genetic diversity leads to greater variation among individuals in a population,which enhances the ability of the population to adapt to changing environments and serves as the raw material for evolution and speciation. Therefore,the statement that 'Higher diversity increases uniformity' is incorrect,as higher diversity actually increases variation and reduces uniformity.

(C) Regional diversity is also known as $\gamma$ (Gamma) diversity.
$\alpha$ (Alpha) diversity refers to the diversity within a particular area or ecosystem (local diversity).
$\beta$ (Beta) diversity refers to the diversity between communities or along a gradient (community diversity).
$\gamma$ (Gamma) diversity represents the total species diversity in a landscape or region.

(C) Diversity is categorized into three levels: $\alpha$ (alpha),$\beta$ (beta),and $\gamma$ (gamma) diversity.
$\alpha$ diversity refers to the diversity within a particular community or habitat (local diversity).
$\beta$ diversity refers to the diversity between communities or habitats along an environmental gradient.
$\gamma$ diversity refers to the total diversity of a landscape or region (regional diversity).
$\beta$ diversity is mathematically expressed as the ratio of $\gamma$ diversity to $\alpha$ diversity,i.e.,$\beta = \gamma / \alpha$.

(C) India covers $2.4\;\%$ of the world's total land area.
It contributes $8.1\;\%$ to the global species diversity,making it one of the $12$ mega-biodiversity countries in the world.

(D) Statement $(A)$ is correct: India,being a tropical country,possesses a much greater variety of ecosystems (such as deserts,rain forests,mangroves,coral reefs,wetlands,estuaries,and alpine meadows) compared to a Scandinavian country like Norway.
Statement $(B)$ is incorrect: According to the $IUCN$ $(2004)$ data,the total number of plant and animal species described so far is slightly more than $1.5$ million,not $15$ million as stated in the question.

(C) Based on the standard $NCERT$ pie chart representing the global diversity of plants:
$1$. The largest sections are occupied by Fungi $(A)$ and Angiosperms $(D)$.
$2$. The smaller sections represent Algae $(F)$,Mosses $(B)$,Ferns and allies $(C)$,and Lichens $(E)$.
$3$. Comparing this with the provided pie chart labels:
- $A$ corresponds to Fungi.
- $B$ corresponds to Mosses.
- $C$ corresponds to Ferns and allies.
- $D$ corresponds to Angiosperms.
- $E$ corresponds to Lichens.
- $F$ corresponds to Algae.
Therefore,the correct option is $C$.

(D) Statement $(A)$ is correct because species diversity is generally higher in the tropics compared to temperate or polar regions.
Statement $(B)$ is correct as Colombia,located near the equator,hosts nearly $1400$ species of birds.
Statement $(C)$ is incorrect because India,with much of its land area in the tropical latitudes,possesses more than $1200$ species of birds,not less than $105$.

(C) According to the $NCERT$ textbook,the Amazonian rain forest is the largest tropical rain forest on Earth. It is home to more than $40,000$ species of plants and $3,000$ species of fishes.