Introduction and Biodiversity Questions in English

(A) Maximum diversity is observed when species from taxonomically distinct groups are present in nearly equal abundance.
In option $A$:
Birds $(4)$,Insects $(4)$,and Elephant $(4)$ represent three distinct classes ($Aves$,$Insecta$,and $Mammalia$).
Since the number of individuals in each group is equal and they belong to different taxonomic groups,this sample area exhibits the highest level of biodiversity compared to the other options where either the taxonomic variety is lower or the distribution is skewed.

(C) The $IUCN$ (formerly known as $WCU$ - World Conservation Union) Red List of Threatened Species classifies organisms into $8$ distinct categories.
These categories are:
$(i)$ Extinct $(EX)$,
$(ii)$ Extinct in the Wild $(EW)$,
$(iii)$ Critically Endangered $(CR)$,
$(iv)$ Endangered $(EN)$,
$(v)$ Vulnerable $(VU)$,
$(vi)$ Lower Risk $(LR)$ (which includes Near Threatened,Least Concern,and Conservation Dependent),
$(vii)$ Data Deficient $(DD)$,
$(viii)$ Not Evaluated $(NE)$.

(C) Taxonomic diversity refers to the diversity of different taxonomic groups (e.g.,families,genera,species) within a given area.
It is considered the highest level of diversity because it accounts for the phylogenetic relationships and the variety of distinct groups present in an ecosystem.
The Assertion is correct.
The Reason states that it represents species of taxonomically different groups occurring in equal balance; however,taxonomic diversity does not require an 'equal balance' of species across groups to be defined as such.
Therefore,the Reason is incorrect.

(C) The Assertion is correct because tropical regions harbor significantly higher species diversity compared to temperate regions.
The Reason is incorrect because tropical regions are characterized by relatively constant,predictable,and less seasonal climates,which promotes niche specialization and higher biodiversity.
In contrast,temperate regions are more seasonal,which is less conducive to high species richness.

(N/A) The species diversity of plants is much less than that of animals because most animals possess a nervous system that controls and coordinates various activities. They also possess receptors to receive environmental stimuli. These responses are often adaptive and ensure the survival of the organism in changing environmental conditions,allowing for greater diversification compared to plants.

(N/A) It is difficult to estimate the global diversity of prokaryotes because conventional taxonomic methods are not suitable for identifying microbial species. Many of these species cannot be cultured under laboratory conditions. Biochemical and molecular biology techniques suggest that their diversity could be in the millions.

(N/A) $1$. Biodiversity: It refers to the variety and variability of all living organisms (microbes,plants,and animals) within a specific area or the entire Earth. It represents the degree of biological variety in nature.
$2$. Species diversity: It refers to the variety of species within a region. It is determined by the number of different species present in a particular area and their relative abundance.

(N/A) Endemic species are those species of plants and animals that are found exclusively in a particular geographical region and are not naturally found anywhere else in the world. These species are restricted to a small or specific area due to factors like physical barriers,climate,or evolutionary history.

(N/A) Endemism is the ecological state of a species being unique to a defined geographic location,such as an island,nation,country,or other defined zone,or habitat type. Organisms that are indigenous to a single location are said to be endemic to that place.

(N/A) Genetic diversity refers to the variation in the genetic constitution of individuals within a species. It represents the total number of genetic characteristics in the genetic makeup of a species,which allows populations to adapt to changing environments.

(B) $\beta$-diversity refers to the variation in species composition between two different habitats or communities along an environmental gradient. It measures the rate of species replacement or turnover as one moves from one habitat to another.

(N/A) $\gamma$-diversity refers to the total species richness across a range of different habitats within a large geographical region or landscape. It represents the overall diversity of an entire ecosystem or region,encompassing the diversity of all the communities present within it.

(A) The full form of $UNESCO$ is United Nations Educational,Scientific and Cultural Organization.
It is a specialized agency of the United Nations aimed at promoting world peace and security through international cooperation in education,arts,sciences,and culture.

(A) The term $Biodiversity$ refers to the variety and variability of life on Earth. It encompasses the number of different species,their genetic diversity,and the variety of ecosystems they inhabit. In the context of biology,the total number and types of organisms present on Earth are collectively referred to as biodiversity.

(A) Robert Costanza and his colleagues have made a very bold attempt to put price tags on nature's life-support services. They estimated that the average price tag for these ecosystem services is $US 33 trillion$ a year, which is largely taken for granted because they are free. This value is significantly higher than the global Gross National Product $(GNP)$ of $US 18 trillion$ at that time.

(B) According to Robert Costanza and his colleagues,the total value of ecosystem services is estimated to be around $33$ trillion $US$ dollars per year. This value is significantly higher than the global Gross National Product $(GNP)$,which is approximately $18$ trillion $US$ dollars. Therefore,the correct value for the global $GNP$ is $18$ trillion $US$ dollars.

(C) Biodiversity is the term used to describe the variety of life found on Earth and all of the natural processes. This includes ecosystem diversity,species diversity,and genetic diversity. Therefore,it encompasses the number and types of organisms present on Earth,as well as the variations within species and ecosystems. Thus,the most comprehensive definition among the given options is the number and types of organisms present on Earth.

(C) According to the $NCERT$ textbook for Class $12$ Biology,Chapter $15$ (Biodiversity and Conservation),there are more than $20,000$ species of orchids on Earth. This is a factual data point provided under the section discussing global biodiversity.

(B) The term $Biodiversity$ was coined by $Walter \text{ } G. \text{ } Rosen$ in $1985$, but it was popularized by the sociobiologist $Edward \text{ } Wilson$ to describe the combined diversity at all the levels of biological organization. Therefore, the correct option is $B$.

(D) The correct matches are as follows:
$(P)$ Genetic diversity refers to the diversity at the genetic level within a species.
$(Q)$ Species diversity refers to the diversity at the species level.
$(R)$ Ecological diversity refers to the diversity at the ecosystem level (e.g., deserts, rain forests, mangroves, etc.).
Therefore, the correct matching is $(P-I), (Q-II), (R-III)$.

(A) According to the $NCERT$ textbook on Biodiversity and Conservation,India is home to a vast amount of genetic diversity.
Specifically,there are more than $50,000$ genetically diverse strains of rice.
Additionally,there are more than $1,000$ varieties of mango in India.
Therefore,the correct option is $A$.

(C) The plant $Rauwolfia$ $vomitoria$ is a medicinal plant found in the Himalayan ranges. It produces an active chemical known as reserpine,which is highly effective in the treatment of high blood pressure (hypertension). However,it is not an edible plant; it is primarily used for its pharmacological properties. Therefore,the statement that it is an edible plant is incorrect.

(D) The Scandinavian countries traditionally include $Norway$,$Sweden$,and $Denmark$. $Finland$ is often grouped with the Nordic countries but is not geographically or culturally considered part of Scandinavia in the strict sense. However,$Russia$ is definitely not a Scandinavian country,as it is a transcontinental country spanning Eastern Europe and Northern Asia. Among the given options,$Russia$ is the most distinct from the Scandinavian region.

(A) $IUCN$ stands for International Union for Conservation of Nature and Natural Resources.
It is an international organization working in the field of nature conservation and sustainable use of natural resources.

(B) According to the $NCERT$ textbook representation of global biodiversity of invertebrates,the pie chart is divided as follows:
$1$. $S$ represents Insects,which constitute the largest group of invertebrates.
$2$. $R$ represents Crustaceans.
$3$. $Q$ represents Molluscs.
$4$. $P$ represents other animal groups.
Therefore,the label $Q$ corresponds to the group of Molluscs.

(C) According to the $NCERT$ textbook (Chapter: Biodiversity and Conservation), the global biodiversity of plant species is represented by a pie chart where:
$Q$ represents Angiosperms, which constitute the largest portion of plant diversity.
$R$ represents Fungi, which occupy a significant portion.
$P$ represents Lichens, which occupy a smaller portion compared to Fungi and Angiosperms.
Therefore, the correct identification is $P = \text{Lichens}, Q = \text{Angiosperms}, R = \text{Fungi}$.
However, looking at the provided options, option $C$ is the most accurate representation based on the standard pie chart provided in the textbook.

(D) The concept of 'megadiverse countries' was identified by Conservation International. There are $12$ countries that have been identified as megadiverse,which harbor the majority of the Earth's species and high numbers of endemic species. These countries are Australia,Brazil,China,Colombia,Ecuador,India,Indonesia,Madagascar,Mexico,Peru,Philippines,and Democratic Republic of Congo.

(A) According to the $NCERT$ textbook,the Amazonian rainforest is home to millions of species,many of which are still unknown to science. It is estimated that at least $2$ million insect species are yet to be discovered and named in these regions. Therefore,the correct option is $A$.

(A) According to the data provided in the $NCERT$ textbook regarding the biodiversity of the Amazon rainforest:
- $(P)$ Plants: $40,000$ species $(I)$
- $(Q)$ Fishes: $3,000$ species $(II)$
- $(R)$ Birds: $1,300$ species $(III)$
- $(S)$ Mammals or Amphibians: $427$ species $(IV)$
- $(T)$ Reptiles: $378$ species $(V)$
Therefore,the correct matching is $(P-I), (Q-II), (R-III), (S-IV), (T-V)$.

(A) According to the $NCERT$ textbook,the Amazon rainforest is the most biodiverse region on Earth.
It is estimated to be home to at least $40,000$ 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 $1,25,000$ species of invertebrates.

(D) Species diversity is higher in tropical regions due to several factors:
$1$. Tropical latitudes have remained relatively undisturbed for millions of years,unlike temperate regions which were subjected to frequent glaciations in the past. This provided a long evolutionary time for species diversification.
$2$. Tropical environments are less seasonal,relatively more constant,and predictable. Such constant environments promote niche specialization and lead to a greater species diversity.
$3$. There is more solar energy available in the tropics,which contributes to higher productivity. Increased productivity is often associated with higher species richness.

(D) The relationship between species richness and area for a wide variety of taxa (angiosperm plants,birds,bats,freshwater fishes) turns out to be a rectangular hyperbola.
On a logarithmic scale,this relationship becomes a straight line described by the equation $\log S = \log C + Z \log A$.
However,when plotted on a normal scale with area $(A)$ on the $X$-axis and species richness $(S)$ on the $Y$-axis,the equation $S = CA^z$ represents a rectangular hyperbola,which appears as a curve that rises steeply at first and then levels off as the area increases.
Among the given options,the graph shown in option $D$ represents this characteristic rectangular hyperbola curve.

(B) The 'Rivet Popper' hypothesis was proposed by the ecologist $Paul \ Ehrlich$.
This hypothesis uses the analogy of an airplane to explain the importance of biodiversity.
In this analogy,the ecosystem is compared to an airplane,and the species are compared to the rivets holding the parts together.
If passengers start popping rivets (removing species) one by one,the flight safety is initially unaffected,but as more rivets are removed,the plane becomes dangerously weak and eventually crashes,representing the collapse of the ecosystem.

(B) According to David Tilman's long-term ecosystem experiments,a stable biological community should possess the following characteristics:
$1$. It should not show too much variation in productivity from year to year.
$2$. It should be resistant to occasional disturbances (either natural or human-made).
$3$. It should be resistant to invasions by alien species.
Therefore,the statement that a stable community should be 'sensitive' to disturbances is incorrect,as stability implies resistance or resilience to such disturbances.

(B) The Rivet Popper Hypothesis was proposed by Paul Ehrlich to explain the importance of species diversity in an ecosystem.
In this analogy,the airplane represents the $Ecosystem$.
The rivets on the wings represent the $Species$ that make up the ecosystem.
If a passenger removes a rivet (extinction of a species),it may not affect the flight safety initially,but if too many rivets are removed,the airplane becomes weak and eventually crashes,leading to the collapse of the ecosystem.

(A) Tropical rainforests are known as the 'lungs of the planet' because they play a crucial role in maintaining the earth's climate and oxygen levels.
Historically,these rainforests covered more than $14 \%$ of the earth's land surface.
Due to rapid deforestation and human activities,their coverage has drastically reduced.
Currently,these rainforests cover no more than $6 \%$ of the earth's land surface.
Therefore,the correct values are $14 \%$ and $6 \%$.

(B) The Amazon rainforest is often referred to as the 'Lungs of the Planet' because its vast vegetation absorbs massive amounts of carbon dioxide and releases oxygen through photosynthesis,playing a crucial role in regulating the Earth's climate.

(B) The arguments for conserving biodiversity are classified into three categories:
$1$. Narrowly utilitarian: Derived from direct economic benefits like food,firewood,fiber,construction material,industrial products,and medicinal products.
$2$. Broadly utilitarian: Derived from ecosystem services that nature provides,such as pollination (by bees,birds,bats),oxygen production,flood control,and aesthetic pleasure.
$3$. Ethical: Based on the belief that every species has an intrinsic value and we have a moral duty to pass on the biological legacy to future generations.
Since pollination is an ecosystem service provided by nature,it falls under the broadly utilitarian argument.

(A) According to the $NCERT$ textbook under the chapter 'Biodiversity and Conservation',it is stated that $25 \%$ of all drugs currently sold in the market worldwide are derived from plants.
Furthermore,$25,000$ species of plants contribute to the traditional medicines used by native peoples around the world.

(B) According to the $NCERT$ textbook under the section 'Biodiversity and Conservation',it is estimated that approximately $25,000$ plant species are used by indigenous people around the world in traditional medicines. This highlights the importance of biodiversity in human health and traditional knowledge systems.

(C) Bioprospecting 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 to identify products that have economic importance,such as pharmaceuticals,industrial chemicals,and agricultural products.
Therefore,the correct answer is $Bioprospecting$.

(D) Biodiversity hotspots are biogeographic regions with a significant reservoir of biodiversity that is under threat from destruction.
Initially,$25$ hotspots were identified by Norman Myers.
Over time,the number has been revised based on further research and criteria.
Currently,there are $36$ recognized biodiversity hotspots globally.

(B) Biodiversity hotspots are regions with very high levels of species richness and high degree of endemism.
Although these hotspots cover less than $2 \%$ of the Earth's land area,the number of species they collectively harbour is extremely high.
Strict protection of these hotspots could reduce the ongoing mass extinctions by almost $30 \%$.

(B) Biodiversity hotspots are regions that are characterized by high levels of species richness and a high degree of endemism,while also facing significant threats to their habitat.
According to the global classification,there are $36$ biodiversity hotspots in the world.
In India,the recognized biodiversity hotspots are the Western Ghats and Sri Lanka,the Himalayas,the Indo-Burma region,and the Sundaland.
The Aravalli Hills are not classified as a global biodiversity hotspot.
Therefore,the correct option is $B$.

(C) Tropical forests are characterized by high biodiversity and a stable climate that supports plant growth throughout the year.
Because of the favorable climatic conditions,many plant species in tropical regions produce fruits at different times of the year.
This continuous availability of food resources (fruits) supports a large population of frugivorous (fruit-eating) birds,as they do not face food scarcity during any season.
Therefore,the primary reason for the abundance of frugivorous birds in tropical forests is the availability of fruits throughout the year.

(C) Species that are restricted to a specific geographic area and are not found naturally anywhere else in the world are known as $Endemic$ species.
Western Ghats are a biodiversity hotspot known for a high degree of endemism,meaning many of its flora and fauna are unique to that region.
$Threatened$ species are those likely to become extinct in the near future.
$Keystone$ species are those that have a disproportionately large effect on their environment relative to their abundance.
$Vulnerable$ species are those that are likely to become endangered unless the circumstances threatening their survival and reproduction improve.

(C) The historic Convention on Biological Diversity,known as 'The Earth Summit',was held in Rio de Janeiro in the year $1992$.
This summit called upon all nations to take appropriate measures for the conservation of biodiversity and the sustainable utilisation of its benefits.

(D) Statement $A$ is correct because tropical latitudes have remained relatively undisturbed for millions of years,allowing more time for evolutionary diversification.
Statement $B$ is incorrect because tropical environments are less seasonal compared to temperate regions.
Statement $C$ is correct as higher solar energy input in the tropics promotes higher primary productivity.
Statement $D$ is correct because constant environments allow species to evolve specialized niches.
Statement $E$ is correct because tropical environments are relatively constant and predictable,which supports higher biodiversity.
Therefore,statements $A, C, D,$ and $E$ are correct.

(A) Statement-$I$ is correct: India is recognized as one of the $12$ mega biodiversity countries in the world due to its rich variety of flora and fauna.
Statement-$II$ is correct: India occupies only $2.4 \%$ of the world's total land area,yet it contributes significantly to global biodiversity (about $8.1 \%$ of the global species diversity).
Therefore,both statements are correct.