Chapter 15: Biodiversity and Conservation

Ans: 1. Species extinction refers to the irrevocable loss of a portion of the earth's biological diversity. There are two types of causes for species extinction: natural causes and manmade causes. Natural disasters like floods, volcanic eruptions, extended droughts, and other natural calamities were common in the early days, resulting in habitat destruction and a lack of acceptable living conditions for creatures.

2. The introduction of new species can sometimes result in the extinction of other species. However, anthropogenic activities are currently the leading cause of species extinction. People are cutting down trees for their beneficial land usage, generating pollution, as a result of the expanding population. Currently, overconsumption of resources without recovery is causing species extinction. Natural disasters and human activities both contribute to habitat degradation, which is a big issue.

Ans: Habitat loss and fragmentation is the most significant of the four major causes of biodiversity loss, as follows:

I The degradation of natural ecosystems occurs as a result of overexploitation of forest regions for agriculture, industrialisation, and urbanisation.

(ii) As the world's population grows, there is a greater need for additional resources, which leads to the destruction of forest area. Several species are losing their habitat as a result of deforestation.

(iii) There is no time for recovery due to overconsumption, which may result in biodiversity loss.

(iv) When huge habitats are broken down into small bits, creatures suffer severe consequences as a result of the new adaptation, resulting in population decrease.

As a result, habitat fragmentation and loss are the leading causes of biodiversity loss.

Ans: 1. Co-extinction occurs when the extinction of one species causes the extinction of another. Co-extinction occurs when two species that are mutually connected or intertwined are affected by one other's extinction. It naturally leads to the extinction of a huge number of interconnected species, posing a threat to species biodiversity.

2. When a host fish species goes extinct, its parasitic species goes extinct as well. Plant pollinator mutualism is another example, in which the disappearance of pollinator insects can result in the extinction of plant species. Parasites that rely on specific creatures for nourishment will eventually become extinct, and the parasite will follow suit. Coextinction can be seen in a variety of ways.

Ans: The number of species in relation to the area is known as a species-area slope. The slope of larger areas is steeper than that of smaller areas. The reason for a steeper slope for greater areas is that there is more food and resources available for animals in larger regions.

They have more opportunities to adapt to changes in food preferences and resources, and there will be no competition among species for resources, whereas in smaller areas, food supply and resources are limited, resulting in competition, and only the fittest among them survive. There is also limitation in resources which leads to competition and only the fittest among them remain alive. 

Ans: It is not always possible for a community's productivity and variety to remain stable over time.

(ii) Natural habitats are never kept in good condition.

(iii) The conditions for reproduction and survival in the environment change with time.

(iv) Species extinction and evolution occur over time, and the productivity and variety of a natural community alter as a result of these changes.

(v) Co-extinction happens as a result of natural disasters and anthropogenic activity, resulting in biodiversity loss.

As a result, it is impossible to maintain the same level of output and diversity.

Ans: 1. Due to the environmental differences in different locations, tropical/subtropical regions have more biodiversity than temperate regions. Near the equator are the tropical and subtropical zones. Due to less fluctuating climatic circumstances, the region remains stable/unaffected.

2. Species have sufficient time to undergo evolutionary changes, resulting in species diversity. Because of their evolution, tropical/subtropical animals have a stronger ability to adapt to their environment. The environment in temperate climates, on the other hand, is more seasonal, unpredictable, and less consistent, resulting in lower species variety. The evolution of organisms is complicated due to changing environmental conditions. As a result, as compared to temperate regions, tropical/subtropical regions have the greatest biological variety.

Ans: 1. Pathogenic bacteria is basically detected by conventional methods mainly based on cultivation procedures. This method is selective for the research of only one type of pathogen at a time. They use enrichment broths followed by the isolation process of colonies. 

2. Biochemical identification is done which provides the information of bacteria's morphology and chemical composition. After this process confirmation of pathogenicity is done.  

3. Many of the bacteria cannot be cultured under normal conditions in vitro which creates problems in studying their morphological and biochemical characters. These characters are used for the assessment of the biodiversity of bacteria. Therefore, conventional methods are not suitable for the assessment of the biodiversity of bacteria. 

Ans:  Criteria for categorizing a species as threatened species are:

1. An increase in predatory or poaching behaviour. People are accustomed to slaughtering animals for the skin and other goods they provide. These skins and materials were used to make leather bags, clothing, cosmetics, and dyes, among other things. Although it is prohibited in some locations, people continue to transport animals illegally for their own use.

2. Changes to or destruction of their natural habitat. This is primarily caused by natural disasters and human actions. Deforestation is a primary driver of habitat loss, which can result in species extinction. Afforestation is a strategy to rescue other species that are still alive. People must use resources in a way that is both sustainable and efficient.

3. The extinction of vast numbers of species is caused by overexploitation of resources and a lack of time for them to regenerate. Some species adapt fast, while others become extinct. And we must take tremendous steps to protect our biodiversity.

Ans: The following is a list of reasons why frogs are more vulnerable to extinction than other animal groups:

1. Climate change on a large scale alters aquatic ecosystems, preventing amphibians from reproducing.

2. The most common cause of extinction is habitat change or destruction. Amphibians require both aquatic and terrestrial environments to survive. As a result, risks to either habitat can have an impact on their populations.

3. Habitat fragmentation also contributes to amphibian extinction. Habitat fragmentation occurs when habitat change isolates a few regions. These small populations that persist are sometimes subject to genetic drift or inbreeding, or they may become extinct as a result of minor environmental changes.

Ans: The estimation of extrapolated species on earth can be done by two methods:

(i) The primary method is to estimate the rate of discovery of new species

(ii) The statistical comparison of the temperate and tropical species richness of group of insects studied exhaustively can extrapolate the total number of species. The ratio is extrapolated then with plant and animal species existing that helps in gross estimation of the number of species on the earth prediction