9th Biology Chapter 3 Biodiversity

Question 1. What is the History of Classification in Biology?
Answer:

The history of classification in biology dates back to ancient civilizations, where organisms were grouped based on observable characteristics. However, modern classification systems began to emerge in the 18th century with the work of Carl Linnaeus, who developed the binomial nomenclature system and established the hierarchical classification system still used today. Since then, classification has evolved with advances in evolutionary biology, genetics, and molecular biology, leading to more accurate and comprehensive methods for organizing and categorizing living organisms.

Question 2. What are Viroids?
Answer:

Viroids are small, circular RNA molecules that infect plants and cause diseases by interfering with the host’s gene expression and metabolism. Unlike viruses, viroids do not encode proteins and rely entirely on the host cell’s machinery for replication. Viroids are simpler in structure compared to viruses and are composed of a single-stranded RNA molecule folded into a characteristic secondary structure. They are responsible for diseases such as potato spindle tuber disease and citrus exocortis.

Question 3. What are Some Extinct and Endangered Animals in Pakistan?
Answer:

Some extinct and endangered animals in Pakistan include:

– Extinct: Pakistan’s extinction record includes species like the Pakistani cheetah (Acinonyx jubatus venaticus), the pink-headed duck (Rhodonessa caryophyllacea), and the Javan rhinoceros (Rhinoceros sondaicus).

– Endangered: Endangered species in Pakistan include the snow leopard (Panthera uncia), the Indus river dolphin (Platanista gangetica minor), the Himalayan brown bear (Ursus arctos isabellinus), the markhor (Capra falconeri), and the gharial (Gavialis gangeticus).

Question 4. What are Prions?
Answer:

Prions are infectious proteins that cause degenerative neurological diseases in animals and humans, such as Creutzfeldt-Jakob disease (CJD), mad cow disease (bovine spongiform encephalopathy), and scrapie in sheep. Unlike viruses, prions lack genetic material (DNA or RNA) and consist solely of misfolded proteins. They can induce normal proteins to adopt the abnormal, infectious conformation, leading to the formation of protein aggregates in the brain and neuronal damage.

Question 5. What are the Five Kingdoms of Living Organisms?
Answer:

The five kingdoms of living organisms are:

1. Monera: Includes unicellular prokaryotic organisms like bacteria and cyanobacteria.
2. Protista: Consists of unicellular eukaryotic organisms such as protozoans, algae, and slime molds.
3. Fungi: Comprises multicellular eukaryotic organisms like mushrooms, molds, and yeasts, which obtain nutrients through absorption.
4. Plantae: Includes multicellular eukaryotic organisms, such as flowering plants, ferns, and mosses, which photosynthesize to produce energy.
5. Animalia: Comprises multicellular eukaryotic organisms with specialized tissues and organ systems, such as mammals, birds, reptiles, amphibians, and fish.

Question 6. Why is Biodiversity Important in Natural Ecosystems?
Answer:

Biodiversity is crucial for the functioning and stability of natural ecosystems due to several reasons:

– It supports ecosystem services such as pollination, nutrient cycling, and climate regulation, which are essential for human well-being.

– Biodiversity increases ecosystem resilience to environmental changes and disturbances, enhancing their ability to recover from disruptions.

– It provides genetic resources for agriculture, medicine, and biotechnology, contributing to human health and economic development.

– Biodiversity enhances ecological productivity and stability, promoting the survival of species and the sustainability of ecosystems over time.

Question 7. What are the Aims and Principles of Classification in Biology?
Answer:

The aims of classification in biology are to organize and categorize living organisms based on their shared characteristics and evolutionary relationships. The principles of classification include:

– Hierarchical Organization: Organisms are grouped into taxonomic levels, such as domain, kingdom, phylum, class, order, family, genus, and species, based on shared characteristics.

– Evolutionary Relationships: Classification reflects the evolutionary history and genetic relatedness of organisms, with closely related species grouped together in the same taxa.

– Binomial Nomenclature: Organisms are assigned scientific names consisting of two parts (genus and species) using Latin or Greek words, providing a universal system for identifying and referring to species.

– Use of Morphological, Molecular, and Ecological Data: Classification is based on a combination of morphological, molecular, and ecological characteristics to ensure accuracy and consistency in grouping organisms.

Question 8. What are the Effects of Deforestation on Biodiversity?
Answer:

Deforestation negatively impacts biodiversity in several ways:

– Loss of Habitat: Deforestation destroys the habitats of countless plant and animal species, leading to population declines and local extinctions.

– Disruption of Ecosystems: Forests are complex ecosystems that support a diverse array of species. Deforestation disrupts ecological interactions and alters ecosystem processes, reducing biodiversity.

– Fragmentation: Fragmentation of forests into smaller, isolated patches increases edge effects and reduces habitat connectivity, making it difficult for species to migrate and survive.

– Loss of Keystone Species: Deforestation can lead to the loss of keystone species, which play crucial roles in maintaining ecosystem structure and function. The disappearance of keystone species can have cascading effects on entire ecosystems.

– Soil Erosion and Degradation: Deforestation increases soil erosion, sedimentation in water bodies, and loss of soil fertility, affecting plant growth and disrupting nutrient cycling.

– Climate Change: Forests act as carbon sinks, absorbing carbon dioxide from the atmosphere and helping mitigate climate change. Deforestation releases stored carbon and reduces the capacity of ecosystems to sequester carbon, contributing to global warming and climate instability.

Question 9. What is Pollution?
Answer:

Pollution refers to the presence of harmful or undesirable substances in the environment, such as air, water, and soil, that adversely affect living organisms and ecosystems. Pollution can be caused by natural processes or human activities, including industrial processes, transportation, agriculture, and waste disposal. Common types of pollution include air pollution (e.g., emissions from vehicles and factories), water pollution (e.g., discharge of chemicals and sewage into rivers and oceans), and soil pollution (e.g., contamination with heavy metals and pesticides). Pollution poses significant threats to biodiversity and human health and requires concerted efforts to mitigate its impacts and prevent further degradation of the environment.

Question 10. What is Conservation of Biodiversity?
Answer:

Conservation of biodiversity refers to the efforts aimed at preserving and protecting the variety of life forms and ecosystems on Earth. It involves the management and sustainable use of natural resources, the protection of endangered species and habitats, and the promotion of biodiversity awareness and education. Conservation efforts are essential for maintaining ecosystem stability, preserving ecosystem services, and safeguarding the planet’s natural heritage for future generations.

Question 11. What is Binomial Nomenclature?
Answer:

Binomial nomenclature is a system of naming species in which each species is given a unique two-part scientific name consisting of the genus name followed by the species name. This naming system was developed by Carl Linnaeus in the 18th century to provide a universal and standardized way of identifying and classifying organisms.

Question 12. What is the Structure of a Virus?
Answer:

A typical virus consists of:

– Genetic Material: Either DNA or RNA, which carries the instructions for viral replication and protein synthesis.

– Protein Coat (Capsid): Surrounds and protects the genetic material, composed of protein subunits called capsomeres.

– Envelope (in some viruses): A lipid membrane derived from the host cell’s membrane, which surrounds the capsid in some viruses.

– Spikes or Glycoproteins: Protein structures on the surface of the virus that facilitate attachment to host cells and entry into them.

Question 13. What are the Issues of Conservation of Biodiversity in Pakistan?
Answer:

Pakistan faces several challenges in the conservation of biodiversity, including:

– Habitat Loss and Degradation: Deforestation, urbanization, and agricultural expansion lead to habitat loss and degradation, threatening many plant and animal species.

– Pollution: Pollution from industrial activities, agriculture, and urban areas contaminates air, water, and soil, harming ecosystems and biodiversity.

– Overexploitation: Unsustainable hunting, fishing, and harvesting of wildlife and plants threaten the survival of many species, particularly those already endangered.

– Invasive Species: Introduction of non-native invasive species disrupts native ecosystems, outcompetes native species, and poses threats to biodiversity.

– Climate Change: Climate change affects habitats, distribution patterns, and reproductive cycles of species in Pakistan, leading to shifts in biodiversity and ecosystem dynamics.

– Lack of Awareness and Enforcement: Limited awareness about biodiversity conservation and weak enforcement of environmental laws contribute to biodiversity loss and degradation.

Question 14. What is Deforestation?
Answer:

Deforestation is the clearing or removal of forests and trees from a land area, typically for agricultural expansion, logging, infrastructure development, or urbanization. It is a significant driver of habitat loss and biodiversity decline worldwide.

Question 15. Why is Binomial Nomenclature Important?
Answer:

Binomial nomenclature is important because it provides a precise and standardized way of identifying and naming species, regardless of language or geographical location. It eliminates confusion caused by common names, which can vary between regions and languages, and ensures clarity and consistency in scientific communication. Binomial names also reflect the evolutionary relationships between species, facilitating the organization and classification of biodiversity.

Question 16. How Do Humans Impact Biodiversity?
Answer:

Humans impact biodiversity through various activities, including:

– Habitat destruction and fragmentation: Clearing forests, draining wetlands, and urbanization lead to loss of habitat and fragmentation of ecosystems, reducing biodiversity.

– Pollution: Release of pollutants into air, water, and soil harms organisms and ecosystems, disrupting ecological balance and contributing to biodiversity loss.

– Overexploitation: Unsustainable hunting, fishing, and harvesting of wildlife and plants can lead to the decline or extinction of species, disrupting ecological communities.

– Introduction of invasive species: Introduction of non-native species into new habitats can outcompete native species, disrupt food webs, and cause ecosystem imbalances, leading to biodiversity loss.

– Climate change: Alteration of climate patterns due to human activities affects habitats, migration patterns, and reproductive cycles of organisms, leading to shifts in species distributions and biodiversity loss.

Question 17. What is a Virus?
Answer:

A virus is a non-cellular infectious agent that consists of genetic material (either DNA or RNA) enclosed in a protein coat called a capsid. Viruses cannot replicate on their own and require a host cell to reproduce. They infect a variety of organisms, including plants, animals, and bacteria, causing diseases such as the common cold, influenza, and COVID-19.

Question 18. What is Biodiversity?
Answer:

Biodiversity refers to the variety of life forms present in a particular ecosystem, including plants, animals, microorganisms, and their interactions. It encompasses genetic diversity, species diversity, and ecosystem diversity, reflecting the richness and complexity of biological systems.