Matric Notes Biology Class 9th Ch 3 Biodiversity Extra Short & Long Questions

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Short Questions

Q.1) How does deforestation lead to desertification?

Answer: Deforestation:

“Deforestation is one of the major cause of the loss of biodiversity.”

Forests are a vital resource for humans. They are the natural factories for the production of oxygen. Forests provide habitats to wildlife. They are also the source of fuel, timber and also provide recreation to man. Forests control floods, prevent the formation of deserts and keep the air clean.

Causes/reasons of deforestation:

  Some of the major reasons for deforestation are:

• Extension of cities requires more land, thus forests are cut to build roads and houses etc.
• Ever increasing population need more land for agricultural activities.
• Trees are also removed to develop pastures for grazing.
• Wood is used both as timber and as fuel wood.
• Timber mafia cut the trees for easy cash. All these factors lead to the removal of trees.

Effects of deforestation:

• Deforestation leads to soil erosion
• Destruction of habitats for wildlife
• Extinction of many species
• Floods, climatic changes, and desertification (the process of formation of deserts).

Q.2) Why is it important for a biologist to understand biological classification?

Answer: The biologist has identified and described 2 million kinds of organisms (0.5 million types of plants and 1.5 million animals). These are only a small percentage of the total kinds of estimated which actually live on earth. To study a large collection of organisms, biologist classifies them. Classification is a method by which biologists divide organisms into groups and subgroups on the basis of similarities and differences.

It is important for a biologist to understand biological classification because this classification allows scientists to identify, group, and properly name organisms according to the rules of taxonomy which is based on similarities found in the organisms DNA/RNA (genetics), their adaptations, and embryonic development.

In order to do this, it is very important for scientists to have first agreed upon a standard approach to naming and classifying an organism because without it unknown organisms could be classified differently. However, by only using the modern international taxonomic approach (domain, kingdom, phylum, class, order, family, genus, species) first proposed by Linnaeus, all organisms are named and grouped in the same manner making them more easy to study and keep track of them.

Q.3) What is the status of viruses in classification?

Answer: Classification of a virus:

  Virus classification is the process of naming viruses and placing them into a taxonomic system. Viruses are mainly classified by phenotypic characteristics, such as morphology, nucleic acid type, mode of replication, host organisms, and the type of disease they cause.

  Viruses are unique particles having circular RNA only. They are not considered as living organisms and are not included in the classification system.

Living characteristics of viruses:

  They have some living characteristics.  They reproduce in host cells only and contain RNA or DNA, hereditary material which is enclosed in a protein coat.

Non-living characteristics of viruses:

  They also have non-living characteristics. They are not made of cells and do not respire or excrete out the host cells. They live as parasites in all types of organisms and cause diseases in them. They use the metabolism of the cells in which they live. Outside the living host cells, they are inactive. Viruses can be crystallized and this is a property of non-living materials. In crystal form, they can be stored for an indefinite period of time, without any loss of reproductive ability. When the crystallized viruses are placed under favorable conditions, they again start reproducing.

Q.4) How you can differentiate between kingdom Monera and Protista?

Answer:

Kingdom Monera	Kingdom Protista
Kingdom Monera is unicellular organisms having a prokaryotic cellular structure.	Protistas are also unicellular organisms though possess eukaryotic cellular organization.
These organisms lack membrane-bound organelles	Well defined membrane-bounded cellular organelles are present in organisms of kingdom Protista
Monera are simple in structure, with no complexity	Protista are complex in structure
Monera’s does not possess a true nucleus.	Protists have a well-defined nucleus, bounded with a nuclear membrane
They are heterotrophic but some produce their food by photosynthesis or chemosynthesis	Some protists contain chlorophyll and make their own food while others lack chlorophyll and cannot prepare their own food.
Examples are bacteria and blue green algae (Cyanobacteria)	Examples of protists are Plasmodium, Euglena, Paramecium, Chlymadomonas etc.

Q.5) List down the endangered species of Pakistan and what are the reasons behind their population decrease.

Answer: Endangered species of Pakistan:

  In Pakistan, the main issues of conservation of biodiversity include deforestation and hunting. We have only 5.2% of forest in our country. Similarly, many species have become extinct or endangered.

Causes:

• Over-fishing in rivers, lakes, and ponds has resulted in the reduction of many fish species like shermahi, mahasher etc.
• Macropolo sheep and Houbara bustard (Markhor) population have been reduced due to overhunting.
• Musk deer are killed for their glands used for making perfume.
• Asiatic cheetah, Indian horned rhinoceros, swamp deer are near to be extinct in Pakistan.
• The most serious threat faced by Indus river dolphin is the release of heavily polluted water into the sea, which is causing the blindness of these dolphins.

Long Questions

Q.1) Differentiate between the two kingdom system and five kingdom system along with their advantages and disadvantages.

Answer:

Two-kingdom system	Five kingdom system
It was proposed by Carolus   Linnaeus in 1751	Five kingdom system was proposed by Robert Whittaker in 1959
Organisms are classified into 2 kingdoms	Organisms are classified into 5 kingdoms
The two-kingdom system is based on nutrition and motility	Five kingdom system is based on the cell structure, complexity of body, mode of nutrition, mode of reproduction and evolution.

Advantages of two-kingdom system:

• The two-kingdom system is based on nutrition and motility.
• It initiated the systematic classification of living organisms.

Disadvantages of two kingdom system:

• This system of classification has not dealt upon the status of viruses.
• The placement of organisms like Euglena, bacteria, fungi in Plantae is questionable due to certain reasons
• In the two kingdom system, the prokaryotes and eukaryotes are placed together and the difference between them is not clear.
• Plants are autotrophs while fungi are heterotrophs but both are placed together in Plantae in two-kingdom system

Advantages of five kingdom system:

• Five kingdom system is based on the cell structure, complexity of body, mode of nutrition, mode of reproduction and evolution.
• In the five-kingdom system, organisms are better placed on the basis of body, cell structure, and evolution
• In this system, prokaryotes are placed in kingdom Monera and eukaryotes are placed separately
  
• Fungi are placed in kingdom Fungi and plants are placed separately in kingdom Plantae.

Disadvantages of five kingdom system:

• The main disadvantage of five kingdom system is it does not specify the position of viruses.
• The five kingdom does not specify the protists properly because some are heterotrophic and some are autotrophic

Q.2) Take one organism and assign it to different ranks according to the hierarchy of taxonomy.

Answer: Taxonomic Hierarchy of Taxonomy:

Kingdom	Animalia
Phylum	Chordata
Class	Mammalia
Order	Carnivora
Family	Felidae
Genus	Panthera
Species	Panthera pardus

Q.3) How human activities affect the biodiversity of the area?

Answer: Impact of human beings on biodiversity:

  Due to human activities, the biodiversity of many areas and the Earth as a whole is decreasing day by day. Some of these activities are as under

1. Habitat loss and deforestation:

       All species have specific food and habitat needs. Habitat loss means the destruction of the natural habitat of species. Humans are utilizing land and natural resources and destroying valuable habitats of wildlife.

For example:

  In order to cope with the demands of food, people are clearing forests and developing agricultural lands and residential colonies. In Pakistan, forests cover only 2.5% of the land. The forest area in Pakistan is shrinking very fast. Pakistan has the highest annual deforestation rate in Asia. According to a report of WWF, since 1947 more than 151,500 acres of forest land have been converted to non-forest land.

2. Over-hunting:

       Over-hunting of animals is also a cause of loss of biodiversity. In Pakistan, various lizards, snakes, crocodiles, and larger mammals are hunted for various purposes. A large number of migratory birds passing through Chitral are hunted and killed during their migration.

3. Introduction or removal of species in a new habitat:

      When a new species is introduced in an ecosystem, it may prove harmful for the existence of other species living there.

 For example:

  Eucalyptus trees were imported to Pakistan from Australia. These trees consume more water and have disturbed the level of underground water. So other smaller plants cannot grow near these trees.

 The removal of a species from an ecosystem also affects other species.

 For example:

  In an ecosystem, starfish eats mussels which are harmful to many other species. If starfish is removed from that ecosystem, the mussels will increase in number and they will be harmful to other species.

4. Rapid industrialization:

      The chemical pollutants released from industries are harmful to species and ecosystems. Pollution is not recognized as a cause of extinction, but it usually harms species which live in small areas.

Q.4) Explain binomial nomenclature. What are its advantages?

Answer: Binomial Nomenclature:

  Carolus Linnaeus (1707-1778) introduced the system of binomial nomenclature. Linnaeus listed about 4000 different species of animals and plants and gave a particular description to each of them.

Rules of binomial nomenclature:

• According to this system, every type of animal and plant should have a particular name consisting of two parts (words).
• The first word is the name of the genus while the second word is the name of species. (specific name)
• The generic name begins with a capital letter and the specific name begins with a small letter.
• When a scientific name is typed, it is Italicized.
• When it is handwritten, two parts are separately underlined.
  

Advantages of binomial nomenclature:

  Some of the advantages of binomial nomenclature are:

• These names are more definite and precise than ordinary names.
• In binomial nomenclature, a single scientific name is used in the whole world.
• It simplifies the study of species.
• The generic name is common to all the species of a particular genus because they all show common features of resemblance with one another, while the specific name is based on certain definite and specific characters, which differentiate the individuals of a particular genus from one another.
• Being generally in Latin, they have a universal acceptance by people of all languages.
• They indicate the generic and evolutionary relationship of individual animal and plant.

For example:

   In the animal kingdom, the three carnivorous animals i.e. cat, lion, and tiger are given the same generic name, Felis. They are given different specific names i.e. Felis domestica, Felis leo, and Felis tigris respectively. Canis familiaris is the name for the dog, whereas Canis lupus is the wolf. The first name (Canis) shows that these two species are in the same genus.

Q.5) What are the reasons for the extinction of biodiversity worldwide and what measures are required to conserve the biodiversity of Pakistan?

Answer: Reasons for the extinction of biodiversity worldwide:

1. Habitat loss and deforestation:

       All species have specific food and habitat needs. Habitat loss means the destruction of the natural habitat of species. Humans are utilizing land and natural resources and destroying valuable habitats of wildlife.

2. Over-hunting:

       Over-hunting of animals is also a cause of loss of biodiversity. In Pakistan, various lizards, snakes, crocodiles, and larger mammals are hunted for various purposes. A large number of migratory birds passing through Chitral are hunted and killed during their migration.

3. Introduction or removal of species in a new habitat:

      When a new species is introduced in an ecosystem, it may prove harmful for the existence of other species living there.

 For example:

  Eucalyptus trees were imported to Pakistan from Australia. These trees consume more water and have disturbed the level of underground water. So other smaller plants cannot grow near these trees.

 The removal of a species from an ecosystem also affects other species.

4. Rapid industrialization:

      The chemical pollutants released from industries are harmful to species and ecosystems. Pollution is not recognized as a cause of extinction, but it usually harms species which live in small areas.

Conservation of biodiversity in Pakistan:

  In Pakistan, the main issues of conservation of biodiversity include deforestation and hunting. We have only 5.2% of forest in our country. Similarly, many species have become extinct or endangered.

Precautionary measures to conserve the biodiversity of Pakistan:

In Pakistan, national parks are made to conserve the biodiversity of an area. Pakistan has 29 national parks. Hunting, polluting water, cleaning of land for cultivation and destruction of wildlife are banned in conservation parks. However, they are accessible to the public for recreation, education, and research. Following are a few steps taken in Pakistan to conserve biodiversity.

• Indus Dolphin Project (IDP) to save Indus Dolphin
• Protected Areas Management Project in Machiara in Azad Jammu and Kashmir
• Marine Turtle Conservation Project
• Ban on the hunting of markhor and urial in Balochistan
• Himalayan Jungle Project to protect the biodiversity in the Himalayan region
• Conservation of biodiversity of the Suleiman Range, Balochistan
• Northern Areas Conservation Project
• Conservation of migratory birds in Chitral, Khyber Pakhtunkhwa
• Himalayan Wildlife Project to check the hunting of brown bears
• Conservation of Chiltan Markhor
• Ban on Bear-baiting in Pakistan