Unit 3 – Biodiversity (Exercise Questions)

Answer The Following Questions.
Q.1. Relate the importance of biodiversity with natural ecosystem through examples.
Q.2. Explain the aims and principle of classification, keeping in view its historical background.
Q.3. Explain the base for establishing five kingdoms of living organisms.
Q.4. Justify why virus are excluded from the Five-Kingdom classification system.
Q.5. Describe the aims and principles of binomial nomenclature.
Q.6. Explain the impact of human beings on biodiversity.
Q.7. Identify causes of deforestation and its effects on biodiversity.
Q.8. Describe some of the programs running in Pakistan for the conservation of biodiversity.
SHORT QUESTIONS – TEXT EXERCISE
Q.1. What is the difference between the modes of nutrition. of fungi and animals?
Q.2. It is difficult to use the criterion of interbreeding to define species of unicellular organisms. Why?
Q.3. How are taxonomy and systematic related?
Q.4. Differentiate between the terms “extinct” and “endangered”.
Q.5. What are the contributions of Whittaker, Margulis and Shwartz in taxonomy?

THE TERMS TO KNOW

Q.1. Relate the importance of biodiversity with natural ecosystem through examples.
Answer:
Definition:
The term biodiversity has been derived from ‘bio’ arid ‘diversity’. Diversity means variety with a species and among species. Biodiversity is a measure of the variety of organisms present in different ecosystems. Formerly it was called ‘natural diversity’
Explanation:
At least 10 million kinds of organisms inhabit the earth but less than one -third of these have been studied and catalogued (put in record) by biologist. Diversity among the earth’s organisms is more obvious than the
fundamental unity of life. This diversity emerged is modifications in organisms. All organisms share many biological characteristics. They are composed of one or more cells carry out metabolism and transfer energy
with DNA. This diversity in life is seen in million of different types of living organisms.
Plants and animals (flora and fauna)
Diversity depends on climate, attitude, soils and the presence of other species. biodiversity is ‘not distributed evenly on earth. It is richer in the polar regions. In the year 2006 large number of Earths species were
classified as endangered or threatened species.

Most of _ the hot spots are located in the tropics and most of them are forests. For example; Brazil’s Atlantic forest contains roughly 20,000 plants species, 1350 vertebrate species, and million of insect species, above half of which occur nowhere else in the world.

Biodiversity found on rough today is the re of 4 billion years of evolution. United evidence suggests their until 600 million years ago, all life consumed of bacteria and similar single celled organisms.
Importance or Significance of Biodiversity
Biodiversity provides food for human in the form of different-crops, fruits, meat, eggs, milk etc.
A significance proportion of drug are derived, directly or indirectly from biological sources such as plants, animals and microbes. e.g. building materials, fibers, dyes, resins, gums, adhesives, rubber and oil ‘are derived
directly from biological resources.

Biodiversity plays importance role in making and maintaining ecosystems. It plays a part in regulating the chemistry of our atmosphere and water supply. It is directly involved in recycling nutients and providing
fertile soils.

Cat Linnaeus (1707-1778) divided the nature into’ three kingdoms. Mineral, vegetable and animal. Linnaeus used five ranks: class, order, genus, species and variety. Linnaeus is best known for his introduction of the method still used to formulate the scientific name of every species.

Since the 1960s a trend has emerged, arranging groups of organisms in an evolutionary tree.
If a group includes all the descendants of the same ancestral form, it is called monophyletic. Other groups are called polyphyletic.


Q.2. Explain the aims and principle of classification, keeping in view its historical background.
Answer:
Classification:
“The systematic grouping of organisms into categories on the basis of evolutionary or structural relationship between them”.
Need for Classification:
There is a large collection of very dissimilar forms of organisms, found on earth. Over 1.5 million types of plants are known to biologist. They range in complexity from small and simple bacteria to large arid complex human beings. All organisms are related to one another or some point in their evolutionary histories. However, some organisms are more closely related than other e.g., sparrows are more closely related to pigeons than either is to the insects.

To study such a large collection, biologist classify the organisms into groups and subgroups and for this task they require some system. In this way morphological, physiological and biochemical characteristics can be studied easily and biochemical characteristics can be studied easily and categories for further study.

Comparisons show relationship among living things. It helps in giving international scientific names to the living organisms by using the method “binominal nomenclature”.
Aims of Classification:
The branch of biology, which deals with classification, is called ‘taxonomy’ and the branch” which deals with classification and also the traces of Evolutionary histories of organisms, is known as ‘systematic’.
The aims of both these branches are as follows.

To determine similarities and differences among organisms so that they can be studied easily.
To find the evolutionary relationships among organisms illustrating the seven levels of classification.
To discuss how various plants, animals and other organisms interact with their environment.
Basis of Classification:
Biologists have classified all known organisms into groups and subgroups on the basis of similarities. These similarities are seen in structures, biochemistry, cytology and genetics. Modem genetics has provided another
type of information to taxonomist.

The genetic differences between two studied organisms can be determined and can be used for getting idea above similarities and differences in their structures and functions.
Interesting Information
Swedish taxonomist Carolus Linneaus (1707 – 1778) was the father of taxonomy.

Q.3. Explain the base for establishing five kingdoms of living organisms.
Answer:
Five kingdom system of classification:
In 1937, E-Chatton suggested the terms or, “Procariotique” to describe bacteria and “Eucariotique” to describe animal and plant cells.
Robert Whittaker 1967 introduced five kingdom classification system on the basis of the cellular organization i.e., prokaryotic, unicellular eukaryotic and multicellular eukaryotic. The principal modes of nutrition i.e..
photosynthesis. absorption and ingestion. Although Lynn Margulis and Karlene shwaiz modified Whittaker five kingdom classification system in 1988 on the basis or cellular organization mode of nutrition, cytology, genetics and organelle symbiotic origin (mitochondria chloroplast) but the kingdom were five and same as proposed by Whittaker.
THE FIVE KINGDOMS
1. Kingdom Monera:
It includes the prokaryotic organisms in which the genetic material is not enclosed in the nuclear membrane. These are unicellular, although some types form chains. clusters or colonies of cells.
Most are interotrophie but some perform photosynthesis because they have chlorophyll in their cytoplasm e.g. photosynthetic bacteria and cyano bacteria (blue green algae)
Archeo bacteria (cxtremophiles i.e., like extreme environmental conditions) and rubaeteria (true bacteria) and cyano bacteria included in kingdom Monera.
2. Kingdom Protista:
It includes cukaryotic unicellular and simple multicellular organisms. There are three main types of protists.
Algae are unicellular, colonial or sometimes simple multicellular. They resemble plant cells because they have chlorophyll in chloroplast but they have cell wall or cellular simple multicellular means that they cannot have
multicellular sex organs and do not form embryos during their life cycles.
Protozoans resemble animals whose cells lack chlorophyll and cell wails.
Some protests arc like fungi.
3. Kingdom Fungi:
They are eukaryotic multicellular organisms. They are heterotrophs and take their food by absorption. Most fungi are decomposers. They live on organic material, secrete digestive enzymes and absorb small organic molecules formed by. the digestion by enzymes. For example: mushrooms rust, smui molds.
4. Kingdom Plantae
(i) It includes eukaryotic multicellular autotrophs i.e. They are capable of preparing their own food by photosynthesis because of the presence of chlorophyll in the .chloroplast.
(ii) They have cell wall composed of cellulose.
(iii) They have multicellular sex organs and form embryos during their life cycles.
(iv) Moses, Ferns, Angiosperms and gymnosperm are included in Kingdom Plantae.
5. Kingdom Animalia
(i) It includes eukaryotic multicellular consumers.
(ii) Animals live mostly by ingesting food and digesting it within specialized cavities.
(iii) They lack cell wall.
(iv) They show movements

Q.4. Justify why virus are excluded from the Five-Kingdom classification system.
Answer:
Status of A cellular livings
This system focuses only the cellular organisms. The A cellular livings i.e. which do not possess cellular organization yet show characteristics of living like viruses prisons and unions. Acellular living are not placed in five Kingdom System.
Viruses
Viruses are the borderline of living and nonliving. Due to their crystalline nature, they are considered as non-living. They are acellular i.e. they do not have cellular organization yet show some characters of living’ organisms (e.g. they possess DNA).
Viruses are infections entities which contain either DNA or RNA as their genetic material, normally encased in protein coat and reproduce in living cells.
Prions are composed of protein only and act as infectious cellular particles in plants.
Viroids are composed of circular RNA are cellular particles. only and act as infectious particles and cause disease in certain plants.
Three Domain System of Classification
Three Domain Classification System
Recent comparisons of different organisms on the basis of molecular genetics (RNA, DNA molecules) suggest that life falls in just three main groups.
Carl Woese proposed three-domain system in 1990

Q.5. Describe the aims and principles of binomial nomenclature.
Answer:
Binomial Nomenclature
“Binomial Nomenclature is the method of giving scientific names to living organisms.”
As the word binomial suggests the scientific name of a species consists of two names: The first is the genus name and the second one is the name of species.
Swedish biologist Carlous Linnaeus (1707-1778) first introduced and adopted the system of binomial nomenclature.
Rules of Binomial Nomenclature
Following are major rules of Binomial Nomenclature
=> Scientific names are usually primed in italics. such as Homo sapiens. When handwritten they are underlined.
=> The first term (generic name) always begins with capital letter, while the species name is never
capitalized (even when derived from a proper name).
=> In scientific journals, the main for the scientific name is followed by the surname of the scientist who
first published the classification. For example Passer domesticus (Linnaeus, 1758).
=> When used with a common name, the scientific name usually follows in parentheses. For example, “The house
sparrow (Passer domesticus) is decreasing in Pakistan.”
=> The scientific name is generally written in full when it is first used. But when several species from the
same genus are being listed, it may then be abbreviated by just using an initial for the genus: for example
Canis lupus becomes C.lupus.
=> The abbreviation ‘cf’ is used when the identification is not confirmed.
For example Corves cf. splendens indicates a bird similar to the House Crow but not certainly identified as
species.
The genus name and specific name may _ come from any source whatsoever. Often they are Latin words, but they may also come from Ancient Greek, from a place, from a person (preferably a naturalist), a name from a local -language etc.

Q.6. Explain the impact of human beings on biodiversity.
Answer:
Impact of Human beings on Biodiversity
The earliest fossils that are clearly Homo sapiens, our species, are 500,000 years old By 1O,OOO years ago-there were about 5 million people on earth. With the advancement in agriculture and industry the human population began to grow rapidly. Today around 600 million people live on ranks. To improve the living condition of 600 million people, we are imposing threats to the survival of much biodiversity. Some of the impacts of human beings are as follows:
1. Habitat loss and deforestation
Habitat loss and deforestation (cutting down of trees) are important causes of species extinction. As deforestation proceeds in tropical forests, it becomes the main cause of the mass extinction of species. All species have
specific food arid habitat needs. Tropical forests are important because they harbour at least 50 percent of the world’s biodiversity. Direct observations prove that these forests are declining. The original extent of tropical rain forests was 15 million square km. Now there remains about 7.5-8 million square km, so half is gone.
The closed canopy forest in the North West Frontier Province (NWFP) of Pakistan is reported to be shrinking at approximately 1 % per year. More significance is the persistent spread of farmers into the forests; the killing of
trees through lopping, burning, and tapping; the development of small agricultural plots among the trees; and excessive grazing by domestic animals.
2. Over-hunting
Over-hunting has been a significant cause of the extinction of hundreds of species and the endangerment of many more, such as whales, ibex, urial, markhor (the national animal of Pakistan) etc. Commercial hunting, both
legal and illegal, is the principal threat.
3. Introduction of new species
Introduction of non-native species is an important and often overlooked cause of extinction. When new species are introduced to ecosystem the established species in that-ecosystem may not survive. The new organisms may be predators, parasites, or simply aggressive species that deprive the established species of nutrients, Water and light. For example Eucalyptus plants were imported from Australia and introduced in Pakistan. These plants consume more water and have disturbed the water table (level of undergrounds water). It harms other small plants that grow near Eucalyptus trees.
4. Domino effects
Domino effects occur when the removal of one species (an extinction event) or the addition of one speciesfan invasion event) affects the entire biological system. Domino effects are especially likely when two or more
species are highly interdependent. For example a starfish, facilitates the coexistence of many-other invertebrates by eating mussles, which otherwise would harm other organisms. If starfish are eliminated from an ecosystem, mussles grow in number and prey on other animals.
5. Pollution
Pollution from chemical contaminants certainly poses a further threat to species and ecosystem. While not commonly a cause of extinction, it harms those species whose range is extremely small.
6.Climate Change
Distribution of species, is largely determined by climate. When changes in climate occurs it affects the distribution of species, many species find it difficult to adjust in new climate.
Climatic change encompasses the temperature rise, sea level rise, changes in precipitation patterns and increase in the frequency of extreme weather events.

Q.7. Identify causes of deforestation and its effects on biodiversity.
Answer:
Deforestation:
Deforestation means cutting down of trees for the conservation of a forest to non forest land.
Causes of Deforestation:
Following ,are the different causes of deforestation.
1. Used for Urban & Construction Purpose.
The cutting down ,of trees for lumber is used for building materials, furniture, & paper products. Forests are also cleared in order to accommodate expanding urban areas.
2. To grow crops
With the increasing population, land is required to grow more crops.
3. To create grazing land
Forests are also cleaned to create grazing land for the cattle’s to fulfill the needs of growing population.
4. Use for Fuel: .
Forests are cleaned to use fire wooed or turned into charcoal, used for heating and cooking purpose.
Effects of Deforestation
Deforestation effects in following ways.

1. Erosion of Soil
Deforestation affects the amount of water, in the soil and the moisture in the atmosphere. When there are t:Io trees to keep the soil in place, the soil becomes exposed for erosion. There is less protection from wind and rain
Heavy rainfall washes the soil into the rivers. Essential nutrients are washed out of the soil all together.
2. Flooding
With heavy rains falls, soil drain off into the rivers and the rivers become choked up with mud and silt, which causes flooding.
3. Reduces storage capacity of dams
The silted water stores in dams and it reduces their water storage capacity and thus their lives.
4. Reduces sources of rains
Deforestation also contributes decreased transpiration, which lessens cloud formation and less humidity. This ultimately reduces sources of rains.

Q.8. Describe some of the programs running in Pakistan for the conservation of biodiversity.
Answer:
Need to conserve biodiversity
Though rich in biodiversity, Pakistan today faces severe threats for its biological resources. The greatest concern is the continuing loss of species and the loss of natural habitats. Main causes of this loss are largely associated with rapid growth in human population and the prevailing poverty in the rural areas of Pakistan. In addition low literacy rate and meagre resources are the reasons for limited success in conservation measures taken so far.

The conservation of biodiversity has become a global concern. Biologists consider biodiversity essential and agree on the significance of current extinction of species. Biologists urge _the national policy makers to state a set of rules necessary to protect a species. They demand that the laws should define species, which are threatened by extinction and must be protected:

The International Union for the Conservation of nature and natural Resources (IUCN) and the World Wild life Fund Pakistan’s Ministry of Environment and other government and non-government institutions. The IUCN has prepared the first national Red List (list of endangered or threatened species). According to this list following are the figures of the living and threatened species in Pakistan.

Examples of environmental work carried out in Pakistan
in order to conserve biodiversity.
Following are a few examples of environmental work that has been carried out in Pakistan in order to conserve species and the associated habitats.
1. National Conservation Strategy:
In 1980’s the IUCN and the government of Pakistan formulated National Conservation Strategy for Pakistan for the conservation Pakistan’s biodiversity.
2. UN Convention on Combating Desertification (CCD):
Data about the living and threatened animal species in Pakistan.’
(Source Biodiversity Action Plan IUCN)

Treaty against damage and poverty in dry lands. Pakistan signed this 1997.
3. Himalayan Jungle Project.(HJP)
It started in the Palas Valley, in NWFP. It aimed at protecting one of richest areas of biodiversity in Pakistan.
4. Conservation of biodiversity of the Suleiman Range, Baluchistan
The Suleiman Range ChiIghoza Forest is the largest Chilghoza forest in world. In 1992 the WWF-P started its conservation program.
5. Northern Areas Conservation Project.
The northern areas of Pakistan serve as a habitat for a number of wildlife species. The survival of these species is under threat. The NACP is project of WWF-P, which is successful in implementing a ban on the hunting of these species.
6. Conservation of migratory birds in Chitral, NWFP
Chitral lies on the migratory rout of several important bird species. The birds face enormous hunting pressure. WWF- Pakistan’ initiated efforts t reduce the hunting pressure in 1992. The efforts proved successful.
The northern areas provide habitats to Musk deer, snow leopard, Astore markhor and Himalayan ibex, Wooly flying squirrel and the Brown bear. It is estimated that about 200,000 of the one million migratory birds passing
through Chitral are killed during migration.
SHORT QUESTIONS – TEXT EXERCISE

Q.1. What is the difference between the modes of nutrition. of fungi and animals?
Answer:
Most fungi are decomposers. They live one organic material, secrete digestive enzymes and absorb small organic molecules formed by the digestion by enzymes. Animals live mostly by ingesting food and digesting
it within specialized cavities.

Q.2. It is difficult to use the criterion of interbreeding to define species of unicellular organisms. Why?
Answer:
The criteria of interbreeding cannot be used for species recognition in organisms who reproduce asexually and. do not interbreed with one another (for example many unicellular organisms).

Q.3. How are taxonomy and systematic related?
Answer:
The aims of both these branches are as follows. To determine similarities and differences among organisms so that they can be studied easily. To find the evolutionary relationships among organisms by illustrating the seven levels of classification.

Q.4. Differentiate between the terms “extinct” and “endangered”.
Answer:
Extinct: The species which are not found now are called extinct Endangered: The species, which ‘has become or is near to extinction, is called endangered species.

Q.5. What are the contributions of Whittaker, Margulis and Shwartz in taxonomy?
Answer:
Robert Whittaker 1967 introduced five kingdom classification system on the basis of the cellular organization i.e., prokaryotic, unicellular eukaryotic and multicellular eukaryotic. The principal modes of nutrition i.e., photosynthesis, absorption and ingestion. Although Lynn Margulis and Karlene shwaiz modified Whittaker five kingdom classification system in 1988 on the basis of’ cellular organization mode of nutrition, ‘cytology, genetics and organelle symbiotic origin (mitochondria chloroplast) but the kingdom were five and same as proposed by Whittaker.

THE TERMS TO KNOW