Chapter: Biodiversity
B Define the following terms
1. Biodiversity: The total variety of life present on earth is called biodiversity.
2. Prokaryotes: Those organism who do not have membrane around nucleus and membrane
bounded organelles are called prokaryotes.
3. Eukaryotes: Those organisms who have nuclear membrane around nucleus and also contain
membrane bounded organelles are called eukaryotes.
4. Binomial nomenclature: The method of giving double names to an organism is called binomial
nomenclature.
5. Taxonomy: It is the study of identification, naming and classification of living organisms into
groups and subgroups.
6. Homologous organs: Homologous organs are those organs who have similar structure but
different functions.
7. Hierarchy: The arrangement of organisms in the form of a ladder in which each step is at a
higher level than lower one is called hierarchy.
8. Deforestation: Deforestation is the cutting down of trees to get land for different purposes such
as agriculture, urbanization, dam construction etc.
9. Genus: The closely resembling species are placed in a group called genus.
10. Phylum: Related classes group together to form a phylum.
11. Monera: It is a kingdom of organisms in which prokaryotes are placed.
12. Classification: The arrangement of organisms in different groups due to similarities is called
classification.
13. Fungi: Fungi are specific multicellular organisms who do not have chlorophyll. They depend
upon other organisms or dead materials for their food e.g. Mushroom, Rhizopus etc.
14. Taxon: Taxon is a group in biological classification in which naturally related organisms are
placed.
15. Conservation of life: conservation is a philosophy or policy to save the environment or
biodiversity for future as well as for present generations.
C. Short Questions
1. Why not fungi fit into plants or animals?
Ans: Fungi do not fit into plants or animals because Fungi resemble plants in many ways but are not
autotrophs. In the same way they are special form of heterotrophs that get their food by absorption but
the mode of nutrition of animal is ingestion.
2. What are fauna and flora?
Ans: The diversity of animals is called fauna and the diversity of plants is called flora.
3. How many types of eukaryotes are found?
Ans: The eukaryotes are of four types i.e. Protista, fungi, plants and animals.
4. What is the importance of biodiversity?
Ans: Biodiversity plays important role in making and maintaining ecosystems. It plays a part in regulating
the chemistry of our atmosphere and water supply. Biodiversity is directly involved in recycling nutrients
and providing fertile soils.
5. What are the aims of classification?
Ans: The aims of classification are:
Identification of organisms
Naming the organisms
Making natural groups of organisms.
6. Difference between autotrophs and heterotrophs.
Ans: Autotrophs: Autotrophs are those organisms who can prepare their own food e.g. plants can
prepare their own food by photosynthesis.
Heterotrophs: Heterotrophs are those organisms who cannot prepare their food and depend upon
others. Heterotrophs are of two types i.e. parasites and saprobes.
7. What do you know about the contribution of Al-Jahiz in the field of biology?
Ans: Al-Jahiz was an Arabic thinker. He wrote a famous book “Kitab Al-Hayawan". In this book he
described the characters of more than 350 animals. He also described the struggle for existence in
animals and influence of environment on animals.
8. What are the main features of kingdom Protista?
Ans: Simple unicellular and multicellular eukaryotic organisms are included in this group. Their cells have
well organized membrane bounded nucleus e.g. Chlamydomonas, Amoeba, Volvox etc.
9. Describe two programmes running in Pakistan for conservation of biodiversity.
Ans: World Wildlife Fund (WWF) Pakistan and IUCN (International Union for the Conservation of Nature
and Natural Resources) are the two programmes running in Pakistan for the conservation of
biodiversity.
10. Why Aristotle is called father of classification of living organisms?
Ans: The earliest known system of classification of organisms comes from the Greek philosopher
Aristotle. He classified all living organisms known at that time as either in the group ‘plantae’ or in
‘animalia’. That is why he is called father of classification of living organisms.
D. Explain the following in detail.
1. What do you know about the work of different biologists to develop a system of classification for
living organisms?
Ans: The earliest known system of classification of organisms comes from the Greek philosopher
Aristotle. He classified all living organisms known at that time as either in the group ‘plantae’ or in
‘animalia’.
In 700s, Abu-Usman Umer Aljahiz described the characteristics of 350 species of animals in his book. He
wrote a lot about the life of ants. In 1172, Ibn Rushd (Averroes) translated Aristotle’s book “de Anima
(On the Soul)” in Arabic. In the end of 15th century, many biologists had started work on classification
methods e.g.
Carolus Linnaeus divided nature into three kingdoms: mineral, vegetable and animal. Linnaeus used five
ranks in classification: 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.
Biologists prefer such a system that can provide maximum information about the basic differences and
similarities among different organisms. According to earlier classification system, organisms were
classified into two kingdoms but now taxonomists agree on five-kingdom classification system.
2. Write a note on the structure of virus (Bacteriophage).
Ans: Structure of virus (Bacteriophage): The body of virus can be divided into two portions i.e. Head and
tail. The head is hexagonal. It is surrounded by a protein coat called capsid. The portion under head is
called neck. Inside the head there is DNA. Under the neck there is a tube like tail which is also
surrounded by protein coat. At the end of tail there is a base plate. Six thread like structures are
attached with base plate called tail fibers. At the lower side of base plate there are pin like structures
called tail pins.
3. Describe the five kingdoms system of living organisms.
Ans: The five kingdoms of living organisms are as follows:
1. Kingdom Monera (Prokaryotes): This kingdom consists of prokaryotic unicellular organisms.
Some species can also form colonies. Some organisms are heterotrophs e.g. bacteria and those
have chlorophyll are autotrophs e.g. blue green algae.
2. Kingdom Protista: Simple unicellular and multicellular eukaryotic organisms are included in this
group. Their cells have well organized membrane bounded nucleus e.g. Chlamydomonas,
Amoeba, Volvox etc.
3. Kingdom Fungi: Members of kingdom fungi are heterotrophs and eukaryotes. Their cell walls are
composed of chitin. Their mode of nutrition is absorption i.e. they digest organic matter and
absorb the breakdown products e.g. Mushroom.
4. Kingdom plantae: Members of kingdom plantae are multicellular eukaryotes. Their cell walls are
composed of cellulose. They are photosynthetic and non motile e.g. flowering plants.
5. Kingdom animalia: They are multicellular eukaryotes. They are heterotrophs. Their mode of
nutrition is ingestion. The food is digested in specific cavities with the help of specific enzymes.
They do not have cell walls around cell membranes. They are motile e.g. lion, deer, birds etc.
4. What is deforestation? What are its causes? What are the effects of deforestation on biodiversity?
Ans: Deforestation: Deforestation is the cutting down of trees to get land for different purposes such as
agriculture, urbanization, dam construction etc.
Causes of deforestation: There are many causes of deforestation. Some are as under:
i. Ti get land for agriculture.
ii. To get land for new roads and new towns.
iii. To construct hydroelectric dams.
iv. To get wood for commercial purposes like for furniture, buildings, papers etc.
v. For mining to get oil, coal and gas.
Effects of deforestation on biodiversity :
Biodiversity is badly affected by deforestation. Some examples are as under:
i. It is responsible for the decline of many species.
ii. It is also a cause of global warming.
iii. It is responsible for the soil erosion.
iv. Due to deforestation there is decrease of oxygen in the air.
v. Deforestation results in reduced rain.
6.What are the problems of conservation of biodiversity in Pakistan?
Ans: Pakistan is rich in biodiversity but there are many issues for the conservation of biodiversity.
i. Loss of Habitat: Loss in the habitat of animals and plants has a great threat to biodiversity.
The loss of habitat is due to over population, new roads, agriculture etc.
ii. Over grazing: over grazing in rangelands has badly affected the productivity of the areas.
iii. Rapid growth in human population: Due to rapid growth in the population of Pakistan, there
is a need of new towns and roads. For this purpose deforestation occurs which reduces
biodiversity.
iv. Low literacy rate: Low literacy rate is also a hurdle to take measures for the conservation of
biodiversity.
v. Poverty of rural areas: Due to poverty in rural areas of Pakistan, the people use wood as a
fuel and hunting the animals for food.
vi. Over hunting: Over hunting of many species has greatly reduced their population.
vii. Harmful Methods of hunting: Many people use harmful methods for hunting which is also a
hurdle in the conservation of biodiversity.
6. What are the human impacts on biodiversity?
Ans: Human impacts on biodiversity: The human population of planet earth is increasing day by day.
According to a careful estimate the human population on earth is nearly about 600 million now a days.
In order to provide facilities of life, human beings are continuously disturbing biodiversity. The threats to
biodiversity from man are the followings:
Over use of natural resources
Habitat destruction
Any kind of pollution
Over hunting of animals
Due to human activities there is a progressive change in the climate which is dangerous for
biodiversity.
