class 9 biology chapter 1 notes

 Chapter 1: Introduction to biology

Q1. What is Science?

Ans:
Science is the study in which observations are made, experiments are conducted, and logical conclusions are drawn to understand the principles of nature.

Q2. Why was scientific knowledge classified into different branches?

Ans:
In ancient times, all scientific knowledge was grouped under one broad category called "Science." However, as the volume of scientific information grew over time, it became necessary to classify it into specific branches like Biology, Physics, Chemistry, and Mathematics for better understanding and specialization.

Q3. What did Dr. Abdul Salam say about scientific knowledge?

Ans:
According to Dr. Abdul Salam, scientific knowledge is the common heritage of mankind.

Q4. What is Biology? Describe the major divisions of Biology.

Ans:

Biology

Biology is the scientific study of life and living organisms.

Origin of the Word "Biology"

The term "Biology" is derived from two Greek words:

• "Bios" meaning life

• "Logos" meaning thought or reasoning

What do we study in Biology?

Biology helps us understand the structure, function, and behavior of living organisms. It also provides solutions to problems related to health, food, the environment, and more.

Major Divisions of Biology:

1. Zoology—The study of animals.

2. Botany—The study of plants.

3. Microbiology—The study of microorganisms, such as bacteria and viruses.

Q5. Define the Different Branches of Biology

Answer:
To study the vast and diverse aspects of life, the three major divisions of Biology—Zoology, Botany, and Microbiology—are further divided into specialized branches. Each branch focuses on a particular area of biological study:

1. Morphology

This branch deals with the form and structure of living organisms.

2. Anatomy

Anatomy is the study of the internal structures of living organisms.

3. Histology

The microscopic study of tissues is called histology.

4. Cell Biology

This branch focuses on the structure and function of cells and their organelles, including the process of cell division.

5. Physiology

Physiology deals with the functions of different parts of living organisms, such as organs and systems.

6. Embryology

Embryology is the study of the development of an embryo into a complete organism.

7. Taxonomy

This branch involves the classification and naming of organisms into groups and subgroups based on similarities and differences.

8. Genetics

Genetics is the study of genes and heredity—how traits are passed from one generation to the next.

9. Palaeontology

Paleontology deals with the study of fossils, which are the preserved remains or impressions of organisms that lived in the past.

10. Environmental Biology

Also known as Ecology, this branch focuses on the interactions between organisms and their environment.

11. Biotechnology

Deals with the practical application of living organisms and biological processes to create useful products for human benefit (e.g., medicines, vaccines, GMOs).

12. Sociobiology

Studies the social behavior of animals, especially those that form structured societies (like ants, bees, and humans).

13. Parasitology

Focuses on the study of parasites, their life cycles, interactions with hosts, and the diseases they cause.

14. Immunology

The study of the immune system in animals and how it defends the body against invading microbes and pathogens.

15. Entomology

The scientific study of insects, including their classification, life cycle, behavior, and impact on ecosystems and agriculture.

16. Pharmacology

Deals with the study of drugs and their effects on the human body. It plays a vital role in medicine and healthcare.

17. Molecular Biology

This field focuses on the molecules of life, such as proteins, carbohydrates, lipids, nucleic acids, and water.
It also includes the study of the structure and function of cells at the molecular level.

Q6. What are Parasites?

Answer:
Parasites are organisms that obtain food and shelter from living hosts and, in return, harm the host.
Examples include

• Viruses

• Bacteria

• Parasitic worms

Q7. What are the Major Biological Issues Today?

Answer:

Human population growth, infectious diseases, addictive drugs, and pollution are the major biological issues today.

Q8. Describe the relationship of biology to other sciences.

Ans:

Introduction

The interrelationship among different branches of science cannot be denied. Biological information relates to the other branches of science as well.
For example, when studying the process of movement in animals, the biologists have to refer to the laws of motion in Physics.
This forms the basis of interdisciplinary sciences.

(i) Biophysics

It deals with the study of the principles of physics, which are applicable to the biological phenomena.
Example: Similarity between the working principles of levers in Physics and limbs of animals in Biology.

(ii) Biochemistry

It deals with the study of the Chemistry of different chemical compounds and processes occurring in living organisms.
Example: The study of basic metabolism of photosynthesis and respiration involves the knowledge of Chemistry.

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(iii) Bio-Mathematics/Biometry

It deals with the study of using mathematical techniques and tools in biology.

Example:
To analyze the data gathered after experimental work, biologists have to apply the rules of mathematics.

(iv) Biogeography

It deals with the study of the occurrence and distribution of different species of living organisms in different geographical regions of the world.

Application of Biogeography:
It applies the knowledge of the characteristics of particular geographical regions to determine the characteristics of living organisms found there.

(v) Bio-Economics

It deals with the study of organisms from an economical point of view.

Example:
The cost value and profit value of wheat can be calculated through this branch, and benefits or losses can be determined.

Q9. Briefly describe the careers in biology.

Ans:
The following are the careers that a student of biology can plan to adopt:

(i) Medicine/Surgery

• Medicine deals with the diagnosis and treatment of diseases in humans.

• In Surgery, the parts of the body may be repaired, replaced, or removed.
  Example: Removal of stones through renal surgery, transplantation of kidney, liver, etc.

Both these professions are studied in the same basic course (MBBS) after higher secondary education, and the students go for specialization afterward.

(ii) Fisheries

It deals with the study of fish production and enhancing the quality and quantity of fish production.
Professionals of fisheries are employed in fisheries departments of Pakistan.
This profession can be adopted after bachelor's or master's level study of zoology and fisheries.

(iii) Agriculture

It deals with the study of food crops and animals, which are the source of food.
An agriculturist works for the betterment of crops like wheat, rice, corn, etc., and animals.
This professional course can be adopted after higher secondary education in biology.

(iv) Animal Husbandry

(a) It is the branch of agriculture concerned with the care and breeding of domestic animals (livestock), e.g., cattle, sheep.
(b) This professional course can be adopted after the higher secondary education in biology.

(v) Horticulture

(a) It deals with the study of the art of gardening.
(b) A horticulturist works for the betterment of existing plant varieties and for the production of new varieties of ornamental and fruit plants.
(c) This professional course can be adopted after the higher secondary education in biology.

(vi) Farming

(a) It deals with the development and maintenance of different types of farms.
For example, in some farms, animal breeding technologies are used for the production of animals that are better sources of protein and milk.
(b) In poultry farms, chickens and eggs are produced.
(c) In fruit farms, different fruit-yielding plants are grown.
This profession can be adopted after courses in agriculture, animal husbandry, or fisheries.

(vii) Forestry

(a) It deals with the study of natural forests and provides advice to the government for planting and growing artificial forests.
(b) This professional course can be adopted after higher secondary education in biology or after bachelor-level study of zoology and botany.

(viii) Biotechnology

(a) It deals with the study and work for the production of useful products through microorganisms.
(b) This professional course can be adopted after higher secondary education in biology or after bachelor-level studies in zoology or botany.

Q10. Explain the Islamic concept about the origin of life.

(Lahore Board 2011 – Short Question)

Ans:
Allah hints about the origin and characteristics of living organisms at many places in the Holy Quran.
Human beings have been instructed to explore the unknown aspects of life by reflecting on and researching the signs (ayat) provided in the Quranic verses.

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Q11. Give comparison in cellular, colonial, and multicellular organization.

Ans:

Five Major Groups of Organisms

All organisms have been divided into five major groups:

• Prokaryotes

• Protists

• Fungi

• Plants

• Animals

Types of Cells

All organisms are made of cells, and there are two basic types:

1. Prokaryotic Cells

Cells lacking membrane-bounded nucleus and organelles are called prokaryotic cells.
Examples: Bacteria, Cyanobacteria

2. Eukaryotic Cells

Cells having membrane-bounded nucleus and organelles are called eukaryotic cells.
Examples: Animal cells, Plant cells

Cell Organization in Living Organisms

Cells in living organisms are organized in three ways to form different types of body structures:

a) Unicellular Organization

(Lahore Board 2012 – Short Question)

• In unicellular organisms, only one cell makes up the entire body of the organism.

• All life activities (nutrition, reproduction, respiration, etc.) are carried out by this single cell.

• These organisms are usually microscopic.

Example: Amoeba, Paramecium, Euglena

b) Colonial Organization

In colonial type of cellular organization, many unicellular organisms live together, but there is no division of labour among them.

• Each unicellular organism in a colony lives its own life independently.

• They do not depend on other cells for their vital requirements.

Example:
Volvox – a green alga found in water – is an example of colonial organization.

• Hundreds of Volvox cells come together to form a colony, but each cell carries out its own life processes.

c) Multicellular Organization

In multicellular organization, cells are organized into tissues, organs, and organ systems.
Each type of cell performs a specific function, and different cell types work together for the survival of the organism.

Example: Mustard Plant (Brassica campestris)

(a) Sowing

• It is sown in winter and produces seeds at the end of winter.

(b) Importance

• The plant body is used as a vegetable.

• Its seeds are used for extracting oil.

(c) Body Parts of Mustard Plant

a) Vegetative Parts

• Includes roots, stems, branches, and leaves.

• These parts do not take part in sexual reproduction.

b) Reproductive Parts

• Flowers are the reproductive parts of the plant.

• They take part in sexual reproduction and produce fruits and seeds

Example: Frog (Rana tigrina)

(a) Body

• The body of frog also shows multicellular organization.

• The body is made up of various organ systems (e.g., digestive, circulatory, nervous systems).

• Each organ system consists of related organs that perform coordinated functions.

• All the organs are made up of specific tissues such as:

• Epithelial tissue

• Glandular tissue

• Muscular tissue

• Nervous tissue

Q12: What do you know about species?

Ans:
A species is defined as a group of organisms capable of interbreeding and producing fertile offspring.

Q13: What is habitat?

Ans:
Habitat means the area of the environment in which an organism lives.

Q14. Describe separate and comparative description of all the levels of biological organization.

Ans:

Biological Organization at Different Levels

(1) Subatomic and Atomic Level

(a) Atoms and Elements

• All types of matter are made up of elements.

• There are about 92 kinds of elements found in nature.

• Each element is made up of a single kind of atoms (from Greek: ‘a’ = not, ‘tom’ = cut).

• Atoms are structures composed of subatomic particles.

• The most stable subatomic particles are:

  • Electrons

  • Protons

  • Neutrons

(b) Bioelements

Out of the 92 natural elements, 16 elements are involved in forming the body mass of living organisms. These are called bioelements.

• Major Bioelements (99% of body mass):

  1. Oxygen (O) – 65%

  2. Carbon (C) – 18%

  3. Hydrogen (H) – 10%

  4. Nitrogen (N) – 3%

  5. Calcium (Ca) – 2%

  6. Phosphorus (P) – 1%

• Trace Elements (1% of body mass collectively):

• Potassium (K)

• Sulphur (S)

• Chlorine (Cl)

• Sodium (Na)

• Magnesium (Mg)

• Iron (Fe)

• Copper (Cu)

• Manganese (Mn)

• Zinc (Zn)

• Iodine (I)

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(2) Molecular Level

(a) Biomolecules

• In organisms, bioelements usually do not occur in isolated forms. Instead, they combine through ionic or covalent bonding.

• The stable particles formed by such bonding are called molecules.

• When these molecules occur in living organisms, they are called biomolecules.

• An organism is made up of an enormous number of biomolecules of hundreds of different types.

• These biomolecules serve as the building material of the body.

• They are constructed in great variety and complexity due to specific bonding arrangements.

Classification of Biomolecules

a) Micromolecules

• Molecules with low molecular weight

• Examples: Glucose, Water, etc.

b) Macromolecules

• Molecules with high molecular weight

• Examples: Starch, Proteins, Lipids, etc.

(3) Organelle and Cell Level

(Lahore Board 2011 – Short Question)

(a) Organelle Formation

• Biomolecules assemble in a specific pattern and form organelles.

(b) Cell Formation

• Organelles are sub-cellular structures, and when they assemble together, cells are formed.

• The cell is the basic structural and functional unit of life.

(c) Division of Labour within the Cell

• Each type of organelle is specialized to perform a specific function.
  Examples:

  • Mitochondria are specialized for cellular respiration.

  • Ribosomes are specialized for protein synthesis.

• In this way, the functions of the cell are accomplished by these specialized structures.

• It is an example of division of labour within the cell.

No. of Cells

• In the case of Prokaryotes and most Protists, the entire organism consists of a single cell.

• In the case of most Fungi, Animals, and Plants, the organism consists of up to trillions of cells.

(4) Tissue Level

(a) Definition

A tissue is a group of similar cells specialized for the performance of a common function.

(b) Explanation

Each cell in a tissue carries out its own life processes (e.g., cellular respiration, protein synthesis)
and also performs special processes related to the function of the tissue.

(c) Examples

• Plant Tissues: Epidermal tissue, Ground tissue, etc.

• Animal Tissues: Nervous tissues, Muscular tissues, etc.

(5) Organ and Organ System Level

Organ Level

(a) Formation of Organ Level

More than one type of tissue having related functions are organized together to form an organ.

(b) Different tissues of an organ

• Different tissues of an organ perform their specific functions, and these functions collectively become the function of that organ.

(b) Example: Stomach

The stomach is an organ specialized for digestion of proteins and storing food.

It contains the following tissues:

1. Epithelial (Glandular) Tissue

   • Secretes gastric juice for digestion.

2. Muscular Tissue

   • Performs contractions of stomach walls to:

     • Grind food

     • Mix enzymes with food

     • Move food to the posterior end

   ➤ These actions are essential parts of digestion.

3. Connective Tissue

   • Helps to connect and support other tissues within the organ.

4. Nervous Tissue

   • Coordinates the actions of the stomach by transmitting nerve signals.

Thus, multiple tissues contribute to the overall function of the stomach — an excellent example of division of labour within an organ.

Organ System Level

(a) Formation of Organ System Level

• Different organs performing related functions are organized together to form an organ system.

• In an organ system, each organ performs its specific task, and the combined actions appear as the function of the entire system.

(b) Example: Digestive System

• Carries out the process of digestion.

• Includes:

  • Oral cavity

  • Stomach

  • Small intestine

  • Large intestine

  • Liver

  • Pancreas

🟢 The organ system level is less definite in plants as compared to animals.

(6) Individual Level

(a) Formation of Individual Level

• Different organs and organ systems are organized together to form an individual (organism).

• In an organism, all the structures are arranged so that the functions, processes, and activities are coordinated.

(b) Example

During continuous and hard exercise:

• Respiration rate and heart beat increase.

• This supplies more oxygen and food to the muscles, which is required for continuous work.

This coordination of systems (muscular, respiratory, and circulatory) shows the integrated function of an individual.

(7) Population Level

(a) Formation of Population Level
A group of organisms of same species located at the same place, in the same time is called population.

(b) Example
Human population in Pakistan in 2010 comprises of 173.5 million individuals.

(8) Community Level

(a) Introduction

A community is an assemblage of different populations interacting with one another within the same environment.

(b) Example

A forest may be considered as a community. It includes different plants, microorganisms, fungi and animal species.
Communities are collections of organisms, in which one population may increases and others may decrease.
Some communities are complex e.g. forest and pond community.
Some communities are simple e.g. a fallen log with various populations under it.
Simple communities have limited number and size and any change in biotic or abiotic factors may have drastic and long lasting effects.

(9) Biosphere Level

The part of the earth inhabited by organisms communities is known as biosphere.
It constitutes all ecosystems (area where living organisms interact with non-living components of the environment) and is also zone of life on earth.

Short Questions and Answers – Biology Class 9

Q.1. What do you know about agriculture?

Ans.
It deals with the study of food crops and animals which are the source of food. An agriculturist works for the betterment of crops like wheat, rice, corn etc and animals. This professional course can be adopted after the higher secondary education in biology.

Q.2. Define anatomy.

Ans.
The branch of biology which deals with the study of internal structure of the organisms is called internal morphology or anatomy.

Q.3. What is animal husbandry?

Ans.
It deals with the study of care and breeding of livestock. Livestock includes all the domestic animals like cattle, sheep etc. This professional course can be adopted after the higher secondary education in biology.

Q.4. Define molecular biology or biochemistry. (Lahore board 2012 G II)

Ans.
The branch of biology which deals with the study of the molecules of life. e.g. water, proteins, carbohydrates, lipids and nucleic acids is called molecular biology. The study of biochemical reactions occurring in living organisms is also included in this branch.

Q.5. What do you know about bioeconomics?

Ans.
The study of organisms from economical point of view. It includes the study of cost effectiveness and viability of biological projects e.g. the cost value and profit value of wheat can be calculated through this branch and benefits or losses can be determined.

Q.6. What are bioelements?

Ans.
The elements which take part in making the body mass of a living organism are called bioelements. These are 16 in number. There are two types of bioelements.
(1) Major elements: Six elements making 99% mass of living organisms are called major elements. These are C, H, O, Ca, N and P.
(ii) Trace elements: Other ten elements making 1% mass of living organisms are called trace elements. These are K, S, Cl, Na, Mg, Fe, Cu, Mn, Zn & I.

Q.7. Define biogeography.

Ans.
The study of occurrence and distribution of different species of animals and plants in different geographical regions of the world is called biogeography.

Q.8. Define biology.

Ans.
The scientific study of living things is called biology. The word "biology" is derived from two Greek words:
(a) "Bios" meaning "life".
(b) "Logos" meaning "thought or reasoning"

Biology has three major divisions:

i. Botany:
The scientific study of plants is called botany

ii. Zoology:
The scientific study of animals is called zoology

iii. Microbiology:
The scientific study of microorganisms is called microbiology.

Q.9. What do you know about biomathematics?

Ans.
The study of practical and theoretical applications of mathematical techniques and tools in biological processes and research is called biomathematics e.g. to analyze the data gathered after experimental work.

Q.10. What do you mean by biomolecules?

Ans.
Atoms of different bioelements combine through ionic or covalent bonding to form stable particles called biomolecules or molecules of life.
An organism is formed by enormous number of biomolecules of hundreds of different types.
Examples: glucose, amino acids, fatty acids, starch, proteins, lipids etc.

Q.11. Define biophysics.

(Lahore board 2012 G11)
Ans.
It deals with the study of the principles of physics, which are applicable to the biological phenomena.
Example: similarity between the working principles of lever in Physics and limbs of animals in Biology.

Q.12. What is biotechnology?

Ans.
The branch of biology which deals with the practical application of the knowledge about microorganisms to carry out processes, which make substances for the welfare of mankind.

Q.13. Define botany.

Ans.
The branch of biology which deals with the study of plants is called botany.
e.g. mustard, rose.

Q.14. What is cell?

Ans.
Cell is the basic unit of structure and function of living organisms.
Different organelles assemble together to form the simplest living unit i.e. the cell.
It may be:

• Prokaryotic cell: without distinct nucleus

• Eukaryotic cell: with distinct nucleus

Q.15. Define Cell biology.

Ans.
The branch of biology which deals with the study of structures and functions of cells and cell organelles is called cell biology.
This branch also deals with the process of cell division.

Q.16. What do you mean by colony? Give example.

Ans.
When many unicellular organisms live together and each of them lives its own life and does not depend on other cells for its vital requirements, it is called a colony.
Example: Volvox is a green colonial alga living in water.

Q.17. What is community? Give example.

(Lahore board 2011 GIT)
Ans.
Different populations interacting with one another and living in the same environment form community.
For example, forest. It includes different plant species (oak trees, ash trees, grasses, bushes), different species of microorganisms, fungi, and animals.

Q.18. Define embryology.

Ans.
The branch of biology which deals with the study of the development of a new individual from fertilized egg to a new born baby is called embryology.
It includes cell growth, differentiation, and morphogenesis (the process that gives rise to tissues and organs).

Q.19. What is entomology?

Ans.
The branch of biology which deals with the study of insects.
It includes the general characteristics and life cycles of beneficial and harmful insects.

Q.20. What do you mean by environmental biology?

Ans.
The branch of biology which deals with the study of the interactions between organisms and their environment is called environmental biology.

Q.21. What do you know about farming?

Ans.
It deals with the study of different types of farm, their development and maintenance.

For example:

• In some farms, animal breeding technologies are used for the production of animals which are better protein and milk sources.

• In poultry farms, chicken and eggs are produced.

• In fruit farms, different fruit-yielding plants are grown.

Q.22. What is fisheries?

Ans.

 It deals with the study of fish production and enhancing the quality and quantity of fish production.
Professionals of fisheries are employed in fisheries departments of Pakistan.
This profession can be adopted after the bachelor or masters level study of zoology and fisheries.

Q.23. What is forestry?

Ans.

 It deals with the study of natural forests and advises to the government for planting and growing artificial forests.
This professional course can be adopted after the higher secondary education in biology or after bachelor level study of zoology and botany.

Q.24. What are fossils?

Ans.

 Fossils are dead remains of extinct organisms and their impressions preserved in rocks. Study of these fossils is called palaeontology.

Q.25. Define Genetics.

Ans. 

The branch of biology which deals with the study of the structure and functions of genes and biological inheritance of characters from one generation to the other is called genetics.

Q.26. What do you mean by histology?

Ans.

 The branch of biology which deals with the microscopic study of tissues is called histology.

Q.27. What do you know about horticulture?

Ans. 

It deals with the study of art of gardening.

A horticulturist works for the betterment of existing varieties and for the production of new varieties of ornamental plants and fruit plants.
This professional course can be adopted after the higher secondary education in biology.

Q.28. Define Immunology.

Ans. 

The branch of biology which deals with the study of immune system of animals which defends the body against invading microbes.

Q.29. What is inheritance?

Ans.

 Inheritance means transmission of characters from one generation to the other.

Q.30. Define macromolecules. Give examples.

Ans. 

The molecules with high molecular weights are called macromolecules e.g. starch, proteins, lipids etc.

Q.31. Define microbiology.

Ans.

 The branch of biology which deals with the study of microorganisms is called microbiology e.g. viruses, bacteria, etc.

Q.32. Define micromolecules. Give examples.

Ans. 

The molecules with low molecular weights are called micromolecules e.g. glucose, amino acids, fatty acids etc.

Q.33. What are microorganisms?

Ans.

The organisms which cannot be seen with naked eye. We use microscope in order to see them are called microorganisms e.g. viruses, bacteria, protozoans etc.

Q.34. What is morphology?

Ans.

The branch of biology which deals with the structure of living organisms is called morphology. It is of two types. If we study the external structure of the organisms, it is called external morphology. When we study internal structure of the organisms, it is called internal morphology or anatomy.

Q.35. Define organ. Give examples.

Ans.

In higher multicellular organisms, particularly in animals, more than one type of tissue having related functions are organized together to form a unit, called organ. For example, stomach is an organ specialized for the digestion of proteins and storing food.

Q.36. What is organ system? Give examples.

Ans.

In higher multicellular organisms, particularly in animals, different organs performing related functions are organized together in the form of an organ system. For example, digestive system carries out process of digestion. It consists of oral cavity, stomach, small intestine, large intestine, liver and pancreas.

Q.37. What do you mean by organelles? Give examples.

Ans. An enormous number of biomolecules become associated in a particular way and form organelles. The organelles are actually sub-cellular structures. e.g. mitochondria, ribosomes etc.

Q.38. Define Palaeontology. (Lahore board 2011 G I)

Ans. The branch of biology which deals with the study of fossils, which are the remains of extinct organisms.

Q.39. What are Parasites?

Ans. Parasites are the organisms that take food and shelter from living hosts and in return, harm them.

Q.40. Define Parasitology. (Lahore board 2011 G I)

Ans. The branch of biology which deals with the study of parasites is called parasitology. The structure, habitats, mode of transmission, life histories and host parasite relationships are studied in this branch.

Q.41. What do you know about Pharmacology?

Ans.

The branch of biology which deals with the study of drugs and their effects on the systems of human body.

Q.42. Define Physiology.

Ans.

The branch of biology which deals with the study of the functions of different parts of living organisms is called physiology.

Q.43. Define Population. Give examples.

Ans. 

A group of organisms of same species located in the same place, at the same time is called population. For example human population in Pakistan in 2010 comprises of 173.5 million individuals.

Q.44. What are Prokaryotes and eukaryotes. Give examples.

(Lahore board 2011 G I)
Ans.

The organisms which do not have well defined nucleus and membrane bounded organelles in their cells are called prokaryotes.
e.g. bacteria and cyanobacteria.
The organisms which have well defined nucleus and membrane bounded organelles in their cells are called eukaryotes.
e.g. all animals and plants etc.

Q.45. What do you know about Protista?

Ans. 

It includes eukaryotic unicellular and simple multicellular organisms. There are three main types of protists.
(i) Algae (Plant like protists)
(ii) Protozoans (Animal like protists)
(iii) Fungi-like protists

Q.46. Define Science.

Ans. 

Science is the study in which observations are made, experiments are done and logical conclusions are drawn in order to understand the principles of nature.

Q.47. Define Socio-biology.

Ans. 

The branch of biology which deals with the study of social behaviour and communal life of living organisms.

Chapter: Introduction to Biology – Class 9 MCQs

1. Members of the same species living in the same place at the same time make a:

(a) Habitat
(b) Biosphere
(c) Community
(d) Population

2. If a scientist is studying the methods of inserting human insulin gene in bacteria, which branch of biology may this be?
(a) Anatomy
(b) Physiology
(c) Biotechnology
(d) Pharmacology

3. Which one will be the correct sequence of the levels of organization of life?
(a) Cell, organelle, molecule, organ, tissue, organ system, individual
(b) Molecule, tissue, organelle, cell, organ system, organ, individual
(c) Molecule, organelle, cell, tissue, organ, organ system, individual
(d) Organ system, organ, tissue, cell, molecule, organelle, individual

4. Which of these major bioelements is the highest percentage in protoplasm?
(a) Carbon
(b) Hydrogen
(c) Oxygen
(d) Nitrogen

4. Which of these major bioelements is the highest percentage in protoplasm?
(a) Carbon
(b) Hydrogen
(c) Oxygen
(d) Nitrogen

5. Which of the following group include organisms all of which are absorptive in their nutrition?
(a) Protists
(b) Animals
(c) Bacteria
(d) Fungi

6. Similar cells organized into groups and performing same functions, are known as:
(a) Organelle
(b) Tissue
(c) Organ
(d) Organ System

7. Which of these tissues also makes the glandular tissue in animals?
(a) Epithelial tissue
(b) Muscular tissue
(c) Connective tissue
(d) Nervous tissue

8. The level of organization that is less definite in plants is:
(a) Tissue level
(b) Organ level
(c) Organ system level
(d) Individual level

9. What is true about volvox?
(a) Unicellular prokaryote
(b) Unicellular eukaryote
(c) Colonial eukaryote
(d) Multicellular eukaryote

10. When we study the feeding relations among different animal species of a forest, at what level of organization we are studying?
(a) Individual
(b) Population
(c) Community
(d) Biosphere

11. __________ knowledge is the common heritage of mankind.
(a) Scientific
(b) Islamic
(c) Biological
(d) None of these

12. The example of colonial organism is:
(a) Amoeba
(b) Volvox
(c) Frog
(d) Mustard plant

13. The example of micromolecule:
(a) Starch
(b) Protein
(c) Fats
(d) Water

14. Microscopic study of tissues is called:
(a) Physiology
(b) Morphology
(c) Histology
(d) Anatomy

15. Which one is a major biological issue today?
(a) Infectious diseases
(b) Addictive drugs
(c) Environmental pollution
(d) All of these

16. Organisms of a species living in a particular habitat at a particular time:
(a) Population
(b) Community
(c) Individual
(d) None of these

17. Study of insects is called:
(a) Immunology
(b) Entomology
(c) Genetics
(d) Ecology

18. Water makes up ________ of the composition of protoplasm of all living things.
(a) 60%
(b) 70%
(c) 50-60%
(d) 60-70%

19. The number of bioelements is:
(a) 92
(b) 6
(c) 16
(d) 10

20. How much nitrogen is present in making body mass of a living organism?
(a) 10%
(b) 3%
(c) 1%
(d) 18%

21. Which of the following are supporting tissues in animals?
(a) Nervous
(b) Epithelial
(c) Muscular
(d) Connective

22. The author of "Al-Qanun-fial-Tib" is:
(a) Jabir Bin Hayan
(b) Abdul Malik Asmai
(c) Bu Ali Sina
(d) None

23. Which of the following is not unicellular organism?
(a) Amoeba
(b) Paramecium
(c) Hydra
(d) Euglena

24. Which one are not vegetative organs?
(a) Roots
(b) Stems
(c) Leaves
(d) Flowers

25. Scientific name of frog is:
(a) Rana tigrina
(b) Rosa indica
(c) Rana Tagrina
(d) Brassica Campestris

26. Forest community is an example of ________ community.
(a) Simple
(b) Complex
(c) Coordinated
(d) None

27. The study of internal structure is called:
(a) Anatomy
(b) Histology
(c) Entomology
(d) Taxonomy

28. As a bioelement, the percentage of carbon is:
(a) 18%
(b) 10%
(c) 2%
(d) 3%

29. Biology is a word of which language?
(a) Latin
(b) Arabic
(c) Greek
(d) English

30. The reproductive part of plant is:
(a) Stem
(b) Leaves
(c) Root
(d) Flower

31. Stomach is an example of:
(a) Tissue level
(b) Organ level
(c) Organ system level
(d) None

Answer Key

Q.No	Answer	Q.No	Answer	Q.No	Answer	Q.No	Answer
1	d	9	c	17	b	25	a
2	c	10	c	18	d	26	b
3	c	11	a	19	c	27	a
4	c	12	b	20	b	28	a
5	d	13	d	21	d	29	c
6	b	14	c	22	c	30	d
7	a	15	d	23	c	31	b
8	c	16	a	24	d