Biology Class 9 Notes Chapter 1

Chapter 01             

Questions & Answers

Q.No: 01 Why the subject biology is named a multidimensional subject?

Ans: Biology is considered a multidimensional subject because it encompasses a wide range of disciplines and levels of organization, from the molecular and cellular levels to the ecosystem level. It includes various branches such as genetics, biochemistry, anatomy, physiology, ecology, evolution, and many more. These different branches and levels of the organization are all interconnected and interdependent, creating a complex and multi-faceted subject.

Q.No: 02 How farming profession helps mankind?

Ans: Farming plays a critical role in supporting human life by providing a steady source of food and other essential resources. Some ways in which the farming profession helps mankind include:

➧Food production: Farming is the primary source of food for the global population, providing essential nutrients and sustenance for people of all ages.

➧Economic development: Agriculture is a significant contributor to the economies of many countries and provides jobs for millions of people.

➧Environmental protection: Farmers play a crucial role in maintaining the balance of ecosystems and preserving biodiversity by practicing sustainable agriculture and conservation techniques.

➧Climate change mitigation: Agriculture has a significant impact on the environment and can contribute to climate change. However, sustainable farming practices, such as conservation tillage, integrated pest management, and agroforestry, can help mitigate the effects of climate change.

➧Food security: Farming helps ensure food security by providing a reliable source of food and reducing the vulnerability of communities to food shortages and price fluctuations.

Q.No: 03 Why species is called as smallest taxonomic level?

Ans: A species is considered the smallest taxonomic level because it is the most basic unit of classification in biology. The term "taxonomy" refers to the science of classifying and naming organisms, and species is the smallest and most fundamental category within that classification system.

Q.No: 04 How the population is different from the community?

Ans: Population and community are two different terms in biology that refer to different levels of organization in ecology.

A population is a group of individuals of the same species that live in the same geographic area and are capable of interbreeding. Populations are defined by their species and their location, and they can vary in size, distribution, and demographics. For example, a population of deer in a forest is made up of all the individuals of that species living in that forest.

A community, on the other hand, is a group of populations of different species living in the same area and interacting with one another. Communities can include both biotic (living) and abiotic (non-living) components, and they reflect the complex interactions between the populations of different species. For example, the community in a forest might include populations of deer, birds, trees, and other organisms, as well as the soil, water, and other non-living components of the ecosystem.

Q.No: 05 How new varieties of plants are produced?

Ans: New varieties of plants can be produced through a variety of methods, including natural processes and human-assisted methods. Some methods include:

➧Natural hybridization: Hybridization occurs when two different species cross-pollinate and produce offspring with characteristics from both parents. This process can result in the creation of new varieties of plants that are well-adapted to their environment.

➧Mutations: Mutations are changes in the genetic code of a plant that can result in new characteristics. These changes can occur naturally or be induced by radiation or chemical exposure. Some mutations can be beneficial and result in the creation of new varieties of plants.

➧Artificial selection: Humans can intentionally select for desirable traits in plants and breed them over time to produce new varieties. This method, also known as selective breeding, has been used for thousands of years to produce crops with improved yields, greater resistance to pests and diseases, and other desirable traits.

➧Genetic engineering: Advances in genetic engineering have made it possible to precisely manipulate the genetic code of plants, introducing new traits and creating new varieties. This method is used to produce crops with improved resistance to pests and diseases, increased tolerance to environmental stress, and other desirable traits.

Q.No: 06 Describe the contributions made by Muslim researchers to the discipline of biology?

Ans: Muslims have made significant contributions to the field of biology, and their work has had a lasting impact on the development of modern science. Here are some of the key roles played by Muslim scientists in the field of biology:

➧Preservation of Greek and Roman knowledge: During the Islamic Golden Age, Muslim scientists preserved and translated the works of ancient Greek and Roman scientists, such as Aristotle and Galen, into Arabic. This helped to preserve and expand upon the knowledge of classical biology and made it accessible to a wider audience.

➧Discovery and classification of plants and animals: Muslim scientists made important contributions to the field of taxonomy by discovering, describing, and classifying new species of plants and animals. For example, Al-Dinawari, a 9th-century botanist, wrote a comprehensive treatise on botany that described more than 600 plants and their uses.

➧Development of surgical techniques: Muslim surgeons made important contributions to the field of medicine, including the development of surgical techniques for treating conditions such as cataracts and hernias.

➧Study of anatomy and physiology: Muslim scientists made important contributions to the study of anatomy and physiology, including the discovery of new organs and the understanding of how the body works. For example, Al-Zahrawi, a 10th-century physician, wrote a comprehensive treatise on surgery that described new surgical techniques and the anatomy of various organs.

➧Advancements in pharmacology: Muslim scientists made important contributions to the field of pharmacology, including the discovery of new drugs and the development of new methods for preparing and administering medications. For example, Rhazes, a 9th-century physician, wrote a comprehensive treatise on medicine that described more than 700 drugs and their uses.

➧These are just a few examples of the important role that Muslim scientists have played in the field of biology. Their work helped to advance our understanding of the natural world and lay the foundation for modern biology.

 
Q.No: 07 Identify the connections of biology to other sciences?

Ans: Biology is an interdisciplinary field that has close relationships with many other sciences. Here are some of the key relationships between biology and other sciences:

➧Chemistry: Biology and chemistry are closely related as many biological processes involve chemical reactions. For example, the metabolism of cells and the biochemistry of enzymes and hormones are studied in detail using chemical principles.

➧Physics: Biology and physics have a relationship in the study of biological systems at the molecular and cellular levels. For example, physical principles such as thermodynamics and fluid dynamics are used to understand processes such as cellular respiration and blood flow.

➧Mathematics: Biology and mathematics have a close relationship, as mathematical models and statistical methods are used to analyze and understand biological data. For example, population dynamics and the spread of diseases can be modeled using mathematical equations.

➧Computer Science: Biology and computer science have a growing relationship as the development of new technologies and computational methods have led to an explosion of biological data. For example, bioinformatics and computational biology use computer algorithms and databases to analyze and understand large amounts of genetic and biochemical data.

➧Earth Sciences: Biology is closely related to earth sciences, especially in the study of ecosystems and the relationships between organisms and their environment. For example, the study of biodiversity, conservation biology, and global climate change all involve interdisciplinary approaches that bring together biologists and earth scientists.

These are just a few examples of the close relationships between biology and other sciences. By working together, biologists and scientists from other fields are able to gain a deeper and more comprehensive understanding of the natural world.

 

Q.No: 08 Describe the level of organization?

Ans: The levels of organization in biology refer to the hierarchical structure of biological systems, from the smallest to the largest. The stages of biological organization are as follows:

➧Chemical level: The chemical level of an organization refers to the smallest building blocks of life, such as atoms, molecules, and macromolecules. These building blocks come together to form the more complex structures that makeup living organisms.

➧Cellular level: The cellular level of an organization refers to the basic unit of life, the cell. Cells are the smallest units that possess all the characteristics of life, and they come in a variety of shapes and sizes.

➧Tissue level: The tissue level of an organization refers to groups of similar cells that work together to perform a specific function. For example, muscle tissue is made up of muscle cells that contract to produce movement, while nervous tissue is made up of neurons that transmit signals throughout the body.

➧Organ level: The organ level of the organization refers to a group of tissues that work together to perform a specific function. For example, the heart is an organ made up of muscle, connective, and epithelial tissues that work together to pump blood throughout the body.

➧Organ system level: The organ system level of an organization refers to a group of organs that work together to perform a specific function. For example, the digestive system is an organ system made up of the mouth, esophagus, stomach, small intestine, large intestine, and rectum that work together to digest food.

➧Organism level: The organism level of an organization refers to a single, complete living entity, such as a plant, animal, or bacterium.

➧Population-level: The population level of an organization refers to a group of individuals of the same species that live in the same geographic area.

➧Community level: The community level of an organization refers to a group of populations of different species that live in the same geographic area and interact with each other.

➧Ecosystem level: The ecosystem level of an organization refers to a community of living and non-living things that interact with each other in a specific environment.

These levels of organization help us to understand the structure and function of biological systems at different scales, from the smallest building blocks to the largest and most complex systems.