Biology Chapter-1

• Biology is the study of living things.
• A large variety of living things exists on the land, in the water and in the air.
• Living things (organisms) include plants, animals including humans and other organisms.
• The main branches of biology are Botany(study of plant), Zoology(study of animals) and Microbiology(study of microscopic organisms).
• The main characteristics of living things are their cellular structure, metabolism, growth, movement, irritability, reproduction and adaptability.
• All living things consist of the living substance called protoplasm which forms the basis of cells.
• Group of cells is tissue. Tissues are made up of cells that work together to carry out a specific function.
• Group of tissues is organ.
• Group of organs is system. Example: digestive system.
• Group of systems is organism.
• Cell is made by protoplasm and protoplasm is made of molecules.
• In Metabolism there are metabolism, anabolism, catabolism, nutrition, respiration and excretion.
• Catabolism is breakdown process.
• Respiration is the process of releasing energy from nutrients.
• Excretion is the removal of waste products from body.
• Nutrition is the process of taking food into body.
• The growth of an organism is seen as an increase in size and weight resulting from the use of food to further develop structures in the organism.
• All living things show some kinds of movement.
• Movement is more obvious in animals since they have organs of movement or locomotion.
• Movements in plants mainly take place inside the cells although some results from a stimulus such as light.
• Living things respond to stimulus.
• The stimulus can be any changes in the environment (light, sound, touch, temperature, etc.) which brings about a reaction in an organism due to a sensitivity to the stimulus.
• Irritability is reaction or responding to stimulus.
• Reproduction is the production of a new generation of offspring.
• There are 2 types of reproduction. Asexual Reproduction and Sexual Reproduction.
• In asexual reproduction, the new individual may be produced by a part of the old one.
• There is only one parent organism needed for asexual reproduction.
• Living organisms are able to adjust and adapt themselves to changes in their external and internal environments.
• Adaptability increases the chances of species surviving and can result in the formation of a new species.
• The science of classification of organisms is taxonomy.
• There are vast numbers of living things in the world.
• The word 'biodiversity' is a short form of 'biological diversity' which means that the abundance of different types of species.
• Classification is essential to biology because there are too many different living things to sort out and compare unless they are organized into manageable categories.
• The scheme of classification has to be flexible.
• As living and extinct species are related, fossils should also be considered in this scheme.
• Taxonomy can be used to examine, the evolutionary history of organisms and the relationships between organisms.
• Taxonomy Hierarchy

  1. Kingdom
  2. Phylum
  3. Class
  4. Order
  5. Family
  6. Genus
  7. Species
• Linnaeus (1707~1778), a Swedish naturalist, studied and gave scientific names to thousands of plants and animals.
• Linnaeus introduced the Binomial System of Nomenclature in the year 1753.
• Each plant and animal is given a two-word name by Binomial System.