Intro To Biology

• Biology

  Branch of natural science that deals with the scientific study of life
• Biology


  Has a broad scope but with several unifying themes that knit it together as a single coherent field
• Life on Earth began more than 3.5 billion years ago
• Today, there are millions of species of organisms that live on the surface of the earth
• Branches of Biology

  • Zoology
  • Botany
  • Entomology
  • Mammalogy
  • Ichthyology
  • Ornithology
  • Mycology
  • Limnology
  • Microbiology
  • Physiology
  • Anatomy
  • Ecology
  • Genetics
  • Cytology (Cell biology)
  • Arthropodology
• The first organisms that emerged were unicellular organisms
• Rules and by-laws for the Biology course
• It is believed that multicellular organisms evolved from single-celled organisms over time
• Aristotle


  Ancient Greek philosopher, reputed to be the "Father of Biology and Zoology"
• Hippocrates


  Greek Physician of the classical period, reputed to be the "Father of Modern Medicine"
• Objectives of Lecture 1

  • Explain the scientific basis of life
  • State the various branches of Biology
  • Pioneers in Biology
  • Themes of Biology
  • Characteristics of living things
  • The scientific method
  • The domains of life
• Antonie van Leeuwenhoek


  Dutch microbiologist, known for pioneering work in microscopy
• Alexander Fleming


  Scottish Physician and bacteriologist, discovered the first antibiotic (penicillin) in the 1940s
• Edward Jenner


  English Physician and Scientist
• Vaccines


  Weakened forms of a disease or disease-causing organisms which prompt the body to make antibodies to fight them
• Cell Structure and Function


  • Cells are small and highly specialized
  • Specialised animal cells have components that enable them to perform specific functions
  • Groups of specialized cells are organized into tissues and organs in multicellular organisms e.g. animals & plants
  • Cells contain specialized structures (organelles) that enable the cell to carry out all life processes
  • All cells are surrounded by a plasma membrane
  • The cell contains a set of instructions called DNA/RNA (genetic information)
  • The process by which organisms maintain a stable internal environment known as homeostasis
  • Homeostasis is a self-regulating process by which biological systems maintain internal stability while adjusting to external environmental changes
• Themes of Biology

  • Cell is the functional unit of life
  • All organisms are made of and develop from cells
  • Unicellular organisms
  • Multicellular organisms
  • Most organisms are multicellular
• Homeostasis

  1. Homeostasis is a dynamic process

  2. Examples of homeostasis are: Body temperature regulation, Blood pressure regulation, Blood sugar regulation, Acid-base balance, etc

  3. In homeostasis, temperature, water contents, chemical contents, etc. must be maintained

  4. The 5 primary components responsible for the maintenance of homeostasis are: Stimulus – a change in the environment, Receptor – detect a stimulus, Control centre – brain, spinal cord or gland, Effector – muscles or glands produce response, Feedback mechanism – negative feedback loop (reduces a response); positive feedback (intensifies a response)

  5. Generally, the 3 types of homeostatic regulations in the body are: Thermoregulation, Osmoregulation, Chemical regulation
• Reproduction and Inheritance

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• Thermoregulation


  Process of regulating body temperature
• Types of homeostatic regulations in the body

  • Thermoregulation
  • Osmoregulation
  • Chemical regulation
• The source of all energy on Earth is the Sun
• Types of genetic material

  • DNA
  • RNA
  • Genes
• All cells contain genetic information
• Genetic continuity from one generation to the next

  1. Genetic information is conveyed from DNA to RNA to proteins (transcription & translation)

  2. Genetic information is transferred from DNA to DNA (replication)
• DNA in somatic cells are identical
• In sexual reproduction, hereditary information is combined from two different organisms of the same species
• Inheritance


  In the course of reproduction, organisms transfer hereditary information to their offspring
• Genes

  DNA contains instruction for traits
• In asexual reproduction, hereditary information is from one parent organism
• Matter, Energy, and Organization

  • Living things are highly organized
  • All living things require a regular supply of energy for maintenance of an orderly state
• Reproduction


  All organisms produce new ones of their own kind
• Photosynthesis


  The process by which some organisms capture the Sun's energy and transform it into chemical energy that can be utilized by other living things
• Types of autotrophs

  • Phototrophs
  • Chemotrophs
• In heterotrophism, complex chemicals are broken down and reassembled into chemicals and structures needed by organisms
• Natural selection is the driving force for evolution
• Characteristics of living organisms

  • Made of cells
  • Organized
  • Require energy (food)
  • Grow and develop
  • Reproduce
  • Move
  • Maintain homeostasis
  • Exchange materials with their environment
  • Respond to the environment
• Evolution explains how many different types of organisms come into existence and how modern organisms are related to past organisms
• Heterotrophs


  Organisms that take in already prepared food to meet their energy requirements
• The concept of evolution provides a basis for exploring the relationships among different groups of organisms