chapter 1

• Biology


  The natural science that studies life and living organisms, including their physical structure, chemical processes, molecular interactions, physiological mechanisms, development and evolution
• Unifying concepts in biology

  • Cell as the basic unit of life
  • Genes as the basic unit of heredity
  • Evolution as the engine that propels the creation and extinction of species
• Living organisms


  Open systems that survive by transforming energy and decreasing their local entropy to maintain a stable and vital condition defined as homeostasis
• Theoretical biology


  Uses mathematical methods to formulate quantitative models
• Experimental biology


  Performs empirical experiments to test the validity of proposed theories and understand the mechanisms underlying life and how it appeared and evolved from non-living matter about 4 billion years ago through a gradual increase in the complexity of the system
• Branches of biology

  • Anatomy
  • Biochemistry
  • Biophysics
  • Biotechnology
  • Botany
  • Cell biology
  • Ecology
  • Evolution
  • Genetics
  • Immunology
  • Marine biology
  • Microbiology
  • Molecular biology
  • Mycology
  • Parasitology
  • Photobiology
  • Phycology
  • Physiology
  • Plant physiology
  • Radiobiology
  • Structural biology
  • Theoretical biology
  • Virology
  • Zoology
• Biology is mainly studying about life
• Biology provides an in-depth, scientific understanding of how all living and nonliving organisms interact with each other
• Biology gives insights on how diverse life forms are
• Biology encompasses other fields of research that are related to the sustainability of life, including the environment, ecosystem, food quality, causes of illnesses, the development of medicines, the study of the human body
• The study of life has helped in shaping the world and given many credible and reliable answers that explain why things happen in a more scientific manner
• Importance of biology

  • Explains the changes of the human bodies
  • Shapes different careers
  • Provides answers to large-scale problems
  • Teaches concepts on basic living
  • Helps in answering the fundamental questions about life
  • Paves way for scientific investigations
• The history of biology traces the study of the living world from ancient to modern times
• The biological sciences emerged from traditions of medicine and natural history reaching back to ayurveda, ancient Egyptian medicine and the works of Aristotle and Galen in the ancient Greco-Roman world
• This ancient work was further developed in the Middle Ages by Muslim physicians and scholars such as Avicenna
• During the European Renaissance and early modern period, biological thought was revolutionized in Europe by a renewed interest in empiricism and the discovery of many novel organisms
• Prominent in this movement were Vesalius and Harvey, who used experimentation and careful observation in physiology, and naturalists such as Linnaeus and Buffon who began to classify the diversity of life and the fossil record, as well as the development and behavior of organisms
• Antonie van Leeuwenhoek revealed by means of microscopy the previously unknown world of microorganisms, laying the groundwork for cell theory
• Over the 18th and 19th centuries, biological sciences such as botany and zoology became increasingly professional scientific disciplines
• Lavoisier and other physical scientists began to connect the animate and inanimate worlds through physics and chemistry
• Explorer-naturalists such as Alexander von Humboldt investigated the interaction between organisms and their environment, and the ways this relationship depends on geography—laying the foundations for biogeography, ecology and ethology
• Naturalists began to reject essentialism and consider the importance of extinction and the mutability of species
• Cell theory provided a new perspective on the fundamental basis of life
• These developments, as well as the results from embryology and paleontology, were synthesized in Charles Darwin's theory of evolution by natural selection
• The end of the 19th century saw the fall of spontaneous generation and the rise of the germ theory of disease, though the mechanism of inheritance remained a mystery
• In the early 20th century, the rediscovery of Mendel's work led to the rapid development of genetics
• In the early 20th century, the rediscovery of Mendel's work led to the rapid development of genetics by Thomas Hunt Morgan and his students, and by the 1930s the combination of population genetics and natural selection in the "neo-Darwinian synthesis"
• New disciplines developed rapidly, especially after Watson and Crick proposed the structure of DNA
• Following the establishment of the Central Dogma and the cracking of the genetic code, biology was largely split between organismal biology—the fields that deal with whole organisms and groups of organisms—and the fields related to cellular and molecular biology
• By the late 20th century, new fields like genomics and proteomics were reversing this trend, with organismal biologists using molecular techniques, and molecular and cell biologists investigating the interplay between genes and the environment, as well as the genetics of natural populations of organisms
• Zacharias Janssen


  Invented the first compound microscope in 1595, associated with the invention of the telescope in the Netherlands in 1608, tried in court for counterfeiting coins
• Antonie Van Leeuwenhoek


  Improved the microscope in 1664, built a single lens microscope that could magnify >200x
• Robert Hooke


  His work around his law of elasticity led to the invention of the balance spring in 1660, which was a key part in allowing the mechanical watch to keep time accurately, member of the Royal Society from 1663
• Carl Linnaeus


  Laid the foundations for the modern biological naming scheme of binomial nomenclature, published the first edition of Systema Naturae in the Netherlands in 1735, sent on several journeys through Sweden to find and classify plants and animals
• Cell Theory


  Developed from the discoveries of Matthias Schleiden, Theodor Schwann, and Rudolph Virchow, Schleiden discovered that all plants were composed of cells, Schwann discovered that all animals were composed of cells, Virchow found that all cells come from other existing cells
• Charles Darwin


  Introduced his scientific theory that the branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding
• Rudolf Virchow


  Stated that new cells are formed only from existing cells in 1855, first person to recognize leukemia cells
• Alfred Wallace


  Co-discoverer of the theory of natural selection, sent Darwin his theory in 1858 which nearly replicated Darwin's own
• Matthias Schleiden


  Concluded that all plants are made up of cells in 1838, recognized the importance of the cell nucleus
• Theodor Schwann

  Developed the cell theory, discovered Schwann cells in the pepsin, discovered the organic nature of yeast, invented the term metabolism