Bio1151 Chapter 1 Introduction: Themes in the Study of Life
  1. Biology is the scientific study of       .

  2. All (most?) living organisms exhibit these properties:

      Do these ordered rings belong to a living organism?
    1. a high level of        as organized in several hierarchical levels.

        Hierarchies of Life: Biosphere.

      • Biosphere
      • Ecosystems
      • Communities
      • Populations
      • Organisms

        All the environments on earth that are inhabited by life constitutes the biosphere.

        An ecosystem consists of all the living things in a geographic area, along with all the non-living components, such as soil, water, gases, and light.

        A deciduous forest is an example of an ecosystem.

        The entire array of organisms inhabiting an ecosystem is called a community.

        The community in our forest ecosystem includes many species of trees, animals, fungi, as well as countless microorganisms.

        A population consists of all the individuals of a species in an area.

        This forest may include populations of sugar maples.

        There may also be populations of animals such as deer.

        Individual living things are called organisms.

        Each of the maple trees in this forest is an organism.

        Hierarchies of Life: Organism.

      • Organs and organ systems
      • Tissues
      • Cells
      • Organelles
      • Molecules

        Levels of life exercise:

        A complex organism may be organized into units called organs, such as this leaf on a maple tree.

        Human organs such as stomach and intestines can be organized into an organ system - the digestive system.

        A tissue is a group of similar cells that perform a specific function.

        The mesophyll tissue in a maple leaf performs photosynthesis - producing carbohydrates (sugars) from light.

        A leaf's mesophyll tissue is made of numerous cells that are similar to each other.

        The cells of a leaf's mesophyll tissue contain organelles called chloroplasts, which carry out photosynthesis.

        Chloroplasts are organelles and contains chlorophyll molecules that can convert light energy to food.

        Another important organelle is the nucleus.

        A molecule is made of two or more atoms.

        Atoms are the smallest chemical units of pure matter called elements such as oxygen and carbon.

        A molecule whose atoms are of different elements is called a compound

    2. capture         from the environment, and          to that environment.

        The dynamics of an ecosystem comprise two major processes.

        Chemical nutrients produced by plants and other photosynthetic organisms cycle through other living and non-living components of the ecosystem.

        Energy flows from a source (usually sunlight) through organisms in the ecosystem, eventually leaving in the form of heat.

    3. reproduce using the hereditary material      (Deoxyribonucleic Acid)

        All cells (such as this lung cell from a newt) reproduce by dividing to produce more cells. During this process, the genetic material DNA must be copied and divided into the two cells.

        The nucleus of many cells contain the genetic material called DNA (Deoxyribonucleic Acid).

        A DNA molecule is made of two strands of polymers wrapped around each other in the three-dimensional form of a double helix.

        Each of the two strands is composed of sequences of building blocks called nucleotides.

    4. grow and         

        Growth and development. A human starts life as a single fertilized egg cell. As it accumulates nutrients, that egg cell can grow by dividing to produce more cells found in an embryo. Eventually the cells develop into various tissues and organs comprising the organism.
    5.         through a process called             .

  3. The cell is the basic unit for life, and contains the hereditary material      .

      The cell is the basic functional unit of life.

      All cells are bound by a membrane that encloses a semi-fluid cytoplasm.

      Eukaryotic cells contain membrane-enclosed organelles, including a DNA-containing nucleus.

      Prokaryotic cells lack organelles; their DNA is not contained in a nucleus.

  4.           is the branch of biology that names and classifies organisms according to a system of broader and broader groups, or       .

      Domains of life.

      All living things are classified into 3 large domains.

      Domains Bacteria and Archaea are unicellular prokaryotes and possess no nucleus.

      Each of these two domains may comprise several kingdoms.

      Domain Eukarya is split into 4 kingdoms of organisms with a nucleus.

    • Protista contains both unicellular and multicellular organisms.
    • Plantae are multicellular, photosynthetic, terrestrial organisms.
    • Fungi are multicellular and digest food externally.
    • Animalia are multicellular and digest food internally.


      Taxonomy is a discipline that classifies organisms into groups (taxa) based on shared descent from a common ancestor.

      Domain is the broadest taxon containing the most organisms.

      Below domain are progressively smaller taxa with more narrowly related organisms:

      • Kingdom

      • Phylum

      • Class

      • Order

      • Family

      • Genus

      • Species
  5. Biologists use various forms of          to explore life.
    • In            science, scientists describe some aspect of the world and use            reasoning to draw general conclusions.

        Inductive reasoning.

        Jane Goodall recorded her observations on chimpanzee behavior in field notebooks, often with sketches.

        From these specific observations she can make generalized inductions about chimpanzee behavior.

    • In                   science, scientists use            reasoning to form a general hypothesis to explain specific details of the world; this is the             method.

      Deductive reasoning is the process of using general principles (hypotheses) to explain individual observations.

      Often this involves "if... then..." logic and can be used to make predictions that can be tested in a process called the scientific method.

      Scientific method.

    • One or more hypotheses are proposed to explain observations.
    • A hypothesis should be testable and lead to predictions.
    • A prediction should be falsifiable through tests.
    • A test may take the form of further observations or a controlled experiment. where the effect of one variable is checked by testing control and experimental groups that differ in only one variable.
    • The test results should either support or reject the hypothesis.
    • If supported, the hypothesis gains theoretical value and is further tested. + If rejected, the hypothesis is either revised or discarded.

      A hypothesis that has sufficient support via many tests may be accepted as a theory.

      Scientific method exercise