chapter 01

Bio1100 Chapter 1 The Science of Biology

Biology is the study of things, which share five basic properties.
- • Basic properties of life.
  - Cellular organization:
    all organisms are made of cells.
  - Metabolism:
    all organisms use energy.
  - Homeostasis:
    all organisms maintain stable internal conditions.
  - Growth and reproduction:
    all organisms grow and reproduce.
  - Heredity:
    all organisms possess heritable information about how they look and function.
- • The cell is the basic unit of life: some organisms consist of a single cell, while others are multicellular.
  These Paramecia are singled-celled protists (kingdom Protista) that have ingested several yeast cells.
- • This kingfisher obtains the energy it needs to move, grow, and carry out its body processes by eating fish.
  It transforms the potential energy in the food into other forms of energy in a process called metabolism.
- • Living things maintain stable internal conditions such as water balance and body temperature in a process called homeostasis.
- • Living organisms grow by accumulating nutrients.
  Growth eventually leads to reproduction.
  Unicelluar organisms such as bacteria (kingdom Bacteria) reproduce by dividing one cell into two.
- • Organisms inherit traits through the genetic material called DNA.
  All calls contain DNA, inherited from predecessor cells.
Living organisms exhibit levels of complexity and organization.
- • Hierarchical organization of life.
  Living things function and interact with each other on many levels.
  - cellular
  - organismal
  - population
  - ecosystem
- • Atoms such as carbon are the fundamental units of matter, and can be joined into molecules, some of which form complex macromolecules.
  DNA is the hereditary macromolecules of most living things and is made of smaller molecules such as Adenine.
  In organisms called eukaryotes, macromolecules may be contained in compartments called organelles, which perform specific activities.
  For example, the nucleus is an organelle that stores DNA in cells.
  The collection of macromolecules and organelles are contained within membrane-bounded cells, the basic unit of life.
  Prokaryotes are cells that do not possess organelles.
- • Groups of similar cells can be organized into tissues that act as a functional unit. Examples include nerve tissue and muscle tissue.
  Several tissues can be grouped into organs to perform a higher level function. The brain is an organ composed of nerve, blood, and other tissue.
  Different organs can be organized into organ systems. The nervous system consists of sensory organs, the brain, and spinal cord.
  An organism may be composed of several organ systems.
- • A group of organisms of the same species in one area comprise a population, such as a flock of geese.
  
  A species is a collection of similar organisms that can interbreed, such as Canada geese.
  
  Populations of several species living and interacting in one area comprise a community; a pond community may consist of geese, cranes, fish, grasses, and insects.
- • The biological community and the abiotic components of the place they live in (habitat) make up an ecosystem, such as a pond.
Living organisms can be divided into six , based on shared characteristics.
- •
  The 6 kingdoms of living organisms are:
  a) Archaea b) Bacteria c) Protista d) Plantae e) Fungi f) Animalia
- • Archaea.
  This kingdom of unicellular prokaryotes (cells that do not have nuclei or other organelles) includes this methanogen, which releases methane as a product of metabolism.
- • Bacteria.
  In addition to Archaea, this group is the other unicellular prokaryotic kingdom.
  These are purple sulfur bacteria that get their energy from hydrogen sulfide.
- • Protista.
  This kingdom comprises unicellular eukaryotes (cells that contain a nucleus) such as Paramecia, as well as some multicellular eukaryotes, such as these kelp, a type of algae.
- • Plantae.
  This kingdom contains multicellular photosynthetic eukaryotes that are mostly terrestrial. Photosynthesis is the process by which these organisms obtain energy from light.
- • Fungi.
  This kingdom contains non-photosynthetic multicellular eukaryotes that digest their food externally, such as these mushrooms.
- • Animalia.
  Organisms in this kingdom are non-photosynthetic multicellular eukaryotes that ingest their food and digest internally, such as this ram.
- • Archaea.
  This kingdom of unicellular prokaryotes (cells that do not have nuclei or other organelles) includes this methanogen, which releases methane as a product of metabolism.
- • Bacteria.
  In addition to Archaea, this group is the other unicellular prokaryotic kingdom.
  These are purple sulfur bacteria that get their energy from hydrogen sulfide.
- • Protista.
  This kingdom comprises unicellular eukaryotes (cells that contain a nucleus) such as Paramecia, as well as some multicellular eukaryotes, such as these kelp, a type of algae.
- • Plantae.
  This kingdom contains multicellular photosynthetic eukaryotes that are mostly terrestrial. Photosynthesis is the process by which these organisms obtain energy from light.
- • Fungi.
  This kingdom contains non-photosynthetic multicellular eukaryotes that digest their food externally, such as these mushrooms.
- • Animalia.
  Organisms in this kingdom are non-photosynthetic multicellular eukaryotes that ingest their food and digest internally, such as this ram.
How Scientists Think:
- Scientists use and reasoning to investigate the natural world.
  - • Inductive and deductive reasoning.
    - Inductive reasoning is using specific observations to formulate general principles.
    - Deductive reasoning is using general principles to guide actions.
  - • Inductive reasoning involves discovering general principles through observation of specific cases.
    Scientists use inductive reasoning to develop hypotheses (inferences) about how the world works.
    For example, you observe that you can encounter only green traffic lights at successive intersections on a street by driving at the speed limit.
    You may form a hypotheses that the lights are synchronized to encourage drivers to stay within the limit.
  - • Deductive reasoning is the process of using general principles (hypotheses) to guide actions.
    Often this involves "if... then..." logic, and scientists use deductive reasoning to make predictions from hypotheses.
    Using your hypotheses of synchronized traffic lights, you can predict that if you exceed the speed limit, then you will run into red lights.
- Scientific investigations involve using to formulate , in a series of steps called the process.
  - • Scientific process.
    1. Make detailed observations.
    2. Form potential explanations - hypotheses.
    3. Make falsifiable predictions based on the hypotheses.
    4. Conduct experiments to test hypotheses and their predictions.
    5. Reject or modify hypotheses that fail the test. Note that positive experimental results usually only support the hypothesis; it is difficult to prove a hypothesis with only a few tests.
    6. Draw conclusions from experimental results.
    Good hypotheses lead to new observations and predictions; science progresses in a spiral of knowledge.
- Hypotheses that hold up to testing over time may be combined into statements called .
- • Theory formation.
  A hypothesis that holds up to repeated testing over time and is accepted by the scientific community becomes a theory that can explain many observations.
  Scientific process exercise