Intro to Biology

Characteristics of Life

  • Evolution:: natural selection and adaptation over generations, fundamental theory of biology
  • Matter:: calls, fundamental unit of life, anything that occupies space and has mass
  • Energy:: neither created nor destroyed, most systems lose energy through heat, matter cycles through energy
  • Information:: central dogma DNA → RNA → proteins, DNA is life’s main info molecule, proteins control metabolic activities
  • Regulation:: how living systems are monitored, coordinated, developed, and maintained
  • Communication & Interaction:: how living systems receive and exchange info, interactions between and within systems

Scientific Investigations

  • hypothesis:: proposed explanation based on limited evidence, starting point for further investigation
  • control setup:: control group, doesn’t receive independent variable, used for comparison to verify conclusions
  • Controlled Variables:: variables that remain constant/unchanged throughout experiment, same for all groups
  • Manipulated Variable:: variables changed by researcher, independent variables, what is being tested
  • Dependent Variable:: response to changing independent variable, what is being measured for effects of independent variable
  • Quantitative Data:: can be counted/measured in numerical values
  • Qualitative Data:: can’t be counted/measured, can be observed/recorded, qualities and characteristics
  • Null Hypothesis:: proposes that no statistical significant exists (reject or fail to reject after experiment)
  • Modal Organisms:: help scientists understand complex biological processes by observing systems of simple organisms (e.g. fruit fly, sea slug, zebrafish)

Feedback Systems

  • Negative Feedback:: output decreases the response and shuts down the pathway, maintains homeostasis
      * examples - regulating body temperature, regulating blood sugar
  • Positive Feedback:: output increases the output, amplifies effects when something needs to happen quickly, helps return to homeostasis faster
      * examples - contractions in child birth, ripening of fruits