What is Science?

Sec. 1-1, 1-2

  • Goal of science
    • Investigate the natural world
    • Understand it
    • Explain events
    • Make predictions
  • Good science questions existing ideas and hypothesis.
  • New ideas develop through research.
  • How theories are developed…
    • Ask a question
    • Develop a reasonable answer to the question…hypothesis
    • Set up a controlled experiment
      • Change one variable each time it is run
    • Record and analyze results
    • Draw a conclusion
    • Theory may develop based on well-tested experiment that confirms a broad range of observations

NO THEORY IS CONSIDERED THE ABSOLUTE TRUTH. IT CAN BE CHANGED BASED ON NEW RESEARCH AND OBSERVATIONS.

Theory of Evolution

Sec. 15-1

The first obvious thing to note when studying life is the vast biodiversity of species and within species. How did this happen?

The hypothesis that led to a theory came from Charles Darwin.

  • Born in 1809 in England
  • After college sailed with the HMS Beagle to travel the world
  • Collected specimens of the biodiversity he found
  • He was fascinated by the adaptations of plants and animals in their habitats.
  • Also collected fossils and wondered why some species die out
  • Trip to Galapagos Islands let to more interest
    • Group of islands off coast of South America
    • Close together but different climates
    • Plants and animals on each island were well-adapted to their habitat
      • Noted variety in land tortoises

                       

  • Noted variety in beaks of what appeared to be the same species of bird

Darwin came up with a theory, but refused to publish his writings for 25 years, until someone else came up with the same theory.

 

Inherited variation and Artificial Selection (done by humans)

  • There is variety within species
  • Humans had been selecting desired traits to create improvement in crops and livestock…artificial selection
  • Darwin was convinced this happened in nature as well.
  • Due to struggle for existence, fitness adaptation allows some to survive….Darwin called this natural selection
  • Natural selection allows populations to change over time.

What was the evidence that supported Darwin’s theory?

  • Fossil record

  • Geographic distribution of living things

  • Homologous body structures

 

Note: not all homologous structures serve a purpose. Some no longer have a function but still exist. They are called vestigial organs.

 

 

  • Similarities in embryology

 

 

Last modified: Tuesday, November 5, 2013, 10:30 AM