Natrual Science

Natural Science 201

  1. Biology and the tree of life
Organism – living entity made up of one or more cells.
Five fundamental characteristics: Energy, cells, information, replication, evolution
Smallest organism: bacteria
Theory- explanation for a very general class of phenomena or observations.
Cell- highly organized compartment that is bounded by a thin flexible structure, plasma membrane and that contains concentrated chemicals in a watery solution.
Cell theory- All organisms are made of cells and all cells come from preexisting cells.
BUT! Direct challenge: where cells come from? (Spontaneous generation)
Two hypotheses: cells from cells & cells from non-living material
Louis Pasteur did experiment about this with straight necked flask& swan necked flask.
Theory proves multicellular organism are connected by common ancestry.
Evolution – change in the characteristics of a population over times. (Darwin and Wallace)
Other scientist had already come to same conclusion, BUT Darwin did natural selection.
Aristotle: Great chain of being, also called the scale of nature.
Species were organized into a sequence based on increased size and complexity, with humans at top
    Characteristic of species were fixed & some species are higher
Jean Baptiste Lamark: France Biologist
Formal theory of evolution (EX/ GIRAFFES)
Evolution to complex, better specie
Darwin vs. Lamark.
George Lecler( Compte de Buffon): France Biologist
Also, formal theory of evolution.
Against Darwin
George Cuvier: France biologist
Detailed analysis of and extinct species.
Think fossil species were victims of the flood at the time of Noah.


Two conditions of natural selection: 1. Heritable – trait that can be passed on off spring
2 particular environment.
+ If certain heritable traits lead to increased success in producing offspring, then...