Bio152 Lecture 2 September 12 , 2013 th
Etymology of Key Terms
Glyco – of, or relating to, sugar.
Iso – equal, same.
Phobic – fear or aversion to.
Poly – many.
A theory is an explanation for a very general class of phenomena or observations.
Theories have two components: Pattern –
All cells come from pre-existing ones, all individuals in a population of single-celled
organisms are related by common ancestry
All of the cells present in a multicellular organism have descended from pre-existing cells
and are connected by common ancestry
Louis Pasteur’s experiment showed that cells do not arise from spontaneous generation
The Theory of Evolution by Natural Selection
All species are related by common ancestry (pattern)
Evolution is a change in the characteristics of a population over time. It means that
species are related to one another and can change through time
A group of individuals of the same species living in the same area at the same time make
Individuals have heritable traits. Certain versions of these traits help individuals survive
If certain heritable traits lead to increased success in producing offspring, these traits
become more common in the population over time (generations)
Humans exert the selective pressure
Adult male rams of Bighorn Sheep reproduce at age 6+
Male mating success is dependent on size and horn length
Large males with long horns are not surviving long enough to