the tree of
life I) Biological Science was founded with the development of:
1) The cell theory, which proposes that all organisms are made of cells and that all cells come
from pre-existing cells,
-Pasteur used swan neck flasks to isolate broth and prove that cells are not spontaneously made
2) The theory of evolution by natural selection, which maintains, that the characteristics of
species change through time, primarily because individuals with certain heritable traits produce more
offspring that do individuals without those traits.
-Natural Selection acts on individuals while evolution acts on populations
- Evolution occurs when heritable variation leads to differential success in reproduction
-Fitness means the ability of an individual to produce offspring
-Adaptation is a trait that increase the fitness of an individual in a particular environment
II) A phylogenetic tree is a graphical representation of the evolutionary relationships among species.
Phylogenies can be established by analyzing similarities and differences in traits. Species that share
many traits are closely related and are placed close to each other on the tree of life.
1) Speciation – the divergence of a species into two distinct ones
2) Use phylogeny (tribe source) to understand actu