there are organisms that are evolving so fast that you may be able to observe evolution!
Many scientists use bacteria or other species that reproduce frequently to study evolution.
Species with short life cycles and that reproduce frequently evolve much faster than others.
Bacteria evolve hundreds (or thousands or more) of times faster than humans do. Bacteria
go through so many generations in a few days, that we can actually witness evolution. A
human takes about 22 years to go through one generation. But some bacteria go through
over a thousand generations in less than two months.
Evolutionary Trees
Charles Darwin came up with the idea of an evolutionary tree to represent the relationships
between different species and their common ancestors (Figure7.29). The base of the tree
represents the ancient ancestors of all life. The separation into large branches shows where
these original species evolved into increasingly different populations that would not come
backtogether again. The branches keep splitting intosmaller and smaller branches as species
continue to evolve into more and more species. Some species are represented by short twigs
spurting out of the tree, then stopping. These are species that went extinct before evolving
into new species. Other “Trees of Life” have been created by other scientists (Figure7.30).
Figure 7.29: Darwin drew this version of the “Tree of Life” to represent how species evolve
and diverge into separate directions. Each point on the tree where one branch splits off from
another represents the common ancestor of the species on the separate branches. ( 25 )
Theory?
Darwin’s Theory of Evolution by Natural Selection is supported by well over 150 years of
scientific evidence, ranging from fossil evidence to DNA evidence. By definition, this is a
well tested scientific theory. An abundance of scientific evidence supports this theory. The