Download BIO Evidence for Natural Selection

Evidence for Natural Selection
Patterns
• There are 4 main patterns for natural selection
• Two are directly tied to speciation rate
– Gradualism—happens slowly (millions to billions of years)
– Punctuated equilibrium—happens fast with long periods of
stability
• The other two are mostly used for comparing why
organisms are the way they are.
– Divergent evolution—differentiation from a single species
• A specific type of divergent evolution would be adaptive radiation
– Convergent evolution—developing something similar
because of a need and not a common ancestor.
6 types of accepted evidence for evolution.
• Structural adaptation
– This is going to be an actual
change in physical appearance
– Usually happens slow
(gradualism)
– Ex: mimicry and camouflage
• Physiological adaptations
– This is going to be a change in
physiology (how the body
works)
– Usually happens relatively
quickly
– Ex: bacteria resistant to
antibiotics
• Fossils
– Provide a record of early life and
evolutionary history
– The record while helpful is incomplete
• Anatomy
– Anatomy is the structure and function of
physical parts
– Homologous structure
• Structure with common evolutionary origin,
similar in arrangement, function, or both
– Analogous structures
• Structures that serve the same purpose but do
not share an evolutionary origin.
– Vestigial structures
• A structure that in present day no longer serves
a purpose but is there because it was useful to
an ancestor.
• Embryology
– Embryo is the earliest stage of growth
and development of an organism
– When comparing how all organisms look
in the beginning of an embryo to the
end the similarities cause scientists to
believe that all organisms are related.
• Biochemistry
– All the tiny parts that make up life such
as DNA, ATP, RNA, enzymes, proteins,
etc.
– Because all life has this and they are all
roughly the same shape and type
scientists think it is strong evidence for
all living organism to be related in some
way.