Download Evidence and Patterns of Evolution

Evidence and Patterns of
Evolution
What Proof Exists About
Evolution?
Homologous Structures
Homologous Structures
• Homologous
– Homo means “equivalent to”
– Logos means “relation” or “reason”
– Comparative Anatomy
• Similar features that originated in a shared
ancestor
– Beaks of birds
– Forelimbs of different animals
Analogous Structures
Analogous Structures
• Analogous
– Features serve identical functions, and
look somewhat alike
• Wings of birds and insects
Vestigial Structures
Vestigial Structures
• Features that seem to serve no useful
function
– Human tailbone
– Whale’s pelvic bones
• Were useful to an ancestor, but not
useful to modern organism
– Evidence that the structure was functional
in some ancestor of modern organisms
– Organism with vestigial feature may share
common ancestry with organism that has a
functional version of the same feature.
Embryology
Embryology
•
•
Early stages of vertebrate
embryos are similar
Ontogeny recapitulates
phylogeny
– Ontogeny – development from egg
to maturity
– Phylogeny - relationships
– Is this true?
Similarities in Macromolecules
• Amino acid sequences in hemoglobin of
different species are similar
– Human and gorilla differ by one amino acid
– Human and frog differ by 67 amino acids
• Number of amino acids differences in
homologous proteins of two species is
proportional to the length of time that has
passed since the two species shared a
common ancestor.
Patterns of Evolution
• Coevolution
– Change of two or more species in close
association
• Predator and prey
• Parasites and hosts
Patterns of Evolution
• Convergent Evolution
– Appear to be similar like shark and
porpoise but not closely related
– Environment selects similar phenotypes
even though ancestral types were
different
Patterns of Evolution
•
Divergent Evolution
– Two or more related population or
species become more and more
dissimilar
•
Different habitats
Patterns of Evolution
•
Adaptive radiation
– Many species from
single ancestral
species
– Divergence in
response to the
different habitats
Patterns of Evolution
•
Artificial selection
– Bred for certain phenotypic
characteristics
– Speeds up divergent evolution