Transcript TRACING EVOLUTIONARY HISTORY

TRACING EVOLUTIONARY
HISTORY
TRACING EVOLUTIONARY HISTORY
• MACROEVOLUTION
– THE MAJOR CHANGES IN THE HISTORY OF LIFE
– THE FOSSIL RECORD CHRONICLES (PROVIDES A
TIMELINE) FOR THE EVOLUTION OF LIFE
– GEOLOGICAL TIME SCALE
• PROVIDES A SEQUENCE OF FOSSILS AND AN OVERVIEW
OF MACROEVOLUTION OVER MILLIONS OF YEARS
TRACING EVOLUTIONARY HISTORY
• THE ACTUAL AGES OF ROCKS AND FOSSILS
MARK GEOLOGIC TIME
– RADIOMETRIC DATING
• BASED ON THE MEASUREMENT OF CERTAIN
RADIOACTIVE ISOTOPES
• EXAMPLE???
TRACING EVOLUTIONARY HISTORY
• CONTINENTAL DRIFT HAS PLAYED A MAJOR
ROLE IN MACROEVOLUTION
– “PANGEA” UNTIL PRESENT
– EXPLAINS THE DISTRIBUTION ACROSS GREAT
GEOGRAPHICAL BARRIERS
TRACING EVOLUTIONARY HISTORY
• PLATE TECTONICS PLAY A MAJOR ROLE IN
MACROEVOLUTION
– FORCES WITHIN THE EARTH THAT FORCE THE
MOVEMENT OF EARTH’S CRUST
– CAN RESULT IN VOLCANOES AND EARTHQUAKES,
WHICH CAN LEAD TO MASS EXTINCTIONS
– MASS EXTINCTIONS ARE ALMOST ALWAYS FOLLOWED
BY HUGE DIVERSIFICATION OF LIFE-FORMS
– EXAPTATIONS
• REFERS TO A STRUCTURE THAT EVOLVED FOR ONE CONTEXT,
BUT LATER WAS ADAPTED TO ANOTHER FUNCTION (SUCH
ADAPTATIONS ARE KEY FOR DIVERSIFICATION AFTER MASS
EXTINCTIONS)
TRACING EVOLUTIONARY HISTORY
• PHYLOGENETIC
TREES STRIVE TO
REPRESENT
EVOLUTIONARY
HISTORY
TRACING EVOLUTIONARY HISTORY
• PHYLOGENY  EVOLUTIONARY HISTORY OF A
GROUP OF ORGANIMS
• PHYLOGENETIC TREES  DIAGRAMS THAT
TRACE EVOLUTIONARY HISTORY AS BEST AS
CAN BE DETERMINED
– BASED ON PHENOTYPIC AND GENETIC
SIMILARITIES!!
TRACING EVOLUTIONARY HISTORY
• CLASSIFICATION, OR
TAXONOMY, IS BASED
ON PHYLOGENY
– BINOMIAL
NOMENCLATURE IS THE
RESULT OF
PHYLOGENETIC STUDIES
TRACING EVOLUTIONARY HISTORY
• PHYLOGENETIC TREES ARE BASED ON
PHENOTYPIC AND GENETIC SIMILARITY
– PHENOTYPIC SIMILARITY
• HOMOLOGOUS STRUCTURES VS ANALOGOUS
STRUCTURES
– CONVERGENT EVOLUTION
VS DIVERGENT EVOLUTION
TRACING EVOLUTIONARY HISTORY
• PHYLOGENETIC TREES ARE
BASED ON PHENOTYPIC AND
GENETIC
SIMILARITY
– GENETIC SIMILARITY IS BASED
ON AMINO ACID, DNA, AND
RNA SEQUENCES
– MORE SIMILAR SEQUENCES
SUGGEST MORE COMMON
ANCENSTRY
TRACING EVOLUTIONARY HISTORY
• PHYLOGENETIC TREES ARE BASED ON
PHENOTYPIC AND GENETIC SIMILARITY
– ***MITOCHONDRIAL DNA IS USED FOR
ORGANISMS BELIEVED TO BE MORE RECENTLY
RELATED***
– IN ADDITION, THERE IS BELIEVED TO BE A
“MOLECULAR CLOCK”
• A RELATIVELY CONSTANT RATE OF GENETIC CHANGE,
THAT SUGGESTS A TIMELINE OF EVOLUTION
TRACING EVOLUTIONARY HISTORY
• CLADOGRAMS VS
PHYLOGENETIC TREES
– CLADOGRAM  A
PHYLOGENETIC TREE
BASED ON CLADISTICS
– CLADES  EVOLUTIONARY
BRANCES THAT CONSIST
OF AN ANCESTRAL SPECIES
AND ALL OF ITS
DESCENDANTS
TRACING EVOLUTIONARY HISTORY
• CLADOGRAM OF ALL LIFE!!
– IT’S A WORK IN PROGRESS!
– 3 DOMAIN SYSTEM 
– WHAT ABOUT THE 5 KINGDOM SYSTEM??
TRACING EVOLUTIONARY HISTORY
• YOU KNOW, ALL THIS TALK ABOUT ORGANISMS
CHANGING IS ALL WELL, AND GOOD…BUT UUMM,
WHERE DID THE VERY FIRST LIVING THING
COME FROM? I
MEAN, DID IT JUST
FALL OUT OF THE SKY?
HOW CAN YOU
HAVE EVOLUTION
WITHOUT LIFE TO
BEGIN WITH?
NEXT CHAPTER 
THE ORIGIN OF LIFE!!!