evolution and diversification of life• earth formed about 4.5 billion years ago (bya) and crust...
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Evolution and Diversification of Life
OCN 201 Science of the SeaBiology Lecture 2
Frogfish
Grieg Steward (Oceanography) Office: CMORE Hale 121
Phone: x6-6775
Sunday, November 9, 2014
Evolution
Nothing in biology makes sense except in the light of evolution - Theodisius Dobzhansky
I am a creationist and an evolutionist. Evolution is God's, or Nature's method of creation. Creation is not an event that happened in 4004 BC; it is a process that began some 10 billion years ago and is still under way. - Theodisius Dobzhansky
Sunday, November 9, 2014
• Heritability of traits from parent to offspring
• Variability among offspring (mutations, recombination)
• Over-production of offspring
• Selection by the environment: Individuals with favorable traits will survive and reproduce more
Basis of Evolution by Natural Selection
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Biological Diversity Arises through Selection
This is not “just a theory”. It is a fact.
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Incomplete Species Separations
donkeyhorse
muleSunday, November 9, 2014
Incomplete Species Separations
False Killer WhaleBottlenose Dolphin
“Keikaimalu”
= Wolphin
+
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Missing Links
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Missing Links
Discovered 2008 (Matt Friedman)
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• Prokaryotes (no nucleus)
• Bacteria
• Archaea
• Eukaryotes (with nucleus
A Fundamental Division
DNA
DNA
DNA
and other internal compartments)
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PhotosyntheticEukaryote
• Eukaryotes arose through the merger of multiple prokaryotic cells
Serial Endosymbiosis Theory
Eukaryote
Animals
PhotosyntheticBacteria
Plants
Archaea
Anaerobic Bacteria
AerobicBacteria
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Origins of Animals
Unicellular
Colonial
Multicellular
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Origins of Plants
Unicellular
Colonial
Multicellularmarine alga terrestrial moss
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Protista
Prokaryotae
Single CellEukaryotes
Prokaryotes
MulticellularEukaryotes
Animalia
Plantae Fungi
The Traditional Five Kingdoms
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Life is a Messy BusinessSymbioses and Horizontal Gene transfer Contribute to the Diversity We See
It is a web of life as much as a tree of life
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Evolution
• Evolution is not uni-directional
• Simple things came first
• Complexity accumulates slowly through trial and error via many known mechanisms
• The simple and the complex continue to co-exist
• As the earth changes, species die off and new ones emerge
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Classification of Life• The vast diversity of life makes sense when considered in
the light of evolutionary history
• The splitting of one species into two leads to a nested hierarchy of characteristics that can be shown as a branching tree
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Hierarchical Classification
• Species
• Genus
• Family
• Order
• Class
• Phylum
• Kingdom
• Domain
vulgaris
Octopus
Octopodidae
Octopoda
Cephalopoda
Mollusca
Animalia
Eukarya
Orcinus
orca
Delphinidae
Cetacea
Mammalia
Chordata
Animalia
Eukarya
delphis
Delphinus
Delphinidae
Cetacea
Mammalia
Chordata
Animalia
Eukarya
CommonOctopus
OrcaBottlenosedolphin
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Protista
Plantae
Animals
Fungi
The Old Five Kingdom View of Life
Monera
Macroscopic organisms
disproportionatelyrepresented
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The History of an Organism is Written in its DNA
• But how do we interpret it?
• Can use changes in DNA sequence over time as a “molecular clock”
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Sequence ComparisonsDiversity and evolutionary relationships
Seq. A ATACGGTCAC..Seq. B ATTCGCTCAC..Seq. C ATGCGGTCAC..
A
C
B
1 22 G
A B CA 2 1B 2 2C 1 2
Pairwise comparisons of sequences to count nucleotide differences
Summarize differences in a distance matrix
Build tree which satisfies the observed distance relationships
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Eukaryota
The Three Domains of Life
Prokaryotes Eukaryotes
and two cell types
Domain
Domain Domain
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• Earth formed about 4.5 billion years ago (bya) and crust solidified 4.1 bya
• Mineral deposits, thought to be produced only by biological activity, dated at 3.8 bya
• Fossils resembling present-day mats of marine microorganisms found at 3.5 bya
First Evidence of Life
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Fossil Stromatolites Modern Stromatolites
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Timeline
First Prokaryotes >3500
Photosynthetic Prokaryotes 2500
Eukaryotes 1000
Invertebrates 700
Vertebrates 500
Land Plants 430
Mammals 190
Apes 7
Humans 2.5
You 0.00002
(millions of years ago)OrganismFirst appeared
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