EvolutionOrigin and and Diversification Evolution of Lifeof Life
OCN 201 Science of the Sea The Handfish Biology Lecture 2 -BBC Blue Planet Grieg Steward, Professor Department of Oceanography
Plankton Ecology
National Academies Press Phytoplankton Bacteria Viruses When do you think life began?
A: > 3 billion years ago B: about 6000 years ago C: < 2000 years ago D: around 1990 E: I’m still waiting 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.
4 Basis of Evolution by Natural Selection
‣ Heritability of traits from parent to offspring ‣ Variability among offspring (mutations, recombination) ‣ Over-production of offspring ‣ Selection by the environment: More individuals with favorable traits will survive and reproduce than those with unfavorable traits
5 Evolution is not “just a theory” Incomplete Separations
donkey horse
mule or hinny Incomplete Separations
False Killer Whale Pseudorca crassidens Bottlenose Dolphin Tursiops truncatus
Wolphin
Keikaimalu Missing Links Missing Links
Discovered 2006 Missing Links
Discovered 2008 (Matt Friedman) Dogs have been partly artificially selected for extreme differences in morphology - but there is frequent interbreeding among the various types.
These whales have been naturally selected with little to no interbreeding, resulting in Different Species speciation
Same Species When was the Theory of Evolution by Natural Selection first publicly presented?
A: 1776
B: 1858 at the Linnean Society of London C: 1903 D: 1918 E: 1982 Whose ideas were presented?
On the Origin of Species - A: Charles Darwin Charles Darwin B: Alfred Russel Wallace On The Tendency of Varieties to Depart Indefinitely from the Original Type - Alfred Russel Wallace C: David Lee Roth D: A &B E: None of the above The Old Five Kingdom View of Life
Plants Animals Fungi
Multi-Cellular Eukaryotes withtime Protists
Single-Cell Complexity Increasing Eukaryotes Prokaryotes Prokaryotes
15 Fossil vs Molecular Evidence
‣ Early work relied on fossils - focus on plants and animals ‣ The evolutionary history of microbes was unclear ‣ Molecular evidence generally confirmed fossil evidence, and also revealed the deep history of the microbial world
16 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” Sequence Comparisons
Diversity and evolutionary relationships
A B C Seq. A ATACGGTCAC.. A 2 1 1 2 Seq. B ATTCGCTCAC.. B 2 Seq. C ATGCGGTCAC.. C 1
A C B Distance matrix can then be used to build a phylogenetic tree Sequence Comparisons
Diversity and evolutionary relationships
A B C Seq. A ATACGGTCAC.. A 2 1 1 2 Seq. B ATTCGCTCAC.. B 2 2 2 Seq. C ATGCGGTCAC..G C 1 2
A C B Distance matrix can then be used to build a phylogenetic tree The Three Domains of Life The Molecular View Prokaryotes Eukaryotes
Eukaryota
20 A Fundamental Division
‣ Prokaryotes (no nucleus)
DNA • Bacteria
• Archaea DNA
‣ Eukaryotes (with nucleus)
DNA
and other internal compartments
21 Serial Endosymbiosis Theory The Origins of the Eukaryotic Cell Type Plants
Lynn Margulis
Animals
22 Origins of Animals Multicellular Colonial
Unicellular Origins of Plants Multicellular marine alga terrestrial moss
Colonial
Unicellular Eukaryote Pick the Bacterium
A B C
D E 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 Hierarchical Classification
Linnean Taxonomy Bottlenose Orca Common dolphin Octopus • Species delphis orca vulgaris • Genus Delphinus Orcinus Octopus • Family Delphinidae Delphinidae Octopodidae • Order Cetacea Cetacea Octopoda • Class Mammalia Mammalia Cephalopoda • Phylum Chordata Chordata Mollusca • Kingdom Animalia Animalia Animalia • Domain Eukarya Eukarya Eukarya Diversification of Life CELL TYPE Prokaryotes Eukaryotes DOMAIN BACTERIA ARCHAEA EUKARYA
Animals Plants
Photosynthesis Phagotrophy New mode of consumption by engulfment
LUCA ? Last Universal Common Ancestor Microbial Fossils back to 3.5 bya
Fossil Stromatolites Modern Stromatolites
29 50 million Whales
190 million Land mammals Fish-like 500 million
700 million ANIMALS
2 billion Eukaryotes (Protists)
Photosynthesis
≥ 3.5 billion Key Points
• Evolution is not uni-directional…but • Simple things came first - complexity accumulates slowly through trial and error via many known mechanisms • Eukaryotes arose through Serial Endosymbiosis • The simple and the complex continue to co-exist • As the earth changes, species die off and new ones emerge