Origin and Evolution of Evolution and Diversification of Life Life OCN 201 Science of the Sea Biology Lecture 2 The Handfish -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 horse donkey 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 speciation Different Species 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? A: Charles Darwin B: Alfred Russel Wallace C: David Lee Roth On the Origin of Species - Charles Darwin On The Tendency of Varieties to Depart Indefinitely from the Original Type - Alfred Russel Wallace D: A &B E: None of the above
The Old Five Kingdom View of Life Fungi Plants Animals Multi-Cellular Eukaryotes Single-Cell Eukaryotes Prokaryotes Increasing Complexity with time Protists Prokaryotes
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 1 2 Seq. A Seq. B Seq. C ATACGGTCAC.. ATTCGCTCAC.. ATGCGGTCAC.. A B C A B C 2 1 2 1 Distance matrix can then be used to build a phylogenetic tree A C B
Sequence Comparisons Diversity and evolutionary relationships Seq. A Seq. B Seq. C 1 2 2 G ATACGGTCAC.. ATTCGCTCAC.. ATGCGGTCAC.. A B C A B C 2 1 2 2 1 2 Distance matrix can then be used to build a phylogenetic tree A C B
The Three Domains of Life The Molecular View Prokaryotes Eukaryotes Eukaryota 20
A Fundamental Division Prokaryotes (no nucleus) Bacteria Archaea DNA 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 dolphin Orca Common Octopus Species Genus Family Order Class Phylum Kingdom Domain delphis Delphinus Delphinidae Cetacea Mammalia Chordata Animalia Eukarya orca Orcinus Delphinidae Cetacea Mammalia Chordata Animalia Eukarya vulgaris Octopus Octopodidae Octopoda Cephalopoda Mollusca Animalia Eukarya
Diversification of Life CELL TYPE DOMAIN BACTERIA Prokaryotes ARCHAEA Eukaryotes 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 500 million Fish-like 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