201 Science of the Sea the Handfish Biology Lecture 2 -BBC Blue Planet
Evolution and Diversification of Life
OCN 201 Science of the Sea The Handfish Biology Lecture 2 -BBC Blue Planet
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
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 Evolution is not “just a theory”
Incomplete Separations
donkey
horse 62 chromosomes 64 chromosomes
mule Incomplete Separations
False Killer Whale Pseudorca crassidens Bottlenose Dolphin Tursiops truncatus
Wolphin
Pohaikealoha Kawili Kai
Missing Links
Discovered 2006 Missing Links
Discovered 2008 (Matt Friedman) The Old Five Animals Kingdom View of Life Fungi Plants
Macroscopic organisms disproportionately represented Monera Protists
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.. 2 A 2 1 1 Seq. B ATTCGCTCAC.. B 2 2 2 Seq. C ATGCGGTCAC..G C 1 2
Distance matrix can then A be used to build a C phylogenetic tree B
The Three Domains of Life The molecular view
Eukaryota
Prokaryotes Eukaryotes A Fundamental Division
Prokaryotes (no nucleus)
Bacteria DNA
Archaea DNA
Eukaryotes (with nucleus and other internal compartments)
DNA
Serial Endosymbiosis Theory Eukaryotes arose through the merger of multiple prokaryotic cells
Photosynthetic Aerobic Bacteria Bacteria Archaea
Photosynthetic Anaerobic Eukaryote Eukaryote Bacteria
Animals Plants Origins of Animals
Multicellular Colonial
Unicellular
Origins of Plants
Multicellular marine alga terrestrial moss
Colonial
Unicellular Evolution
Simple things came first
Complexity is slowly added through trial and error via many mechanisms (mutation and symbiosis)
The simple and the complex continue to co- exist The Traditional Five Kingdoms
Fungi Multicellular Plantae Eukaryotes Animalia
Single Cell Eukaryotes Protista
Prokaryotes Prokaryotae
First Evidence of Life
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 Fossil Stromatolites Modern Stromatolites
Timeline
First appeared Organism (millions of years ago) 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 For much of the history of life on earth, life was microscopic Questions?