Evolution and Diversification of Life. Origin and Evolution of. Life. OCN 201 Science of the Sea Biology Lecture 2. The Handfish -BBC Blue Planet

Transcription

1 Origin and Evolution of Evolution and Diversification of Life Life OCN 201 Science of the Sea Biology Lecture 2 The Handfish -BBC Blue Planet

2 Grieg Steward, Professor Department of Oceanography Plankton Ecology National Academies Press Phytoplankton Bacteria Viruses

3 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

4 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

5 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

6 Evolution is not just a theory

7 Incomplete Separations horse donkey mule or hinny

8 Incomplete Separations False Killer Whale Pseudorca crassidens Bottlenose Dolphin Tursiops truncatus Wolphin Keikaimalu

9 Missing Links

10 Missing Links Discovered 2006

11 Missing Links Discovered 2008 (Matt Friedman)

12 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

13 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

14 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

15 The Old Five Kingdom View of Life Fungi Plants Animals Multi-Cellular Eukaryotes Single-Cell Eukaryotes Prokaryotes Increasing Complexity with time Protists Prokaryotes

16 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

17 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

18 Sequence Comparisons Diversity and evolutionary relationships 1 2 Seq. A Seq. B Seq. C ATACGGTCAC.. ATTCGCTCAC.. ATGCGGTCAC.. A B C A B C Distance matrix can then be used to build a phylogenetic tree A C B

19 Sequence Comparisons Diversity and evolutionary relationships Seq. A Seq. B Seq. C G ATACGGTCAC.. ATTCGCTCAC.. ATGCGGTCAC.. A B C A B C Distance matrix can then be used to build a phylogenetic tree A C B

20 The Three Domains of Life The Molecular View Prokaryotes Eukaryotes Eukaryota 20

21 A Fundamental Division Prokaryotes (no nucleus) Bacteria Archaea DNA DNA Eukaryotes (with nucleus) DNA and other internal compartments 21

22 Serial Endosymbiosis Theory The Origins of the Eukaryotic Cell Type Plants Lynn Margulis Animals 22

23 Origins of Animals Multicellular Colonial Unicellular

24 Origins of Plants Multicellular marine alga terrestrial moss Colonial Unicellular Eukaryote

25 Pick the Bacterium A B C D E

26 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

27 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

28 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

29 Microbial Fossils back to 3.5 bya Fossil Stromatolites Modern Stromatolites 29

30 50 million Whales 190 million Land mammals 500 million Fish-like 700 million ANIMALS 2 billion Eukaryotes (Protists) Photosynthesis 3.5 billion

31 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