1. The Diversity of Life

2. The Diversity of Life
I. A Brief History of Life
II. Classifying Life
III. The Prokaryotic Domains

3. Ecological Roles Played By Prokaryotes The Diversity of Life
I. A Brief History of Life
A. Introduction
ATMOSPHERE
N fixation
Photosynthesis
Respiration
BIOSPHERE
Energy harvest of animals and plants
Absorption
Decomposition
LITHOSPHERE

4. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
4.5 bya: Earth Forms

5. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks

6. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils

7. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils
Stromatolites - communities of layered 'bacteria'

8. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
bya: Oxygen in Atmosphere
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils

9. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
2.0 bya: first eukaryotes
bya: Oxygen
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils
Grypania spiralis – possibly a multicellular algae, dating from 2.0 by

10. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
The classical model of endosymbiosis explains the origin of eukaryotes as the endosymbiotic absorption/parasitism of archaeans by free-living bacteria.

11. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
- Life was exclusively bacterial for ~40% of life’s 3.5 by history
- Ecosystems evolved with bacterial producers, consumers, and decomposers.
- Multicellular eukaryotic organisms evolved that use and depend on these bacteria

12. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
0.7 bya: first animals
2.0 bya: first eukaryotes
bya: Oxygen
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils

13. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
0.7 bya: first animals
2.0 bya: first eukaryotes
bya: Oxygen
0.5 bya: Cambrian
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils

14. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
0.7 bya: first animals
2.0 bya: first eukaryotes
bya: Oxygen
0.5 bya: Cambrian
0.24 bya:Mesozoic
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils

15. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
0.065 bya: Cenozoic
0.7 bya: first animals
2.0 bya: first eukaryotes
bya: Oxygen
0.5 bya: Cambrian
0.24 bya:Mesozoic
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils

16. I. A Brief History of Life 4.5 million to present
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
4.5 million to present
(1/1000th of earth history)
0.065 bya: Cenozoic
0.7 bya: first animals
2.0 bya: first eukaryotes
bya: Oxygen
0.5 bya: Cambrian
0.24 bya:Mesozoic
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils

17. I. A Brief History of Life
The Diversity of Life
I. A Brief History of Life
Introduction
B. Timeline
0.065 bya: Cenozoic
0.7 bya: first animals
2.0 bya: first eukaryotes
bya: Oxygen
0.5 bya: Cambrian
0.24 bya:Mesozoic
4.5 bya: Earth Forms
4.0 bya: Oldest Rocks
3.5 bya: Oldest Fossils
For ~40% of life’s history, life was exclusively bacterial

18. I. A Brief History of Life II. Classifying Life
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
- a ‘nested’ hierarchy
based on morphology

19. I. A Brief History of Life II. Classifying Life
Genus Felis
Panthera
Family Felidae
Acinonyx
Lynx
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
- a ‘nested’ hierarchy
based on morphology

20. I. A Brief History of Life II. Classifying Life
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
Cladistics and Phylogenetic Systematics
Evolution explained this nested pattern as a consequence of descent from common ancestors.
Modern biologists view the classification system as a means of showing the phylogenetic relationships among groups

21. I. A Brief History of Life II. Classifying Life
Genus Felis
Panthera
Family Felidae
Acinonyx
Lynx
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
Cladistics and Phylogenetic Systematics
But there are inconsistencies to correct:
Cougar (Felis concolor) is in the genus Felis but is biologically more closely related to Cheetah (which are in another genus), than to other members of the genus Felis.
The goal is to make a monophyletic classification system, in which descendants of a common ancestor are in the same taxonomic group.

22. I. A Brief History of Life II. Classifying Life
Genus Felis
Genus Panthera
Family Felidae
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
Cladistics and Phylogenetic Systematics
The goal is to make a monophyletic classification system, in which descendants of a common ancestor are in the same taxonomic group.
Now, all members of the genus Felis share one common ancestor. * *

23. I. A Brief History of Life II. Classifying Life
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
Cladistics and Phylogenetic Systematics
The goal is to make a monophyletic classification system, in which descendants of a common ancestor are in the same taxonomic group.
NEW
HOMINIDAE
Genera:
Australopithecus
Homo
PONGIDAE
Pan
Gorilla
Pongo
OLD

24. I. A Brief History of Life II. Classifying Life
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
Cladistics and Phylogenetic Systematics
The goal is to make a monophyletic classification system, in which descendants of a common ancestor are in the same taxonomic group.
OLD
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Class: Mammalia
Class: Aves

25. I. A Brief History of Life II. Classifying Life
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
Cladistics and Phylogenetic Systematics
NEW

26. I. A Brief History of Life II. Classifying Life
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
Cladistics and Phylogenetic Systematics
The goal is to make a monophyletic classification system, in which descendants of a common ancestor are in the same taxonomic group.
OLD

27. I. A Brief History of Life II. Classifying Life
The Diversity of Life
I. A Brief History of Life
II. Classifying Life
The Linnaean System
Cladistics and Phylogenetic Systematics
The goal is to make a monophyletic classification system, in which descendants of a common ancestor are in the same taxonomic group.
NEW

28. III. The Prokaryote Domains: Eubacteria and Archaea
Overview

29. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
“Horizontal Gene Transfer” complicates phylogenetic reconstruction in prokaryotes and dating these vents by genetic similarity and divergence.

30. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
Bacteria
Archaea
Eukarya
No nucleus
no nucleus
nucleus
no organelles
no organelles
organelles
peptidoglycan no
1 RNA Poly
several
F-methionine
methionine
Introns rare
present
common
No histones
histones
Circular X’some
Linear X’some

31. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
1. Archaea
“Extremeophiles”
- extreme thermophiles: sulphur springs
and geothermal vents
- extreme halophiles: salt flats
“Methanogens”
Also archaeans that live in benign
environments across the planet.

32. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
1. Archaea
2. Bacteria
- proteobacteria
- Chlamydias
- Spirochetes
- Cyanobacteria
- Gram-positive bacteria

33. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
1. Archaea
2. Bacteria
These groups are very diverse genetically and metabolically. Their genetic diversity is represented by the “branch lengths” of the groups, showing how different they are, genetically, from their closest relatives with whom they share a common ancestor.

34. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
B. Metabolic Diversity of the Prokaryotes
The key thing about bacteria is their metabolic diversity. Although they didn't radiate much morphologically (spheres, rod, spirals), they DID radiate metabolically. As a group, they are the most metabolically diverse group of organisms.

35. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
B. Metabolic Diversity of the Prokaryotes
1. Oxygen Demand
all eukaryotes require oxygen.

36. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
B. Metabolic Diversity of the Prokaryotes
1. Responses to Oxygen:
all eukaryotes require oxygen.
bacteria show greater variability:
- obligate anaerobes - die in presence of O2
- aerotolerant - don't die, but don't use O2
- facultative aerobes - can use O2, but don't need it
- obligate aerobes - require O2 to live

37. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
B. Metabolic Diversity of the Prokaryotes
1. Responses to Oxygen:
2. Nutritional Categories:
- chemolithotrophs: use inorganics (H2S, etc.) as electron donors for electron transport chains and use energy to fix carbon dioxide. Only done by bacteria.
- photoheterotrophs: use light as source of energy, but harvest organics from environment. Only done by bacteria.
- photoautotrophs: use light as source of energy, and use this energy to fix carbon dioxide. bacteria and some eukaryotes.
- chemoheterotrophs: get energy and carbon from organics they consume. bacteria and some eukaryotes.

38. III. The Prokaryote Domains: Eubacteria and Archaea
Overview
B. Metabolic Diversity of the Prokaryotes
C. Ecological Importance
- major photosynthetic contributors (with protists and plants)
- the only organisms that fix nitrogen into biologically useful forms that can be absorbed by plants.
- primary decomposers (with fungi)
pathogens
endosymbionts with animals, protists, and plants

39. Bacteria still drive major dynamics of the biosphere