Lecture 7
The thing Darwin created to show evolutionary relationships
What is the phylogeny?
what is life, what does it require, and what was the first genetic material
-Life is a physical entity that is capable of replicating itself with errors
- life requires replication
- first genetic material was likely RNA, not DNA, it plays a role in protein synthesis, enzyme catalysts, and ribosomes, and can spontaneously form inside vesicles
What did Aristotle build and how was it organized?
- first hierarchical structure of life
- humans at the top, animals, plants, then minerals at the bottom
-placed "blooded" animals above "non-blooded"
- developed categories named genera, but not those used today
What did Carl Woese propose that we use today for classification?
-3 domains:bacteria, eukaryotes, archea
- applied genetics to phylogenic tree
-identified a separate bunch of unicellular organisms: archaea
what are the differences between monophyletic, paraphyletic, or polyphyletic in a phylogeny?
monophyletic: a unified group that shares a common ancestor
polyphyletic: a divided group whose members do not share a common ancestor
paraphyletic: a group that contains unaffiliated members
When did life first appear?
~4 billion years ago
early photosynthesis and great oxygenation, what caused them and the immediate affect
-early bacteria developed anoxic-photosynthesis, so did not use oxygen for photosynthesis, similar bacteria today like green sludge and black sea, ~3.4 billion ya
- cyanobacteria developed oxygenic-photosynthesis, nearly doubled oxygen in atmosphere and caused almost all life to disappear & coincided with development of more complex eukaryotic cells, ~2 billion ya
How did Carl Linnaeus organize life?
-proposed a nested hierarchy
- 3 kingdoms: animal, vegetable, mineral
- each had 4 levels: class, order, genus, species
- species used bionomial name
Define Synamorphology
a trait shared by the common ancestor of a taxonomic group that distinguishes them from their nearest relatives
describe the anatomy of a bacterial cell and the materials that composes the cell wall, and what kind of phyletic are they
-bacterial cell walls contain peptioglycan
-have been used to ferment and preserve food, bacteria can produce acids
-can be spherical, rod-shaped, spiral
-lack a nucleus or membrane bound organelles, sticky capsule/slime layer surrounds cell wall
-may have hair like appendages called fimbriae and/or flagella
-short generation times and can rapidly evolve
modern phylogenies combined the use of these 3 things:
fossil records, genetics, and laboratory experiments
what is endosymbiotic theory?
-one prokaryote ate another but did not digest it
- discovery of prokaryote-like DNA inside organelles supported this theory
- symbiotic relationship
How did Darwin Organize life?
-created first phylogenetic tree
- applied evolution to the classification of life
- showed how fossil taxa could split and evolve from a common ancestor
- became the dominant method of species classificaiton
Which of the following is a synapomorphy for all Eukaryotes?
A. cell membrane
B. Information Coded in DNA
C. Multicellularity
D. Membrane-bound organelles
E. All of the above
D. Membrane bound organelles
-used to identify bacteria based on staining cells with a violet dye
-gram positive have a thick layer of peptidioglycan that retains dye, negative have a thin layer and outer lipid membrane that does not retain dye
- respond differently to antibiotics based on negative or postive
first life required what 3 components
raw organic molecules (amino acids)
vesicle (a surrounding cell wall or membrane
a blueprint for replication (RNA or DNA)
what was the cambrian explosion
~540 million ya
- 20 million year period where most multicellular animal phyla organisms evolved
- early vertabrate ancestors
-drew an actual tree
- removed minerals and focused on 3 kingdoms: Protista-Plantae-Animalia
-Protista were not clearly defined and were a catch all for anything else
What does a node on a phylogeny represent and what are the primary methods used to build a phylogenetic tree?
-a node represents a common ancestor
-uses morphological traits and genetics to reconstruct evolutionary history
-three primary techniques: morphology based, gene-based, fossil tree
What three mechanisms allow bacteria to share genetic material?
transformation: horizontal gene transfer through the environment
transduction: horizontal gene transfer through a bacterial phage
conjugation: horizontal gene transfer through direct cell to cell contact
Miller Urey Experiment used what process and proved what
combined water, methane, ammonia and hydrogen and simulated early earth conditions
heated these to simulate hydrothermal vents, including sparks for lightning
proved amino acids could be produced in these conditions
What is the significance of the big 5 mass extinction events?
- documented in the fossil record and usually signify the beginning and ends of new Eras
- during each, 50% or more of marine species went extinct
- happen over long periods of time and caused by climate change events (CO2, volcanoes, etc)
What did Robert Whittaker propose?
-proposed new kingdoms based on cell structures
-all prokaryotes with simple cells were proposed as 'monera"
-eukaryotes with complex cells were divided into 4 kingdoms:protista-plantae-fungi-animalia
-all unicellular eukaryotes else goes under protista
what is maximum parsimony? how does this relate to occum's razor
morphology-based tree based on simplest explanation for trait evolution
- relates because no more assumptions should be made than necessary
What organisms come together to form lichen?
nevermind