WK - Microbial Diversity Flashcards
What are 2 characterisitcs of Early Earth?
- Occurred about 4.5 billion years ago
- Highly anaerobic and reducing world
What are some features of Early Microbes? (5)
- Anaerobic microbes that could tolerate extreme environments (e.g. deep-sea vents)
- A number of single-cell bacterium-like organisms
- Likely living off of H2 and S
- Probably hyperthermophilic
- Can withstand the very high temperatures in boiling muds
What is an example of one of these early microbes?
LUCA
- The organism from which the evolution of life as we know it began
- Two-domain system (eukaryotes within archaea)
What is the significance of endosymbiosis in microbial evolution? (3)
- Mitochondria evolved from Alphaproteobacteria (rickettsia bacteria)
- Nucleus may have originated from archaea
- Chloroplast evolved from cyanobacteria (photosynthesis)
What are 3 microbial prokaryotic groups?
- Myxobacteria
- Spirochetes
- Haloquadratum
Who discovered a new domain of life using 16S rRNA genes?
Carl Woese (1977)
Used molecular biology to identify archaea as a new domain of life
What are 2 microbial eukaryotic groups?
- Fungi
- Protists
What distinguishes archaea from bacteria? (3)
- Thrive in extreme environments (hot springs, salt lakes)
- Have ether-linked lipids
- Only a small number have been studied in the lab
Bacterial Groups (6)
1) Actinobacteria
2) Wolbachia
3) Nitrogen Cyclers:
- Nitrogen fixers
- Ammonia-oxidisers
- Nitrite-oxidisers
- Denitrifiers
4) Spirochetes
5) Cyanobacteria
6) Bdellovibrionota
What conditions can archaea survive in? (3)
- Extreme high temperatures
- High salinities
- Anaerobic environments
What are some features of methanogens? (4)
- Strict anaerobes
- Found in anoxic environments (e.g. sediments, animal guts)
- Perform methanogenesis, producing methane as a byproduct
- Belong to the euryarchaeota
What are asgard archaea?
Believed to be the branch that led to eukaryotes
What are the two main morphological types of fungi?
1) Yeasts (unicellular) – usually asexual budding
2) Filamentous (hyphal / mycelium) – sexual growth
- Mushrooms (macroscopic fruiting bodies)
- Tubular, elongated, and filamentous structures, which can contain multiple nuclei
What are some major fungal groups? (4)
Ascomycota
- Sac fungi
- Most diverse and most heavily studied from a diversity context
Basidiomycota
- Club fungi
- Many are ectomycorrhizal fungi
Glomeromycota
- Very ancient fungal lineage
- Obligate symbionts with plants (~90% of plants)
- Responsible for terrestrialisation
Chytridiomycota
- Earliest diverging fungal lineages
- Motile spores (need moisture)
- Chytridiomycosis - Devasting amphibian populations worldwide
What are the 4 types of protist groupings?
Flagellates
- Flexible flagella that beat back and forth
- Free-living predators
- Giardia
Amoebae
- Amorphous (lack shape)
- Free-living predators
- Pseudopodia (false feet) for motility
Ciliates
- Cilia for locomotion
- Microbial predators
Stationary (Sporozoa)
- Some strictly parasitic nonmotile protozoans
- Non-motile spores but some have undulating ridges
