Microbial Evolution and Ecology Flashcards
how old is Earth
4.5 - 4.6 billion years old
abiotic synthesis
biological molecules from inorganic precursors
Stanley Miller
1953
abiotic synthesis research using what we think the conditions were for early Earth
deepsea hydrothermal vents
best idea currently for what atmosphere was like
panspermia
seeding from space
ribozymes
RNA that copies itself/other strands
RNA World
early cells used RNA instead of DNA
life needs containment, which is theorized to be via
liposomes
liposomes are made from
phospholipids
prokaryotes came around
3.8 - 3.5 billion years ago
stromatolites
sedimentary rock formations
can have evidence of early prokaryotic cells
which is the likely first major metabolic pathway to evolve
glycolysis, it is universal across all life
photosynthesis
earliest forms did not use water or release oxygen
when did oxygenic photosynthesis occur? from who?
2.7 billion years ago
cyanobacteria
The Great Oxygenation Event
2 billion years ago
made oxygen prevalent in atmosphere
eukaryotes evolved
about 2 billion years ago, after oxygenation
how did eukaryotes evolve
endosymbiosis
eukaryotes and archaea share a common ancestor
lokiarcheota
lokiarcheota
oldest archaea
discovered in 2015
multicellular organisms
evolved 1.5 billion years ago
unicellular cells specialized
more advantages
slower rate of growth
natural selection
descent with modification
artificial selection
humans guiding evolution by selecting traits
example of selection in bacteria
drug resistance
vancomycin
antibiotic that targets normal cell wall
ecology
study of relationships of organisms to each other and to their environment
biotic interactions
between organisms
abiotic interactions
environmental
population
all members of a species living in a defined geographical area
ecological community
populations within a defined region
ecosystem
ecological populations and abiotic factors of specific area
food chain
path of food consumption
producers, herbivores, carnivores
food web
more complex
omnivores, decomposers
biomass
lessens as goes up food chain
microenvironment
area immediately surround the organism
biofilms
microbial community growing on a surface
play role in disease and antibiotic resistance
quorum sensing
intercellular communication amongst bacteria
autoinducers
chemical signal secreted by bacteria
receptors
proteins that detect signals
topsoil
mix of broken-down rock and dead plant matter
made of humus (organic substances)
rhizosphere
soil environment surrounding root systems
has mycorrhizal associations
microorganisms are important
primary producers
phytoplankton
photosynthetic organisms, mainly algae and cyanobacteria
zooplankton
protozoa, small crustaceans, other small organisms
lake zones
photic
littoral
profundal
benthic
photic zone
extends to deepest sunlight penetration
high oxygen content
phytoplankton only producers
littoral zone
photic zone where light hits the bottom of multicellular aquatic plants serve as producers
profundal zone
oxygen limited
sunken organic matter
facultative anaerobes abundant
benthic zone
deepest region
including sediments
obligate anaerobes and methanogens abundant
thermocline
sharp demarcation in temperature in water
oligotrophs
can grow in relatively low levels of nutrients
eutrophs
require high nutrient abundance
algal blooms
excessive algal growth
high phosphate levels
warm temperatures
cyanobacteria and water pollution
turns water green
turns environment anaerobic
eutrophication
eutrophication
pendulum swing change in bacterial populations
oceans also have these zones
pelagic
intertidal
pelagic zone
within photic zone, in open-ocean
intertidal zone
shoreline exposed to sea at high tide and air at low tide
near-shore littoral zone
rich in nutrients from shore
green due to abundant photosynthetic phytoplankton
what is the dissolved salt content in the ocean
3.5%
below ocean photic zone
dark, cold, low nutrients, high pressure
barotolerant
organisms able to survive in high pressure
exobiology
search for extraterrestrial life
nitrogen fixation
atmospheric nitrogen cannot be used by plants or animals
some bacteria break it into ammonium ions
ammonification
bacteria such as Proteus and Clostridium degrade dead organic matter
nitrification
ammonium to nitrite
nitric to nitrate
nitrate back
root nodules
houses nitrogen-fixing bacteria