Recitation 8- Universal tree of life Flashcards
microbes
single celled organisms including bacteria, some fungi and algae, and protozoa
where there is water, there are microbes
need water to live and reproduce
as small as 1/1000 of a millimeter
inhabit zones from at least 5 km beneath earth’s surface to more than 10 km high in the atmosphere
live at temps from -20 to 100 degrees C
most genetically diverse group of organisms on earth
where do microbes live
air, soil, rocks, piles of toxic waste, frozen snowfields, water bodies (of all types, including boiling hot springs)
why do geologists study microbes
to understand their important roles in
- early evolution of Earth’s biosphere before the advent of higher organisms
- dissolving and precipitating minerals
extremophiles
microbes that grow in hostile environments
three major groups or domains of descendants
bacteria, archaea, eukarya
prokaryotic cells
bacteria, archaea
probably appeared first
single-celled microorganisms
eukarya
appeared later
distinguished by cells with more complicated internal structure, such as the presence of a nucleus
halophile
type of extremophile
tolerance to high salinity
lives in playa lake
ex: great salt lake
acidophile
type of extremophile
tolerance to high acidity
lives in mine drainage
thermophile
type of extremophile
tolerance to high temp
lives in thermal spring
ex: yellowstone hot springs
anaerobe
type of extremophile
tolerance to no oxygen
lives in pores of wet sediments, groundwater, microbial mats, mid-ocean ridge vents
extremophiles cause their environments to turn colorful
isn’t that cool?
microbial mats
layered microbial communities
restricted to places on earth where plants and animals can’t interfere with their growth. However, before the existence of plants and animals, microbial mats were widespread and are one of the most common features preserved in Precambrian sedimentary rocks formed in marine and lake environments
stromatolites
rocks with distinctive lamination
believed to have been formed by ancient microbial mats
stromatolites range in shape from flat sheets to domal structures with complex branching patterns
one of the most ancient types of fossils on earth and give us a glimse of a world once ruled by microorganisms
stromatolites formation
trapping and binding:
- microbes live on the surface of the stromatolite
- sediment is deposited on the microbes
- which react by growing upward through the sediment, forming a new layer
indirect mineral precipitation
occurs when dissolved minerals in an oversaturated solution of individual microbes. mineral precip often leads to the complete encrustation of the microbes, which are effectively buried alive. Microbial precip of carbonate minerals and silica in hot springs are good examples of this types of microbial biomineralization. Thermophiles may become completely overgrown by the mineral deposits they help precipitate
minerals directly precipitated
by metabolic activities of microorganisms.
Ex: iron and maganese oxides are depisited by microbes that use these substances to generate energy for growth
microbial precip of pyrite occurs in anaerobic zone of sediments that contain iron-bearing minerals and water with sulfate
precipitated by organisms pooping, essentially
mineral dissolution
some elements that are essential for metabolism, such as sulfur and nitrogen, are readily available from natural waters; but others, such as iron and phosphorus, must be actively scavenged from minerals by the microbe
deep sea hydrothermal vents
deep ocean temps go from freezing to 750 F
entirely unique ecosystem with 100s of new species
despite extreme temps and pressure, toxic materials, lack of sunlight, they thrive
cheomosysnthesis
bacteria convert toxic vent minerals (hydrothermal fluid) into usable forms of energy through this process
how hydrothermal vents work
seawater circulates deep in the ocean’s crust and becomes super heated by hot magma. As pressure builds and seawater warms it begins to dissolve minerals and rise toward the surface of the crust. the hot, mineral-rich waters then exit the oceanic crust and mix with the cool seawater above. As the vent minerals cool and solidify into mineral deposits, they form different types of hydrothermal vent structures
characteristics of black smoker hydrotermal vents
emit the hottest, darkest plumes, which are higher in sulfur content and form chimneys up to 18 stories tall, or 55 meters
characteristics of white smoker hydrotermal vents
lightly colored and rich in barium, calcium, and silicon
emit cooler plumes and form smaller chimneys (than black smokers)
seeps
vents with even cooler, weaker flows
appear to shimmer bc of differences in water temps or bubble because of the presence of gases, like CO2
