Prokaryotes take over the world and the deep biosphere Flashcards
How did prokaryotes demonstrate darwinian evolution?
As these cells divided random mutations would alter their genes.
Some mutations would be neutral, some detrimental
and some beneficial.
Over time populations with beneficial mutations would outcompete competitors
Different niches in the environment would select for different genes allowing populations to evolve into separate species.
When were stromatolites found?
3.5 billion years ago
How do prokaryotic cells adhere to form biofilms and microbial mats?
Adhere using fimbriae, pili and capsules.
What are the advantages of being part of a biofilm?
Helps prevent detachment (stay in favourable location).
Helps protect cells from environment.
Trap nutrients.
Genetic exchange.
Sharing of nutrients and enzymes (public goods).
What is Black Queen hypothesis?
Organisms loose genes over time and rely on those produced in the community
Individual cells depend on each other (symbiosis).
How many prokaryotic cells in the human body?
Estimated 30-40 trillion prokaryotic cells in the human body
What habitats on earth haven’t been colonised by microbes?
Places with no (available) liquid water
Places above >130°c (hot volcanic vents, magma , the Earths crust at depths where temperatures >130°c)
Enrichment cultures
Isolate bacteria from diverse and densely populated samples, by selecting for desired organisms through manipulation
of medium and incubation conditions
This means favouring the growth of target organisms while
inhibiting the growth of non-target organisms.
What is the deep biosphere features
Twice the volume of the oceans, biggest biosphere on the planet, potentially has 70% of all prokaryotic life and 1/3 of biomass on the planet.
Which domains have been found in biosphere?
All domains of life have been found there (bacteria, archea and eukarya)
What is the deepest depth into the surface of the Earth that viable microbes have been recovered?
> 5 Km
What does it mean for life on other planets?
If life can generate energy from iron, co2, sulfur, methane, and if it doesn’t require oxygen or light and requires little water it broadens the environments life could begin in.
How dominant in biomass was the biosphere in evolutionary history?
Now plants dominate biomass and believed deep biosphere contributes 10-15%
Before plants deep biosphere was 70-80% of all life on earth.
What is its significance to the planet?
How big is it?
Twice the volume of the oceans, biggest biosphere on the planet, potentially has 70% of all prokaryotic life and 1/3 of biomass on the planet.
Ecosystem of organisms that are found in the sublayer of earth.
Which domains of life are found there?
All domains of life have been found there (bacteria, archea and eukarya)
Genetic diversity in deep biosphere equal, if not greater than surface diversity.
