ecosystems Flashcards
ecosystem
sum of all organisms and abiotic factors in a particular environment
abiotic components
arenon-living chemical and physical factors in the environments
species diversity is made up of
species richness and species abundance
Species richness
total number of species present in an ecosystem
species abundance
the proportion of each species in an ecosystem
abundance and richness are a function of
nutrient variety and availability
marine microbial ecosystems
- Pelagic zone- nutrient poor
- primary producers are prochlorophytes
- photic zone= 200m below surface
- pelagibacter ubique- nonphototrophic oligotrophy
archaea are more suited to the
extreme conditions below the photic zone
symbiosis
mutalisma nd commensalism
mutualism
both species benefit
commensalism
one species benefits, the other is neither harmed or benefited
synthrophy
two or more organisms catabolising a nutrient that cannot be catabolised by one on its own
where are syntrophs abundant
in deltaproteobacteria and low GC gram positive bacteria
symbiosis
the relationship between 2 or more organisms that share a particular ecosystem
bacteria living on our large intestine
supply us with vitamins K, thus evolving from commensalism to mutualism
in the rumen of a cow
fibrobacter succinogenes and Ruminococcus albus hydrolyze cellulose to sugars and ferment the sugars to volatile fatty acids
bacteria in the environment grow at rate typical to
1% of those seen in the labs due to : limited resources of nutrients, poor distribution of nutrients and mixed populations
the gut micro biome include
the stomach, s.intestine and the large intestine
stomach
10^4 bacteria at pH2
jejunum
10^3- 10^5 bacteria at pH4
ileum
10^8 bacteria at pH5
colon
10^11-10^12 at pH 7
gut micro biome is made up of
23% bacteriodetes and 64% firmicutes
role of gut micro biome in obesity
lean mice have more bacteriodetes and less firmicutes and methanogens –> therefore more H2 is produced and less fermentation occurs
mutualistic behaviour of plants and bacteria
Legume-root nodule symbiosis- essential in fixing nitrogen and supplying to plants
e.g. rhizobia–> symbiosis between these plants and bacteria prove the plant with the ability to grow well without nitrogen fertiliser. under normal conditions, neither the league plant nor its bacterial symbiont can nitrogen
Which organisms live in the photic zone (200m below sea)
Prochlorophyta is a group of photosynthetic bacteria, an important component of picoplankton.
pelagic zone
Any water in a sea or lake that is neither close to the bottom nor near the shore can be said to be in the pelagic zone
which organisms live in the pelagic zone
pelagibacter ubique
