Midterm2- Ecology Flashcards
Ecological roles
What are the 4 main ecological roles of protists?
- Diversity and abundance 2. Photosynthetic productivity 3. Controling bacterial populations 4. Parasites
Ecological roles
What is the microbial loop?
Marine chain
Entirely composed of bacteria and protists- Primary producers leak/lyse and release DOC, microbes are required to loop this back into chain or else it would be lost
Ecological roles
What groups contribute to photosynthesis as much as plants?
Diatoms , Dinoflagalletes, green algae, coccolithophorids
DDGC
Ecological roles
What is DOC?
Marine chain
Dissolved organic carbon- phytoplankton produce more carbon than they need and actively pump it out into ocean. Sometimes can lyse/break before they are eaten
Ecological roles
Who can take advantage of DOC?
Marine chain/ Osmotrophy
ONLY heterotrophic bacteria - take molecules from outside and absorb it in, then they are eaten by small protists - big protists - zoo plankton and loop back in
Ecological roles
What are the 3 symbionts of plants?
Soil processes
FUNGI- extend surface area and bring nutrients to plant NITROGEN FIXING BACTERIA and PROTISTS
Ecological roles
How do plants attract their symbionts?
Soil processes
They produce more carbon than they need and actively pump it out- bacteria and fungi are attracted to come closer. Bacteria-eating protists are then attracted as well
Ecological roles
Why do bacteria-eating protists benefit the plant?
Soil processes
Bacteria have PEPTIDOGLYCAN WALL which = N, when eaten by protist they then have TOO MUCH nitrogen and excrete it out- the plant wants N close to them
If no protists- the nitrogen is immobolized in the bacteria
Protists as symbionts
What is Lignocellulose?
Mixture of plant produced compounds that make up wood/grass, very difficult to digest but large source of carbon
Protists as symbionts
2 Facts about lower termites
- Main recycler of lignocellulose: eat ONLY wood but cant digest it (use acetate for energy) 2. Produce methane (no metabolic pathway for it)
Protists as symbionts
What groups live in the hind gut of lower termites?
Excavata
Bacteria/Archae and PROTISTS: excavata- parabasalia/oxymonads
Acetogens/methanogens
Protists as symbionts
Protists (parabasalian/oxymonads) cycle in termites
Whos happy?
Grinded down wood –> pyruvate –> HYDROGENESOMES break down into CO2 + H2 and ACETATE
T uses acetate for energy = happy / P use pyruvate for CO2 = happy
Protists as symbionts
Bacteria cycle in termites
Whos happy?
Autotrophic- CO2 –> inorganic carbon
Use CO2 and H2 from protists –> produce MORE acetate
Termite uses excess acetate = happy and bacteria uses CO2 = happy
= acetogens
Protists as symbionts
Archae cycle in termites
Whos happy?
Takes CO2 and H2 from protists and produces Methane (CH4)
Archae use CO2 and H2 = happy SPEEDS UP termite reaction = happy
= methanogens
Protists as symbionts
WHY are acetogens/methanogens/protist/termites happy?
Mutualism
By removing products, reactions are sped up. Bacteria/archae take products from protist reaction (happy) which speeds up reaction (protist happy) which makes more acetate for termite (happy) YAY!
