Intro Flashcards
Why study nutrient cycling + prokaryotes?
studying prokaryotes allows us to classify organisms at a fundamental level and provide an understanding of life that evolved prior to organisms with nuclei
What was Carl Woese’s main discovery when he studied 16s rRNA?
He determined that prokaryotes are not monophyletic as was previously thought, but instead, exist as 2 different groups with different sequences of nucleic acids and rRNA
(EU) bacteria and (Archae) bacteria = bacteria and archaea
What environments do Archaea typically live in?
extreme environments typically with high sulphur content
What are the points of view that biological systems can be defined by?
community structure
trophic dynamic levels (population)
energy transfer and nutrient cycling
Describe how community structure can be used as a point of view to describe complex biological systems
the system is defined by the primary producers and the plant community (ex. trees)
Describe how trophic dynamic levels (population) can be used as a point of view to describe complex biological systems
the system is defined by the animal populations and their interactions
Describe how energy transfer and nutrient cycling can be used as a point of view to describe complex biological systems
the system is defined by the prokaryotes that function and have functioned in the past
Why is studying prokaryotes important for understanding eukaryotes?
the current paradigm is that eukaryotic cells evolved from a symbiosis of prokaryotic cells billions of years ago that retained their ancestral rRNA
What key nutrients do bacteria and archaea play an essential role in transforming? How?
organic carbon, nitrogen, sulfur
they are key regulators of ecosystem productivity
How are trophic interactions linked to nutrient cycling?
primary producers produce different phytochemicals which influence trophic interactions and ecosystem nutrient dynamics (ex. lignin, cellulose, tannins, terpenes)
the phytochemicals will influence the herbivorous populations which will influence the carnivorous populations and the herbivorous community will limit the type of and abundance of plants
the phytochemicals will influence the nutrient dynamics which in turn will influence which plants grow and how well they grow
there’s 3 feedback loops:
- between the phytochemicals produced by plants and trophic interactions
- between the phytochemicals produced by plants and ecosystem nutrient dynamics
- between trophic interactions an ecosystem nutrient dynamics which includes the other 2 loops
How are spatial and temporal variations linked by feedback loops?
there’s different layers on the phytochemical landscape (ie., the way the phytochemicals influence other aspects of the ecosystem) which include:
nutrient availability
phytochemistry
herbivore activity
predation pressure
What kind of qualitative and quantitative methods are needed to develop and provide evidence for the spatial and temporal links to the feedback loops on the phytochemical landscape?
- observation and identification of members of the ecosystem (plants, animals, bacteria)
- quantitative data collection
- field sampling and statistical analysis using bio, chemical, and physical methods
- uni- and multivariate
- correlation/regression - experimenting in the lab and in the field
- statistical theory of decision
- use random block design
- mathematical distribution (ex., Guassian, Lognormal, Poisson)
What are the practical reasons for studying nutrient cycling + prokaryotes?
agricultural reasons:
- N2 fixation
- nutrient cycling
- animal husbandry
- gut bacteria in the animal gut microbiome
food industry:
- food preservation (heat, cold, radiation, chemicals)
- fermented foods
- food additives (monosodium glutamate, citric acid, yeast)
disease:
- identifying new diseases
- treatments, cures, and prevention`
energy/environmental reasons:
- biofuels
- fermentation
- bioremediation
- microbial mining
biotechnology:
- GMOs
- pharmaceuticals (ex. insulin)
- gene therapy
Where are prokaryotes?
everywhere! in all biomes
What are biomes?
a biogeographical unit within which a biological community exists in response to a similar regional climate
ex. temperate rainforest, steppe, grassland
Who was the first to establish the major biogeoclimatic zones in BC?
Krajina
How can the communities within a biome vary? explain why
multiple communities, aside from the dominant one, can develop on specific habitats within a biome and this can include different plants and bacteria
this occurs because:
- water moisture levels can vary depending on the slope (low at the top of the slope, high at the bottom of the slope = different habitats
define xeric
when moisture levels are low
define hydric
when moisture levels are high
Explain how Mt Doug is a good representation of multiple communities existing in different habitats related to elevation gradient
there are 3 communities on Mt Doug
at the bottom, where moisture levels are high and nutrients are abundant: Western Red Cedar dominates
in the middle, where moisture and nutrient levels are intermediate: Douglas-fir dominates
at the top, where moisture levels and nutrient levels are low: Garry Oak dominates
What conditions do Douglas-fir grow best in?
high nitrate (NO3-) rather than ammonia (NH4+)
What did Krajini suggest as an explanation for how Douglas-fir has come to dominate the forest ecosystem on Mt Doug? What other factor is being considered now as well?
nitrification of ammonia to nitrate
now being more considered is the role of mycorrhiza
What is the scientific name for Douglas-fir?
Pseudotsuga menziesii
What is the scientific name for Western Red Cedar?
Thuja plicata
What is the scientific name for Garry Oak?
Quercus garryana
Explain the relationship between Monotropa uniflora, Thuja plicata and Mahonia nervosa (Oregon grape), and Russula sp. fungi
Monotropa uniflora look like fungi but are actually plants that have lost the gene that codes for chlorophyll so they appear white (hence, the name ‘ghost plant’)
this plant parasitizes Russula sp. fungi
Russula sp., infect the roots of WRC and provide the tree with N and P and receive carbon from the tree in return (ie., mycorrhizal relationship)
because of the parasitism, the Monotropa uniflora steals the carbon from the Russula provided by the tree and the N and P from the Russula
Why are soil bacteria difficult to study?
the scale is sooo small
bacteria are the roughly the same size as clay particles (1-5 microns)
What are the biogeoclimatic zones on Vancouver Island?
Alpine tundra
mountain hemlock
coastal douglas-fir
coastal western hemlock
What’s the Ecological Reserve Act?
a Land Act approved in 1971 to set aside ecological reserves that people do not have access to
reserve sites are meant to be representatives of the biogeoclimatic zones in BC
Which province in Canada was the first to set aside land parcels with representative ecosystems?
BC for both terrestrial and marine ecosystems
Where are some nearby ecological reserves?
10 Mile Point and Oak Bay Island in the Saanich Inlet include both terrestrial and marine ecosystems
Why is it important to reserve land in regards to the ecology of bacteria?
some reasons include:
- only specific bacteria can fix nitrogen into forms that are usable for plants (agriculture and forestry reasons)
- bacteria can be used in wastewater treatment
- bacteria can degrade anthropogenic chemicals like oil and pesticides
- bacteria and archaea have key roles in biogeochemical cycles in soil and aquatic ecosystems (including the transformation of C, N, S, and P)
What forms of nitrogen are essential for plant growth? What forms of nitrogen are available in the terrestrial environment?
Mineral forms (ammonia, nitrate) are essential to plant growth but these are limited
Nitrogen (N2) is most common form of nitrogen in the environment
How do bacteria contribute to soil fertility and plant growth?
Specific bacteria can fix/convert N2 into ammonia - these are called diazotrophs
What are diazotrophs?
bacteria that can convert N2 into ammonia (NH3)
What are the key forms of nitrogen in the nitrogen cycle?
ammonium (NH4+)
nitrate (NO3-)
nitrite (NO2-)
Who suggested that nitrogen was a limiting factor in plant growth?
Justus Liebig of the University of Giessen
Who won the Nobel Prize in atmospheric chemistry for discovering the relationship of N2O to the ozone degradation in 1970?
Paul Crutzen
Where is the biggest reservoir of nitrogen?
the atmosphere
Which form of nitrogen is the most common key form?
ammonium (NH4+)
In the nitrogen cycle, what catalyzes the transformation between different forms (ie., what are the arrows)? give an example
enzymes coded by genes in specific bacteria
ex. Nitrosomonas
Which form of carbon is most commonly used by bacteria in combination with ammonium for energy?
CO2
What angle is the carbon cycle conceptualized from?
based on CO2
What does all organic matter eventually become?
CO2 and methane
Describe the change of atmospheric methane historically?
pre-industrial: methane levels in the atmosphere were stable
massive increase = indicates instability = there’s either too much production and not enough consumption or both
How is the level of atmospheric methane studied?
gas chromatography