Unit 12 #2 - Ecosystems Flashcards
List populational levels in order
population, species, community, ecosystem, biosphere
Every populational level is an emergent property of the level below it or above it?
Below it
*emergent properties: properties found in the whole but not in individuals alone (the whole is greater than the sum of the parts)
What does genetics explain
how chemicals are organised into a living
organism, and how this information is transmitted.
What does evolution explain
how selection operates on genetic
variation within populations, so that populations adapt to the
biotic and abiotic elements of their environments
it is seen in genes, populations, species and communities
What does ecology explain
how the environment is determined by the
interactions between its living and non-living components.
Name an exmaple of geological phenomenon created and maintained by a living ecosystem
Soil
In fact, some cliffs are formed of crushed shells of mollusks
What is an ecosystem
Interaction between a community (biotic) and abiotic factors in the environment
Name 2 things an ecosystem needs and how they relate to one another
- Energy: solar (photoautotrophs) or chemical (chemoautotrophs), it enters from space and leaves by heat radiation though the food chain
- Matter : N, P, C, H2O…, it cannot enter or leave earth so it circulates through biochemical cycles
Link between both: energy is needed, ultimately from the sun to move matter around and transform it
What are the 2 laws of thermodynamics and their link to chemical transformations of life processes involving energy transfer?
1st law: energy cant be created or destroyed
2nd law: total entropy of universe must increase
there is flow of energy from sun to earth to space as heat
This is because energy is used to organize matter in an open system, but heat is lost at each energy transfer because of 2nd law
How does lavoisier’s principle apply to matter
Conservation of mass: matter on earth stays on earth (closed system)
In a food web, what does the arrow point
the consumer (from the consumed)
The arrow shows energy flow
What is biomass and its main component
The total mass of organisms in a given volume or area
Its main component is carbon (ie we have lots of carbon)
What is productivity
the amount and rate of production
which occur in a given ecosystem
over a given time period.
It is either dry matter or energy produced per area per time.
What is the difference between primary and secondary productivity
Primary productivity: biomass of autotrophs produced
Secondary productivity: biomass of heterotrophs produced
What is the percent loss of energy from solar energy to heat
99%, so 1% to primary producers
What is the percent energy transferred from one trophic level to the next
10%
How do zooplankton and phytoplankton relate
zooplanktons are heterotrophs that eat phytoplankton, a photoautotrophs
detritivores
eat dead organic matter
Decomposers
break down non-living organic molecules to smaller molecules: take carbs., nucleic acids, lipids, proteins and breaks them down into CO2, CH4, NH3
How are pyramids of energy flow, biomass and numbers alike
all have first-level carnivores on top , but fewer, and shows that organisms are being eaten as fast as they are being produced (biomass=numbers)
What is the difference between a top-down trophic cascade and a bottom-up trophic cascade
A bottom-up trophic cascade can happen if the primary producers
are eliminated or greatly reduced ie draves killed aquatic vegetation
Biomagnification
subsatnces such as pesticides and mercury stored in tissues get concentarted in tissues of animals up the food chain becasue they eat all the pther animals that have fewer conenctrations within them ie belugas st-lawrence lots of mercury
Does microplastics biomagnify
No, but the toxins they absorb do! The microplastics are ingested by animals in water
Anthropocene
current geological age seen in segmentation rocks that is more compressed
Draw the nitrogen, phosphorus, water and carbon cycle
notes
Denitrifying bacteria
use nitrate as a source of energy, producing acid and
removing nitrogen from the soil
What allows nitrogen fixation (N2 to NH3)
nitrogen fixing bacteria in soil (rhizobium), cyanobacteria in water, symbiotic relationship with plants that gives rhizobium low o2 environment for fixation in exchange for nitrates.
What is the ammonification step of the nitrogen cycle
Nitrogen is excreted from organisms as urea, uric acid or ammonia (organic N to NH3) ie bird crystalize water to uric acid
How do plants in low nitrogen soils get their nitrogen
become carnivorous ie pitcher plants trap flies or symbiotic relationship with nitrogen fixing bacteria ie alder trees
name 4 sources of nitrogen
biological fixation, lightning (energy breaks down strong triple N2 bond), fossil fuels and nitrogen fertilizers
What is eutrophic
increase level of nitrogen and phosphorus which reduces oxygen and prevents organisms apart form cyanobacteria of living
What is oligotrophic
decrease levels of nitrogen and phosporus, which increases o2 and leads to many organisms being alive in these clear lakes.
What did Hubbard Brook’s experiment show
If no trees on 2 mountains side to side: eutrophication between, erosion, flooding
How does acid rain occur
burn fossil fuels, becomes sulfuric acid in atmosphere which acidifies the soil when it rains and kills organisms excpet denitrifying bacteria (removes nitrogen) so: acidic and nutrient-poor soil
Name 4 greenhouse gases
CO2, CH4, N2O and O3
What is produced by bacterial decomposition in low o2 and wet conditions
oil, coal, ch4 (by methanogens) and peat (by methanogens)
What does cyanobcteria produce and what did it lead to in terms of the atmosphere
Cyanobacteria produces o2 so atmosphere is now an oxidising atmosphere
