Ecosystem Ecology - 10-13

Front 1

What is an ecosystem?

Back 1

Multiple communities and their abiotic (chemical and physical) environment.

Front 2

What are 4 primary components of ecosystems?

Back 2

1) Abiotic environment - light, water, temp, nutrient availability

2) Primary producers (autotrophs) - produce their own food

3) Consumers (heterotrophs) - eat autotrophs and other heterotrophs

4) Decomposers/detritivores - heterotrophs that get energy from dead material

Front 3

Regardless of size or type, ecosystems have two main processes: ______________ and _____________. What laws of physics apply to ecosystems?

Back 3

Energy flow; chemical cycling.

First and 2nd laws of thermodynamics, law of conservation of mass

Front 4

What is positive and negative feedback?

Back 4

Positive: X produces changes in Y that leads to more X (example is forest fire melting permafrost).

Negative: X produces changes in Y that leads to less X (example is increased plant growth).

Front 5

What is homeostasis and homeorhesis?

Back 5

Homeostasis: behaviour of system in a dynamic equilibrium (where negative feedback returns system to a set POINT).

Homeorhesis: tendency to return to particular TRAJECTORY - direction and nature of path ecosystem follows is more important than destination!

Front 6

Ecosystems are more stable than the sum of their parts. Why?

Back 6

Functional groups and functional redundancy make this more stable!

Front 7

What is resistance and resilience?

Back 7

WITHIN ECOSYSTEM ECOLOGY - THEY ARE USUALLY NEGATIVELY RELATED.

Resistance: is ability of system to not change under forces of disturbance

Resilience: ability of system to recover following a disturbance.

Front 8

Going from tropics to tundra, resistance _________, resilience __________, and niche breadth _________________ (why)?

Back 8

Resistance will decrease, resilience will increase (peaking in temperate areas). Niche breadth will increase - remember that LDG, seasonality occurs more with higher latitudes, so up there, species will have to take up bigger niches (less diversity!).

Front 9

Explain what you know about specialists and generalists. Which are more resilient?

Back 9

Specialists: take up a few niches, aka a few conditions, with little competition.

Generalists: can cope with wide range of conditions, lots of competition.

Generalists are more resilient because they can tolerate more change.

Front 10

Is an ecosystem an open or closed system? What is it?

Back 10

Open system - energy and matter can move in and out.

Front 11

Primary products (autotrophs) are the base of the ecosystem because they...

Back 11

Use sunlight and store chemical energy.

Front 12

What is primary productivity?

Back 12

Rate at which solar energy is converted by photosynthesis (or chemosynthesis).

Front 13

What is GPP?

Back 13

Gross primary productivity - rate of energy fixation per unit area per unit time.

Front 14

What is NPP?

Back 14

GPP - R.

R = respiration.

Rate of energy storage available to higher trophic levels. g/m2/year

Front 15

What is the standing crop biomass?

Back 15

SCB is the amount of accumulated organic matter in an area at a given time. g/unit area

Front 16

What is the difference between standing crop biomass and primary production?

Back 16

Standing crop biomass is a snapshot of the org matter present at a given time, productivity is rate at which organic matter is created.

Front 17

What does BAR stand for?

Back 17

Biomass accumulation ratio: SCB/NPP with end unit in years.

Front 18

What factors affect terrestrial primary productivity?

Back 18

Temperature, light, water and nutrients.

Areas that are both warm and moist have highest productivity. Warm temps increase evapotranspiration and hence water demand. If temp is warm, but little water available, productivity is low. At low temperatures, productivity will always be low.

Front 19

What is AET?

Back 19

Actual evapotranspiration - combines surface evap and transpiration and reflects demand and supply of water. It is a factor to affects primary productivity on terrestrial ecosystems, and NPP increases with evapotranspiration, which depends on precipitation and temperature.

Front 20

What limits marine NPP (net primary production)?

Back 20

Limited by light and nutrients.

Front 21

What is the compensation depth?

Back 21

GPP = respiration, NPP = 0. Varies among aquatic systems!

Front 22

Why is there a greater NPP at coastal regions?

Back 22

1) light penetrates more

2) nutrients are transported from nearby sediments

3) nutrient enters from terrestrial systems

Front 23

What do we know about iron fertilization?

Back 23

Iron is a limiting nutrient within marine environments. The idea is that this will increase NPP, and decrease CO2. However - nutrient overloading is a serious concern, like algal toxins and oxygen depletion!

Front 24

What do food chains and webs explain?

Back 24

How energy moves between organisms and trophic levels.

Front 25

Draw out a detrital food chain and grazing food chain.

Back 25

Er........ just check your notes kek.

Front 26

What are the four levels of heterotrophs?

Back 26

Primary consumers, secondary, tertiary, quaternary consumers.

Front 27

What is a detritivore?

Back 27

A heterotroph that feeds on dead tissues (detritus) and does not mineralize organic material back into nutrients. Examples are scavengers or insects.

Front 28

What is a decomposer? What is humus?

Back 28

Heterotrophs that mineralize dead organic material back into inorganic nutrients. Usually bacteria or fungi.

They actually break down the dead material and make it into soil organic matter (partially and completely decomposed detritus). Humus is what they call completely decayed organic material. Then decomposition converts the nutrients in soil organic matter to an inorganic form, which is taken up by plants.

Front 29

What are 3 reasons explaining why detritivores and decomposers are important?

Back 29

1) No decomposition = one way nutrient street.

2) Detritivores and decomposures cycle energy.

3) Food chains are leaky - matter can move from one ecosystem to another via decomposition.

Front 30

What do we know about energy transfer in food chains?

Back 30

We lose energy with each trophic level because not all energy is consumed by the next level. Only a fraction of total energy consumed is used for growth and repro. This is usually 10%.

Front 31

A ______________ slope to food pyramid means greater efficiency.

Back 31

Steeper.

Front 32

What are the two reasons that energy transfer efficiency varies?

Back 32

1) Differences in consumption efficiency.

2) Differences in energy conversion efficiency (ex. ectotherms (like sneks), are more efficient, large is more efficient aka small SA:V ratio).

Front 33

What is TE and CE?

Back 33

Trophic efficiency = Pn/P(n-1)

Ratio of productivity at a given trophic level to ratio of productivity at lower trophic level.

CE = consumption efficiency = proportion of net production at one trophic level consumed by the next

Front 34

Is CE and TE bigger for terrestrial systems?

Back 34

No - bigger for aquatic (steeper slope).

Front 35

What is biomagnification?

Back 35

Increase in concentration of a substance that occurs in a food chain. Often used when talking about contaminants like DDT. This occurs because contaminant transfer is near 100%.

Front 36

What is bioconcentration, biomagnification, bioaccumulation?

Back 36

Bioconcentration - uptake of contaminants from water.

Biomagnification - uptake of contaminants from food.

Bioaccumulation - uptake of contaminants from all sources (water, food, air, soil).

Front 37

What do we know about bioaccumulation?

Back 37

Many contaminants bioaccumulate and increase with size, age and trophic level.

Front 38

What do we know about Hg in arctic fishes?

Back 38

Age explained the variation, not trophic level. Hg bioaccumulates.

Front 39

The rate of nutrient cycling is affected by the _______________. This rate is affected by ______________.

Back 39

Rate of decomposition, affected by abiotic environment (such s temperature and quality of detritus).

Front 40

Where do you gain and lose nutrients in the nutrient cycle?

Back 40

Nutrients leave an ecosystem when bbiomass leaves.

Gain: water, wind, migrating animals. N (like in fertilizers).

Lose: Erosion, leaching, migrating animals. Human activities that reduce vegetation also helps decrease nutrients.

Front 41

What is the biogeochemical cycle?

Back 41

Path that an element or compound taken as it moves from abiotic systems through producers, consumers, decomposers and back again.

Front 42

What are some examples of biogeochemical reservoirs?

Back 42

Atmosphere, lithosphere, hydrosphere, biosphere, living organisms.

Front 43

What do we know about the water cycle?

Back 43

More flux over the ocean - with greater evapo than precip.

Less flux over land - greater precip than evapo.

Runoff and GW = movement by wind.

Front 44

What's the human effect on water cycle and what are some solutions?

Back 44

Agriculture and irrigation destroy natural ecosystems, and increase surface runoff. Impervious surfaces prevent GW recharge. GW is not able to stay underground, so water tables decrease.

Many places do not have water anymore! We must find more sources of water thru desalination, or decrease usage per capita.

Front 45

What do we know about nitrogen cycle?

Back 45

Lots of N in atmosphere, but has to be fixed to be useful! It is fixed via bacteria or lightning, and N-fixing plants are usually in symbiosis with N-fixing bacteria, working together!

Front 46

How have humans altered the N cycle?

Back 46

We've added huge amounts of fixed N - causing things like eutrophication and run off! We increase productivity, but decrease diversity!

We do this by adding fertilizers, cultivating crops that have N-fixing bacteria, and fossil fuels.

Front 47

What do we know about the carbon cycle?

Back 47

Ocean is the biggest reservoir. Photosynthesis takes C out, respiration puts it back in.

Front 48

What have humans done to the carbon cycle?

Back 48

Burning fossil fuel moves C from the lithosphere to atmosphere (burning gasoline releases carbon atoms that have been locked up). Land clearing also increases C. Atmosphereic reservoir of C is INCREASING cause fluxes do not balance due to fossil fuels!

Front 49

What are the two most important human effects on environment due to CO2 and why?

Back 49

1) Species loss.

2) Global warming.

Massive increase in human population, and high resource use in developed countries.

Front 50

How does coral bleaching work?

Back 50

Increased temperatures cause coral to expel their symbiotic algae.

Front 51

What is ocean acidification and it's consequences?

Back 51

Acidification of the ocean due to CO2 in the air seeping into ocean. It kills coral, and OVERSATURATES the water with needed elements for marine species to build their shells, will affect ability to produce and maintain shells (a lot of these are primary producers!).

Front 52

How does climate change cause extinctions and evolutionary change?

Back 52

Tundra and alpine are disappearing - biotia has nowhere to go. Species with limited dispersal is not able to keep up (we've had climate change before, but not at this fast of a rate!). It also causes allele frequency changes.

Front 53

What human induced changes do we see in productivity?

Back 53

Increased NPP on land, decreased in oceans.

Increased NPP on land: increase in temperatures, increase in rainfall, CO2 fertilization, increases photosynthesis and causes a negative feedback! This varies regionally though, increased in equator but decreased in Arctic.

Decrease in oceans: Global warming increases density gradient, making it less likely for layers to mix (benthic layers arent able to bring nutrient rich water to upper). This is positive feedback!

Front 54

What are 7 impacts on organisms due to climate change?

Back 54

1) Species ranges (birds move north).

2) Phenology (birds migrate sooner, bloom sooner)

3) Extinctions (Tundra alpine habitats are disappearing, limited dispersal species have no where to go, ex polar bears, poor amphibians and their fungal infections :( ).

4) NPP (higher land, lower in ocean).

5) Ocean acidification

6) coral bleaching

7) Allele frequency changes.

Front 55

Climate change leads to both positive and negative feedbacks. List an example of each.

Back 55

Positive: Forest fire frequency increases due to warmer climate... fires release even more CO2.

Negative: plants that grow due to increase in CO2 which acts as fertilizer. Plants take away CO2.

Front 56

Why did Tikopia thrive while Easter Island collapsed?

Back 56

People on Tikopia could see the whole island and developed alternatives to forestry and agriculture. Tikopia was also closeby to other islands so they could migrate, unlike Easter Island.

Front 57

Give an example of a positive and negative change in NPP.

Back 57

Positive: Increased plant biomass.

Negative: Increased algal blooms, anoxic areas, and declining fishery productivity.

Front 58

Where is nutrient cycling the fastest?

Back 58

Warm, wet areas such as tropical wet forest. This is because temperatures are higher, so rate of decomp is higher, so rate of nutrient cycling is higher.

Front 59

How does CO2 work as a greenhouse gas?

Back 59

It traps heat and redistributes over the Earth, makes it so that it cannot escape earth.

Front 60

Current models say that there will be a ____________ by the year 2100.

Back 60

1.1 - 6.4 degrees celcius increase