Ekstra

Question 1

Long food webs sammenlignet med korte food webs - hvilke er mest produktive?

Answer 1

Ofte er kortere fødekæder mere produktive, fordi der er færre led og mindre der går til spilde i hvert trofisk led
Størrelsen på fytoplankton er vigtig for effektiviteten af the food web.

Question 2

Forskellen på lys i tropiske vande og andre steder?

Answer 2

Det er lys der driver systemerne. I topiske vande er det mere forudsigeligt, da lys er mere ens i løbet af året. Sæsoner gør systemerne mere komplekse og dyrene må ændre deres liv ift sæsonerne. Dog ved troperne er der stadig lidt sæson ift monsoons osv som kan påvirke nutrients, percipitation, wind driven vertical mixing

Question 3

Hvad er ecosystem functions - kom med eksempler på ecosystem functions?

Answer 3

Økologiske processer som kontrollerer flux af energi, næringsstoffer og organisk stof gennem miljøet.

Ift. primary production then the main generic ecosystem functions are
- recycling (of nutrients),
- export (e.g. carbon sequestration),
- trophic transfer (e.g. to biomass production of fish)

Question 4

Hvad er eksempler på ecosystem services?

Answer 4

Fiskeri, rekreationelt fiskeri, sejle, bade, osv.

Question 5

Hvad siges det predator/prey ratio er? Størrelsesforholdet for at blive spist.

Answer 5

Sizee selectivity spectra of 28 planktonic predators from 18 studies in the literature are compared. The linear size ratio between predators and their optimal prey is
1 : 1 for a dinoflagellate,
3 : 1 for other flagellates,
8 : 1 for ciliates,
18 : 1 for rotifers and copepods,
and - 50 : 1 for cladocerans and meroplankton larvae.

These size ratios seem consistent within groups, and their validity is supported by quantitative information from the literature. However, a difference between filter feeders and raptorialinterception feeders, preferring relatively smaller and larger prey respectively, is evident across the taxonomic groups.

A classification of planktonic predators into functional groups is therefore crucial for the construction of models of pelagic food webs.

Question 6

Forklar nogle ting om tropiske vande. Hvor meget af havet er tropisk? Hvordan er diversitet, variabilitet og hvor vigtige er tropiske vande?

Answer 6

• 40 % of global Ocean are within the tropic
• High diversity compared with the northern
  systems
• Smaller variability in the forcing factors
• Large fraction of global population dependent
  on tropical Seas

Question 7

Hvad er the photic (euphotic) zone i havet?

Answer 7

De første 200 m af vandsøjlen, hvor lys stadig kan trænge ned gennem

Question 8

Hvad er mesopelagiske fisk? og hvad er the mesopelagic zone?

Answer 8

Fisk som lever i the mesopelagic zone
- som er fra 200 m ned til 1000 m.

Question 9

Hvad er bathypelagiske fisk? og hvad er the bathypelagic zone?

Answer 9

Fisk som lever i the bathypelagic zone
- som er fra 1000 m ned til 4000 m

Question 10

hvad er epipelagic fish? hvad er the epipelagic zone

Answer 10

Fisk der lever i the epipelagic zone
- som er ned til 200 m.

Question 11

hvad er osmotrophs (organismer)? Hvordan fungerer det og hvorfor er det effektivt?

Answer 11

Organisms that feed on dissolved substrates.

Osmotrophy is a feeding mechanism involving the movement of dissolved organic compounds by osmosis for nutrition. Organisms that use osmotrophy are called osmotrophs. Some mixotrophic microorganisms use osmotrophy to derive some of their energy. Osmotrophy is used by many diverse organisms.

Osmotrophy is an efficient means of gathering nutrients in microscopic organisms that relies on the surface area to ensure that proper diffusion occurs throughout the cell. When organisms increased in size the surface area per volume ratio drops and osmotrophy becomes insufficient to meet the nutrient demands

Question 12

hvad er definitionen af osmosis?

Answer 12

In biology, osmosis is the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell’s partially permeable membrane.
Denne passive bevægelse af vand kaldes osmose og vil fortsætte, indtil koncentrationsforskellene er udlignet.

Question 13

Forklar osmoregulerende organer i en ørrede. Hvorfor gør den det? Hvilke organer i fisken er med til at styre salt og vand balancen?

Answer 13

Ørreden skal som alle andre dyr opretholde en relativ konstant mængde af salt og vand i kroppen for, at cellerne kan fungere.

De vigtigste organer, der hjælper fisken med at styre salt- og vandbalancen, er gæller, nyrer og tarmsystemet. Disse organer betegnes derfor som osmoregulerende organer.

Når to opløsninger, i dette tilfælde fiskens blod og det omgivende vand, med forskellige koncentrationer af salt er i kontakt med hinanden, vil salt altid bevæge sig fra opløsningen med den højeste saltkoncentration til opløsningen med den laveste saltkoncentration (diffusion), mens vand vil bevæge sig i modsat retning (osmose).

Denne passive bevægelse af vand kaldes osmose og vil fortsætte, indtil koncentrationsforskellene er udlignet.

Question 14

hvad er non-limiting substrates i relation til organism growth?

Answer 14

A nutrient used in the growth of microorganims in a concentration that restricts or limits the rate of growth.
Non-limiting er så nogle af de nutrients der er nok af.

Question 15

Coexistence of two organisms competing for the same nutrient is possible if…

Selvom to organismer kæmper om den samme næring, kan de stadig eksistere sammen, hvis….

(forklar deres strategier og forklar hvilke vande de hver især vil dominere over den anden i)

Answer 15

De har forskellige strategier
one of them is “an uptake specialist” and one of them is “a defense specialist”

hvis den ene er god til at optage næringsstoffer, og den anden er god til at forsvare sig mod rovdyr.

The balance between the two competitors then becomes resource dependent: in oligotrophic situations with a low total concentration of resources (e.g. low total phosphorous) the competition specialist will dominate, while in eutrophic situations the predator defence specialist will dominate.
In the steady state of this idealized food web, one can thus talk of a resourcecontrolled predator defence specialist co-existing with a predator-controlled competition specialist.

Question 16

Forklar hvad en “uptake specialist” er

Answer 16

Små celler, der optager næring, har en stor overflade i forhold til deres størrelse. Derfor er de specialiseret i at optage næringsstoffer.

linked to cell size.
Small cells, with their high surface : volume ratio, have been argued to be uptake specialists.
De optager mange næringsstoffer ift hvor store de er

Question 17

Forklar hvad en “predation specialt” er (celler).

Answer 17

Større celler undgår at blive spist af små rovdyr og er derfor bedre til at forsvare sig.

Larger organisms avoiding the intense grazing pressure from small protozoan predators might represent predation defence specialists.

These defenses may be mechanical, chemical, physical, or behavioral. Mechanical defenses, such as the presence of thorns on plants or the hard shell on turtles, discourage animal predation and herbivory by causing physical pain to the predator or by physically preventing the predator from being able to eat the prey

Question 18

Forklar nutrient diffusion

Answer 18

Diffusion is the movement of nutrients to the root surface in response to a concentration gradient. When nutrients are found in higher concentrations in one area than another, there is a net movement to the low-concentration area so that equilibrium is reached.

Mange små organismer i havet benytter denne form for nutrient uptake

Question 19

Is it better for cells to have a large surface area to volume ratio
rather than being very large with a small surface area?

Answer 19

A larger surface area to volume ratio is more efficient than a smaller ratio. This is due to the amount of plasma membrane relative to the volume of the cell. The more plasma membrane available to transport materials in and out of the cell, the more efficient the cell will be in completing its specific functions.

Question 20

What is the importance of surface area to volume ratio as a factor limiting cell size?

Answer 20

If the surface area to volume ratio gets too small then substances won’t be able to enter the cell fast enough to fuel the reactions and waste products will start to accumulate within the cell as they will be produced faster than they can be excreted.

Question 21

What Limits Cell Size?

Answer 21

Cell size is limited by the surface area to volume ratio of the cell. As the volume of a cell increases, it becomes harder to efficiently transport materials in and out of the cell.

Question 22

Forklar Osmotrophy

Answer 22

The process of taking in of dissolved organic compounds that are absorbed into the cells via extracellular digestions for nutrition.

Question 23

The presence of an organism is, in itself, a proof
of

Answer 23

the success of the life strategy of that organism within the
context given by the environment and its interactions with
its co-evolving neighbours in the food web

Question 24

Assuming one common limiting substrate for all members of a phytoplankton community, one is then forced to ask, not only the classical why are there so many co-existing species? but also the additional question: why are there anything but small-celled picoplanktonic phytoplankton species?
To our knowledge, the simplest theoretical solution to both these questions is embedded in the three-member idealized food web of Figure 1.

Forklar
Figure 1 Generic 3-member food web allowing co-existence of two
competing osmotrophs with different life strategies on one
common limiting substrate

Predator or parasite <-
Competition specialist <- Common limiting nutrient -> Defence specialist

Figure 1 seems to provide a framework that accounts for/fits an amazingly large set of theories and observations linking food web properties and organism life strategies

Answer 24

• Det er fint der er trade-offs og flere arter så der ikke bare er ét super individ. Diversitet.

The relative success of the two osmotroph strategies depends entirely on the nutrient content of the environment.
The balance between the two competitors is resource dependent:
- in oligotrophic situations with a low total concentration of resources (e.g. low total phosphorous) the competition specialist will dominate,
- in eutrophic situations the predator defence specialist will dominate.

This idealized structure contains a killing the winner mechanism where the biomass of the competition-specialized osmotroph is kept in check by predator or parasite control, which allows some of the limiting element to be incorporated into the predator/ parasite defence specialist.

In the steady state of this idealized food web, one can thus talk of a resourcecontrolled predator defence specialist co-existing with a
predator-controlled competition specialist

Question 25

In Figure 1, however, the relative success of the two
osmotroph strategies depends entirely on….

Answer 25

the relative success of the two osmotroph strategies depends entirely on the nutrient content of the environment.

The balance between the two competitors is resource dependent:
- in oligotrophic situations with a low total concentration of resources (e.g. low total phosphorous) the competition specialist will dominate,
- in eutrophic situations the predator defence specialist will dominate.

Question 26

The existence of trade-offs is considered an important factor in biodiversity maintenance - hvorfor?
Altså det er godt at der er trade offs ved at enten vælge defence eller competition specialist for biodiversitet - hvorfor

Answer 26

Built into the generic model in Fig. 1 is the assumption of
a trade-off between the osmotroph strategies. In the absence
of any trade-off, an osmotroph that could optimize
competitive ability and predator defence simultaneously
could, in the extreme case, take over all resources and thus
reduce diversity in this idealized system.

• Det er fint der er trade-offs og flere arter så der ikke bare er ét super individ. Diversitet.

Question 27

Hvad hedder de første 200 m af vandsøjlen, hvor lys stadig kan trænge ned gennem

Answer 27

the photic (euphotic) zone i havet
epipelagic zone

Question 28

Hvad hedder den zone i havet der er fra 200 til 1000 m?

Answer 28

Mesopelagic zone

Question 29

Hvad hedder den zone i havet der er fra 1000 m til 4000 m ?

Answer 29

Bathypelagic zone

Question 30

Forklar “killing the winner” begrebet for bakterier og virus i havet

Answer 30

De bakterier i havet som klarer sig bedst/der er flest af, er ofte dem virus vil gå efter - dermed holder de populationerne i skak og sørger for, at ikke én slags bakterie overtager det hele

Phages reduce populations of their susceptible hosts to a low steady state level, which is independent of hosts’ growth rate thus allowing multiple species per nutrient type

Question 31

How many major upwelling areas are there and where are they

Answer 31

Worldwide, there are five major coastal currents associated with upwelling areas:
the Canary Current (off Northwest Africa),
the Benguela Current (off southern Africa),
the California Current (off California and Oregon),
the Humboldt Current (off Peru and Chile),
and the Somali Current (off Somalia and Oman)

Question 32

Why is upwelling areas important?

Answer 32

This dynamic and diverse upwelling current system is
highly productive and
extraordinarily biodiverse, and
serves as foraging habitat for many species of highly migratory fish, marine mammals, and seabirds that travel across the vast Pacific Ocean basin