Basics ofequatic ecology

Question 1

Ecology

Answer 1

Is the scientific study f the interactions that determine the distribution and abundance of organisms. Organisms interact with their environment and are the product of asaption through evolution (natural selection)

Question 2

Fitness

Answer 2

Is the measure of a genotypes long term success. Fitness is alway relatice to the other species in the system (no maximum –> optimizations) and the species which can sustaain the largest growth is the fittest. The teo main components are reproduktive potential and suvival.

Question 3

Abiotic Factors

Answer 3

Temperature
Oxygen
pH
Other Ions
Water flow in streams
Density

Question 4

Temperature

Answer 4

smaller range than on lang
less lethal to aquatic organisms
important for speed of physiological and biochemical processes

Question 5

Oxygen

Answer 5

solubility is limited: depens on Temp, salinity, and pressure
To handle limitations and fluctuartion: organisms developed different coping mechnaisms

Question 6

pH

Answer 6

damages and disfunctions due to the role of pH in the ion transfer through cell membranes
coluility of metals, …

Question 7

Other Ionsa

Answer 7

Salinity
Species in freshwater must maintain their ions and are surrounded by more diluted water and must constantly remove water to retain their salts. Because this does not happen in saltwater there are very few species which can live in between them both (riverdeltas)

Question 8

Water flow in streams

Answer 8

responsible for changes in resources
disastrous if the are fluctuation
morphological and behavioral adaptions to cope with these challenges

Question 9

Density

Answer 9

organisms are denser than water and must swim (high energy cost) or reduce their sinking speed through adaption to move/stay flow

Question 10

Ressources

Answer 10

Light
Dissolved Inorganic Carbon (DIC)
Mineral nutrients
Inorganic energy sources
Anaerobis respiration
Dissolves organic substances (DOC)
Particulate organic substances (POC)

Question 11

Light

Answer 11

formular
Light is not a boundary condition for photosynthesis

Question 12

DIC

Answer 12

Mainly dissolved CO2, carbonic acid, carbonate ion and bicarbonate ion

Question 13

Mineral nurtients

Answer 13

Macroelements (N, P, S, K, Mg, Ca, Na, Cl) and Trece elements (Fe, Mn, Cu, Zn, B, Si, Mo, C, CO, etc)

Question 14

Inorganic energy sources

Answer 14

Chemolithoautotrophic bacteria are extremely important for nutreient sysling in freshwater

Question 15

Anaerobic respiration

Answer 15

Heterotrophic bacteria use DOC as source of energy

Question 16

DOC

Answer 16

Most organic matter in lakes is dissilved
Mostly important as energy and carbon source
Is a mixture of several substances

Question 17

POC

Answer 17

Occus as either living or dead matter (detritus)
In streams: exclusively detrius

Question 18

Populations

Answer 18

The definition of population depends on the abjective and the scale of the observer

Question 19

Def of densiy

Answer 19

Abundance is the density of organisms in a defined area of water, it fluctuates over time and there are major variations between species. Abundance changes through reproduction, moratily, import and export.

Question 20

Demography

Answer 20

Type III
juveniles have a high rate of mortality until a critical age is reaches, where the mortality falls off
The mortaliy in the remaining age groups is random

Question 21

Distribution

Answer 21

Random (Species that do not conrol their environment)
Even (Soecies which compete among individuals, common on strems)
Clupmed (Swarms offer protection of predators, lakes or micorhabitats in streams)

Question 22

Dispersal

Answer 22

Lakes as islands vs Rivers as continuous systems

Active dispersal vs. passive dispersal

Question 23

Interactions between populations

Answer 23

Most species have a more limited distrbution than it would be predicted by their physiological tolerances (reason: interactions between populations)

Question 24

Competition

Answer 24

for resources
space
position

Question 25

Allelopathy or antibiosis

Answer 25

Direct effect of competitors through releases of chemicals that inhibit other species

Question 26

Predator prey relationship

Answer 26

energy transfer from one organism to another
represent a mortality factor for the prey
lead to evolution of defense mechanism which lead to evolution of more efficient predators (cycle)

Question 27

Examples

Answer 27

Grazing on phytoplankton by zooplankton (algae ward off via toxins, bad taste, digestion resistance, …)
grazing on periphyton by the microfauna, ertebrates (like fish which catch individual prey by sight)

invertebrates (detect prey by mechano- or chemoreception like water fleas)

Prey defends itself through various mechanisms like reducing their detectabiliy (colo adaption), hiding during the day, chemical defendese, fleeing

Question 28

Parasitsm

Answer 28

predator is considerably smaller and closely associated with the prey and they do not always harm the host
Endoparasites: within the host
Ectoparasites; Ouside

Question 29

Symbiosis

Answer 29

Positive Interaction for both parties