Ecology Test 1 Chapter 26

Question 1

What is primary production? Examples involved

Answer 1

the production of organic compounds through the process of photosynthesis; plants, algae, and cyanobacteria

Question 2

What is gross primary production? What is the efficiency of gross primary production formula?

Answer 2

equivalent to the carbon fixed during a given time period of photosynthesis; (energy fixed by GPP)/(energy in incident sunlight)

Question 3

What is net primary production? What is the formula

Answer 3

gross primary production minus the energy lost in plant cellular respiration, the amount of energy available to primary consumers; NPP= GPP-R

Question 4

What are nutrients?Whatcanitlimit?

Answer 4

key elements in usable form particularly nitrogen and phosphorus, can also limit primary production in terrestrial ecosystems

Question 5

What is a limiting factor?

Answer 5

the scarcest in relation to need

Question 6

What is the Liebig’s law of the minimum?

Answer 6

Justus von Liebig 19th century German chemist which states that species biomass or abundance is limited by the scarcest factor

Question 7

What are dead zones?

Answer 7

havehigh nutrient levels where fish and other marine life can no longer survive

Question 8

What is decomposition? What is the end result?

Answer 8

the physical and chemical breakdown of dead plant and animal biomass. The end result is a conversion of organic matter into inorganic nutrients, carbon dioxide, and heat

Question 9

What is leaching? What does fresh litter lose and when?

Answer 9

Leaching transfers water-soluble material away from the organic matter; fresh litter can lose 5% of its biomass during the first 24 hours by leaching alone

Question 10

What is fragmentation? What do detritivores facilitate?

Answer 10

where detritivores break down organic matter into small pieces, eventually creating a large surface area for microbial colonization; facilitate a more favorable habitat for the succeeding species

Question 11

What is chemical alteration? How do some chemical changes occur?

Answer 11

where fungi and bacteria chemically change dead plant material; some chemical changes occur spontaneously in the soil without microbial mediation, but occur over a long time span

Question 12

What is soil organic matter? What are some examples?

Answer 12

after chemical alteration, the identity of the dead organic matter is no longer recognizable; bacteria and fungi account for 80-90% of the decomposer biomass during this stage?

Question 13

What is decomposition constant? What is the formula?

Answer 13

k, is an exponent that characterizes the decomposition rate under specified conditions; k=litterfall/litterpool

Question 14

What is residence time? What is the equation?

Answer 14

the mean or time required for litter to decompose under these conditions is 1/k; residence time= litterpool/litterfall

Question 15

The amount of energy that is fixed during photosynthesis is ?

Answer 15

Gross primary production

Question 16

Which type of producers have the highest efficiencies of gross primary production?

Answer 16

Coniferous trees

Question 17

Primary production in aquatic ecosystems is limited mainly by?

Answer 17

Light and nutrients

Question 18

The most highly productive terrestrial communities on Earth are?

Answer 18

Forests

Question 19

In unpolluted areas of tropical oceans, primary productivity is limited most often by?

Answer 19

Nitrogen, iron, phosphorus

Question 20

Which of the following leaf constituents are the first to decline during decomposition?
Cell solubles, cellulose, hemicellulose, microbial products, lignin

Answer 20

Cell solubles

Question 21

Decomposition rates are affected by?

Answer 21

temperature, nutrient availability, lignin: carbon ratios

Question 22

Which organisms are the most important consumers of energy in a Georgia salt marsh?

Answer 22

Spartina grass and algae

Question 23

As measured by satellite imagery ocean chlorophyll concentrations are the highest in the Tropics.
True of False

Answer 23

False

Question 24

Across the globe, increasing precipitation always increases net primary productivity.
True or False

Answer 24

False