lecture 22- ecosystems

Question 1

what are the two fundamental processes of an ecosystem

Answer 1

energy flow
nutrient cycling

Question 2

is energy flow 100% efficient

Answer 2

no energy is always lost as heat

Question 3

what is energy flow

Answer 3

energy entering as light exits as heat
passing through primary producers
then primary consumers
then secondary consumers

Question 4

how does decomposition relate to trophic levels

Answer 4

it connects them all

Question 5

how does decomposition work

Answer 5

bacteria and fungi recycle nutrients/organic matter (fungi produce exoenzymes)

Question 6

how does energy flow

Answer 6

one way
in and out

Question 7

what are the four trophic levels composed of

Answer 7

first: primary producers
second: primary consumers
third: secondary consumers
fourth: tertiary consumers

Question 8

what type of organism is a primary producer

Answer 8

green plant

Question 9

what type of organism is a primary consumer

Answer 9

herbivores/omnivores

Question 10

what type of organism is a secondary consumer

Answer 10

carnivores/omnivores

Question 11

what type of organism is a tertiary consumer

Answer 11

second level carnivore

Question 12

what are decomposers also called

Answer 12

saprotrophs

Question 13

what is a food chain

Answer 13

ladder of organisms and what they eat (single animal eats a single plant, that animal is eaten by a single other animal)
simple and rare in nature

Question 14

what is a food web

Answer 14

interconnected web of animals and all the food they eat (carnivores eat more than one prey)
complex and more accurate

Question 15

what is biomass

Answer 15

chemical energy stored in an organism

Question 16

what is primary production

Answer 16

amount of energy that autotrophs can incorporate in their biomass

Question 17

what is GPP

Answer 17

gross/total primary production in the plants

Question 18

what is the NPP

Answer 18

net primary production
chemical energy available to consumers
GPP - R

Question 19

what is R

Answer 19

energy used by primary producers (cellular respiration for example)

Question 20

what energy is available to secondary consumers

Answer 20

chemical energy stored by the herbivores’ biomass

Question 21

what is a limiting nutrient

Answer 21

element that must be added for primary production to increase in an area

Question 22

what is the limiting nutrient in aquatic ecosystems

Answer 22

nutrients such as nitrogen, phosphorous, iron

Question 23

what is the limitation in terrestrial ecosystems

Answer 23

temperature, sunlight, availability of water

Question 24

what is evapotranspiration vs annual evapotranspiration

Answer 24

amount of water transpired by plants and evaporated from landscape
amount of water annually transpired by plants and evaporated from landscape

Question 25

relation between primary production and evapotranspiration and why

Answer 25

more evapotranspiration = more primary production more water and sunlight = more primary production = more evapotranspiration

Question 26

what are the best conditions for terrestrial ecosystems

Answer 26

warm and humid environments (tropical rainforests)

Question 27

what is the disadvantage of a warm and humid ecosystem

Answer 27

nutrient cycle is very fast (decomposition is fast) so the soil is nutrient poor/nutrients dont stay in the soil long little organic matter accumulation

Question 28

what is the secondary production

Answer 28

amount of chemical energy is consumer's food that is converted to their own biomass during a given period of time

Question 29

where does the majority of the energy consumed by organisms go

Answer 29

feces

Question 30

how does energy transfer through trophic levels

Answer 30

since only a small % of the energy is used for growth (and can be available to the next level) the next level only gains about 10% of the energy of the last level so there is less and less energy per level and the organism needs to eat more to gain it

Question 31

what is the range of trophic efficiency

Answer 31

5-20%

Question 32

why is energy lost at each trophic level

Answer 32

indigestible substances chemical energy in carbon compound bonds is usually lost as heat energy is always lost as heat (movement)

Question 33

why do toxins accumulate in the environment

Answer 33

they are extremely stable

Question 34

how do toxins accumulate in organisms

Answer 34

it the organism doesnt break down the toxin it gets stored in fatty tissue and accumulates

Question 35

what is bioaccumulation

Answer 35

built up toxin in organism's body

Question 36

what is biomagnification

Answer 36

increase in concentration as it passes from one trophic level to the next

Question 37

what do nutrients cycle through

Answer 37

from organism to another from organism to environment and back

Question 38

what is nitrogenase

Answer 38

enzyme used in nitrogen fixation (anaerobic)

Question 39

what is nitrogen fixation and what mainly does it

Answer 39

conversion of nitrogen gas to ammonia and ammonium by free living and mutualistic nitrogen fixers bacteria

Question 40

what is the carbon cycle

Answer 40

carbon enters plants as CO2 cellular respiration, combustion and erosion return C to environment

Question 41

steps of the water cycle

Answer 41

precipitation (atmosphere to land) evaporation (land to atmosphere) transpiration (plants to atmosphere) runoff to ocean percolation through soil (ground water)

Question 42

what is nutrient cycling regulated by

Answer 42

vegetation

Question 43

what does internal cycling within an ecosystem do

Answer 43

conserve most of the mineral nutrients

Question 44

lack of vegetation?

Answer 44

more soil erosion = more runoff = less nutrients = more eutrophication

Question 45

how do humans disrupt the nutrient cycles

Answer 45

add new materials to ecosystems move nutrients form one part of biosphere to the other (agriculture and run off) release compounds in the air (burning fossil fuels)

Question 46

forms of restoration ecology

Answer 46

bioremediation biological augmentation

Question 47

what is bioremediation

Answer 47

using living organisms to detoxify or remove toxins from polluted ecosystems prokaryotes, fungi, plants

Question 48

what is biological augmentation

Answer 48

using living organisms (often native to land) to re establish the nutrient cycle into the ecosystem