Biology 6 Chapter 55 Ecosystems

Front 1

Ecosystems

Back 1

all organisms within a community as well as all biotic and abiotic factors with which they interact

Front 2

Law of Conservation of Energy:

Back 2

energy can neither be created nor destroyed, only transformed

Front 3

Second Law of Thermodynamics:

Back 3

energy transfers/transformations are not completely efficient –
some energy will be lost as heat

Front 4

Primary consumers

Back 4

heterotrophs feeding directly on plants (herbivores)

Front 5

Secondary consumers

Back 5

heterotrophs feeding directly on herbivores (carnivores)

Front 6

Tertiary consumers

Back 6

heterotrophs feeding on other carnivores (carnivores

Front 7

Detritivores

Back 7

heterotrophs that obtain energy from dead/decaying organic material (detritus) and
recycle nutrients back to producers

1. EX prokaryotes, protists, fungi

Front 8

Primary Production

Back 8

amount of light energy converted into chemical energy by producers during a
given time

Front 9

Gross primary production

Back 9

amount of light energy converted into chemical energy by
producers during a given time

Front 10

Net primary production

Back 10

gross primary production minus the energy used by producers during respiration

a. Determined by (primary producers):
i. size of area covered
ii. efficiency
(GROSS PP) - (used E) = NPP

Front 11

Primary Production in Aquatic Ecosystems

Back 11

1. 50 %+ solar radiation is absorbed in the first meter of water

2. solar radiation increase from the poles to the equator where the greatest amount of light hits
the earth

Front 12

Nutrient limitation

Back 12

element that must be added in order for production to increase in a
particular area

a) marine limiting nutrients:

i. phosphorus

ii. Nitrogen

iii. iron

Front 13

Upwellings

Back 13

when nutrient-rich waters circulate to the ocean’s surface

a. results in high primary production

Front 14

Eutrophication

Back 14

process in which nutrients (P, N) become highly concentrated in a body of
water results in increased algal growth

a. mainly human sources (agriculture, sewage)

Front 15

temperature and moisture are two key factors in

Back 15

terrestrial primary production

a. highest primary production = tropical rainforest

b. lowest primary production = tundra and desert

Front 16

Actual evapotranspiration

Back 16

annual amount of water transpired by plants and evaporated from
landscapes

a. greater the precipitation and solar radiation, the greater the evapotranspiration

Front 17

Secondary Production

Back 17

amount of chemical energy converted into biomass by heterotrophs
during a given amount of time

Front 18

Trophic Efficiency:

Back 18

percentage of production (energy) transferred from one trophic level to the
next

a. 10% energy is transferred between levels

b. 90% energy is lost between levels

Front 19

Green World Hypothesis:

Back 19

predators (carnivores, parasites, diseases, etc.) hold terrestrial
herbivores in check, preventing them from consuming excessive amounts of plant biomass

a. herbivores annually consume less than 17% of total plant biomass

Front 20

Keeping Herbivores in Check:

Back 20

a. Intraspecific competition

b. Interspecific interactions

c. Abiotic factors (climate)

d. Nutrient limitations

e. Plant defenses

Front 21

Biogeochemical Cycles:

Back 21

nutrients cycles involving both biotic and abiotic components

1. carbon (global)

2. water (global)

3. nitrogen (local)

4. phosphorous (local)

Front 22

Decomposition

Back 22

1. Detritivore: decomposer

2. rate of nutrient cycling is dependent upon decomposition rate

3. tropical rainforest – 10% nutrients in soil

a. faster nutrient cycling

4. temperate forest – 50% nutrients in soil

a. slower nutrient cycling

Front 23

Nutrient Enrichment

Back 23

1. nitrogen is the main nutrient lost in agriculture

2. synthetic fertilizers increase nitrogen in the soil

3. legumes increase nitrogen in the soil

Front 24

Contamination of Aquatic Ecosystems

Back 24

amount of nutrients added (N/P) that can be absorbed by plants without
damaging the ecosystem integrity

2. excess nutrients leach into groundwater or runoff into aquatic ecosystems

a. contaminates water supplies

b. chokes waterways (eutrophication)

c. kills fish

Front 25

Sources of contamination:

Back 25

a. fertilizer runoff – fertilizer/landscaping

b. sewage/industrial waste

c. animal waste runoff

Front 26

Results of contamination:

Back 26

a. algal blooms

b. oxygen saturation during photosynthesis (day)

c. oxygen depletion during respiration (night)

Front 27

Acid precipitation

Back 27

rain, snow, sleet or fog with a pH of less than 5.6

a. burning of wood, coal or fossil fuels releases sulfur and nitrogen which reacts with
water forming sulfuric and nitric acids

Front 28

Results of Acid Precipitation:

Back 28

a. lowers the pH of aquatic ecosystems

b. alters soil chemistry of terrestrial ecosystems

Front 29

Bioaccumulation

Back 29

increasing concentrations of potentially toxic substances in living
organisms; easily ingested, but not biodegradable (in the individual, build up of a toxic substance due to not being able to degrade)

Front 30

Biomagnification:

Back 30

increasing concentrations of potentially toxic substances through food chains, exponentially increasing at each level

Front 31

First Generation Pesticides

Back 31

a. heavy metals (As, Pb, Hg)

b. expensive to produce

c. persistent in the environment

d. toxic to all living organisms

e. insects developed resistance

Front 32

Second Generation Pesticides

Back 32

a. synthetic organics (DDT)

b. inexpensive to produce

c. persisted in the environment

d. toxic to insects only – at first

e. covered a broad spectrum

Front 33

Environmental Toxins – DDT

Back 33

1. DDT accumulated in the tissues of eagles, interfering with the deposition of Calcium eggshells

2. during incubation, the egg shells would break resulting in a significant decline in reproductive
rates

Front 34

Atmospheric Carbon Dioxide

Back 34

1. CO2 concentration has been increasing since the Industrial Revolution due to combustion of
fossil fuels and burning of enormous quantities of wood (also, deforestation)

Front 35

Greenhouse effect:

Back 35

carbon dioxide, water vapor, etc intercept much of the reflected solar
radiation from earth’s surface, reflecting some of it back to earth

Front 36

Global warming

Back 36

increase in average temperature of earths near-surface air and oceans

Front 37

Results from Global Warming:

Back 37

a. shifting precipitation patterns

b. melting polar ice caps

c. rising sea levels (100 m)

d. coastal flooding (150 km)

e. mass extinctions

Front 38

Ozone layer:

Back 38

17 – 25 km high layer in earth’s atmosphere containing high concentrations of
ozone (O3), blocking 97 – 99% of solar ultraviolet radiation

Front 39

Ozone Layer Depletion:

Back 39

a. thinning since 1975

b. due to CFC’s (ChlorafloraCarbons ??)

c. Most apparent over Antarctica

Front 40

Consequences of Ozone Layer Depletion:

Back 40

a. increase in cases of skin cancer, cataracts

b. adverse effects on ecosystems

c. adverse effects on crops