Ecosystem, Energy Flow & Food Webs

Question 1

ecosystem

Answer 1

all orgs living in the same geographic area juntos w/ abiotic components that affect or exchange materials w/ orgs

community + its physical environ

Question 2

nutrient

Answer 2

any substance org require for normal growth, maintenance or reproduction

Question 3

biosphere

Answer 3

thin zone surrounding earth where all life exists

- sum of all terrestrial & aquatic ecosystems

Question 4

primary producer

Answer 4

any org that creates its own food via photosynthesis or from reduced inorganic compounds

• food source for otro species in its ecosystem
• aka autotroph

Question 5

autotroph

Answer 5

any org that synthesizes reduced organic compounds from simple inorganic sources (CO2, CH4)

Question 6

gross primary productivity (GPP)

Answer 6

total amount of carbon fixed by photosynthesis

- cellular respiration (55%) + growth/reproduction (45%)

Question 7

net primary productivity (NPP)

Answer 7

total amount of carbon fixed by photosynthesis over a given period of time minus amount oxidized during cellular respiration
- growth/reproduction part of GPP

Question 8

consumer

Answer 8

org that cannot synthesize reduced organic compounds from inorganic sources, obtain them from otro orgs
- aka heterotroph

(ie) some bacteria/archaea & all fungi and animals

Question 9

primary consumer

Answer 9

herbivore; org that eats plants, algae or otro primary producers

Question 10

secondary consumer

Answer 10

carnivore; org that eats herbivores

Question 11

tertiary consumer

Answer 11

or that feeds on secondary consumers

Question 12

decomposer

Answer 12

org that eats mainly dead organic matter
- aka detritivore

(ie) various bacteria, fungi, protists & animals

Question 13

trophic level

Answer 13

feeding level in an ecosystem

Question 14

food chain

Answer 14

relatively simple pathway of energy flow through a few species

• each @ diff. trophic level in an ecosystem
• includes: PP, PC, SC & decomposer
• subset of food web

Question 15

grazing food chain

Answer 15

ecological network of herbivores, predators & parasites that consume them

Question 16

decomposer food chain

Answer 16

ecological network of detritus

decomposers that eats detritus + predators/parasites that eat decomposers

Question 17

primary decomposer

Answer 17

decomposer that consumes detritus from plants

Question 18

food web

Answer 18

complex interaction network among species in an ecosystem formed by energy & nutrient transfer
- consists of many food chains

Question 19

biomagnification

Answer 19

increase in molecules conc. @ higher levels in a food chain
- higher orgs not able to metabolize or excrete molecule

(ie) DDT spray on crops affect birds

Question 20

trophic cascade

Answer 20

series of changes in species abundance in a food web
- caused by addition/removal of a key predator

(ie) wolf removal from ecosystem effects

Question 21

top-down control

Answer 21

hypothesis that population size is limited by predators or herbivores (consumers)
- removal of top predators = widespread/unexpected effects on species abundance of a community