Ch 38: Communities and Ecosystems (Exam 1)

Question 1

Ecosystem

Answer 1

includes the community plus the abiotic, or non living environment

Question 2

Niche

Answer 2

the total of all the recourses a species requires for its survival, growth, and reproduction

Question 3

Competitive Exclusion vs Resource Partitioning

Answer 3

COMPETITIVE EXCLUSION-states that two species cannot coexist indefinitely in the same niche
RESOURCE PARTITIONING-multiple species use the same resource in a slightly different way or at a different time

Question 4

Competition vs Symbiosis

Answer 4

COMPETITION-occurs when two or more organisms vie for the same limited resource, such as shelter, nutrients, water, light, or food
SYMBIOSIS-(“literally living together”) two species share a close (and often lifelong) relationship in which one typically lives in or on the other

Question 5

Mutualism vs Commensalism

Answer 5

MUTUALISM-a symbiosis that improves the fitness of both partners
COMMENSALISM-a type of symbiosis in which one species benefits but the other is not significantly effected

Question 6

Primary vs Secondary Succession

Answer 6

PRIMARY SUCCESSION-occurs in an area where no community previously existed
SECONDARY SUCCESSION-occurs where a community is disturbed but not destroyed

Question 7

Food Chain

Answer 7

a linear sequence of feeding relationships: a beetle eats a plant, a bird eats the beetle, and so on

Question 8

Trophic Level

Answer 8

describes each organisms position in the food chain
EX: Tertiary Consumers (Carnivores), Secondary Consumers (Carnivores), Primary Consumers (Herbivores), Primary Producers, and Decomposers

Question 9

Autotroph vs Heterotroph

Answer 9

AUTOTROPH-(primary producer/”self feeder”), is any organism that can use energy, Co2, H2O, and other inorganic substances to produce all the organic material it requires
HETEROTROPH-(consumers/”other eaters”), which obtain energy either from producers or from other consumers

Question 10

Secondary Consumers

Answer 10

carnivores that eat primary consumers, and tertiary consumers eat secondary consumers

Question 11

Decomposers

Answer 11

microbes that complete the recycling process, they secrete enzymes that digest the remaining organic molecules in dendrites
EX: fungi, bacteria
-they return carbon, nitrogen, and phosphorus, and other inorganic nutrients to the environment w/o decomposers ecosystems would hault

Question 12

Keystone Species

Answer 12

a type of organism that makes up a small portion of the community by weight, yet has a large influence on community diversity, that sometimes many species in a community depend on (KEEPS OTHER PREDETORS IN CHECK)

Question 13

Net Primary Productivity

Answer 13

the amount of energy available for consumers to eat
HIGH NET=TROPICAL RAINFOREST(good temp and moisture)
LOW NET=DESERT

Question 14

Energy in a Trophic Level

Answer 14

on average 10% of the energy in a trophic level is available to the next, but it can range from 2-30% due to food quality variation

Question 15

Evaporation (water cycle)

Answer 15

organisms use some of the water, and the remainder evaporates, runs off into streams and the ocean, or enters the ground

Question 16

How Carbon is Returned/Removed (carbon cycle)

Answer 16

HOW CARBON RETURNS-CO2 enters the ecosystem from the air and water through photosynthesis then passes along food chains, and respiration and combustion also return CO2-also returned by organisms through cellular respiration
HOW CARBON IS REMOVED-dissolved by plants and oceans and stored, then turned into fossil fuels

Question 17

Denitrification (nitrogen cycle)

Answer 17

bacteria and archaea return nitrogen to the atmosphere as they convert nitrate to N2

Question 18

Weathering of Rocks (phosphorous cycle)

Answer 18

releases phosphate into the soil, where it can be absorbed by plants