Ch. 36 Communities and Ecosystems

Question 1

Community

Answer 1

An assemblage of all the organisms living together and potentially interacting in a particular area

Question 2

Diversity

Answer 2

The variety of different kinds of organisms that make up a community (Species richness and abundance of each species)

Question 3

Stability

Answer 3

Community’s ability to resist change and return to its original species composition after being disturbed
- depends on type of community/distrubance

Question 4

Trophic Structure

Answer 4

The feeding relationship in an ecosystem

- determines the route of energy flow and the pattern of chemical cycling in an ecosystem

Question 5

What are the forces that tie populations together into communities?

Answer 5

1) Competition
2) Predation
3) Symbiosis

Question 6

Example of Competition

Answer 6

1) Interspecific Competition

2) Competitive Exclusion Principle

Question 7

a contest between individuals of two populations that require a limited resource (helps structure communities)

Answer 7

Interspecific Competition

Question 8

Concept that populations of two species cannot coexist in a community if their niches are nearly identical
- using resources more efficiently and having a reproductive advantage, one will outcompete the other

Answer 8

Competitive Exclusion Principle

Question 9

Niche

Answer 9

A population’s role in its community

- the sum total of a population’s use of the biotic and abiotic resources of its habitat

Question 10

An interaction between species in which the predator eats the prey

Answer 10

Predation

Question 11

Evolutionary change, in which adaptations in one species acts as a selective force on a second species, inducing adaptations that in turn act as a selective force on the first species

• mutual influence on the evolution of two different interacting species
• evolves thru natural selection

Answer 11

Coevolution

Question 12

Example of predation

Answer 12

Plants using chemical toxins and antipredator thorns

Bright colors, camouflage, mimicry

Question 13

Batesian Mimicry

Answer 13

A species that a predator eats looks like a different dangerous species.

Question 14

Mullerian Mimicry

Answer 14

A mutual mimicry by 2 species, both harmful to the predator

Question 15

Why is it difficult to assess predation in natural communities?

Answer 15

Predators never drive species to extinction. With so many species, predators are prey too so their numbers are limited. Due to this, it is hard to assess when so many organisms are linked and continue to be linked.

Question 16

Keystone Predator

Answer 16

A predator species that reduces the density of the strongest competitors in a community therefore maintain diversity

Question 17

Symbiotic Relationship

3 types

Answer 17

An interaction between 2+ species in which one species lives in/on another

1) Parasitism 2) Commensalism 3) Mutualism

Question 18

Parasitism

Answer 18

A parasite (predator) lives in/on the surface of a host, from which it derives its food

Question 19

Commensalism

Answer 19

One partner benefits without significantly affecting the other

Question 20

Mutualism

Answer 20

Both partners benefit

Question 21

A force that changes a biological community and usually removes organisms from it
- small ones tend to have positive effect

Answer 21

Disturbance

Question 22

Process of biological community change resulting from disturbance

Answer 22

Ecological succession

Question 23

Primary succession

Answer 23

Biological community arises in an area without soil

Question 24

Secondary Succession

Answer 24

Occurs where a disturbance has destroyed an existing biological community but left the soil intact

Question 25

How are disturbances a characteristic of many communities?

Answer 25

Fires (major one) and floods are examples.

In deciduous forest, decomposition occurs fast so no fire fuel. Grassland prairies depend on fire to avoid tree growth.

Question 26

All the organisms in a given area along with the ABIOTIC factors with which they interact

Answer 26

Ecosystem

Question 27

Passage of energy through components

- continuous new energy from sun

Answer 27

Energy Flow

Light -> Chemical -> Heat -> Chemical Cycling

Question 28

Circular moment of materials within the ecosystem. Involved abiotic and biotic.

Answer 28

Chemical cycling

Question 29

Food Chain

Answer 29

sequence of food transfer between trophic levels

Question 30

Quaternary Consumers

Answer 30

An organism that eats tertiary consumers

Question 31

Tertiary consumers

Answer 31

An organism that eats secondary consumers

Question 32

Secondary Consumer

Answer 32

An organism that eats primary consumers

Question 33

Primary Consumer

Answer 33

An organism that only eats autotrophs

Question 34

Producers

Answer 34

An organism that makes organic food molecules from inorganic raw material

Question 35

Detritivores

Answer 35

An organism that derives its energy from organic waste

Question 36

Detritus

Answer 36

Nonliving matter

Question 37

Decomposition

Answer 37

Breakdown of organic material to inorganic

Question 38

Food Web

Answer 38

A network of interconnecting food chains

- animals can be multiple consumers

Question 39

Biomass

Answer 39

Amount (mass) of organic material in an ecosystem

Question 40

Primary Productivity

Answer 40

Rate at which an ecosystem’s producers convert solar energy to chemical energy

Question 41

Part of an ecosystem where a chemical, such as carbon or nitrogen, accumulates or is stockpiled outside of living organisms

Answer 41

Abiotic Reservoir

Question 42

An increase in productivity of an aquatic ecosystem

• balance of freshwater is easily upset by this increased
• reduces species diversity if accelerated

Answer 42

Eutrophication

Question 43

An extensive region of land that includes one or more areas that are undisturbed by humans; surrounded by altered lands

Answer 43

Zoned Reserves

Question 44

What are the dominant pathways of water, carbon, nitrogen, and phosphorous cyclic movements?

Answer 44

Water is driven by solar heat and the ocean.
Carbon is ran by plants but increased excessively by fossil fuel burning.
Nitrogen is from the atmosphere as main reservoir and driven by plants/soil bacteria though there can be excess by humans.
Phosphorous has a reservoir of rock in which it relies on weathering.