Ecology Test 2: Chapters 17 & 18

Front 1

What term defines a group of different species that occupy a given area, interacting either directly or indirectly?

Back 1

community

Front 2

What term describes the count of the number of species occurring within a community, represented by the symbol (S)?

Back 2

species richness

Front 3

What represents the percentage each species contributes to the total number of individuals of all species?

Back 3

relative abundance

Front 4

What depends on the number of species as well as relative abundance?

Back 4

species diversity

Front 5

What is species richness?

Back 5

number of species in a community

Front 6

What term describes how close in numbers the different species in an environment are (relative abundance)?

Back 6

species evenness

Front 7

What provide a way to quantify the relationship between species number and relative abundance?

Back 7

diversity indexes

Front 8

In reference to the Shannon-Weiner Index, when there is an absence of diversity and only one species is present, what does H equal?

Back 8

0

Front 9

When a single or few species predominate within a community, these species are referred to as __________.

Back 9

dominants

Front 10

What is the converse of diversity?

Back 10

dominance

Front 11

Which species has a disproportionate impact on the community relative to its abundance?

Back 11

keystone species

Front 12

What would occur if a keystone species was removed from a community?

Back 12

changes in community structure
significant loss of diversity

Front 13

How are the form and structure of terrestrial ecosystems primarily defined?

Back 13

by their vegetation

Front 14

How are the physical structures of aquatic communities primarily defined?

Back 14

features of the abiotic environment (e.g. salinity, water depth)

Front 15

What is the upper layer of the forest, which is primary site of energy fixation through photosynthesis?

Back 15

canopy

Front 16

Which layer of the forest is situated underneath the canopy and will only form if enough sunlight reaches the lower layers?

Back 16

understory

Front 17

Which layer of the forest depends on various abiotic conditions (e.g. soil, moisture) and density of the canopy and understory?

Back 17

herb layer

Front 18

Which layer of the forest is where decomposition takes place and nutrients and minerals are recycled?

Back 18

forest floor

Front 19

How is the vertical structure of terrestrial environments determined?

Back 19

by the growth form of plants

Front 20

How is the vertical structure of aquatic environments determined?

Back 20

by light penetration through the water column

Front 21

Which zone of water is where the availability of light supports photosynthesis?

Back 21

photic zone

Front 22

Which zone of water is an area without light?

Back 22

aphotic zone

Front 23

Which zone of water is where decomposition is most active?

Back 23

benthic zone

Front 24

What term describes the changes in the physical and biological structures of communities as one moves across the landscape?

Back 24

zonation

Front 25

__________ is spatial change in community structure.

Back 25

Zonation

Front 26

What term describes the differences in environmental conditions from one area to the next?

Back 26

environmental heterogeneity

Front 27

Environmental heterogeneity influences ________ _________.

Back 27

community diversity

Front 28

Who was the first to quantify the relationship between structural heterogeneity of vegetation and diversity of animals?

Back 28

Robert MacArthur

Front 29

What term encompasses the idea that the niche is the role a species plays in a community?

Back 29

Eltonian niche

Front 30

What is the term that describes a group of organisms (usually animals) that all "make their living" in the same way or exploit a common resource in a similar fashion?

Back 30

guild

Front 31

What are some examples of a guild?

Back 31

seed-eating organisms in a desert

fruit-eating birds in a tropical rainforest

Front 32

What is the term used for plants, which is a combination of structure and growth dynamics?

Back 32

life-form

Front 33

What is a descriptive diagram that represents the flow of energy from prey (the consumed) to predator (the consumer)?

Back 33

food chain

Front 34

What are highly interwoven diagrams with linkages representing a wide variety of species interactions?

Back 34

food webs

Front 35

In a food chain, how do arrows flow?

Back 35

Arrows flow from prey (consumed) to predator (consumer).

Front 36

What is the term that describes the arrows from one species to another that indicate the consumed and the consumer?

Back 36

links

Front 37

Which species feed on no other species but are fed upon by others?

Back 37

basal species

Front 38

Which species feed on other species, and they themselves are prey of other species?

Back 38

intermediate species

Front 39

Which species prey on intermediate and basal species?

Back 39

top predators

Front 40

What is a trophic level?

Back 40

position in a food web

Front 41

How do ecologists often simplify species into broader categories that represent general feeding groups based on the source of which they derive energy?

Back 41

trophic levels

Front 42

What is the trophic level of primary producers?

Back 42

autotrophs

Front 43

What is the trophic level of herbivores, carnivores, and omnivores?

Back 43

heterotrophs

Front 44

What is the first trophic level?

Back 44

primary producers (autotrophs)

Front 45

What is the second trophic level?

Back 45

primary consumers

Front 46

What is the third trophic level?

Back 46

secondary consumers

Front 47

What is the fourth trophic level?

Back 47

tertiary consumers

Front 48

What occur when one species does not interact with a second species directly, but instead influences a third species that does directly interact with the second?

Back 48

indirect interactions

Front 49

What is the indirect interaction where the predator enhances one or more inferior competitors by reducing the abundance of the superior competitors?

Back 49

keystone predation

Front 50

Name the term.

influence of chemical and physical factors on ecosystems

the structure of food chains and food webs is controlled (limited) by the productivity and abundance of populations in the trophic level below

Back 50

bottom-up control

Front 51

Name the term.

influence on consumers on ecosystems

the predator populations control the abundance of prey species, and the prey of the prey, and so on

Back 51

top-down control

Front 52

Name the term.

may involve indirect interactions linked through intermediary species

effects of predators on prey--alterations in abundance, biomass, or productivity

can be top-down or bottom-up

Back 52

trophic cascade

Front 53

What describes the scenario in which the food chain/food web is disrupted by the removal of a top predator, or a third or fourth level consumer?

Back 53

top-down cascade

Front 54

What describes the scenario in which a primary producer, or primary consumer is removed, and there is a diminishment of population size throughout the community?

Back 54

bottom-up cascade