Chapter 54 Community Ecology

Question 1

What is a community?

Answer 1

An assemble of populations of various species living close enough for potential interaction

Question 2

What are interspecific interactions?

Answer 2

Interactions in a community that either help, harm, or have no effect on the species involved

Question 3

What are some examples of interspecific interactions? (5)

Answer 3

• competition
• predation
• herbivory
• symbiosis (parasitism, mutualism, and commensalism)
• facilitation

Question 4

What is interspecific competition?

Answer 4

Occurs when species compete for a resource in a short supply

Question 5

What is negative/negative interaction? Provide an example.

Answer 5

Interaction between species are harmful on each other

Example: Interspecific competition

Question 6

What is competitive exclusion?

Answer 6

Local elimination of a competing species

Question 7

What is the competitive exclusion principle?

Answer 7

States that 2 species competing for the same limiting resources cannot coexist in the same place.

Question 8

What is ecological niche?

Answer 8

The sum of a species’ use of biotic and abiotic resources

Question 9

What is resource partitioning?

Answer 9

Differentiation of ecological niches, enabling similar species to coexist in a community

Question 10

What is a species’ fundamental niche?

Answer 10

The niche potentially occupied by that species

Question 11

What is a species’ realized niche?

Answer 11

The niche that is actually occupied by that species

Question 12

What is character displacement?

Answer 12

Tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species

Question 13

What is predation?

Answer 13

An interaction in which one species, the predator, kills and eat the other, the prey

Question 14

What is positive/negative interaction? Provide 2 examples.

Answer 14

One species benefits from the interaction, the other species is harmed

Example: Predation and Herbivory

Question 15

What are some feeding adaptations of predators? (3)

Answer 15

• claws
• fangs
• poison

Question 16

What are the various types of defensive adaptations of prey? (5)

Answer 16

• Behavioral defenses
• Morphological defenses
• Physiological defenses
• Mechanical/chemical defenses

Question 17

What is aposematic coloration?

Answer 17

A bright warning coloration as an effective chemical defense of animals

Question 18

What is cryptic coloration?

Answer 18

Camouflage/ coloration that makes prey difficult to spot

Question 19

What is atesian mimicry?

Answer 19

Palatable or harmless species mimics an unpalatable or harmful model

Question 20

What is Mullerian mimicry?

Answer 20

Two or unpalatable species resemble each other

Question 21

Can mimicry also be used by predators?

Answer 21

Yes, predators can use mimicry to confuse/manipulate the prey

Question 22

What is herbivory?

Answer 22

Refers to an interaction in which an herbivore eats parts of a plant of algae

Question 23

What is symbiosis?

Answer 23

Relationship where two or more species live in direct and intimate contact with one another

Question 24

What happens in parasitism?

Answer 24

One organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process

Question 25

What are endoparasites?

Answer 25

Parasites that live within the body of their host

Question 26

What are ectoparasites?

Answer 26

Parasites that live on the external surface of a host

Question 27

What is positive/positive interaction? Provide an example.

Answer 27

Interspecific interaction that benefits both species. Example: Mutualism

Question 28

What are the two types of mutualism?

Answer 28

- Obligate - Facultative

Question 29

What is obligate mutualism?

Answer 29

One species cannot survive without the other

Question 30

What is facultative mutualism?

Answer 30

Both species can survive alone

Question 31

What is positive/zero interaction? Provide an example

Answer 31

Interspecific interaction where one species benefit but the other species is not harmed/helped Example: Commensalism

Question 32

What is faciliation?

Answer 32

Interaction in which one species has positive effects on another species without direct and intimate contact

Question 33

What are the two fundamental features of community structure?

Answer 33

- Species diversity - Feeding relationships

Question 34

What is species diversity?

Answer 34

The variety of organisms that make up the community

Question 35

What are the two components of species diversity?

Answer 35

- Species richness - Relative abundance

Question 36

What is species richness?

Answer 36

The number of different species in the community

Question 37

What is relative abundance?

Answer 37

Proportion of each species that represents of all individuals in the community

Question 38

What is the Shannon diversity index?

Answer 38

A diversity index that compares diversity of communities H = - (pA ln pA + pB ln pB + pC ln pC + …)

Question 39

What are the 4 characteristics of communities with higher diversity?

Answer 39

- More productive; they produce more biomass (the total mass of all organisms) - More stable in their productivity - Better able to withstand and recover from environmental stresses - More resistant to invasive species, organisms that become established outside their native range

Question 40

What is trophic structure?

Answer 40

The feeding relationships between organisms in a community

Question 41

What do food chains do?

Answer 41

Link trophic levels from producers to top carnivores

Question 42

What is a food web?

Answer 42

A branching food chain with complex trophic interactions

Question 43

What does the energetic hypothesis suggest?

Answer 43

Suggests that the length is limited by inefficient energy transfer

Question 44

What is important about the energy stored in the organic matter?

Answer 44

Only about 10% of the energy stored in organic matter at each trophic level is converted to organic matter at the next trophic level

Question 45

What are dominant species?

Answer 45

Species that are the most abundant or have the highest biomass

Question 46

What are invasive species?

Answer 46

Species that are typically introduced to a new environment by humans and become dominant due to a lack of predators or disease

Question 47

What are keystone species?

Answer 47

Species that exert strong control on a community by their ecological roles or niches

Question 48

What are ecosystem engineers?

Answer 48

Foundation species that cause physical changes in the environment that affect community structure

Question 49

What is the bottom-up model?

Answer 49

A model that proposes a unidirectional influence from lower to higher trophic levels N (nutrient) -> V (plants) -> H (herbivores) -> P(predators)

Question 50

What is top-down model?

Answer 50

The trophic cascade model that proposes that control comes from the trophic level above In this case, predators limit herbivores, herbivores limit plants, and plants limit nutrient levels N <- V <- H <- P

Question 51

What does biomanipulation help with?

Answer 51

Helps to restore polluted communities

Question 52

What is a disturbance?

Answer 52

An event that changes a community, removes organisms from it, and alters resource availability

Question 53

What is a nonequlilibrium model?

Answer 53

A model that describes communities as constantly changing after being buffeted by disturbances

Question 54

What are the most significant sources of disturbances in ecosystems? (2)

Answer 54

- storms - fires

Question 55

What is high level of disturbance a result of?

Answer 55

A high intensity and high frequency of disturbance

Question 56

What is low levels of disturbance a result of?

Answer 56

Low frequency or low intensity of disturbance

Question 57

What does the intermediate disturbance hypothesis state?

Answer 57

States that moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance

Question 58

What is ecological succesion?

Answer 58

The sequence of community changes after a disturbance

Question 59

What is primary succession?

Answer 59

Succession that occurs where no soil exists when succession begins *begins from nothing*

Question 60

What is secondary succession?

Answer 60

Succession that begins in an area where soil remains after a disturbance

Question 61

What does human disturbance due to a community's species diversity?

Answer 61

Reduces its species diversity

Question 62

What are the two key factors that affect a community's species diversity?

Answer 62

- Latitude - Area

Question 63

What are the two key factors in equatorial-polar gradients of species richness?

Answer 63

- Evolutionary history - Climate

Question 64

What are the 2 main climatic factors correlated with biodiversity?

Answer 64

- sunlight - precipitation

Question 65

What is evapotranspiration?

Answer 65

Evaporation of water from soil plus transpiration of water from plants

Question 66

What does the species-area curve quantify?

Answer 66

Quantifies the idea that, all other factors being equal, a larger geographic area has more species S = cA^z S is the number of species, c is a constant, A is the area, and z represents how many more species should be found as habitat area increases

Question 67

What are pathogens?

Answer 67

Disease-causing microorganisms, viruses, viroids, and prions

Question 68

What are zoonotic pathogens?

Answer 68

Pathogens that have been transferred from other animals to humans

Question 69

What is a vector?

Answer 69

Transfer of pathogens that are direct or through an intermediate species

Question 70

What is an example of a vector?

Answer 70

Malaria that goes to a human from a mosquito