Community Ecology

Question 1

What is a biological community?

Answer 1

A group of populations of different species living and interacting within a defined area.

Question 2

Species richness refers to:
a) The total number of individuals in a community
b) The relative abundance of different species
c) The dominant species in a community
d) The trophic levels within a community

Answer 2

a) The total number of individuals in a community

Question 3

Species diversity encompasses both species _____ (number of species) and species _____ (the relative abundance of those species) within a community.

Answer 3

richness, evenness

Question 4

TF: Community structure is influenced by both biotic factors (interactions among living organisms) and abiotic factors (nonliving physical and chemical factors).

Answer 4

True

Question 5

How can factors like competition, predation, and herbivory influence species diversity and community structure?

Answer 5

Competition can limit the number of similar species that can coexist. Predation and herbivory can affect prey populations and indirectly influence other species in the community. These interactions can contribute to the overall diversity and stability of the community.

Question 6

What is a niche?

Answer 6

The ecological role and position of a species within its community, including how it acquires resources and interacts with other species.

Question 7

Niche differentiation refers to:
a) Specialization of a species’ niche to reduce competition with other species
b) Overlap in the niches of different species
c) The dominant species occupying the largest niche
d) All species having identical niches

Answer 7

a) Specialization of a species’ niche to reduce competition with other species

Question 8

__________ play a crucial role in maintaining community structure and function even though they may not be the most abundant species. (e.g., sea star predators in kelp forests)

Answer 8

Keystone species

Question 9

What are the different types of interspecific interactions, and briefly describe each?

Answer 9

Competition: Species compete for resources (e.g., food, space)
Predation: One organism (predator) captures and feeds on another (prey)
Herbivory: An animal consumes plant material
Symbiosis: A close and long-term association between two different species

Question 10

Predation can be beneficial for the prey population in some cases. How might this be true?
a) Predators can help keep prey populations in check and prevent overgrazing
b) Predators have no impact on prey populations.
c) Predators always drive prey populations to extinction.
d) Predation benefits only the predator.

Answer 10

a) Predators can help keep prey populations in check and prevent overgrazing

Question 11

_____ is a symbiotic relationship where one species benefits while the other is neither harmed nor benefitted. (e.g., barnacles attached to whales)

Answer 11

Commensalism

Question 12

TF: Mutualism is a symbiotic relationship where both species benefit from the long-term association. Examples include some plant-pollinator interactions and nitrogen-fixing bacteria in legume root nodules.

Answer 12

True

Question 13

How can coevolution, where two or more species reciprocally influence each other’s evolution, be observed in predator-prey interactions and plant-pollinator relationships?

Answer 13

Predators and prey can evolve adaptations to improve their success in the interaction (e.g., prey developing camouflage, predators evolving better eyesight). Plants and pollinators can coevolve traits that benefit both, such as flowers developing colors and scents attractive to specific pollinators.

Question 14

What is parasitism, and how does it differ from predation?

Answer 14

Parasitism is a symbiotic relationship where one organism (parasite) benefits by living on or in another organism (host), often harming the host in the process. Parasites typically have a longer lifespan than their hosts and may not necessarily kill them. Predation usually involves the predator killing and consuming the prey

Question 15

Interspecific competition can lead to:
a) Resource partitioning, where species evolve to use resources differently
b) Increased species diversity within a community
c) Always the extinction of one of the competing species
d) None of the above

Answer 15

a) Resource partitioning, where species evolve to use resources differently

Question 16

_____ _____ _____ states that two species cannot coexist indefinitely in a stable environment if they compete for the same limiting resource.

Answer 16

Competitive exclusion principle

Question 17

Primary succession refers to ecological succession that occurs on:
a) Previously existing communities
b) Stable and mature ecosystems
c) Areas with rich soil and abundant resources
d) Land that has never been colonized by living organisms

Answer 17

a) Previously existing communities. Secondary succession occurs on disturbed areas that previously had a community.

Question 18

_____ succession is a type of ecological succession that establishes a new community on a disturbed area that was once occupied by a different community.

Answer 18

Secondary

Question 19

TF: Climax communities are relatively stable, mature ecosystems with a high degree of species diversity and complex trophic interactions. However, they are not immune to disturbances and can undergo further successional changes.

Answer 19

True

Question 20

What is meant by community stability and resilience?

Answer 20

Community stability refers to a community’s ability to resist disturbances and maintain its structure and function. Resilience is the ability of a community to recover from a disturbance and return to a stable state.

Question 21

Factors that can disrupt community stability and resilience include:
a) Invasive species introductions
b) Natural processes like predation and competition
c) None of the above
d) Both a and b

Answer 21

a) Invasive species introductions

Question 22

Biodiversity plays a crucial role in community stability and resilience. A diverse community has more functional _____, meaning that if one species is lost, other species can take over its role and maintain ecosystem processes.

Answer 22

redundancy

Question 23

TF: Disturbances are natural events that can alter a community’s structure and function. Examples include fires, floods, and storms. While they can disrupt stability, disturbances can also create opportunities for new species to establish themselves and contribute to long-term community diversity.

Answer 23

True

Question 24

How can human activities, such as habitat destruction, pollution, and overexploitation of resources, negatively impact community stability and resilience?

Answer 24

These activities can reduce biodiversity, disrupt ecological interactions, and make communities more susceptible to disturbances and less able to recover.

Question 25

What is the concept of island biogeography, and how does it relate to species richness and extinction rates?

Answer 25

Island biogeography examines how factors like island size and distance from the mainland influence species richness and extinction rates on islands. Smaller, more isolated islands tend to have lower species richness and higher extinction rates compared to larger, closer islands.

Question 26

Species richness is typically higher in:
a) Large and connected habitats
b) Small and isolated habitats
c) There is no relationship between habitat size and species richness
d) All habitats have similar species richness

Answer 26

a) Large and connected habitats

Question 27

Conservation efforts aimed at protecting biodiversity often focus on establishing protected areas and corridors to connect fragmented habitats. This can help maintain viable populations and promote species _____.

Answer 27

dispersal

Question 28

Community ecology helps us understand:
a) How populations of organisms change over time and space
b) The energetic relationships within ecosystems
c) The classification and diversity of living organisms
d) The biochemical processes within cells

Answer 28

a) How populations of organisms change over time and space

Question 29

TF: Biodiversity loss can have negative consequences for ecosystem services, such as water purification, pollination, and flood control.

Answer 29

True

Question 30

How can an understanding of community ecology principles be applied to conservation efforts?

Answer 30

Understanding factors influencing community structure, stability, and threats like invasive species can help us develop strategies to protect biodiversity and maintain healthy ecosystems.

Question 31

Briefly explain the concept of ecosystem services and their importance to human well-being.

Answer 31

Ecosystem services are the benefits people obtain from ecosystems. These include provisioning services (food, water), regulating services (climate regulation, flood control), cultural services (recreation, spiritual), and supporting services (nutrient cycling, soil formation).

Question 32

Sustainable practices that promote community stability and resilience can contribute to:
a) Maintaining ecosystem services essential for human well-being
b) Uncontrolled economic development
c) Increased pollution and resource depletion
d) All of the above

Answer 32

a) Maintaining ecosystem services essential for human well-being