Biology Chapter 54 Flashcards

Questions and Answers

What is a biological community?

An assemblage of various species living close together (correct)

A group of the same species

A collection of abiotic factors

None of the above

What are inter-specific interactions?

Relationships between species in a community

What type of interaction does competition represent?

a -/- interaction

What does competitive exclusion lead to?

Local elimination of an inferior competing species Signup and view all the answers

What is an ecological niche?

The total of a species' use of biotic and abiotic resources Signup and view all the answers

What is resource partitioning?

Ecologically similar species can coexist with niche differences Signup and view all the answers

A species' is the niche potentially occupied by that species and a species' is the niche actually occupied by that species.

fundamental niche, realized niche Signup and view all the answers

What does spatial niche partitioning involve?

The presence of one barnacle species limits the realized niche of another Signup and view all the answers

What is temporal niche partitioning?

Species utilizing the same habitat at different times Signup and view all the answers

What does predation describe?

a +/- interaction where one species kills and eats another Signup and view all the answers

What is herbivory?

a +/- interaction in which an herbivore eats parts of a plant or alga Signup and view all the answers

Define symbiosis.

A relationship where two or more species live in direct and intimate contact Signup and view all the answers

List the three types of symbiosis.

Parasitism, mutualism, commensalism Signup and view all the answers

What distinguishes parasitism from other interactions?

One organism derives nourishment while harming another Signup and view all the answers

What is mutualism?

a +/+ interaction that benefits both species Signup and view all the answers

What does commensalism involve?

(+/0 interaction) where one species benefits and the other is unbothered Signup and view all the answers

Define facilitation in ecological terms.

(+/+ or 0/+) where one species has positive effects on another without direct contact Signup and view all the answers

What is species diversity?

The variety of organisms that make up a community Signup and view all the answers

Species richness is the total number of different species in the community and relative abundance is the proportion each species represents of the total individuals in the community.

species richness, relative abundance Signup and view all the answers

What are the benefits of higher species diversity in communities?

More productive, more stable, better at withstanding stresses, more resistant to invasives Signup and view all the answers

What does trophic structure refer to?

The feeding relationships between organisms in a community Signup and view all the answers

What is the energetic hypothesis in ecology?

The length of the food chain is limited by inefficient energy transfer Signup and view all the answers

Define dominant species.

Most abundant or have the highest biomass Signup and view all the answers

What are keystone species?

Species that exert strong control on a community by their ecological roles Signup and view all the answers

What are ecosystem engineers?

Organisms that cause physical changes in the environment affecting community structure Signup and view all the answers

What is ecological succession?

The sequence of community and ecosystem changes after a disturbance Signup and view all the answers

What occurs during primary succession?

Successions beginning where no soil exists Signup and view all the answers

What defines secondary succession?

Begins in areas where soil remains after a disturbance Signup and view all the answers

Species richness is especially _ in the tropics and generally _ along an equatorial-polar gradient.

great, declines Signup and view all the answers

Two main climatic factors correlated with biodiversity are _ and _.

solar energy, water availability Signup and view all the answers

Define evapotranspiration.

Evaporation of water from soil plus transpiration of water from plants Signup and view all the answers

Study Notes

Biological Communities

Comprised of populations from different species that interact within a specific area.
Example: Carrier crab uses a sea urchin for protection against predators.

Inter-specific Interactions

Relationships between different species in a community categorized as:
- Competition
- Predation
- Herbivory
- Symbiosis (parasitism, mutualism, commensalism)
- Facilitation
Can have positive, negative, or neutral effects.

Competition

Characterized by a -/- interaction where species vie for limited resources.

Competitive Exclusion

Inferior species can be locally eliminated due to competition.
Competitive exclusion principle states that two species targeting the same limited resource cannot coexist in the same area.

Ecological Niche

Refers to the totality of a species' use of both biotic (living) and abiotic (non-living) resources.
Represents an organism's ecological role in its environment.

Resource Partitioning

Similar species can coexist in a community if their niches differ significantly.

Niche Definitions

Fundamental niche: potential niche a species can occupy.
Realized niche: actual niche occupied, often influenced by competition.
Species can partition niches spatially and temporally.

Spatial Niche Partitioning

Example: One barnacle species limits the realized niche of another, illustrating spatial competitive dynamics.

Temporal Niche Partitioning

Example: The golden spiny mouse adapts from nocturnal to diurnal activity to coexist with the common spiny mouse.

Predation

Defined as a +/- interaction where a predator kills and consumes prey.

Herbivory

Characterized by a +/- interaction where herbivores consume parts of plants or algae.

Symbiosis

Involves direct, intimate relationships between two or more species.

Types of Symbiosis

Parasitism: One organism benefits at the expense of another (e.g., endoparasites vs. ectoparasites).
Mutualism: Both species benefit (e.g., termites and microorganisms).
Commensalism: One species benefits while the other is unaffected.

Facilitation

Interaction where one species positively impacts another without direct contact (e.g., black rush improving soil for other plants).

Species Diversity

Refers to the assortment of organisms within a community.
Components include:
- Species richness: total diversity of species in the area.
- Relative abundance: proportion of each species relative to the total population.

Community Productivity and Stability

Communities with higher species diversity are:
- More productive and stable.
- Better at withstanding environmental stress.
- More resistant to invasive species.

Trophic Structure

Describes the feeding relationships among organisms within a community.

Energetic Hypothesis

Suggests food chain length is limited by energy transfer efficiency (e.g., only a fraction of plant biomass supports herbivores).

Dominant Species

Most numerous or biomass-dominant species in a community, potentially competitive for resources or adept at evading predators.

Keystone Species

Certain species exert strong control over the community structure due to their ecological roles, regardless of their abundance.

Ecosystem Engineers

Organisms that modify their environments, such as beavers creating dams impacting local ecosystems.

Ecological Succession

Refers to the sequence of changes in communities following a disturbance.

Primary Succession

Initiates in areas devoid of soil, such as volcanic islands or glacial retreats, progressing from simple to complex organisms.

Secondary Succession

Occurs in areas where soil remains post-disturbance, typical after events like forest fires.

Biodiversity Gradient

Species richness is most abundant in tropical regions and decreases along an equatorial-to-polar gradient.

Correlated Climatic Factors

Key factors influencing biodiversity include solar energy and water availability.

Evapotranspiration

Represents the combined processes of water evaporation from the soil and plant transpiration.
High in warm, wet regions, low in cooler or drier areas, and correlated with species richness.

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Test your knowledge with these flashcards covering key concepts from Biology Chapter 54. This set focuses on biological communities and inter-specific interactions, highlighting essential relationships and examples in ecological contexts. Perfect for review or study sessions!