Community Ecology: Species Interactions, Biodiversity & Succession

What does the niche of a species encompass?

The physical habitat and ecological role of a species.

What are the four antagonistic interactions in ecology?

Competition, predation, parasitism, and herbivory.

What is the difference between a species' fundamental niche and realized niche?

The fundamental niche is how a species could live in any ecosystem, while the realized niche is how they do live in a specific ecosystem.

What are mutualisms in ecological interactions?

Interactions in which both species benefit.

What defines a community in ecology?

A set of populations of different species that live in the same area and can potentially interact.

What is interspecific competition?

Competition that occurs when different species use the same limiting resource.

What is intraspecific competition?

Competition that occurs when individuals of the same species use the same limiting resource.

What is competitive exclusion?

The principle that two species with similar niches will compete for limited resources, leading to one species being the winner and the other the loser.

What is resource partitioning?

The process where species whose niches overlap diverge and become different subspecies or species to reduce competition.

How do habitat refuges promote species coexistence?

They allow prey populations to persist, leading to cycles of increase and decline of both predators and prey.

What is the role of predators in ecological time?

Predators exert top-down control on prey populations and others.

What is parasitism?

A relationship where one species benefits at the expense of another, often species-specific.

How do prey species adapt to evade predation?

They evolve mechanical/physical defenses, use crypsis, aposematic coloration, or mimicry.

What is crypsis in prey species?

A form of camouflage that helps prey avoid detection by predators.

What is aposematic coloration?

Bright coloration in prey species that warns predators of toxicity or distastefulness.

What is mimicry in prey species? (Example?)

When prey appearance or behavior resembles something hazardous to deter predation. (Butterfly wings)

What are the characteristics of communities?

The species present, the abundance of each species, and how the species interact.

What are the effects of mutualisms on species?

They can be beneficial (+), harmful (-), or null (0).

What does obligate mean in mutualistic relationships?

It means that the relationship is absolutely required for survival.

What is a key example of mutualism involving aphids?

Aphids gain essential amino acids from bacteria, while bacteria receive a stable environment.

What is the significance of digestive symbioses for humans?

They involve a population of cellulose-digesting microbes living in the gut of herbivores.

What are the three key ecologically important mutualisms for humans?

1. Algae provide nutrients for corals. 2. Bees cross-pollinate plants. 3. The seafood industry supports people

What role do zooxanthellae play in coral ecosystems?

They provide photosynthetically-produced nutrients, forming the basis of the ocean food web.

What is the estimated annual economic value of bees in pollination?

$265 billion globally.

What is commensalism?

An interaction where one species benefits and the other has zero impact.

What is facilitation in ecological interactions?

A type of indirect interaction where one species creates a suitable habitat for another.

What is the definition of a community in ecology?

A community is composed of local populations of multiple species that may interact with one another.

What does biodiversity encompass?

Diversity of genetic sequences, cell types, species, life histories, phylogenetic groups, communities, and ecosystems.

Why is species diversity important in community structure?

It affects ecological functions and dynamics, and diverse communities capture more resources and produce more biomass.

What is a trophic structure?

It describes feeding relationships within a community.

What distinguishes a keystone species?

The integrity of the community depends on the stable population of that single species.

What are ecosystem engineers?

A type of keystone species that actively shapes the physical environment, creating habitats for others.

What is succession in ecological terms?

A process of recovery from disturbance in a community.

What are some examples of disturbances in ecosystems?

Fire, storms, and tree falls that create light gaps in forests.

What factors influence the number of species on an island?

Island size and distance from the source of colonists.

What is the species-area relationship in island biogeography?

S = cAx, where S is the number of species, c is a constant, A is island area, and x relates island size to species numbers.

What is meant by ecological balance?

The concept of stability in species abundance and interactions within an ecosystem.

What is the impact of biodiversity loss on ecosystems?

Reduce the overall support for life and ecological functions.

What is do competition, predation, parasitism, and herbivory in ecosystems have in common?

Interactions in which at least one species is harmed.

What is mutualism?

An interaction in which both species benefit.

How do diverse communities affect resource capture?

They are more efficient in capturing resources and producing biomass.

What is the relationship between biodiversity and ecological functions?

Higher biodiversity generally leads to improved ecological functions and resilience.

What is “Top-Down” Control in the context of predators?

Regulating abundance/behavior of lower trophic levels like herbivores