Exam #2

Regional Pool of Species

A set of species in a given region that can potentially colonize local communities

Intraspecific Competition

Competition between members of the same species

Interspecific Competition

Competition between members of different species

Competition Coefficients

Convert’s individuals of one species into the equivalent number of individuals of the other species in terms of their impact on the shared resource

Competitive Exclusion Principle

Two species competing for the same limited resource cannot coexist. The better predator will drive the other species to extinction

Interference

Direct physical interference for limited resources

Exploitative

Indirect competition reducing the resource pool

Apparent

Negative indirect interactions between species that arise because they share a natural predator

Niche Theory

An ecological community is made up of a limited number of niches and each niche is occupied by a single species

Niche Partitioning

A process in which ecologically similar species coexist by using different resources or specializing in different factors of the environment

Niche Shift

An adaptive change in a species in one or more of its niche dimensions

Neutral Theory

Assumes all species are ecologically identical and competitively equal. Species abundance and diversity is purely random, therefore niche differences are not needed to explain biodiversity patterns

Top-Down Control

Predators regulate the abundance and behavior of prey

Bottom-Up Control

The productivity and abundance of populations are controlled by the productivity and abundance of the populations in the trophic level below them

Temporal Avoidance

Shift in plant phenology to avoid enemies

Masting

Producing as many seeds as possible to reduce the proportion of seeds destroyed by predators

Mimicry

Evolutionary adaptation of plants and prey species to mimic toxic or dangerous species

Endosymbionts

Symbiotic relationship between plant and fungal species which give plants defensive chemicals

Alkaloids

Interferes with neurotransmitters to create a bitter taste

Cyanogenic Glucosides

Creates toxic compounds produced by two separate compounds within the plant

Non-Protein Amino Acids

Creates fake amino acids that make proteins unviable to stop herbivore feeding

Tannins and Phenolics

Bind to proteins to reduce digestibility stopping protein access and creating an astringent taste

Terpenoids

Deter or attract insects using volatiles

Constitutive Defenses

Amounts and kinds of defenses used by undamaged plants

Induced Defenses

Increases in plant defenses in response to damage by herbivores

Trophic Cascades

Powerful indirect interactions that can control population dynamics, community structure, and ecosystem processes, triggered when predators limit the density and/or behavior of their prey, indirectly benefiting lower trophic levels

Green World Hypothesis

Argues that predators keep herbivore populations in check preventing herbivores from overgrazing plants, this top-down control allows plant communities to thrive, resulting in a “green world”

The Ecology of Fear

Behavioral, psychological, and neurobiological costs of avoiding predation may reduce prey fecundity and survival

The Landscape of Fear

Relative levels of predation risk as peaks and valleys that reflect the level of fear of predation a prey experiences in different parts of its areas of use

Indirect Interactions

the effect of one species on another is mediated by a third species

Facilitation

An interaction in which the presence of one species alters the environment in a way that enhances growth, survival, or reproduction of a second neighboring species

Pollinator Syndromes

flower traits or characteristics that may appeal to a particular type of pollinator such characteristics can be used to predict the type of pollinator that will aid the flower in successful reproduction

Seed Dispersal Syndromes

Fruits and frugivores co-evolved, each exerting sufficient selective pressure resulting in suites of fruit traits that match frugivore behavior, morphology, and sensory capabilities

Biodiversity

The number of entities (how many genotypes, species, traits, or ecosystems)

Taxonomic/Species Diversity

The number and relative abundance of taxa (Ex. species, genera, families, and onward) defined by a hierarchical, evolutionary classification)

Phylogenetic Diversity

Relationships among taxa based on elapsed time since divergence (Ex. sum of the branch lengths linking species)

Functional Diversity

Variation in the degree of expression of multiple functional traits

Species Richness

Variation in species (# of species)

Species Abundance

Total number of individuals in a community

Relative Abundance

Abundance of a species relative to the total abundance

α

Number of species in a local community

γ

Number of species in all local communities

B

Number of species that are not shared among communities

Complementarity

Communities with greater biodiversity have greater niche partitioning and overall greater resource utilization therefore generating greater primary productivity han communities with lower biodiversity

Redundancy

The idea that certain species may perform overlapping functions in an ecosystem, so the loss of one species can be compensated for by others, leading to a saturation point where additional diversity does not necessarily enhance ecosystem function

Genetic Diversity

High levels of genetic variation within a species provide the raw material for natural selection to act upon, enabling adaptation to changing environments and ultimately leading to the evolution of new species