JMU - Bio 250 Test 3

Succession

Change in community structure over time typically following a disturbance event

Disturbance

An event that disrupts an ecosystem and kills a majority or all of the organisms within

Autogenic Succession

Changes in species composition are driven solely by internal dynamics

Primary Succession

An ecological succession that begins in an area where no biotic community previously existed

Secondary Succession

Succession following a disturbance that destroys a community only partially, leaving few organisms alive

Facilitation Model of Succession

Early species facilitate colonization by later, more competitive species ; models mostly primary or severe secondary succession

Inhibition Model of Succession

Assumes all species can inhabit a habitat from start of colonization and once an organism is living in an area it inhibits the growth of all other individuals in that area until death ; only models secondary succession

Tolerance Model of Succession

Assumes all species can initially colonize the habitat and specie do not inhibit but simply tolerate each other and share space ; the best competitors for resources win in this model ; only models secondary succession

Allogenic Processes

Outside influences that ensure communities are almost never in equilibrium

Autogenic Processes

Changes in a community as a result of the community itself (internal)

Disturbance Regimes

The general pattern or occurrence of a disturbance in a given ecosystem

The Intermediate Disturbance Hypothesis

Predicts that moderate scales of disturbance, frequency, and magnitude lead to greatest community diversity

Trophic level

Each step in a food chain or food web

Primary Producers

First trophic level, bottom of the food chain, provide energy for the rest of the chain usually through photosynthesis,

Herbivors

Second trophic level, animals that eat plants/primary producers

Predators

Third trophic level, animals that feed on herbivors

Tertiary Predators

Fourth trophic level, predators that only feed on predators

Top Predator

Animal at the top of the food chain

Ecosystem engineers

organisms that cause changes in the physical environment sufficient to influence the structure of landscapes, ecosystems, or communities

Extirpated

Locally extinct

Trophic Cascade

When adding or removing higher trophic levels in a community drastically alters other trophic level abundance, known as top-down control

Behavioral Cascade

When adding or removing top predators effects herbivore behavior patters affecting the abundance of primary producers.

Autogenic Engineers

Alter environment by simply existing, i.e trees

Allogenic Engineers

Alter environment by moving and building shit, i.e humans and beavers

Climax Communities

Late stage succession communities that are fully autogenic until disturbance

If top-down interactions determine the structure of communities...

Primary producers in food chains with an odd number of trophic levels will be limited by resource competition

Primary producers in food chains with an even number of trophic levels will be limited by consumers

Productivity Hypothesis of Food Chain Length

Argues more productive ecosystems will have longer food chains

Ecosystem Size Hypothesis of Food Chain Length

Argues that food chain length should increase with ecosystem size

Productive Space Hypothesis of Food Chain Length

Argues both productivity and ecosystem size are important in the possible length of food chains

Succession goes from...

Bottom-up to top-down control over time

Resistance

Describes how much a community changes due to a particular disturbance, if the individuals do not die then community resistance is high

Return Time

The amount of time it takes for a community to reach equilibrium again after a disturbance event

Resilience

Measure of how similar a post-disturbance community is to pre-disturbance

Persistance

The overall degree to which a community stays the same over time ; long term resilience

Constancy

How much a given ecosystem changes in the absence of a disturbance event, how variable population sizes are

Connectance

How connected all species are in a community

C = (# of actual links) / (# of species)^2

Keystone Species

Have great effects on community dynamics given small proportion of overall biomass, i.e foxes

Dominant Species

Have great effects on community dynamics but that effect is proportional to overall biomass

Community Importance

The change in a quantitative community or ecosystem trait that results from a change in that species' abundance

Total Impact

The magnitude of change that results when a species has been removed, regardless of the direction of the change

Exotics

Species that are new to a community

Invasive Species

Exotic species that pose a risk to environmental health as a product of their interactions

Balls

testicles

Autotroph

An organism that makes its own energy, usually from photosynthesis

Chemoautotroph

Organism makes own energy using chemicals from environment

Gross Primary Production (GPP)

All of the solar energy captured by a plant during photosynthesis

Net Primary Production (NPP)

The difference between Photosynthesis and respiration

Respiration (Ra)

The breaking down of sugar by organisms to conduct work

Memorize

GPP = NPP + Ra

Sustainable

Describes processes that can be continued indefinitely

Ecological Footprint

The equivalent productive surface area needed to supply someone's needs

1st law of thermodynamics

Energy cannot be created or destroyed

2nd law of thermodynamics

Energy cannot be changed from one form to another without a loss of usable energy

Photosynthesis Equation

6CO2 + 6H2O + Light Energy ------> C6H12O6 + 6O2

Respiration Equation

C6H12O6 + 6O2 ------> 6CO2 + 6H20 + Energy

Photoinhibition

When light is so intense that it interrupts photosynthesis

Phytoplankton

Microscopic, free-floating, autotrophic organisms that function as producers in aquatic ecosystems and contribute the most to NPP in ocean ecosystems

Consumption Efficiency (CE)

How efficiently an organism feeds (Ingestion / Plant Production)

Assimilation Efficiency (AE)

Efficiency of the consumer to extract energy from the food it consumes (Assimilation/Ingestion)

Production Efficiency (PE)

efficiency of the consumer to incorporate assimilated energy into growth and reproduction (Sheep production/Assimilation)

Trophic Efficiency (TE)

Percentage of production transferred from one trophic level to the next (Sheep production/Plant production)

Endotherm

An organism that is internally warmed by a heat-generating metabolic process

Ectotherm

An organism that relies on environmental heat sources to stabilize body temperature

Grazer Food Chain

A food chain that starts with a primary producer

Detrital Food Chain

A food chain that starts with decomposers

Ecosystem Services

Supporting, provisioning, regulating, cultural

Heterotrophic Ecosystems

Ecosystems which rely on outside sources to sustain resource use

Tragedy of the Commons

situation in which people acting individually and in their own interest use up commonly available but limited resources, creating disaster for the entire community

Alpha Diversity

Species diversity at the local or community scale

Gamma Diversity

Species diversity at the regional scale

Beta Diversity

The number of species that differ in occurrence between two communities

Equilibrium Theory of Biogeography

States that the number of species on an island depends on a balance between immigration or dispersal rates and extinction rates

Dispersal

The movement of organisms between patches of inhabitable area

Corridors

Natural Routes between habitable areas that almost all individuals can cross

Filters

Routes that selectively prevent some species from crossing while allowing other species through

Sweepstakes Route

Routes that are nearly impossible for most species to cross

Diffusion

When a species expands into unoccupied habitats nearby

Jump Dispersal

When many individuals of a species jump the same filter to a new environment all at once, i.e humans crossing the Atlantic

Secular Migration

Occurs when populations move so slowly from one area to another that they evolve en route

Carbon Footprint

The area of land required to assimilate the added CO2 to the atmosphere

Endemic Species

Species that live in only one area

Vicariance

The splitting of one population into two separate ones by physical means, i.e tectonic plates separating

Sympatric Speciation

When a population speciates without a physical barrier splitting individuals into different habitats

Allopatric Speciation

When speciation occurs because a population is separated by a physical barrier

Weather

Short term state of the atmosphere

Climate

Long term state of the atmosphere

Anomalie

Differences between observed values and long-term means

Hydrosphere

All the liquid water on earth

Biosphere

All life on earth

Cryosphere

All frozen water on earth

Lithosphere

All rocks and minerals and ground like shit on earth

Albedo

A description of a surface's reflective properties, the higher the albedo the more reflective a surface is

Greenhouse Gasses

Gasses that generate a greenhouse effect by being transparent to incoming short-wave solar radiation and absorbing outgoing long-wave radiation and reradiate it as thermal energy

4 main components to an accurate climate model

Distance from Sun

Albedo

Solar Output

Greenhouse Gasses

Forcings

Major Factors that affect earth's climate

Phenology

Seasonal timing of biological events

Multitrophic Species Pair

The success of one or both populations depends on the synchronization of phylogenic processes

Acclimation

An organisms response to changing environmental conditions

Climate Velocity

The speed at which a species must move across the landscape in order to maintain constant climatic conditions

4 Ways Species Respond to Climate Change

Go extinct (Species)

Acclimation (Individual)

Shift Range (Species)

Evolve/Adapt (Populations)