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86 Cards in this Set

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Consists of all the organisms living in a community as well as the abiotic factors with which they interact

Two main processes in an ecosystem

1. Energy Flow: autotrophs convert in organic carbon into organic carbon that the heterotrophs can use.

2. Chemical Cycling: Includes nitrogen and phosphorus cycles

1st law of thermodynamics

energy is transferred not created nor destroyed

2nd law of thermodynamics

every exchange of energy increases the entropy of the universe

Conservation of Mass

matter cannot be created nor destroyed


(Decomposers) They derive energy from detritus, nonliving organic matter

Primary Production

The amount of energy created by the primary producers (autotrophs) This sets the energy "spending" limit for an ecosystem

Gross Primary Production (GPP)

Total energy produced by vegetation via photosynthesis (measured over a period of time)

Net Primary Production (NPP)

NPP= GPP - autrophic respiration

This calculates the amount of new biomass available to consumers

Net Ecosystem Production (NEP)

Measures the total biomass accumulation during a given period. This is computed by measuring the net flux between CO2 and O2

Factors that control primary production

Light and Nutrients

Limiting Nutrient

An element that must be present in order to achieve primary production. Aquatic ecosystems require nitrogen and phosphorus

Redfield Ratio

C: 106, N:16, P:1 (Optimal nutrients needed for algae growth)


loading of nutrients into a system that results in algae production

cultural eutrophication

eutrophication caused by humans

Limiting Element for cynobacteria blooms


Lake Atitlan

An oligotrophic lake that began experiencing harmful cynobacteria blooms due to hurricanes destroying water treatment plants, people pumping their waste into the water

What affects primary production in terrestrial ecosystems

higher temperature and higher moisture creates higher primary production


plant transpiration and evaporation from landscape. Is affected by precipitation, temperature and sunlight.

Nutrients that limit the soil

1. Young soil limited by nitrogen

2. Old soil limited by phosphorus

Plants get nutrients from...

nitrogen fixing bacteria, mycorrhizal fungi, root hairs on plant roots, and many plants release enzymes that increase the availability of limiting nutrients

Secondary Production

Amount of chemical energy in food converted to new biomass during a given period of time.

Production Efficiency

(Net secondary production)/(assimilation of primary production) times by 100. Shows how well certain species are at converting food into energy. Insects have higher production efficiency compared to birds and mammals.

Trophic Efficiency

The percentage of production transferred from one trophic level to the next. It's about 10%.

Turnover Time

(Standing Crop Density)/ (Production Density/day)

Decomposition Rates

1. Determined by temperature, moisture, and nutrient availability

2. Rapid Decomposition results in more productive ecosystems which caused there to be less nutrients in the soil.

Carbon Cycle

Phosynthesis fixes inorganic carbon into carbon, fossil fuels bring stored carbon into the environment

Nitrogen Cycle

Main reservoir is the atmosphere, some bacteria including cyanobacteria can fix nitrogen gas.

What happens to Nitrogen in anaerobic conditions

We get denitrofication. (NO3- becomes N2 gas)

Aquatic Environments (cyanobacteria) are most often limited by...

phosphorus (Although they are limited by nitrogen too)

Interspecific Interactions

Interactions between different species


(-,-) Occurs when two species compete for the same resource

Competitive Exclusion

Local elimination of a compering species (This occurs often)

Fundamental Niche

The niche that can potentially be occupied by a a certain species

Realized Niche

the niche actually occupied by a certain species

Leibig's Law of the Minimum

There are always limiting resources that prevents uncontrollable growth

Resource Partitioning

Species that occupy different niches exploit different resources

Character Displacement

When species with similar traits occupy the same region, their differences will be more pronounced than if they did not live in close proximity to each other.


(+,-) One organism kills the other for food

Prey Adaptations

1. Cryptic Coloration: Camouflage

2. Aposematic Coloration: Bright Colors convey that a prey is poisonous

3. Batesion Mimicry: A harmless species mimic a harmful species

4. Mullerian Mimicry: two unpalatable species mimic each other


(+,-) Refers to interactions in which herbivores eat parts of a plant or algae. Some plants have evolved ways to prevent this.


Situation where two or more species live in direct and intimate contact with one and other.


(+,-) Interaction where the parasite derives its nourishment from its host. More dense populations have higher parasitism burden.


Both species are positively affected. Example: Bull horn acacia trees and ants. The tree provides shelter and the ants protect the tree from other pest.


(+,o) One species benefits the other one isn't affected. Examples: Whales and Barnacles.


(+,+) or (o,+) Is an interaction in which one species has positive effects on another species without direct and intimate contact. Example: beaver's making a dam.

Species Diversity

Variety of organisms from different species that make up the community.

Species Richness

The number of different species in a community

Relative Abundance

How abundant a species is in an environment

Shannon Diversity Index (H)

Shows how diverse an area is. The highest amounts of diversity exists around a pH of 7. Communities with a higher biodiversity are more stable.

Trophic Structure

Feeding relationships between organisms in a community.

Food Chains

Link trophic levels from producers to top predators

Food Web

A branching food chain with complex trophic interactions

Dominate Species

Highly Abundant Species because they are most successful at getting resources and avoiding predation.

Keystone Species

Have a unique pivotal role in the community. (Doesn't have to be positive or abundant)

Example: Starfish in the tide poos in California

Ecosystem Engineers

Foundation Species that cause physical changes in the environment. Example: Beavers with their dams

Bottom-Up Model

Proposes a unidirectional influence from low to higher trophic levels

Top-Down Model

Trophic cascade model. Proposes that control comes from the top.


Deliberate altering of an ecosystem by adding or removing species. Used to improve water quality in polluted lakes


Any event that changes a community

Intermediate Disturbance Levels

A community that experiences some disturbances but not a crazy amount. Provides the highest amount of species richness.

ecological succession

the sequence of community and ecosystem changes after a disaster

Primary Succession

Occurs when vegetation or microorganism colonize a piece of land that hasn't had any life. Occurs after big disturbances like glacier receding.

Secondary Succession

When vegetation or microorganism colonize an area that has recently experienced a disturbance but had like there prior to the disturbance.

Species Area Curve

When all other factors are help constant, larger geographic areas have more species

Lake Tahoe clarity driven by...

small watershed to lake ratio


looks at the record of fresh water lakes by studying the bottom core of sediment at the bottom of the lake. (Tahoe has a lot of Iron in top layer)

Air Pollution's affect on Tahoe

Inversion in the atmosphere causes pollutants to settle in the lake

Reasons Water Quality is Declining

Historically: Lumber Removal

Intermediate Years: The lake recovered

Recent Years: Air Pollution, lake warming, and the loss of wetlands (tahoe keys), cultural eutrophication

Fate of endemic Species in Tahoe

72% of invertebrates in the benthic zone have disappeared, tahoe has 10 endemic species that are at risk because of invasive species

Legal Introduction of Invasive Species (In Tahoe)

Lake Trout was introduced so people could get larger fish, mysid shrimp were also introduced and ate all the filtering zooplankton

Illegal Introduction of Invasive Species (In Tahoe)

Asian Clams (excrete feces that make good conditions for algae growth), Invasive plants (make good habitats for invasive species), Bass another big fish

Culural Imperialism

When people bring species from there home to make their new home like their old one.


Statistical averages (weeks, decades) Over a 30 year period.


Anomalies from the average

Climate Change

can mean change up or down in various variable including precipitation and temperature.

Climate Forcing

When an event causes climate change like El nina or El nino


A global warm period about 50 million years ago

Predicted Future Climate (Globally)

1. Change will be greatest towards to poles

2. There will probably be global changes in precipitation

Climate Change Effects (Sierra Nevada) (Good understanding)

1. Less Mountain Snow

2. Less water to go around in the summer

3. Increased drought, changes in vegetation

4. Increased need for management

Climate Change Effects (Globally) (Good Understanding)

1. Sea level rises

2. Ecosystem change

3. Melting of the polar ice

4. Coral Reefs disappear

Climate Change Effects (Sierra Nevada) (Medium Understanding)

1. Changes in how well forest grow

2. Increased habitat for invasive

3. Shifts in Farming crops

Climate Change Effects (Globally) (Medium understanding)

1. Increase intensity of hurricanes

2. Increase drought in some places

3. Increase in rain/ snow in some places

Climate Change Effects (Low understanding)

How will people and ecosystems react to the change

Affects of Global Warming on Agriculture

1. More extreme weather

2. Loss of farm land new coasts

3. Increased amount of pests

4. Loss of biodiversity

How climate change will affect health

Disease will spread more. Examples: Malaria, West Nile, and Lyme Disease