AP Biology Chapter 42 Ecosystems and Energy

Ecosystem

The sum of all the organisms living in a given area and the abiotic factors with which they interact. Boundaries not always discrete.

Energy Flow and Chemical Cycling

2 distinct processes unique to ecosystem level of ecology are _________________________

Chemicals; energy

______________ are recycled but ___________ cannot be within an environment.

First Law of Thermodynamics

Energy cannot be created or destroyed only transferred or transformed.

Sun

The ultimate source of energy in ecosystems is the _______.

Second Law of Thermodynamics

Every exchange of energy increases the entropy of the universe.

Inefficient, heat

Energy conversions are ___________ and energy is almost always lost as ______.

Law of Conservation of Mass

Matter cannot be created or destroyed. In a closed system, mass is constant. This law can be applied to study how chemicals cycle through and move in and out of ecosystems.

Primary Producers

An autotroph, usually a photosynthetic organism. They make up the trophic level of an ecosystem that ultimately supports all other levels. Ex: plants, algae, photosynthetic producers.

Primary Consumers

An herbivore, an organism that eats plants or other autotrophs.

Secondary Consumers

Carnivores that eat herbivores

Tertiary Consumers

Carnivores that eat other carnivores

Detritivores/Decomposers

A consumer that derives its energy and nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms. Includes some prokaryotes and fungi.

Heterotroph/Consumer

An organism that relies on other organisms for it’s food source

Autotroph/Producer

An organism that can capture it’s own energy and organic compounds from inorganic sources.

Detritus

Nonliving organic material such as the remains of dead organisms, feces, fallen leaves, and wood.

Detritivores

_____________ play a critical role in recycling chemical elements to primary producers. They convert organic matter from all trophic levels to inorganic compounds reusable by primary producers.

Primary Production

The amount of light energy converted to chemical energy (organic compounds) by the autotrophs in an ecosystem during a given time period.

Gross Primary Production

The total primary production of an ecosystem. The amount of energy from light converted to the chemical energy of organic molecules per unit time.

Net primary production

Gross primary production minus the energy used by the primary producers for their autotrophic respiration. NPP=GPP-Ra. THe amount of chemical energy that is actually available to consumers in the ecosystem.

1/2

Net primary production is usually about _____ of Gross Primary Production due to the energy used by molecules of autotrophs.

Energy; biomass

Net Primary Production can be expressed as _____ per area per unit time or as _________ per unit area per unit time.

Standing Crop

The total biomass of photosynthetic autotrophs present. Not the same as NPP.

Net Ecosystem Production (NEP)

The gross primary production of an ecosystem minus the energy used by all autotrophs and heterotrophs for respiration. A measure of the total biomass accumulation during a period of time. Gross primary production minus total respiration of all the organisms in the system. NEP= GPP-Rt

Carbon

NEP is a valuable measure of whether an ecosystem is gaining or losing ______ over time.

Net Ecosystem Production

A common way to estimate _______ is to measure the net flux (flow) of CO2 or O2 entering or leaving the ecosystem.

Light

In aquatic environments the amount of ______ can be a limiting factor for primary production.

Depth

The intensity of light depends on the ________ of water.

Limiting Nutrient

An element that must be added for production to increase in a particular area. Common elements that limit marine production are nitrogen and phosphorus.

Upwelling

Where deep nutrient-rich waters circulate to the ocean surface allowing for areas of high primary production.

Eutrophication

A process by which nutrients, particularly phosphorus and nitrogen become highly concentrated in a a body of water leading to increased growth of organisms such as algae or cyanobacteria. This can lead to a decrease in oxygen when detritivores decompose the algae and cyanobacteria when they die.

Temperature; Moisture

In terrestrial ecosystems ______ and ________ are the main factors controlling primary production.

Evapotranspiration

A useful predictor for levels of primary production; the total amount of water transpired by plants and evaporated from a landscape. Increases with the temperature and amount of solar energy available.

Soil

Nutrient availability in _____ can also affects terrestrial primary production.

Adaptations

Various _________ have evolved in plants that can increase their uptake of limiting nutrients. Ex: symbiosis with nitrogen-fixing bacteria, root hairs, and enzymes.

Fertilizers

Substances added to soils by farmers to increase the yield of crops by increasing the amount of limiting nutrients

Secondary Production

The amount of chemical energy in consumer’s food that is converted to their own new biomass during a given time period.

Chemical

Only the ________ energy stored by herbivores as biomass, through growth or the production of offspring, is available as food to secondary consumers.

Growth

Only small amounts of potential energy are used for secondary production, or __________. The other energy may be stored in organic compounds used in respiration (assimilated), or is passed out as feces.

Production Efficiency

_______________= (Net secondary production * 100%)/ (Assimilation of primary production)

Net Secondary Production

The energy stored in biomass represented by growth and reproduction.

Assimilation

The total amount of energy and organisms has consumed and used for growth, reproduction, and respiration.

Production Efficiency

The percentage of energy stored in assimilated food that is not used for respiration or eliminated as waste.

Trophic Efficiency

The percentage of production transferred from one trophic level to the next. They take into account energy contained in feces and energy lost through respiration, energy converted to new biomass in a lower trophic level but not consumed by the next trophic level.

Trophic Efficiency

Which is lower trophic efficiency or production efficiency?

10%

Average trophic efficiency

4-5

Most food webs have only ____-_______ trophic levels due to the limitations of trophic Efficiency.

Energy Pyramid

A diagram that represents the loss of energy with each transfer in a food chain where the net productions of different trophic levels are arranged it tiers

Biomass pyramid

A diagram where each tier represents the standing crop (total dry mass of all organisms) in a trophic level. Typical pattern: sharp narrowing from top to bottom.

Rapidly

An inverted biomass pyramid can occur when the primary producers reproduce and are consumed ________.

Warmer; wetter

Decomposers usually grow faster and decompose more material in ________, __________ conditions with higher nutrient availability.

Soil

In cooler, dryer environments where decomposition occurs slowly the ____ may contain large amounts of the ecosystem’s organic material.

Oxygen

Decomposers rely on __________ therefore in anaerobic environments decomposition can take 50 years or longer.

Biogeochemical Cycles

Any of the various chemical/nutrient cycles that involves both biotic and abiotic components of ecosystems. Occurs globally and locally.

Globally

Gaseous forms of chemicals like carbon or oxygen tend to cycle more ________ through the atmosphere while heavier elements cycle more locally.

Water

__________ is essential to all organisms and it’s availability influences the rates of ecosystem processes particularly primary production and decomposition. Mostly used in liquid form but can be taken in in vapor form. Solid form usually harms because of cold temperatures.

Water

Reservoirs of __________= ocean, glaciers and polar ice caps, lakes, rivers, ground water

Carbon

___________ forms the framework of the organic molecules essential to all organisms.

Photosynthesis

Atmospheric carbon is made available to organisms through the process of ___________ by which producers fix atmospheric carbon into organic compounds.

Cellular Respiration

All organisms release carbon dioxide back into the atmosphere through the process of ______________ ___________.

Carbon

Reservoirs for __________ include:

fossil fuels, sediments of aquatic ecosystems, oceans, plant and animal biomass, and the atmosphere, and limestone.

Nitrogen

_________ is a part of amino acids, proteins, and nucleic acids and can be a limiting Nutrient.

Plants; bacteria, animals

________ can assimilate ammonium (NH4) and nitrate (NO3), ___________ bacteria can assimilate these forms and NO2 and ___________ can only use organic forms of nitrogen.

Nitrogen

Reservoirs for _______: the atmosphere, soils and sediments, biomass.

NH4+, NO3-

Useable forms of inorganic nitrogen in plants

Nitrogen fixation

The conversion of N2 to forms that can be used to synthesize organic nitrogen compounds. Done by certain bacteria, lightening, volcanic activity. Nitrogen also provided from human activities like fertilizers.

Nitrogen Fixation

N2 → __________ →NH3→ ammonification → NH4 → nitrification→ NO3 →denitrification →N2

Ammonification

N2 → nitrogen fixation →NH3→_________ → NH4 → nitrification→ NO3 →denitrification →N2

Nitrification

N2 → nitrogen fixation →NH3→ ammonification → NH4 → _________→ NO3 →denitrification →N2

Denitrification

N2 → nitrogen fixation →NH3→ ammonification → NH4 → nitrification→ NO3 →_________ →N2

Phosphorus

__________ the nutrient needed for nucleic acids, phospholipids, and ATP and other energy storing molecules. Also used in bones and teeth.

PO43-

The most biologically important inorganic form of phosphate.

Phosphorus

Reservoirs of _________:

sedimentary rocks of marine origin, soil, oceans, and in organisms

Phosphorus

Cycling of _____________ is very localized because it has no gaseous forms.

Track

Scientists can______ cycles of chemicals through tracking radioactive isotopes.

Conserves

The Hubbard Brook experiment showed that internal cycling _________ most of the mineral nutrients in the system.

Plants

The Hubbard Brook deforestation experiment showed that the amount of nutrients leaving an intact forest ecosystem is mainly controlled by _______ and retaining nutrients in an ecosystem helps to maintain the productivity system.

Gene Likens

Scientist who studied nutrient cycling in Hubbard Brook Experimental Forest.

Restoration ecologists

Scientists who work to initiate or speed up the recovery of degraded ecosystems. They work to identify and manipulate the processes that most limit recovery of ecosystems from disturbances

Physical

In biological restoration ___________ reconstruction occurs first then biological restoration.

Kissimmee River

The project that reversed damage done when the river was made into a canal to prevent flooding and divert water from the flood plain which dried up the wetlands threatening many populations. Restoration filled the canal and restored the natural river channel. Project will restore natural flow patterns and foster self-sustaining populations.

Succulent Karoo

The restoration project that reversed damage done in this desert by overgrazing. Scientists are revegetating the land and drastically increasing diversity.

Maungatautari

A forested volcanic zone in New Zealand with damage from introduced invasive species. Project is excluding all exotic mammals to protect active wildlife.

Coastal Japan

A project is taking place here to restore seaweed and seagrass beds wiped out from development. Scientists are constructing suitable seafloor habitats, and transplanting seagrass and seaweeds.

Bioremediation

Using organisms to detoxify and restore polluted and degraded ecosystems. Usually prokaryotes, fungi, or plants like lichens.

Biological Augmentation

An approach to restoration ecology that uses organisms to add essential materials to a degraded ecosystem. Ecologists first need to determine which factors have been lost from a system and are limiting its recovery. Ex: using nitrogen fixing plants to speed up succession and ecosystem recovery.