Understanding the Biosphere and Energy Transfer

Biosphere

All areas of earth that are inhabited by and support life - consists of atmosphere, lithosphere, and hydrosphere.

Hydrosphere

All of the water, SOLID and LIQUID, that exists in the lithosphere.

Lithosphere

Solid, mainly rocky part of earth, also called the geosphere.

Atmosphere

Gaseous part of earth, composed of: 21% oxygen, 78% nitrogen, 0.934% argon, and 0.036 other gases.

Isolated System

Matter and energy are not exchanged.

Closed System

Energy is exchanged but matter is not.

Open System

Energy and matter are exchanged between the system and its surroundings.

Energy Transfer - Radiation

Transmission through electromagnetic waves; reflected or absorbed by particles of matter.

Energy Transfer - Conduction

Transfer of thermal energy through direct contact between the particles of a substance, without moving the particles to a new location.

Energy Transfer - Convection

Transfer of thermal energy through the movement of particles from one location to another, usually occurs in fluids.

Solar Energy

Majority of the energy on earth originates from the sun.

One Way Flow of Energy

Solar energy and chemical energy harnessed by producers moves through the living components of the biosphere in a series of energy transfers.

1st Law of Thermodynamics

Energy can neither be created nor be destroyed, it can only be transferred from one form to another.

2nd Law of Thermodynamics

The entropy of any isolated system always increases.

Entropy

A measure of disorder or randomness in a system.

Kinetic Energy Increase

If the radiation is absorbed by matter, the kinetic energy of the particles will increase resulting in a temperature increase.

Energy Loss

Some energy is 'lost' (entropy) as heat with each energy transfer that takes place.

Thermal Energy Radiation

Thermal energy eventually radiates back out into space.

Incoming Solar Radiation

Some incoming solar radiation is reflected back into space by components of the atmosphere, lithosphere, and hydrosphere.

Photosynthesis

A very small amount of incoming solar radiation is absorbed by plants for use in photosynthesis.

Photosynthesis

Process by which photosynthetic organisms (PHOTOAUTOTROPHS) convert SOLAR ENERGY into CHEMICAL POTENTIAL ENERGY.

First oxygenic photoautotrophs

Cyanobacteria, responsible for the first oxygenation of the atmosphere - around 2.5 billion years ago.

Chemosynthesis

Is the process in which some organisms, called CHEMOAUTOTROPHS, split inorganic molecules, such as H2S(g), to release energy used to convert carbon-containing compounds, such as CH4(g) or CO2(g) into carbohydrates.

Chemoautotrophs

Microorganisms that live in hostile environmental conditions and do not require sunlight as an initial energy source.

Nitrogen-fixing bacteria

Chemoautotrophs that live in the soil.

Iron oxidizing bacteria

Chemoautotrophs that live in lava beds.

Sulfur oxidizing bacteria

Chemoautotrophs that live inside of tubeworms near deep sea hydrothermal vents, forming a symbiotic relationship.

Cellular Respiration

Process in which organisms react glucose with oxygen to produce carbon dioxide, water, and energy.

ATP

The usable form of energy for cells.

Energy-storing processes

Processes that balance out energy in ecosystems.

Energy-releasing processes

Processes that balance out energy in ecosystems.

Producers

Also called autotrophs, includes photoautotrophs and chemoautotrophs, forming the base of all food chains/webs.

Consumers

Also called heterotrophs, meaning they consume autotrophs or other heterotrophs as a food source.

Primary Consumers

Consume producers directly—e.g., insects, snails, grazing mammals, and some fish.

Secondary Consumers

Consume mainly primary consumers (herbivores)—e.g., spiders, frogs, and some birds.

Tertiary Consumers

Consume mainly secondary consumers—e.g., snakes, giant crabs, and sharks.

Quaternary Consumers

Consume mainly tertiary consumers—e.g., wolves and whales.

Decomposers

Organisms that consume detritus (dead organic matter and waste), important for recycling inorganic matter so it is available to autotrophs.

Examples of decomposers

Bacteria and fungi.

Trophic Levels

A feeding level in an ecosystem at which matter and energy are transferred.

First Trophic Level

Consists of producers.

Second Trophic Level

Consists of primary consumers.

Third Trophic Level

Consists of secondary consumers.

Fourth Trophic Level

Consists of tertiary consumers.

Fifth Trophic Level

consists of quaternary consumers

Trophic Levels

There is always less energy available at higher trophic levels - thus there are fewer organisms at higher levels, also limiting the number of trophic levels

Energy Transfer

~ 10% of energy available at one trophic level is transferred to the next trophic level

Abiotic Factors

The number of trophic levels is also limited by the availability of abiotic factors such as sunlight, water, and inorganic nutrients.

Food Chain

A food chain is a model that shows the linear pathways through which energy is transferred through the trophic levels.

Food Web

A food web is a model of energy transfer that shows the connections among food chains.

Ecosystem Stability

Increased food web complexity/larger numbers of energy transfers results in increased ecosystem stability.

Pyramid of Numbers

Type of ecological pyramid that represents the relative numbers of organisms at each trophic level.

Pyramid of Biomass

Type of ecological pyramid that represents the amount of biomass—dry mass of living or once-living organisms per unit area—at each trophic level.

Pyramid of Energy

Type of ecological pyramid that represents the amount of energy at each trophic level.

Biogeochemical Cycles

Pathway by which chemical substance moves through the biotic and the abiotic compartments of Earth.

Recycling of Matter

The recycling of matter through the biotic and abiotic components of the ecosystem allows all organisms to obtain essential nutrients.

Nutrient Reservoirs

At each step in a biogeochemical cycle, substances are temporarily stored in nutrient reservoirs, such as organisms, air, soil, and water.

Rapid Cycling of Nutrients

The rapid cycling of nutrients is when substances cycle between nutrient reservoirs relatively quickly—e.g., the movement of carbon from producer, to consumer, to decomposer.

Slow Cycling of Nutrients

The slow cycling of nutrients is when substances accumulate and are unavailable to organisms for a long period of time—e.g., fossil fuels, peat, and rocks.

Role of Water in Biogeochemical Cycles

Water is essential to all known living organisms.

Nutrient Transport

All living cells require water for transport of nutrients and biochemical reactions.

Photosynthesis

Photoautotrophs need water for photosynthesis.

Role of Water in Biogeochemical Cycles

Water is a polar molecule and consists of 2 hydrogen atoms bonded covalently to an oxygen atom.

Polarity of Water

The polarity results in hydrogen bonding between water molecules, giving water its unique properties.

Carbon and Oxygen Cycle

The carbon and oxygen cycles are closely linked through the processes of photosynthesis and cellular respiration.

Rapid Cycling of Carbon

The rapid cycling of carbon involves photosynthesis, cellular respiration, decomposition, combustion, dissolving of CO2 in water, and evaporation of CO2 from water.

Slow Cycling of Carbon

The slow cycling of carbon involves the formation of fossil fuels, formation of rocks, formation of sediments in the deep ocean, and weathering.

Carbon Sinks

The ocean is the largest carbon sink - water absorbs CO2 and producers use CO2.

Photosynthetic Producers

Photosynthetic producers use CO2 in photosynthesis.

Effects of Deforestation

Deforestation and rising ocean temperatures result in increased atmospheric CO2 levels.

Carbon Sources

Burning of fossil fuels releases CO2.

Cellular Respiration

Cellular respiration produces CO2.

Natural Carbon Sources

Forest fires and volcanoes (natural carbon sources) release CO2.

Limestone Weathering

Limestone (CaCO3) formed from shells of aquatic organisms or precipitation in water weathers over time, releasing carbon back into the soil, air, and water.

Nitrogen as Essential

Nitrogen is a component of ATP, proteins, and genetic material (DNA).

Atmospheric Nitrogen

Our atmosphere is 78% nitrogen, but organisms cannot use it.

Usable Nitrogen Forms

Most plants can only use the nitrate ion (NO3+) or the nitrite ion (NO2-).

Ammonium Ion Usage

Some plants can use the ammonium ion (NH4-).

Nitrogen Fixation

Nitrogen fixation is the process by which some bacteria convert nitrogen gas (N2(g)) into ammonium ions (NH4+).

Ammonification

Ammonification is a process by which decomposers break down organic matter into ammonium ions (NH4+).

Nitrification

Nitrification is a process by which nitrifying soil bacteria convert the ammonium ion (NH4+) into nitrite (NO2-).

Lightning's Role in Nitrogen Cycle

Lightning can also convert atmospheric nitrogen into nitrate ions.

Denitrification

Denitrification is a process by which anaerobic denitrifying bacteria convert nitrate (NO3-) or nitrite (NO2-) back into nitrogen gas (N2(g)).

Phosphorus Importance

Phosphorus is essential for DNA, ATP, bones, cell membranes, and teeth.

Usable Phosphorus Form

Producers can only use phosphorus if it is in the form of a phosphate ion (PO4^3-).

Rapid Cycling of Phosphorus

The rapid cycling of phosphorus involves uptake of phosphorus by plants, consumption of plants and animals, and decomposition.

Slow Cycling of Phosphorus

The slow cycling of phosphorus involves formation of sediment, geological uplifting, and weathering from rocks.

Biological Productivity

Biological productivity is the rate at which an ecosystem's producers capture and store energy within organic compounds over a certain length of time (g/m2/a).

Factors Affecting Biological Productivity

Biological productivity depends on the number of producers, the amount of light and heat available, time of year, available nutrients, and the amount of rainfall a system receives.

Biosphere Equilibrium

Equilibrium between photosynthesis and cellular respiration influences atmospheric composition of carbon dioxide and oxygen.

The Gaia Hypothesis

The Gaia Hypothesis, proposed by ecologist James Lovelock in 1979, suggests the biosphere acts like an organism that regulates itself, maintaining environmental conditions within certain limits, referred to as dynamic equilibrium.