Biology 20Biology 20Energy and Matter Exchange in Energy and Matter Exchange in

the Biospherethe Biosphere

"The ultimate test of a moral society is the kind "The ultimate test of a moral society is the kind

of world that it leaves to its children."of world that it leaves to its children."Dietrick Bonhoeffer, Dietrick Bonhoeffer, German Theologian German Theologian

Equilibrium in the BiosphereEquilibrium in the Biosphere

According to the According to the Gaia hypothesis,Gaia hypothesis, the earth is the earth is like a complex organism where many living like a complex organism where many living (biotic) and non-living (abiotic) systems interact. (biotic) and non-living (abiotic) systems interact. Like a living organism the earth is said to be in Like a living organism the earth is said to be in dynamic equilibriumdynamic equilibrium where changes are where changes are continually occurring, but small adjustments are continually occurring, but small adjustments are made to keep the whole system stable. made to keep the whole system stable. Unfortunately, evidence suggests that humans Unfortunately, evidence suggests that humans are causing a disruption to the earth’s systems are causing a disruption to the earth’s systems that can be detrimental to its, and our survival.that can be detrimental to its, and our survival.

TheThe BiosphereBiosphere

refers to all areas of the refers to all areas of the earth in which living earth in which living organisms are found. organisms are found. This includes:This includes:– Atmosphere – airAtmosphere – air– Lithosphere – landLithosphere – land– Hydrosphere – waterHydrosphere – water

The BiosphereThe Biosphere

Biotic componentsBiotic components – are the biological or – are the biological or living components of the biosphere, living components of the biosphere, include all living things.include all living things.

Ex. bacteria, fish, birds, mammals, plantsEx. bacteria, fish, birds, mammals, plants

A-biotic componentsA-biotic components – are the non-living – are the non-living components of the biosphere, include all components of the biosphere, include all chemical and physical factors.chemical and physical factors.

Ex. Temperature, weather, soil acidity, Ex. Temperature, weather, soil acidity, sunlightsunlight

In studying the health of the earth, scientists find it useful to In studying the health of the earth, scientists find it useful to study the biosphere at a variety of different levels. To study the biosphere at a variety of different levels. To determine the interactions between organisms and the determine the interactions between organisms and the environment, scientists may choose to study:environment, scientists may choose to study:

Populations Populations – groups of organisms of a – groups of organisms of a species living in a specific place at a species living in a specific place at a specific time. Population studies allow specific time. Population studies allow scientists to study the interactions scientists to study the interactions between the population and its between the population and its environment.environment.

CommunitiesCommunities – all of the populations that – all of the populations that live in a specific area at a specific time. live in a specific area at a specific time. Studying communities shows scientists Studying communities shows scientists how populations of different species affect how populations of different species affect one another.one another.

EcosystemsEcosystems – include communities and – include communities and their abiotic environments. Studying their abiotic environments. Studying ecosystems allows scientists to investigate ecosystems allows scientists to investigate the interactions between the living and the interactions between the living and non-living components or the earth.non-living components or the earth.

"When one tugs at a single thing in nature..."When one tugs at a single thing in nature...he finds it attached to the rest of the he finds it attached to the rest of the

world." world." John MuirJohn Muir

BiodiversityBiodiversity

The key to healthy ecosystems, and a healthy The key to healthy ecosystems, and a healthy

planet involves biodiversity.planet involves biodiversity.

Biodiversity Biodiversity – describes the biological diversity, – describes the biological diversity, number and variety of organisms, in an number and variety of organisms, in an ecosystem.ecosystem.

More diverse food chains are more stable. All More diverse food chains are more stable. All organisms in an ecosystem are either directly organisms in an ecosystem are either directly or indirectly affected by one another. If one or indirectly affected by one another. If one species is removed from a limited food web, a species is removed from a limited food web, a domino effectdomino effect occurs and the system will occurs and the system will collapse. collapse.

Equilibrium UnbalancedEquilibrium Unbalanced

Dynamic EquilibriumDynamic Equilibrium – describes any – describes any system with constant change, where the system with constant change, where the components can adjust to the change components can adjust to the change without disturbing the entire system.without disturbing the entire system.

When the dynamic equilibrium becomes When the dynamic equilibrium becomes unbalanced for any reason, the healthy or unbalanced for any reason, the healthy or numbers or organisms in that ecosystem numbers or organisms in that ecosystem are affected. Organisms can be classified are affected. Organisms can be classified according to their degree of riskaccording to their degree of risk

Special concernSpecial concern – numbers are – numbers are declining at the range / fringe of declining at the range / fringe of the areathe area

ThreatenedThreatened – species may – species may become endangered if become endangered if threatening conditions are not threatening conditions are not reversedreversed

ExtirpatedExtirpated – a species no longer – a species no longer exists in one particular area, but exists in one particular area, but is still found in other areasis still found in other areas

EndangeredEndangered – a species is close – a species is close to extinction in all parts of their to extinction in all parts of their natural habitatnatural habitat

ExtinctExtinct – a species no longer – a species no longer existsexists

Less severe risk

Most severe risk

Indicator SpeciesIndicator Species are species of organisms that provide an early are species of organisms that provide an early

warning that an ecosystem is being affected by warning that an ecosystem is being affected by some factor. Usually, these species are very some factor. Usually, these species are very sensitive to changes in an ecosystem, or to sensitive to changes in an ecosystem, or to specific changes of ecosystem conditions. specific changes of ecosystem conditions. Indicator species also play a specific role in an Indicator species also play a specific role in an ecosystem and their decline will affect other ecosystem and their decline will affect other organisms in the food web.organisms in the food web.– FishFish– AmphibiansAmphibians– AlgaeAlgae– PlantsPlants

Types of Indicator Species:Types of Indicator Species:

Producers Producers – plants that convert sunlight energy – plants that convert sunlight energy into foodinto food

HerbivoresHerbivores – animals that only feed on plants – animals that only feed on plants CarnivoresCarnivores – animals that only feed on other – animals that only feed on other

animalsanimals Omnivores Omnivores – animals that eat both plants and – animals that eat both plants and

other animalsother animals Decomposers Decomposers – organisms that feed on detritus, – organisms that feed on detritus,

dead and decaying biological material and return dead and decaying biological material and return nutrients to the soil and water.nutrients to the soil and water.

The Disappearing FrogsThe Disappearing FrogsFrogs begin as eggs and brow into tadpoles Frogs begin as eggs and brow into tadpoles

in ponds. Next they enter their second life in ponds. Next they enter their second life as adults in forest and grassland areas. as adults in forest and grassland areas. Frogs are exposed to hazards in both their Frogs are exposed to hazards in both their aquatic and their terrestrial ecosystems, aquatic and their terrestrial ecosystems, where they are a part of two very different where they are a part of two very different food chains.food chains.

Tadpoles – are herbivores and eat algae Tadpoles – are herbivores and eat algae and detritus. They are food for larger fish.and detritus. They are food for larger fish.

Adult frogs – are carnivores and eat Adult frogs – are carnivores and eat insects and small fish. They are also food insects and small fish. They are also food for birds and small mammals.for birds and small mammals.

Factors causing the disappearance Factors causing the disappearance of specific organisms include:of specific organisms include:

Loss of HabitatLoss of Habitat - clean, healthy habitats are - clean, healthy habitats are often reduced or destroyed by human activity often reduced or destroyed by human activity such as farming, industry and recreation.such as farming, industry and recreation.

Pollution Pollution – causes poor air and water quality – causes poor air and water quality which are detrimental to many organisms.which are detrimental to many organisms.

Climate ChangeClimate Change – such as global warming – such as global warming causes the abiotic conditions such as temperature causes the abiotic conditions such as temperature and humidity to change. Caused by pollutants.and humidity to change. Caused by pollutants.

Ultraviolet RadiationUltraviolet Radiation – increases the incidence – increases the incidence of mutations and causes damage at the cellular of mutations and causes damage at the cellular level. Caused by damage to the ozone layer.level. Caused by damage to the ozone layer.

The Biosphere and ClimateThe Biosphere and Climate

TroposphereTroposphere – up to 12 km, contains – up to 12 km, contains 80% of earth’s atmospheric mass (water 80% of earth’s atmospheric mass (water vapour and dust). Weather systems occur vapour and dust). Weather systems occur here.here.

StratosphereStratosphere – up to 50 km above the – up to 50 km above the troposphere, oxygen absorbs UV radiation troposphere, oxygen absorbs UV radiation forming ozone.forming ozone.

MesosphereMesosphere – up to 90 km above the – up to 90 km above the stratosphere, cold temperatures, trace stratosphere, cold temperatures, trace amounts of gas.amounts of gas.

Layers of the Atmosphere

IonosphereIonosphere – above the mesosphere, – above the mesosphere, contains ionized gases that produce the contains ionized gases that produce the northern lights and absorb harmful X rays northern lights and absorb harmful X rays and gamma rays from the sun.and gamma rays from the sun.

MagnetosphereMagnetosphere – above the ionosphere, – above the ionosphere, created by the earths magnetic field, created by the earths magnetic field, deflects large particles that are emitted deflects large particles that are emitted from the sun or from space.from the sun or from space.

Threats to the BiosphereThreats to the Biosphere Ozone Thinning – Ozone Thinning – in specific global areas, in specific global areas,

the ozone levels in the ozone layer have the ozone levels in the ozone layer have been reduced. Scientists believe this been reduced. Scientists believe this phenomenon is caused by chemicals such phenomenon is caused by chemicals such as CFC’s released into the atmosphere. as CFC’s released into the atmosphere. The result is an increase in the amount of The result is an increase in the amount of harmful ultra-violet radiation that reaches harmful ultra-violet radiation that reaches the earth, which causes increased rates of the earth, which causes increased rates of skin cancers and eye problems.skin cancers and eye problems.

Stratospheric Ozone: Background MaterialStratospheric Ozone: Background Material Total Ozone Mapping Spectrometer ozone iTotal Ozone Mapping Spectrometer ozone i

magesmages

The Albedo The Albedo Effect – Effect – describes the describes the extent to which extent to which light is reflected light is reflected from the earth’s from the earth’s surface by surface by clouds, snow or clouds, snow or other highly other highly reflective reflective surfaces.surfaces.

Energy Flow in the BiosphereEnergy Flow in the Biosphere

ONE WAYONE WAY

Most of the energy in the biosphere Most of the energy in the biosphere comes from the sun, however only a comes from the sun, however only a small portion of the sun’s energy small portion of the sun’s energy reaches the earth’s atmosphere. reaches the earth’s atmosphere.

30% - is reflected by clouds or the Earth’s surface30% - is reflected by clouds or the Earth’s surface44% - heats the atmosphere and maintains Earth’s 44% - heats the atmosphere and maintains Earth’s

temperatures temperatures25% - heats water and drives the water cycle25% - heats water and drives the water cycle 1% - generates wind and weather patterns 1% - generates wind and weather patterns.02% - is used by photosynthesis to produce food .02% - is used by photosynthesis to produce food

energy energy

Energy Transfer and Food WebsEnergy Transfer and Food Webs

Living things can be categorized according Living things can be categorized according to where they are in a hierarchy of to where they are in a hierarchy of energy. energy.

Trophic LevelTrophic Level – category that defines – category that defines how living things gain energy for life how living things gain energy for life processes. (feeding level)processes. (feeding level)

Producers / Autotrophs –Producers / Autotrophs – organisms organisms that produce their own energy from that produce their own energy from either sunlight (photosynthesis) or either sunlight (photosynthesis) or chemical energy (chemosynthesis)chemical energy (chemosynthesis)

Heterotrophs –Heterotrophs – organisms that feed on organisms that feed on other organismsother organisms

Primary consumers –Primary consumers – feed on autotrophs feed on autotrophs (herbivores)(herbivores)

Secondary consumers –Secondary consumers – feed on primary feed on primary consumers (carnivores)consumers (carnivores)

Top CarnivoresTop Carnivores – organisms that are not – organisms that are not consumed by any other organism.consumed by any other organism.

Food ChainsFood Chains single sequences illustrating a one way single sequences illustrating a one way

flow of energy in an ecosystem. flow of energy in an ecosystem.

Food WebsFood Webs are interlocking food chains that illustrate are interlocking food chains that illustrate

more complex feeding relationships between more complex feeding relationships between organisms.organisms.

Energy ConversionsEnergy Conversions

Photosynthesis Photosynthesis – is the process where – is the process where producers capture solar energy and converted producers capture solar energy and converted into food. into food.

COCO2(g) 2(g) + H+ H22OO(l)(l) + sunlight + sunlight C C66HH1212OO6(s)6(s) + O + O2(g)2(g)

Cellular RespirationCellular Respiration – is the process where – is the process where consumers break down glucose into carbon consumers break down glucose into carbon dioxide and water, releasing useable energy.dioxide and water, releasing useable energy.

CC66HH1212O6O6(s)(s) + O + O2(g)2(g) CO CO2(g)2(g) + H + H22OO(l)(l) + energy + energy

ChemosynthesisChemosynthesis – the process where – the process where non-photosynthetic organisms convert non-photosynthetic organisms convert inorganic chemical compounds such as inorganic chemical compounds such as sulphur, iron, ammonia and hydrogen sulphur, iron, ammonia and hydrogen sulphide into energetic organic molecules. sulphide into energetic organic molecules. Bacteria capable of doing this are called Bacteria capable of doing this are called chemoautotrophs.chemoautotrophs.

In all food chains, the amount of available energy In all food chains, the amount of available energy decreases as you move up the chain. Valuable decreases as you move up the chain. Valuable energy is lost in each and every energy energy is lost in each and every energy conversion. So why is energy transfer so conversion. So why is energy transfer so inefficient?inefficient?

1. Most of the energy produced by 1. Most of the energy produced by autotrophs is used to promote the autotrophs is used to promote the survival and growth of the organism.survival and growth of the organism.

2. Consumers don’t process all of the food 2. Consumers don’t process all of the food they eat. Some is eliminated through they eat. Some is eliminated through waste. Much of the energy metabolized waste. Much of the energy metabolized is also lost as heat. (also a necessary is also lost as heat. (also a necessary process for homeotherms)process for homeotherms)

3. Some of the energy taken in by a 3. Some of the energy taken in by a consumer is required to acquire, digest consumer is required to acquire, digest and metabolize the food eaten.and metabolize the food eaten.

4. Energy transfer in biological systems 4. Energy transfer in biological systems always follows the first and second laws always follows the first and second laws of of thermodynamicsthermodynamics::

– First LawFirst Law – energy cannot be created or – energy cannot be created or destroyed, it can only be converted to other destroyed, it can only be converted to other forms.forms.

– Second lawSecond law – during any energy conversion, – during any energy conversion, some of the energy is converted to heat, a some of the energy is converted to heat, a form that is not recovered.form that is not recovered.

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If Bessie here eats 100 kJ of energy, how If Bessie here eats 100 kJ of energy, how much energy is available as heat and for much energy is available as heat and for use?use?

Scientific ModelsScientific Models

Ecological Pyramids - Ecological Pyramids - can be used to can be used to represent the energy flow in food chains or represent the energy flow in food chains or food webs by showing the amount of food webs by showing the amount of energy, the number of organisms or the energy, the number of organisms or the biomass. All pyramids illustrate the first / biomass. All pyramids illustrate the first / lowest trophic level on the bottom with lowest trophic level on the bottom with successive trophic levels towards the top.successive trophic levels towards the top.

Pyramids of Energy – Pyramids of Energy – illustrates the decreasing illustrates the decreasing amount of energy available at each successive amount of energy available at each successive trophic level.trophic level.

Pyramids of NumbersPyramids of Numbers – describe the number of – describe the number of organisms at each successive level of the food organisms at each successive level of the food chain. These pyramids can often appear chain. These pyramids can often appear “inverted” when consumers are very small or “inverted” when consumers are very small or producers are very large.producers are very large.

Pyramids of Biomass – Pyramids of Biomass – represents the dry mass represents the dry mass of plant and animal tissues in a food chain. The of plant and animal tissues in a food chain. The amount of dry mass decreases at each trophic amount of dry mass decreases at each trophic level.level.

Here is a comparison of the three types of Here is a comparison of the three types of pyramids:pyramids:

The Cycling of Matter in the The Cycling of Matter in the BiosphereBiosphere

The earth is a closed system, so although The earth is a closed system, so although energy from the sun can come into the energy from the sun can come into the system and heat energy can leave, matter system and heat energy can leave, matter cannot. All of the molecules that make up cannot. All of the molecules that make up everything on our planet stay here. Matter everything on our planet stay here. Matter in the biosphere regularly changes form or in the biosphere regularly changes form or cycles. Food molecules become cellular cycles. Food molecules become cellular structures that become tissues and structures that become tissues and organisms. Eventually, those tissues and organisms. Eventually, those tissues and organisms become food for other organisms become food for other organisms or decompose becoming part of organisms or decompose becoming part of the soil. The cycling of matter is a the soil. The cycling of matter is a necessary part of all living things. necessary part of all living things.

WaterWater Water is required by all living things. It is Water is required by all living things. It is

important for a variety of reasons:important for a variety of reasons:– it absorbs and releases thermal energyit absorbs and releases thermal energy– most metabolic reactions take place in water most metabolic reactions take place in water

solutionssolutions– it is an excellent solvent due to its polar natureit is an excellent solvent due to its polar nature– it supplies hydrogen in photosynthetic it supplies hydrogen in photosynthetic

reactions and oxygen during cellular reactions and oxygen during cellular respiration respiration

– it dissociates into acidic H+ and basic OH-it dissociates into acidic H+ and basic OH-– it exists as a solid, liquid or a gas in earth’s it exists as a solid, liquid or a gas in earth’s

atmosphereatmosphereWater Cycle - Animated DiagramWater Cycle - Animated Diagram

The Hydrologic CycleThe Hydrologic Cycle

TranspirationTranspiration – is the loss of water to the – is the loss of water to the atmosphere through the leaves of plants.atmosphere through the leaves of plants.

PercolationPercolation – is the movement of water – is the movement of water through porous soil.through porous soil.

LeachingLeaching – is the removal of soluble – is the removal of soluble minerals by percolation.minerals by percolation.

Acid DepositionAcid Deposition – is the precipitation of – is the precipitation of acidic solutions due to SOx and NOx gases acidic solutions due to SOx and NOx gases combining with water (acid rain).combining with water (acid rain).

CarbonCarbon On earth, all organic substances are On earth, all organic substances are

compounds of carbon, including those that compounds of carbon, including those that make up living things. Carbon is also make up living things. Carbon is also found in inorganic forms such as CO2 and found in inorganic forms such as CO2 and carbonates. Combustion, decomposition carbonates. Combustion, decomposition and cellular respiration all produce and cellular respiration all produce inorganic carbon dioxide. Photosynthesis inorganic carbon dioxide. Photosynthesis is required to capture inorganic carbon is required to capture inorganic carbon and convert it to organic carbon. These and convert it to organic carbon. These processes together are known as the processes together are known as the carbon cycle. carbon cycle.

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The Carbon CycleThe Carbon Cycle

Global Warming and the Greenhouse Global Warming and the Greenhouse EffectEffect

Scientists believe that the average annual Scientists believe that the average annual global temperatures are increasing. A global temperatures are increasing. A number of theories exist that account for number of theories exist that account for this phenomenon, however one of the this phenomenon, however one of the more prevalent theories is the greenhouse more prevalent theories is the greenhouse effect. effect.

Greenhouse effectGreenhouse effect – is caused by – is caused by increased amounts of atmospheric gases increased amounts of atmospheric gases ((CO2CO2 and CH4) that prevent heat from and CH4) that prevent heat from escaping causing in increase in escaping causing in increase in temperature on the earth’s surface. temperature on the earth’s surface.

Energy Flows: The Greenhouse EffectEnergy Flows: The Greenhouse Effect

NitrogenNitrogen Nitrogen is an important building block of Nitrogen is an important building block of

proteins and nucleic acids. Proteins are proteins and nucleic acids. Proteins are required to build tissues and enzymatically required to build tissues and enzymatically mediate biochemical reactions. Nucleic mediate biochemical reactions. Nucleic acids (DNA, RNA and ATP) are components acids (DNA, RNA and ATP) are components of key hereditary and metabolic of key hereditary and metabolic compounds in all living things. Nitrogen compounds in all living things. Nitrogen gas is abundant on our planet and accounts gas is abundant on our planet and accounts for 79% of the atmosphere. To be useful to for 79% of the atmosphere. To be useful to organisms, however, nitrogen must be in a organisms, however, nitrogen must be in a more useable form like nitrate. more useable form like nitrate.

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The Nitrogen CycleThe Nitrogen CycleNitrogen fixationNitrogen fixation is the process by which is the process by which

atmospheric nitrogen is converted to a useable atmospheric nitrogen is converted to a useable form, nitrates. This is done by lightening and form, nitrates. This is done by lightening and nitrogen fixing bacteria. nitrogen fixing bacteria.

DenitrificationDenitrification is the process where bacteria convert is the process where bacteria convert nitrates to nitrites, then to nitrogen gas which is nitrates to nitrites, then to nitrogen gas which is released back into the atmosphere. released back into the atmosphere.

AmmonificationAmmonification is the process where decomposers is the process where decomposers break down organic nitrogen containing compounds break down organic nitrogen containing compounds into simpler chemicals like ammonia. Bacteria in into simpler chemicals like ammonia. Bacteria in turn, change the ammonia into useable nitrates. turn, change the ammonia into useable nitrates.

These conversions of nitrogen are all part of the These conversions of nitrogen are all part of the nitrogen cycle.nitrogen cycle.

The Nitrogen CycleThe Nitrogen Cycle

PhosphorusPhosphorus

Phosphorus is required in cell Phosphorus is required in cell membranes, ATP, DNA and in bone membranes, ATP, DNA and in bone formation. Phosphorus cycles though formation. Phosphorus cycles though the earth’s crust and through living the earth’s crust and through living organisms.organisms.

Library of Crop Technology LessonsLibrary of Crop Technology Lessons

The Phosphorus Cycle

Fertilizers and EcosystemsFertilizers and EcosystemsFertilizers Fertilizers – are materials used to restore – are materials used to restore

nutrients to plants. Most fertilizers contain nutrients to plants. Most fertilizers contain a ratio of Phosphorus, Nitrogen and a ratio of Phosphorus, Nitrogen and Potassium (PNK)Potassium (PNK)

The accumulation of phosphates and The accumulation of phosphates and nitrogen caused by fertilizer use and nitrogen caused by fertilizer use and spring runoff, allows algae to grow very spring runoff, allows algae to grow very rapidly in ponds and streams. When the rapidly in ponds and streams. When the algae die, bacteria use the available algae die, bacteria use the available oxygen to decompose them. This results oxygen to decompose them. This results in less oxygen available for fish and other in less oxygen available for fish and other aquatic organisms.aquatic organisms.