How Ecosystems WorkHow Ecosystems Work

The SunThe Sun

Life depends on the sunLife depends on the sun The sun is the ultimate source of energy for The sun is the ultimate source of energy for

almost all organismsalmost all organisms PhotosynthesisPhotosynthesis – a series of chemical – a series of chemical

reactions that use light to convert water and reactions that use light to convert water and carbon dioxide into sugar and oxygencarbon dioxide into sugar and oxygen 6CO6CO22 + 6H + 6H22O O → C→ C66HH1212OO6 6 + 6O+ 6O22

Plants, algae and some bacteria do photosynthesisPlants, algae and some bacteria do photosynthesis

Producers & ConsumersProducers & Consumers

ProducersProducers – organisms that make their own – organisms that make their own foodfood AutotrophsAutotrophs – self-feeders – self-feeders Get their energy Get their energy directlydirectly from the sun from the sun

ConsumersConsumers – organisms that get their energy – organisms that get their energy by eating other organismsby eating other organisms HeterotrophsHeterotrophs – other-feeders – other-feeders Get their energy Get their energy indirectlyindirectly from the sun by eating from the sun by eating

producers or other consumersproducers or other consumers

Producers & ConsumersProducers & Consumers

The Exception to the RuleThe Exception to the Rule

Deep-ocean ecosystems Deep-ocean ecosystems thrive where there is no thrive where there is no sunlightsunlight

Producers make food Producers make food from hydrogen sulfide from hydrogen sulfide from the hot ocean from the hot ocean vents instead of sunlightvents instead of sunlight

Other organisms then Other organisms then eat these producerseat these producers

Types of ConsumersTypes of Consumers

HerbivoresHerbivores – consumers that eat only – consumers that eat only producers (plant-eaters)producers (plant-eaters)

CarnivoresCarnivores – consumers that eat only other – consumers that eat only other consumers (meat-eaters)consumers (meat-eaters)

OmnivoresOmnivores – consumers that eat both plants – consumers that eat both plants and animals (eaters of all)and animals (eaters of all)

DecomposersDecomposers – consumers that break down – consumers that break down dead organismsdead organisms

What Eats WhatWhat Eats What

NameName Energy SourceEnergy Source ExamplesExamples

ProducerProducer Makes its own foodMakes its own food Grasses, ferns, algae, Grasses, ferns, algae, bacteriabacteria

ConsumerConsumer Gets energy by eating Gets energy by eating other organismsother organisms

Mice, starfish, humans, Mice, starfish, humans, antsants

HerbivoreHerbivore Eats only producersEats only producers Cows, sheep, deer, Cows, sheep, deer, grasshoppersgrasshoppers

CarnivoreCarnivore Eats only other Eats only other consumersconsumers

Lions, hawks, spidersLions, hawks, spiders

OmnivoreOmnivore Eats both producers and Eats both producers and consumersconsumers

Bears, pigs, humansBears, pigs, humans

DecomposerDecomposer Breaks down dead Breaks down dead organismsorganisms

Fungi, bacteriaFungi, bacteria

RespirationRespiration

Cellular Cellular respiration - gets the energy out of respiration - gets the energy out of the food by using oxygen to break it downthe food by using oxygen to break it down

All living things use cellular respiration to get All living things use cellular respiration to get energy from foodenergy from food CC66HH1212OO6 6 + 6O+ 6O22 → → 6CO6CO22 + 6H + 6H22OO Essentially the reverse of photosynthesisEssentially the reverse of photosynthesis

Food ChainsFood Chains

Each time an organism Each time an organism eats another organism, eats another organism, energy is transferredenergy is transferred

Food chainFood chain – a – a sequence in which sequence in which energy is transferred energy is transferred from one organism to from one organism to the next as each the next as each organism eats anotherorganism eats another

Food WebsFood Webs

Ecosystems are Ecosystems are much more much more complicated than a complicated than a simple food chainsimple food chain

Food webFood web – shows – shows many feeding many feeding relationships in an relationships in an ecosystemecosystem

Trophic LevelsTrophic Levels

Trophic levelTrophic level – each step in the transfer of – each step in the transfer of energy through an ecosystemenergy through an ecosystem

Each time energy is transferred, less of it is Each time energy is transferred, less of it is available to organisms at the next levelavailable to organisms at the next level

Some energy is lost during the process of Some energy is lost during the process of respiration; most is used for daily functionsrespiration; most is used for daily functions

About 90% of the energy is used; only 10% is About 90% of the energy is used; only 10% is left for the next trophic levelleft for the next trophic level

Trophic LevelsTrophic Levels

Water CycleWater Cycle

Water moves between the Earth’s surface and Water moves between the Earth’s surface and the atmosphere the atmosphere

The sun provides the energy to drive the cycleThe sun provides the energy to drive the cycle EvaporationEvaporation – water changes from a liquid to – water changes from a liquid to

a gasa gas PrecipitationPrecipitation – water vapor cools and falls to – water vapor cools and falls to

Earth as rain, sleet, or snowEarth as rain, sleet, or snow GroundwaterGroundwater – layer of water underground – layer of water underground

Water CycleWater Cycle

Living organisms move water about…Living organisms move water about… Carried within bodies (by drinking it or extracting Carried within bodies (by drinking it or extracting

it from food)it from food) During respiration, water is excretedDuring respiration, water is excreted Water also evaporates from the skin as sweatWater also evaporates from the skin as sweat Plant roots collect water from the soilPlant roots collect water from the soil

Some is used for photosynthesisSome is used for photosynthesis Some is evaporated or transpired from the leavesSome is evaporated or transpired from the leaves

Water CycleWater Cycle

What are the 3 phases of water?What are the 3 phases of water? SolidSolid

Ex. Glaciers, ice on the surface of a lake or pondEx. Glaciers, ice on the surface of a lake or pond LiquidLiquid

Ex. oceans, rivers, streams, lakesEx. oceans, rivers, streams, lakes GasGas

Ex. Water vaporEx. Water vapor Water vapor cannot be seen, but we know that fog and Water vapor cannot be seen, but we know that fog and

clouds contain itclouds contain it

Water CycleWater Cycle

Carbon CycleCarbon Cycle

Carbon is an essential part of proteins, fats, Carbon is an essential part of proteins, fats, and carbohydrates needed for lifeand carbohydrates needed for life

Producers take COProducers take CO22 from the atmosphere from the atmosphere Consumers eat the producers to obtain carbonConsumers eat the producers to obtain carbon COCO22 is released back to the atmosphere during is released back to the atmosphere during

cellular respirationcellular respiration Fossil fuels store carbon that is then released Fossil fuels store carbon that is then released

when they are burnedwhen they are burned

Carbon CycleCarbon Cycle

Four main reservoirs of carbon:Four main reservoirs of carbon: AtmosphereAtmosphere

Carbon dioxide, carbon monoxideCarbon dioxide, carbon monoxide Terrestrial BiosphereTerrestrial Biosphere

Includes freshwater, soilIncludes freshwater, soil OceansOceans

Dissolved carbon, living organisms in the oceanDissolved carbon, living organisms in the ocean SedimentsSediments

Fossil fuelsFossil fuels

Carbon CycleCarbon Cycle

Four processes involved in the carbon cycle:Four processes involved in the carbon cycle: Biological processes – photosynthesis, respiration Biological processes – photosynthesis, respiration

& decomposition& decomposition Geochemical processes – release of carbon dioxide Geochemical processes – release of carbon dioxide

gas into the atmosphere by volcanoesgas into the atmosphere by volcanoes Mixed biogeochemical processes – burial of Mixed biogeochemical processes – burial of

carbon-rich organisms and their conversion to carbon-rich organisms and their conversion to fossil fuelsfossil fuels

Human activity – mining, burning of fossil fuelsHuman activity – mining, burning of fossil fuels

Carbon CycleCarbon Cycle

Nitrogen CycleNitrogen Cycle All organisms need nitrogen to build All organisms need nitrogen to build

proteinsproteins Nitrogen gas makes up 78% of the Nitrogen gas makes up 78% of the

atmosphereatmosphere Nitrogen-fixing bacteriaNitrogen-fixing bacteria – Convert – Convert

nitrogen from the air into ammonia nitrogen from the air into ammonia ((nitrogen fixationnitrogen fixation))

Nitrogen CycleNitrogen Cycle

Ammonia is converted into nitrates and Ammonia is converted into nitrates and nitrites, which plants and other producers nitrites, which plants and other producers can use (can use (nitrificationnitrification))

Bacteria convert nitrogen in the soil into Bacteria convert nitrogen in the soil into atmospheric nitrogen (atmospheric nitrogen (denitrificationdenitrification))

Decomposers return nitrogen to the soilDecomposers return nitrogen to the soil

Nitrogen CycleNitrogen Cycle

Phosphorus CyclePhosphorus Cycle

Phosphorus is an element that is part of many Phosphorus is an element that is part of many molecules that make up the cells of living organisms.molecules that make up the cells of living organisms.

Plants get the phosphorus they need from soil and Plants get the phosphorus they need from soil and water, while animals get their phosphorus by eating water, while animals get their phosphorus by eating plants or other animals that have eaten plants.plants or other animals that have eaten plants.

The The phosphorus cyclephosphorus cycle is the cyclic movement of is the cyclic movement of phosphorus in different chemical forms from the phosphorus in different chemical forms from the environment to organisms and then back to the environment to organisms and then back to the environment.environment.

Phosphorus Cycle ContinuedPhosphorus Cycle Continued

Phosphorus may enter soil and water when rocks Phosphorus may enter soil and water when rocks erode. Small amounts of phosphorus dissolve as erode. Small amounts of phosphorus dissolve as phosphate, which moves into the soil.phosphate, which moves into the soil.

Plants absorb phosphates in the soil through their Plants absorb phosphates in the soil through their roots.roots.

Some phosphorus washes off the land and ends up in Some phosphorus washes off the land and ends up in the ocean.the ocean.

Because many phosphate salts are not soluble in Because many phosphate salts are not soluble in water, they sink to the bottom and accumulate as water, they sink to the bottom and accumulate as sediment.sediment.

Fertilizers and the Nitrogen and Fertilizers and the Nitrogen and Phosphorus CyclesPhosphorus Cycles

Fertilizers contain both nitrogen and phosphorus.Fertilizers contain both nitrogen and phosphorus. Excessive amounts of fertilizer can enter terrestrial Excessive amounts of fertilizer can enter terrestrial

and aquatic ecosystems through runoff.and aquatic ecosystems through runoff. Excess nitrogen and phosphorus can cause rapid Excess nitrogen and phosphorus can cause rapid

growth of algae.growth of algae. Excess algae can deplete an aquatic ecosystem of Excess algae can deplete an aquatic ecosystem of

important nutrients such as oxygen, on which fish and important nutrients such as oxygen, on which fish and other aquatic organisms depend.other aquatic organisms depend.

Acid PrecipitationAcid Precipitation

When fuel is burned, large amounts of nitric When fuel is burned, large amounts of nitric oxide is release into the atmosphere.oxide is release into the atmosphere.

In the air, nitric oxide can combine with In the air, nitric oxide can combine with oxygen and water vapor to form nitric acid.oxygen and water vapor to form nitric acid.

Dissolved in rain or snow, the nitric acid falls Dissolved in rain or snow, the nitric acid falls as acid precipitation.as acid precipitation.

Trees killed by acid rain

Acid rain damage on gargoyle

Sulfur CycleSulfur Cycle Sulfur is one of the components that make up proteins Sulfur is one of the components that make up proteins

and vitamins. and vitamins. Proteins consist of amino acids that contain sulfur Proteins consist of amino acids that contain sulfur

atoms. atoms. Sulfur is important for the functioning of proteins and Sulfur is important for the functioning of proteins and

enzymes in plants, and in animals that depend upon enzymes in plants, and in animals that depend upon plants for sulfur. plants for sulfur.

Plants absorb sulfur when it is dissolved in water. Plants absorb sulfur when it is dissolved in water. Animals consume these plants, so that they take up Animals consume these plants, so that they take up enough sulfur to maintain their health.enough sulfur to maintain their health.

Sulfur Cycle ContinuedSulfur Cycle Continued

Most of the earth's sulfur is tied up in rocks and salts or Most of the earth's sulfur is tied up in rocks and salts or buried deep in the ocean in oceanic sediments. buried deep in the ocean in oceanic sediments.

Sulfur can also be found in the atmosphere. It enters the Sulfur can also be found in the atmosphere. It enters the atmosphere through both natural and human sources. atmosphere through both natural and human sources.

Natural recourses: volcanic eruptions, bacterial Natural recourses: volcanic eruptions, bacterial processes, evaporation from water, or decaying processes, evaporation from water, or decaying organisms. organisms.

When sulfur enters the atmosphere through human When sulfur enters the atmosphere through human activity, this is mainly a consequence of industrial activity, this is mainly a consequence of industrial processes where sulfur dioxide (SO2) and hydrogen processes where sulfur dioxide (SO2) and hydrogen sulphide (H2S) gases are emitted on a wide scale.sulphide (H2S) gases are emitted on a wide scale.

Sulfur Cycle ContinuedSulfur Cycle Continued

When sulfur dioxide enters the atmosphere it will When sulfur dioxide enters the atmosphere it will react with oxygen to produce sulfur trioxide gas react with oxygen to produce sulfur trioxide gas (SO3), or with other chemicals in the atmosphere, to (SO3), or with other chemicals in the atmosphere, to produce sulfur salts. produce sulfur salts.

Sulfur dioxide may also react with water to produce Sulfur dioxide may also react with water to produce sulphuric acid (H2SO4). Sulphuric acid may also be sulphuric acid (H2SO4). Sulphuric acid may also be produced from demethylsulphide, which is emitted to produced from demethylsulphide, which is emitted to the atmosphere by plankton species.the atmosphere by plankton species.

All these particles will settle back onto earth, or react All these particles will settle back onto earth, or react with rain and fall back onto earth as acid depostion.with rain and fall back onto earth as acid depostion.

Rock CycleRock Cycle

Group of changesGroup of changes Igneous rock can change into sedimentary Igneous rock can change into sedimentary

rock or into metamorphic rockrock or into metamorphic rock Sedimentary rock can change into Sedimentary rock can change into

metamorphic rock or into igneous rockmetamorphic rock or into igneous rock Metamorphic rock can change into igneous or Metamorphic rock can change into igneous or

sedimentary rock sedimentary rock

Igneous RockIgneous Rock

Igneous rock forms when magma cools and Igneous rock forms when magma cools and makes crystals. makes crystals.

Magma is a hot liquid made of melted Magma is a hot liquid made of melted minerals. The minerals can form crystals when minerals. The minerals can form crystals when they cool. they cool.

Igneous rock can form underground, where the Igneous rock can form underground, where the magma cools slowly. Or, igneous rock can magma cools slowly. Or, igneous rock can form above ground, where the magma cools form above ground, where the magma cools quickly. quickly.

Sedimentary RockSedimentary Rock

On Earth's surface, wind and water can break On Earth's surface, wind and water can break rock into pieces. rock into pieces.

The rock pieces, called sediments, drop from The rock pieces, called sediments, drop from the wind or water to make a layer. the wind or water to make a layer.

After a long time the sediments can be After a long time the sediments can be cemented together to make sedimentary rock. cemented together to make sedimentary rock. In this way, igneous rock can become In this way, igneous rock can become sedimentary rock. sedimentary rock.

Metamorphic RockMetamorphic Rock

Baked rock does not melt, but it does change. Baked rock does not melt, but it does change. It forms crystals. It forms crystals.

Because this rock changes, it is called Because this rock changes, it is called metamorphic. metamorphic.

Metamorphosis can occur in rock when they Metamorphosis can occur in rock when they are heated to 300 to 700 degrees Celsius. are heated to 300 to 700 degrees Celsius.

SuccessionSuccession

A regular pattern of changes over time in the A regular pattern of changes over time in the types of species in a communitytypes of species in a community

May take hundreds or thousands of yearsMay take hundreds or thousands of years Climax communityClimax community – the community that – the community that

eventually forms if the land is left undisturbedeventually forms if the land is left undisturbed Two types of successionTwo types of succession

Primary successionPrimary succession Secondary successionSecondary succession

Primary SuccessionPrimary Succession

Occurs on surfaces where no ecosystem Occurs on surfaces where no ecosystem existed beforeexisted before New islands created by volcanic eruptionsNew islands created by volcanic eruptions Land exposed when a glacier retreatsLand exposed when a glacier retreats

No soil existsNo soil exists It takes several hundred to several thousand years It takes several hundred to several thousand years

to produce soil naturallyto produce soil naturally Pioneer speciesPioneer species – first organisms to populate – first organisms to populate

an area (usually lichens)an area (usually lichens) Lichens Lichens → mosses → grasses → shrubs → trees→ mosses → grasses → shrubs → trees

Primary SuccessionPrimary Succession

Secondary SuccessionSecondary Succession Occurs on a surface where an ecosystem has Occurs on a surface where an ecosystem has

previously existedpreviously existed Volcanic eruption, forest fire, abandoned farmlandVolcanic eruption, forest fire, abandoned farmland

Occurs much more quickly than primary succession Occurs much more quickly than primary succession because there is already fertile soilbecause there is already fertile soil