science 10 - ecosystems

Science 10 - Ecosystems

Ecosystem – Ecosystem – includes all the organisms in includes all the organisms in an area that interact with each other and an area that interact with each other and with their non-living environment.with their non-living environment.

ex. Ocean Ecosystemex. Ocean Ecosystem

DesertDesert

Rain ForestRain Forest

Factors Affecting EcosystemsFactors Affecting Ecosystems

1) Biotic Factors – living things.1) Biotic Factors – living things.

ex. Organismsex. Organisms

2. Abiotic Factors – non-living2. Abiotic Factors – non-living

eg. Sunlight, wind, temperature, etc.eg. Sunlight, wind, temperature, etc.

Biome – a large geographic area with a Biome – a large geographic area with a characteristic climate (ex. tropical rain characteristic climate (ex. tropical rain forest).forest).

Biosphere – 3 regions on earth in which all Biosphere – 3 regions on earth in which all life exists.life exists.

a. Lithosphere – solid portion of earth’s a. Lithosphere – solid portion of earth’s surface.surface.

b. Hydrosphere – layer of water which b. Hydrosphere – layer of water which covers ¾ of earth’s surface.covers ¾ of earth’s surface.

c. Atmosphere – mass of air surrounding the c. Atmosphere – mass of air surrounding the earth. earth.

Cycles of LifeCycles of Life All life requires nutrients and nutrients are All life requires nutrients and nutrients are

continuously recycled…if they were not, continuously recycled…if they were not, they would become used up and life on they would become used up and life on Earth would cease to exist.Earth would cease to exist.

Carbon CycleCarbon Cycle Photosynthesis and cellular respiration Photosynthesis and cellular respiration

make up the stages of the carbon cycle.make up the stages of the carbon cycle. Carbon is absorbed by plants (as COCarbon is absorbed by plants (as CO22) )

which then release Owhich then release O22 back into the back into the atmosphere. This COatmosphere. This CO22 is converted into is converted into chemical energy [carbohydrates (sugars chemical energy [carbohydrates (sugars starches)].starches)].

Animals eat the plants and these Animals eat the plants and these sugars/starches are used to provide sugars/starches are used to provide energy. The product released back to the energy. The product released back to the atmosphere is COatmosphere is CO22 and the cycle is and the cycle is complete.complete.

Carbon is still present in the bodies of Carbon is still present in the bodies of plants and animals and will be recycled by plants and animals and will be recycled by decomposers, which also use Odecomposers, which also use O22 and and return Carbon into the atmosphere in the return Carbon into the atmosphere in the form of COform of CO2.2.

This cycle has become unbalanced due to the burning of This cycle has become unbalanced due to the burning of fossil fuels.fossil fuels.

During the Carboniferous Period (a. 300mya) large During the Carboniferous Period (a. 300mya) large amounts of Carbon (in the tissues of plant matter) was amounts of Carbon (in the tissues of plant matter) was trapped under ground.trapped under ground.

Because of lack of oxygen and tremendous pressure, Because of lack of oxygen and tremendous pressure, the plant matter was compressed into fossil fuels (coal, the plant matter was compressed into fossil fuels (coal, natural gas, and oil)natural gas, and oil)

Burning these for energy releases COBurning these for energy releases CO22 into the into the

atmosphere; too much for plants to use…causing an atmosphere; too much for plants to use…causing an unbalanced C-cycle.unbalanced C-cycle.

Large amounts of the carbon cycle takes place in Earth’s Large amounts of the carbon cycle takes place in Earth’s oceans but if the temperature of the oceans increases, oceans but if the temperature of the oceans increases, more COmore CO22 will escape back into the atmosphere will escape back into the atmosphere

(increase in temp. = decrease in solubility of a gas = (increase in temp. = decrease in solubility of a gas = COCO22).).

Nitrogen CycleNitrogen Cycle Plants use N, P, & K for growth and Plants use N, P, & K for growth and

development (these are the main development (these are the main ingredients in fertilizers).ingredients in fertilizers).

Nitrogen gas makes up about 80% of Nitrogen gas makes up about 80% of Earth’s atmosphere but most organisms Earth’s atmosphere but most organisms cannot absorb nitrogen directly.cannot absorb nitrogen directly. Nitrogen fixationNitrogen fixation – is when nitrogen gas is – is when nitrogen gas is

converted into compounds (NHconverted into compounds (NH44++ & NO & NO33

--) that ) that can be used by plants. Animals get Nitrogen can be used by plants. Animals get Nitrogen by eating the plants.by eating the plants.

Nitrogen fixing bacteriaNitrogen fixing bacteria – are some of the – are some of the few species that convert nitrogen into few species that convert nitrogen into useable compoundsuseable compounds

Nitrogen in these compounds will pass Nitrogen in these compounds will pass through the plants to the animals then to through the plants to the animals then to the soil and water through wastes and dead the soil and water through wastes and dead organismsorganisms

These compounds can reenter plants before These compounds can reenter plants before going back to the atmosphere, creating a cycle going back to the atmosphere, creating a cycle within a cyclewithin a cycle

Decomposers (bacteria) will break down the Decomposers (bacteria) will break down the wastes/dead organisms and produce Ammonia wastes/dead organisms and produce Ammonia which is converted back into Nitrates for use by which is converted back into Nitrates for use by the plants by the plants by Nitrifying bacteriaNitrifying bacteria.. This process is called This process is called nitrificationnitrification. .

Denitrifying bacteriaDenitrifying bacteria – convert nitrates in – convert nitrates in the soil or water back into nitrogen gas = the soil or water back into nitrogen gas = denitrification.denitrification.

This cycle can also be altered by humans. E.g. This cycle can also be altered by humans. E.g. Adding too much fertilizers to soils causes root Adding too much fertilizers to soils causes root damage, stunts growth, and increases soil damage, stunts growth, and increases soil acidity.acidity.

The build up of nitrogen and other nutrients in The build up of nitrogen and other nutrients in aquatic ecosystems is called aquatic ecosystems is called eutrophicationeutrophication – – this increases plant growth at the water’s this increases plant growth at the water’s surface, not allowing sunlight to get to deeper surface, not allowing sunlight to get to deeper waters and therefore “strangles” plants and waters and therefore “strangles” plants and animals because photosynthesis cannot take animals because photosynthesis cannot take place in the deeper waters.place in the deeper waters.

Water CycleWater CycleAssignment: Define the following.Assignment: Define the following.a)a) EvaporationEvaporationb)b) TranspirationTranspirationc)c) CondensationCondensationd)d) PrecipitationPrecipitatione)e) Surface RunoffSurface Runofff)f) PercolationPercolationg)g) Ground WaterGround Waterh)h) Water TableWater Tablei)i) RespirationRespiration

How Energy is Transferred in an EcosystemHow Energy is Transferred in an Ecosystem

1. Producers (Autotrophs) 1. Producers (Autotrophs) – green plants – green plants that convert radiant energy into chemical that convert radiant energy into chemical energy (photosynthesis).energy (photosynthesis).

2. Consumers (Heterotrophs)2. Consumers (Heterotrophs) – consume – consume other organisms.other organisms.

a) Primary Consumer (Herbivore) – a) Primary Consumer (Herbivore) – animals that eat plants.animals that eat plants.

b) Secondary Consumer (Carnivore) – b) Secondary Consumer (Carnivore) – animals that feed on plant eaters.animals that feed on plant eaters.

c) Decomposers – organisms (generally c) Decomposers – organisms (generally fungus and bacteria) that obtain energy fungus and bacteria) that obtain energy from breaking down remains or wastes of from breaking down remains or wastes of other organisms.other organisms.

Green plants produce more energy per unit of land area Green plants produce more energy per unit of land area and only a portion of this energy is passed on to and only a portion of this energy is passed on to consumers that eat plants. consumers that eat plants.

Thus animals and animal products contain less energy Thus animals and animal products contain less energy than plants on the same amount of land.than plants on the same amount of land.

Feeding LevelsFeeding Levels- Food chains are made up of several - Food chains are made up of several

feeding (energy) levels we call feeding (energy) levels we call Trophic Trophic LevelsLevels..

ProducerProducer LeavesLeaves 11stst Trophic Level Trophic Level

Primary ConsumerPrimary Consumer CaterpillarCaterpillar 22ndnd Trophic Trophic LevelLevel

HerbivoreHerbivore

Secondary ConsumerSecondary Consumer RobinRobin 33rdrd Trophic Level Trophic Level

CarnivoreCarnivore

Tertiary ConsumerTertiary Consumer EagleEagle 4 4thth Trophic Trophic LevelLevel

Top CarnivoreTop Carnivore

Quaternary …Quaternary … Detritivores and DecomposersDetritivores and Decomposers

only 5-20% of energy is passed from one only 5-20% of energy is passed from one trophic level to another.trophic level to another.

Most of the usable energy at each level is Most of the usable energy at each level is converted to thermal (heat) energy and converted to thermal (heat) energy and waste matter.waste matter.

Energy remains in the tissues of dead Energy remains in the tissues of dead organisms which is used by detritivores organisms which is used by detritivores and scavengers.and scavengers.

Detritivores Detritivores – feed on – feed on bodies of smaller dead bodies of smaller dead animals. Dead plant animals. Dead plant matter, and animal dung.matter, and animal dung.

ex. Crabs, earthworms, ex. Crabs, earthworms, wood beetles, antswood beetles, ants

DecomposersDecomposers – bacteria and fungi which – bacteria and fungi which break down the cells and extract the last break down the cells and extract the last remaining energy.remaining energy.

Maggots Saprobes

FOOD CHAIN - an autotroph is producer is eaten by a primary consumer and its food energy is transferred to a secondary consumer who is gobbled up by a tertiary consumer and eventually its energy is transferred to the top consumer of this food chain. This is only a small part of a food web within the ecosystem. P. 829** arrows go from food to eater (don’t draw animal pictures.) eg. shrub rabbits cougar

BIOLOGICAL MAGNIFICATION = increasing amounts of toxins like DDT or mercury as you follow a food chain from producer to top consumer.

Video Energy Flow in the Ecosystem

FOOD CHAIN - an autotroph or producer is eaten by a primary consumer and its food energy is transferred to a secondary consumer who is gobbled up by a tertiary consumer and eventually its energy is transferred to the top consumer of this food chain. This is only a small part of a food web within the ecosystem. P. 829** arrows go from food to eater (don’t draw animal pictures.) eg. shrub rabbits cougar



FOOD CHAIN - an autotroph is producer is eaten by a primary consumer and its food energy is transferred to a secondary consumer who is gobbled up by a tertiary consumer and eventually its energy is transferred to the top consumer of this food chain. This is only a small part of a food web within the ecosystem. P. 829** arrows go from food to eater (don’t draw animal pictures.) eg. shrub rabbits cougar



FOOD CHAIN - an autotroph is producer is eaten by a primary consumer and its food energy is transferred to a secondary consumer who is gobbled up by a tertiary consumer and eventually its energy is transferred to the top consumer of this food chain. This is only a small part of a food web within the ecosystem. ** arrows go from food to eater (don’t draw animal pictures.) eg. shrub rabbits cougar



Food Web

FOOD CHAIN - an autotroph is producer is eaten by a primary consumer and its food energy is transferred to a secondary consumer who is gobbled up by a tertiary consumer and eventually its energy is transferred to the top consumer of this food chain. This is only a small part of a food web within the ecosystem. ** arrows go from food to eater (don’t draw animal pictures.) eg. shrub rabbits cougar



BIOLOGICAL MAGNIFICATION = increasing amounts of toxins like DDT or mercury as you follow a food chain from producer to top consumer

ENERGY PYRAMIDSENERGY PYRAMIDS

-the base if the pyramid is the first trophic level (always a producer)-the trophic levels above continue to be numberedupwards (Handout has ______ trophic levels)-there are energy pyramids which represent the transfers of

energy in a food chain and there are pyramids of biomass.

(=2 kinds of pyramids)-biomass = the mass of all organisms in a trophic level that

compete for the same food.-competition = organisms can compete in the communities for

food, habitat space, and other resources. No two populations

can occupy the same niche (ones got to go) = competitive

exclusion principle

PYRAMIDSPYRAMIDS

-the base of the pyramid is the first trophic level (always a producer)-the trophic levels above continue to be numberedupwards (Handout has ______ trophic levels)-there are energy pyramids which represent the transfers of






exclusion principle

PYRAMIDSPYRAMIDS







exclusion principle

PYRAMIDSPYRAMIDS


energy in a food chain . There are pyramids of biomass & numbers.





exclusion principle

What two ecosystems in the world What two ecosystems in the world have the greatest biomass ?have the greatest biomass ?



energy in a food chain . There are pyramids of biomass & numbers.





exclusion principle



energy in a food chain . There are pyramids of biomass and numbers.





exclusion principle

Releases toxinsInto the soil toPrevent other plant growth = competition



energy in a food chain . There are pyramids of biomass and numbers.




can occupy the same niche (one’s got to go) = competitive

exclusion principle

ENERGY/BIOMASS PYRAMIDENERGY/BIOMASS PYRAMID

10% energy passed to next level




Energy andBiomass decreaseAs you go up A food chain


so it can support less biomass




so it can support less biomass



Biomagnification of DDT or mercury are NOT illustrated by this pyramid, because they increase as you go up the food chain

Pyramid of NumbersPyramid of Numbers Counting organisms in Counting organisms in

an ecosystem.an ecosystem. This type of pyramid This type of pyramid

does not take into does not take into account the sizes of account the sizes of individual organisms.individual organisms.

For example many For example many insects can feed off of insects can feed off of one tree, so the one tree, so the bottom of the pyramid bottom of the pyramid could be very small.could be very small.

Pyramid of BiomassPyramid of Biomass

Measured in grams per Measured in grams per square meter.square meter.

Shows biomass Shows biomass decreases from each decreases from each trophic level.trophic level.

Disadvantage: the Disadvantage: the biomass of the biomass of the herbivores may be herbivores may be much greater then the much greater then the producers causing the producers causing the pyramid to look inverted.pyramid to look inverted.

Pyramid of EnergyPyramid of Energy Measures the Measures the

total chemical total chemical energy that flows energy that flows through each through each trophic level.trophic level.

The best pyramid The best pyramid because it because it eliminates the eliminates the exceptions in the exceptions in the other pyramids.other pyramids.

There is always There is always less energy less energy available for each available for each successive successive trophic level.trophic level.

ActivityActivity : Questions: Questions

1.1. Give an example of an organism in the Give an example of an organism in the second trophic level of an ecosystem.second trophic level of an ecosystem.

2.2. Why are there rarely more than four Why are there rarely more than four links in a food chain?links in a food chain?

3.3. What is a pyramid of numbers?What is a pyramid of numbers?4.4. Which would you expect to have the Which would you expect to have the

greatest biomass, a population of rabbits greatest biomass, a population of rabbits or a population of foxes living in the or a population of foxes living in the same ecosystem? Explain.same ecosystem? Explain.

Biological CommunitiesBiological Communities::

SYMBIOTIC RELATIONSHIPS = close living associations of different species (members of different

species do not interbreed) in which one organism benefits from

the relationship. There are three kinds:1.mutualism = a relationship in which organisms both benefits2.commensalism = one organism benefits but the other is not

3.helped nor harmed4.parasitism = one organism benefits while the other harmed

SASKATCHEWAN EXAMPLES1.Nodule bacteria provide nitrogen in a form plants can use,

2.while the legume plant provides protection/home for bacteria.This is .

2. Intestinal worms absorb nutrients from deer, and reproducesinside. With heavy infestations the deer can be a weakened target for predators. It is .

3.

A community is all the populations of A community is all the populations of organisms living together and potentially organisms living together and potentially interacting in a particular areainteracting in a particular area

Communities are made up of many Communities are made up of many different kinds of relationships: different kinds of relationships: producer/consumer, predator/prey, and producer/consumer, predator/prey, and symbiotic relationshipssymbiotic relationships

Predator – Predator – living things that catch, kill, and eat living things that catch, kill, and eat other living things.other living things.

Prey – The organisms that are eaten.Prey – The organisms that are eaten.

- predation plays an important role in - predation plays an important role in shaping communities.shaping communities.

- help to control the size of prey - help to control the size of prey populations.populations.

- maintain diversity in an ecosystem.- maintain diversity in an ecosystem.

Biological Communities:Biological Communities:




3.helped nor harmed4.parasitism = one organism benefits while the other harmed




3.




the relationship. There are three kinds:1.mutualism = a relationship in which organisms both benefits2.commensalism = one organism benefits but the other is not helped nor harmed1.parasitism = one organism benefits while the other harmed




3.





helped nor harmed3.parasitism = one organism benefits while the other is harmed

SASKATCHEWAN EXAMPLES•Nodule bacteria provide nitrogen in a form plants can use,

•while the legume plant provides protection/home for bacteria.This is .


3.





helped nor harmed3.parasitism = one organism benefits while the other harmedSASKATCHEWAN EXAMPLES1.Nodule bacteria provide nitrogen in a form plants can use,

while the legume plant provides protection/home for bacteria.This is .


3.




the relationship. There are three kinds:1.mutualism = a relationship in which organisms both benefits2.commensalism = one organism benefits but the other is not helped nor harmed3. parasitism = one organism benefits while the other harmedSASKATCHEWAN EXAMPLES1.Nodule bacteria provide nitrogen in a form plants can use,

while the legume plant provides protection/home for bacteria.This is mutualism .


3.

Biological Communities:Biological Communities:SYMBIOTIC RELATIONSHIPS = close living associations of different species (members of different species do not interbreed) in which one organism benefits from the relationship. Three kinds:1.mutualism = a relationship in which organisms both benefits2.commensalism = one organism benefits but the other is not

helped nor harmed3.parasitism = one organism benefits while the other harmedSASKATCHEWAN EXAMPLES•Nodule bacteria provide nitrogen in a form plants can use,



3.


helped nor harmed3. parasitism = one organism benefits while the other harmedSASKATCHEWAN EXAMPLES1.Nodule bacteria provide nitrogen in a form plants can use,


2. Intestinal worms absorb nutrients from deer, and reproducesinside. With heavy infestations the deer can be a weakened target for predators. It is parasitism .

3.


helped nor harmed 3.parasitism = one organism benefits while the other harmedSASKATCHEWAN EXAMPLES1.Nodule bacteria provide nitrogen in a form plants can use,


2. Intestinal worms absorb nutrients from deer, and reproducesinside. With heavy infestations the deer can be a weakened target for predators. It is parasitism .

3.


helped nor harmed3.parasitism = one organism benefits while the other harmedSASKATCHEWAN EXAMPLES1.Nodule bacteria provide nitrogen in a form plants can use, while the legume plant provides protection/home for bacteria.

This is mutualism .2. Intestinal worms absorb nutrients from deer, and reproduces

inside. With heavy infestations the deer can be a weakened target for predators. It is

parasitism .3. Vultures do not affect the wolves that ate this deer.This is _____________________.


helped nor harmed3.parasitism = one organism benefits while the other harmedSASKATCHEWAN EXAMPLES1.Nodule bacteria provide nitrogen in a form plants can use, while the legume plant provides protection/home for bacteria.

This is mutualism .2. Intestinal worms absorb nutrients from deer, and reproduces

inside. With heavy infestations the deer can be a weakened target for predators. It is

parasitism .3. Vultures do not affect the wolves that ate this deer.This is _______commensalism__.

Natural Communities Change Over Time (Sask.)Succession = the long process of ecological change of communities.eg. #1. PRIMARY SUCCESSION: (P.836, P. 839) bare rock lichens (break it down to form soil) weeds = pioneer plants grasses meadow ecosystem (this is what end climax community would be in SW

Sask.) brush (brushes & low trees) forest ( aspen trees) Coniferous forest (evergreens, spruce , fir)Climax Community = the end of succession where the community can no longer change due to limits of climate and soil. P.836, p.853, p.839*** succession can end anyplace in this chain above* Animal populations change accordingly.

Natural Communities Change Over Time (Sask.)Succession = the long process of ecological change of communities.eg. #1. PRIMARY SUCCESSION: bare rock lichens (break it down to form soil) weeds = pioneer plants grasses meadow ecosystem (this is what end climax community would be in SW

Sask.) brush (brushes & low trees) forest ( aspen trees) Coniferous forest (evergreens, spruce , fir)Climax Community = the end of succession where the community can no longer change due to limits of climate and soil. P.836, p.853, p.839*** succession can end anyplace in this chain above* Animal populations change accordingly.

Natural Communities Change Over Time (Sask.)Succession = the long process of ecological change of communities.eg. #1. PRIMARY SUCCESSION: bare rock lichens (break it down to form soil) weeds = pioneer plants grasses meadow ecosystem (this is what end climax community would be in SW

Sask.) brush (brushes & low trees) forest ( aspen/poplar trees) Coniferous forest (evergreens, spruce , fir)Climax Community = the end of succession where the community can no longer change due to limits of climate and soil. P.836, p.853, p.839*** succession can end anyplace in this chain above* Animal populations change accordingly.

Secondary SuccessionSecondary Succession (occurs after a forest fire, or a

farmer clears land. It’s different from primary succession because

it occurs where there used to be an established community)

Eg. #2 pond

silt settles on bottom P. 839 marsh meadow brush

Aspen/poplars Coniferous forest

***** succession ends when climate and soil limits the climax community




Eg. #2 pond

silt settles on bottom marsh meadow brush






Eg. #2 pond

silt settles on bottom P. 839 marsh meadow brush






Eg. #2 pond

silt settles on bottom marsh meadow brush



PopulationsPopulations

Habitat –Habitat – the place in an organisms life. the place in an organisms life.

Niche –Niche – the role an organism plays in an the role an organism plays in an environment.environment. (ex. The place it lives, the (ex. The place it lives, the food it eats, the organisms that feed on it food it eats, the organisms that feed on it and interact with it, the amount of light and and interact with it, the amount of light and humidity required, etc.)humidity required, etc.)

Carrying Capacity –Carrying Capacity – the largest population the largest population of a species that an environment can of a species that an environment can support.support.

Four Factors that Limit Carrying Four Factors that Limit Carrying CapacityCapacity

1.1. Materials and Energy – sun, water, Materials and Energy – sun, water, carbon.carbon.

2.2. Food Chains – populations are limited by Food Chains – populations are limited by their food supply.their food supply.

3.3. Competition – the demand for resources Competition – the demand for resources such as food, water, mates, and space.such as food, water, mates, and space.a) Intraspecific – among members of the a) Intraspecific – among members of the

same species.same species.b) Interspecific – between different b) Interspecific – between different species.species.

4. Density – dependant on size, environment, 4. Density – dependant on size, environment, and way of life.and way of life.

Population Density – how many individuals Population Density – how many individuals can live in an area at one can live in an area at one

time.time.

Density Dependant Factors – factors that Density Dependant Factors – factors that increase in significance as a population increase in significance as a population grows (overcrowding).grows (overcrowding).

Density Independent Factors – factors that do Density Independent Factors – factors that do not depend on the size of the population not depend on the size of the population (forest fires).(forest fires).

Symbiotic relationshipSymbiotic relationship – an interaction – an interaction between two or more species where one between two or more species where one species lives in or on another speciesspecies lives in or on another species

There are 3 main types: parasitism, There are 3 main types: parasitism, commensalisms, and mutualismcommensalisms, and mutualism

ParasitismParasitism (para = near; sitos = food) is a predator- (para = near; sitos = food) is a predator-prey relationship where one organism (the parasite) prey relationship where one organism (the parasite) derives its food at the expense of its hostderives its food at the expense of its host

E.g. Tapeworms living inside larger animals E.g. Tapeworms living inside larger animals absorbing nutrients from its host; mistletoe or rusts on absorbing nutrients from its host; mistletoe or rusts on plants; and lungworms in the air passages of white plants; and lungworms in the air passages of white tailed deertailed deer

Tape worms in a horse Mistletoe on a tree

CommensalismCommensalism (com = together, mensa = table) is a (com = together, mensa = table) is a relationship where one partner benefits without relationship where one partner benefits without significantly affecting the other. Few cases of absolute significantly affecting the other. Few cases of absolute commensalisms probably exist because it is unlikely that commensalisms probably exist because it is unlikely that one of the partners will be completely unaffectedone of the partners will be completely unaffected

Commensal relationships sometimes involve one Commensal relationships sometimes involve one species obtaining food that is inadvertently exposed by species obtaining food that is inadvertently exposed by anotheranother

E.g. Several kinds of birds feed on insects flushed out of E.g. Several kinds of birds feed on insects flushed out of the grass by grazing cattlethe grass by grazing cattle

Robin nest in a Hydrangea tree

MutualismMutualism (mutualis = reciprocal) is a relationship (mutualis = reciprocal) is a relationship that benefits both partners in the relationship.that benefits both partners in the relationship.

E.g. Legume plants with their nitrogen-fixing E.g. Legume plants with their nitrogen-fixing bacteria; the interactions between flowering plants bacteria; the interactions between flowering plants and their pollinatorsand their pollinators

THE ENDTHE END

science 10 - ecosystems

Documents

nitrogen gas

earths atmosphere

nitrogen fixation

bodies of plants

atmosphere increase

carbon cyclephotosynthesis

form of co2

nitrogen cycleplants