Ch. 5 – Cycles in the BiosphereCh. 5 – Cycles in the BiosphereBio – means “life”Bio – means “life”

Lesson 1Lesson 1

Oxygen & Carbon DioxideOxygen & Carbon Dioxide

Photosynthesis & RespirationPhotosynthesis & Respiration Plants provide oxygen & food because they Plants provide oxygen & food because they

can carry out photosynthesis.can carry out photosynthesis. PhotosynthesisPhotosynthesis is a process during which is a process during which

energy from the Sun is used to change carbon energy from the Sun is used to change carbon dioxide & water into glucose & oxygen. dioxide & water into glucose & oxygen.

The simple glucose provides energy for plants, The simple glucose provides energy for plants, for animals that eat the plants, & then for for animals that eat the plants, & then for animals that eat other animals. The oxygen is animals that eat other animals. The oxygen is released into the atmosphere. released into the atmosphere.

Photosynthesis – cont.Photosynthesis – cont. Plants are not the only organisms that conduct Plants are not the only organisms that conduct

photosynthesis. Tiny algae that live in water photosynthesis. Tiny algae that live in water also carry out photosynthesis. also carry out photosynthesis.

Essay question – In fact, algae in the ocean Essay question – In fact, algae in the ocean supply most of Earth’s oxygen. supply most of Earth’s oxygen.

What might happen if all of the algae in the What might happen if all of the algae in the world’s oceans suddenly stopped carrying out world’s oceans suddenly stopped carrying out photosynthesis?photosynthesis?

If these algae were unable to carry out If these algae were unable to carry out photosynthesis, the atmosphere would have photosynthesis, the atmosphere would have much less oxygen.much less oxygen.

Photosynthesis – Cont.Photosynthesis – Cont. During photosynthesis, the light energy from During photosynthesis, the light energy from

the Sun is converted into chemical energy. the Sun is converted into chemical energy. This energy stored in food. Living things need This energy stored in food. Living things need that energy to carry out all of their life that energy to carry out all of their life processes.processes.

Photosynthesis & respiration can be thought of as Photosynthesis & respiration can be thought of as opposite processes. Plants produce oxygen that opposite processes. Plants produce oxygen that animals need & animals produce carbon dioxide animals need & animals produce carbon dioxide that plants need.that plants need.

The products of respiration are used for The products of respiration are used for photosynthesis. In this way, oxygen & carbon photosynthesis. In this way, oxygen & carbon dioxide keep cycling through the biospheredioxide keep cycling through the biosphere

Photosynthesis:Photosynthesis: Carbon dioxide Carbon dioxide + water + energy + water + energy glucose + water glucose + water

Respiration:Respiration: Glucose + oxygen Glucose + oxygen carbon dioxide + carbon dioxide + water + energywater + energy

RespirationRespiration The way that most organisms are able to use The way that most organisms are able to use

the energy in food is through respiration.the energy in food is through respiration. RespirationRespiration is the process through which is the process through which

oxygen & glucose are combined to produce oxygen & glucose are combined to produce carbon dioxide & water. carbon dioxide & water.

During this process, stored energy is released. During this process, stored energy is released. Both plants & animals perform respiration.Both plants & animals perform respiration. Respiration is why oxygen is so important to Respiration is why oxygen is so important to

life on Earth.life on Earth.

Respiration – Cont. Respiration – Cont. You take in oxygen with every breath. The You take in oxygen with every breath. The

blood carries it to cells throughout the body, blood carries it to cells throughout the body, where respiration constantly takes place.where respiration constantly takes place.

The relationship between photosynthesis & The relationship between photosynthesis & respiration is one way that organisms depend respiration is one way that organisms depend on one another. on one another.

Animals & other organisms need plants for Animals & other organisms need plants for food & oxygen. Plants rely on other organisms food & oxygen. Plants rely on other organisms for carbon dioxide.for carbon dioxide.

Why is respiration necessary for Why is respiration necessary for both plants and animals?both plants and animals?

They both use the process to release energy They both use the process to release energy stored in sugar. stored in sugar.

CarbonCarbon Carbon is the 4Carbon is the 4thth most abundant element on most abundant element on

Earth & is the basic part of all living things.Earth & is the basic part of all living things. Carbon is found in the Earth’s crust as fossil Carbon is found in the Earth’s crust as fossil

fuels such as coal, oil, & natural gas.fuels such as coal, oil, & natural gas. Carbon moves through our in environment Carbon moves through our in environment

through cyclesthrough cycles

Carbon CycleCarbon Cycle Carbon moves through the carbon cycle mostly as Carbon moves through the carbon cycle mostly as

carbon dioxide gas. carbon dioxide gas. There are 4 ways carbon moves through the There are 4 ways carbon moves through the

environment.environment. Photosynthesis – by plants, carbon dioxide is usedPhotosynthesis – by plants, carbon dioxide is used Respiration – plants and animals; carbon dioxide is Respiration – plants and animals; carbon dioxide is

producedproduced Decomposition – the break down of dead organisms; Decomposition – the break down of dead organisms;

carbon dioxide is producedcarbon dioxide is produced Combustion (Burning) of fossil fuels - to run our cars, heat Combustion (Burning) of fossil fuels - to run our cars, heat

our homes, the making of products; carbon dioxide is our homes, the making of products; carbon dioxide is producedproduced

OxygenOxygen

The flow of oxygen through the environment The flow of oxygen through the environment is essential for life. is essential for life.

Less than 1 % of the atmosphere consists of Less than 1 % of the atmosphere consists of carbon dioxide, but oxygen makes up nearly carbon dioxide, but oxygen makes up nearly 21 % of the atmosphere.21 % of the atmosphere.

Like carbon, oxygen also cycles through the Like carbon, oxygen also cycles through the environment.environment.

Oxygen CycleOxygen Cycle Oxygen is produced during photosynthesisOxygen is produced during photosynthesis Consumed during respirationConsumed during respiration When water is evaporated into the atmosphere When water is evaporated into the atmosphere

oxygen is produced, it is broken down chemically.oxygen is produced, it is broken down chemically. Oxygen is also consumed during combustion, rusting Oxygen is also consumed during combustion, rusting

& when rocks are weathered. & when rocks are weathered. Because oxygen is part of carbon dioxide, the oxygen Because oxygen is part of carbon dioxide, the oxygen

cycle is linked to the carbon cycle. Both elements cycle is linked to the carbon cycle. Both elements cycle between living & nonliving things in the cycle between living & nonliving things in the environment. Look at diagram in text on pgs. B8&9environment. Look at diagram in text on pgs. B8&9

Events on Earth can upset these Events on Earth can upset these cycles – Essay questioncycles – Essay question

If people slash & burn rainforests, If people slash & burn rainforests, photosynthesis decreases. Less oxygen will photosynthesis decreases. Less oxygen will enter the atmosphere & less carbon dioxide enter the atmosphere & less carbon dioxide will leave. If respiration were to increase will leave. If respiration were to increase (population increase), more oxygen would (population increase), more oxygen would leave the atmosphere & more carbon dioxide leave the atmosphere & more carbon dioxide would enter.would enter.

Read “Disrupting the Cycle” textbook pg. B10Read “Disrupting the Cycle” textbook pg. B10

What are some causes of increasing What are some causes of increasing carbon dioxide in the environment?carbon dioxide in the environment?

Burning more fossil fuels leads to greater Burning more fossil fuels leads to greater amounts of carbon dioxide in the atmosphere, amounts of carbon dioxide in the atmosphere, & deforestation results in less carbon dioxide & deforestation results in less carbon dioxide being removed from the atmosphere.being removed from the atmosphere.

Ch. 5 Lesson 2Ch. 5 Lesson 2Nitrogen & Water Nitrogen & Water

Most of Earth’s water is in the oceans. Most Most of Earth’s water is in the oceans. Most of the nitrogen is a gas in the air. Living of the nitrogen is a gas in the air. Living things use both water & nitrogen, which things use both water & nitrogen, which

cycle between Earth’s surface and cycle between Earth’s surface and atmosphere.atmosphere.

Nitrogen & WaterNitrogen & Water Nearly 80% of Earth’s atmosphere consists of Nearly 80% of Earth’s atmosphere consists of

nitrogen gas.nitrogen gas. Plants & animals need nitrogen to form Plants & animals need nitrogen to form

proteins & other important compounds. proteins & other important compounds. However, most living things cannot use However, most living things cannot use nitrogen in the form in which it occurs in the nitrogen in the form in which it occurs in the atmosphere. It has to be converted to a usable atmosphere. It has to be converted to a usable form. form.

The process of changing nitrogen gas into The process of changing nitrogen gas into usable nitrogen compounds is usable nitrogen compounds is nitrogen nitrogen fixation.fixation.

Nitrogen fixationNitrogen fixation

There are 2 main things responsible for There are 2 main things responsible for nitrogen fixation: lightening & bacterianitrogen fixation: lightening & bacteria

Lightening – the energy released by lightening Lightening – the energy released by lightening acts to combine nitrogen and oxygen in the air. acts to combine nitrogen and oxygen in the air. The new compounds dissolve in rainwater. The new compounds dissolve in rainwater.

Special bacteria – this produces most of the Special bacteria – this produces most of the nitrogen fixation. Some bacteria live in soil, nitrogen fixation. Some bacteria live in soil, water, or on roots of some plants.water, or on roots of some plants.

Nitrogen CycleNitrogen Cycle

http://www.h2ou.com/h2nitrogencycle.htm

Nitrogen cycleNitrogen cycle

Human activities can disrupt the nitrogen cycle, Human activities can disrupt the nitrogen cycle, resulting in a shortage or surplus of usable resulting in a shortage or surplus of usable nitrogen in the soil. When crops are harvested, nitrogen in the soil. When crops are harvested, the nitrogen in the plants leaves with the plants the nitrogen in the plants leaves with the plants & does not return. Erosion & irrigation can & does not return. Erosion & irrigation can also wash nitrogen out of the soil.also wash nitrogen out of the soil.

To replace nitrogen, farmers add nitrogen-rich To replace nitrogen, farmers add nitrogen-rich fertilizers. They also plant peanuts or other fertilizers. They also plant peanuts or other plants that general support the special bacteria plants that general support the special bacteria that produce nitrogen fixation.that produce nitrogen fixation.

Lets image we planted 2 plants at the same Lets image we planted 2 plants at the same time. They have received the same amount of time. They have received the same amount of water & sunlight, but for some reason Plant water & sunlight, but for some reason Plant

B is much taller then Plant A. Can you give a B is much taller then Plant A. Can you give a reason why they may be different and how we reason why they may be different and how we

might improve Plant A’s growth?might improve Plant A’s growth?

Plant A may not be getting as much nitrogen Plant A may not be getting as much nitrogen as Plant B. Plant A’s growth might be I as Plant B. Plant A’s growth might be I improved by adding nitrogen-rich fertilizer to improved by adding nitrogen-rich fertilizer to the soil.the soil.

Water in the EnvironmentWater in the Environment All living things are made up mostly of water. Living All living things are made up mostly of water. Living

things need water to carry out life processes. things need water to carry out life processes. Water as a cycle through the environment like carbon Water as a cycle through the environment like carbon

& nitrogen.& nitrogen. Most of Earth’s water is contained in oceans & is Most of Earth’s water is contained in oceans & is

salty. Fresh water is found in lakes, rivers, & streams. salty. Fresh water is found in lakes, rivers, & streams. Some water is underground. Water is also frozen in Some water is underground. Water is also frozen in snow, ice, glaciers, & polar ice caps.snow, ice, glaciers, & polar ice caps.

Water in the atmosphere is water vapor & tiny Water in the atmosphere is water vapor & tiny droplets of water or ice in clouds.droplets of water or ice in clouds.

Water cycleWater cycle

The water cycle is the continuous movement The water cycle is the continuous movement of water from Earth’s atmosphere & back to of water from Earth’s atmosphere & back to the surface. the surface.

Water cycles over & over again Earth’s air, Water cycles over & over again Earth’s air, ground, oceans, & living things. The power ground, oceans, & living things. The power for the water cycle comes from the Sun. for the water cycle comes from the Sun. Without it, water would stay in the oceans.Without it, water would stay in the oceans.

Water Cycle ProcessWater Cycle Process Evaporation & TranspirationEvaporation & Transpiration

Energy from the Sun causes water in the oceans & Energy from the Sun causes water in the oceans & on land to heat up. When this happens, water on land to heat up. When this happens, water evaporation increases. During, evaporation increases. During, evaporationevaporation, water , water consumes energy & changes from the liquid state consumes energy & changes from the liquid state to the gas state. Water in the gas state is called to the gas state. Water in the gas state is called water vapor.water vapor.

Plants also release water into the atmosphere. The Plants also release water into the atmosphere. The process through which water evaporates from a process through which water evaporates from a plant’s leaves is known as plant’s leaves is known as transportationtransportation..

Water Cycle Process – Cont.Water Cycle Process – Cont. PrecipitationPrecipitation

Water vapor in the atmosphere can condense into Water vapor in the atmosphere can condense into tiny droplets of water and form clouds. When the tiny droplets of water and form clouds. When the droplets become heavy enough, they fall to Earth droplets become heavy enough, they fall to Earth as rain, sleet, hail, or snow. Water that falls to the as rain, sleet, hail, or snow. Water that falls to the Earth from a cloud is called Earth from a cloud is called precipitationprecipitation. .

Most precipitation falls on Earth’s oceans. The Most precipitation falls on Earth’s oceans. The precipitation that falls on land is either absorbed precipitation that falls on land is either absorbed into the ground or flows to a body of water. Then into the ground or flows to a body of water. Then the cycle continues. Look at diagram in Txt. pg. the cycle continues. Look at diagram in Txt. pg. B17B17

Describe the role of trees & other Describe the role of trees & other plants in the water cycle – Essay plants in the water cycle – Essay

questionquestionDuring transpiration, water evaporates from the During transpiration, water evaporates from the

leaves of plants and enters the atmosphere as leaves of plants and enters the atmosphere as water vapor. Water vapor will condense to water vapor. Water vapor will condense to form clouds. Eventually, the water will fall form clouds. Eventually, the water will fall back to Earth’s surface as precipitation.back to Earth’s surface as precipitation.

Water ConservationWater Conservation Although almost ¾ of Earth’s surface is Although almost ¾ of Earth’s surface is

covered with water, about 97% of Earth’s covered with water, about 97% of Earth’s water is salt water in oceans.water is salt water in oceans.

Of the remaining 3%, less than 1% is usable Of the remaining 3%, less than 1% is usable fresh water. This water is not spread evenly fresh water. This water is not spread evenly around Earth.around Earth.

Water Conservation is key to survival. Water Conservation is key to survival.

Ch. 5 Lesson 3Ch. 5 Lesson 3Food ChainFood Chain

Energy moves in one direction Energy moves in one direction through the ecosystem from through the ecosystem from

producers to consumersproducers to consumers

Trophic LevelsTrophic Levels Organisms that make food are known as Organisms that make food are known as

autotrophs or autotrophs or producersproducers. Plants (which . Plants (which include trees) & algae are producers. include trees) & algae are producers.

Energy is stored in food. A plant uses some of Energy is stored in food. A plant uses some of the energy for its own life processes. It stores the energy for its own life processes. It stores the rest. An animal that eats a plant obtains the the rest. An animal that eats a plant obtains the stored energy. It then uses some of the energy stored energy. It then uses some of the energy & stores the rest. If another animal then eats & stores the rest. If another animal then eats the 1the 1stst animal, it obtains the stored energy. In animal, it obtains the stored energy. In this way, energy flows through an this way, energy flows through an ecosystemecosystem..

Trophic Levels – Cont.Trophic Levels – Cont.

Suppose, for example, that a mouse eats a Suppose, for example, that a mouse eats a plant. Energy is transferred from the plant. Energy is transferred from the plant to the mouse. If a hawk then eats plant to the mouse. If a hawk then eats the mouse, energy is transferred from the the mouse, energy is transferred from the mouse to the hawk. Each step in the mouse to the hawk. Each step in the movement of energy is known as a tropic movement of energy is known as a tropic level. Look at diagram in txtbook pg. B25level. Look at diagram in txtbook pg. B25

This is an example of a food chain,also.This is an example of a food chain,also.

Trophic Levels – Cont.Trophic Levels – Cont. The lowest level on the trophic level is the The lowest level on the trophic level is the

producers – trees, ferns, mosses, algaeproducers – trees, ferns, mosses, algae The second level is the The second level is the Primary consumersPrimary consumers, ,

this consists of heterotrophs – organisms that this consists of heterotrophs – organisms that can not make their own food. – squirrels, deer, can not make their own food. – squirrels, deer, seed-eating birds, insects, herring & other seed-eating birds, insects, herring & other small fish, baleen whales.small fish, baleen whales.

The third and last level is the The third and last level is the Secondary Secondary Consumers,Consumers, an organisms that eats a primary an organisms that eats a primary consumer consumer

Trophic Levels – Cont.Trophic Levels – Cont. Note that energy flows in one direction, from Note that energy flows in one direction, from

producers up through the trophic levels.producers up through the trophic levels. In nature, food chains & trophic levels may In nature, food chains & trophic levels may

overlap. Some animals eat both producers & overlap. Some animals eat both producers & primary consumers. For example, bears eat primary consumers. For example, bears eat fruit & fish. Some of the fish they eat may be fruit & fish. Some of the fish they eat may be secondary consumers that eat other fish. secondary consumers that eat other fish.

Overlapping food chains in an ecosystem for a Overlapping food chains in an ecosystem for a food webfood web..

Scavengers & DecomposersScavengers & Decomposers Scavengers are organisms that live off dead Scavengers are organisms that live off dead

animals. Example of large scavengers: vultures, animals. Example of large scavengers: vultures, hyenas, & ravens. Many insects are scavengers hyenas, & ravens. Many insects are scavengers too.too.

Scavengers help the break down of a dead Scavengers help the break down of a dead organism.organism.

Dead organisms that are left to Dead organisms that are left to decomposedecompose, , meaning to rot or break down, are food for meaning to rot or break down, are food for decomposers.decomposers.

Organisms called Organisms called decomposersdecomposers live by breaking live by breaking apart dead organic matter into simpler parts. apart dead organic matter into simpler parts.

Decomposers- Cont.Decomposers- Cont.Bacteria are Earth’s most important Bacteria are Earth’s most important

decomposers. Fungi & many protists are decomposers. Fungi & many protists are decomposers, too.decomposers, too.

Decomposers play a very important role by Decomposers play a very important role by breaking down old organisms, they return breaking down old organisms, they return minerals & nutrients to the soil.minerals & nutrients to the soil.

What is the relationship between decomposers & other organisms? – Essay question

• Decomposers break down the wastes of other organisms themselves when they die. They return chemicals to the soil to be used by other organsism.

Energy PyramidEnergy Pyramid We talked how energy is transferred to one We talked how energy is transferred to one

trophic level to the next, but remember, only trophic level to the next, but remember, only the stored energy can be transferred. the stored energy can be transferred.

A energy pyramid is a model that shows how A energy pyramid is a model that shows how energy moves from one level to another. It energy moves from one level to another. It shows that there is more energy available for shows that there is more energy available for use at lower trophic levels. Only about 10% of use at lower trophic levels. Only about 10% of the energy from each level is passed on to the the energy from each level is passed on to the next level.next level.

Look at energy pyramid in Txtbook pg. B27Look at energy pyramid in Txtbook pg. B27

Energy Pyramid- Cont. Energy Pyramid- Cont. Scientists also use a pyramid of biomass.Scientists also use a pyramid of biomass. A pyramid of biomass is a model that shows A pyramid of biomass is a model that shows

how much organic matter each trophic level how much organic matter each trophic level produces. produces.

Only about 10% of the biomass from each Only about 10% of the biomass from each level is passed on to the next level.level is passed on to the next level.

Read Pg. B28 and learn about The energy Read Pg. B28 and learn about The energy pyramid & Agriculture.pyramid & Agriculture.

Suppose that the number of secondary Suppose that the number of secondary consumers in an ecosystem increased. consumers in an ecosystem increased. How might this change affect other How might this change affect other organisms in this ecosystem? – Essay organisms in this ecosystem? – Essay questionquestion

If the number of secondary consumers If the number of secondary consumers increased, they would eat all the primary increased, they would eat all the primary consumers. The secondary consumers would consumers. The secondary consumers would then have no food, which could cause their then have no food, which could cause their populations to get smaller.populations to get smaller.