Cycles of Matter

Summary

This educational script delves into the fundamental elements of life—oxygen, carbon, hydrogen, and nitrogen—and their role in forming essential compounds like water, carbohydrates, lipids, proteins, and nucleic acids. It underscores the law of conservation of mass and energy, highlighting that these elements are recycled through biogeochemical cycles, influenced by biological, geological, and chemical processes. The script explores the water cycle, emphasizing its five main processes: evaporation, condensation, transpiration, percolation, and precipitation. It also touches on the carbon and nitrogen cycles, detailing how they are integral to life's sustenance, with human activities significantly impacting these cycles on a global scale.

Takeaways

• 🌿 Living organisms are primarily composed of oxygen, carbon, hydrogen, and nitrogen, with phosphorous playing a role in nucleic acids.
• 🔄 The law of conservation of mass and energy states that matter and energy cannot be created or destroyed, only transformed.
• 🌎 Organisms do not manufacture elements; they are recycled within ecosystems through biogeochemical cycles.
• 💧 The water cycle involves processes such as evaporation, condensation, transpiration, percolation, and precipitation, demonstrating how water is recycled in the biosphere.
• 🌱 Photosynthesis and respiration are key biological processes in the carbon cycle, where carbon dioxide is either taken in or released.
• 🔥 Human activities, including burning fossil fuels and deforestation, significantly impact the carbon cycle and the cycling of matter on a global scale.
• ♻️ The nitrogen cycle is complex and involves the conversion of atmospheric nitrogen into forms usable by organisms, primarily through nitrogen fixation by bacteria and lightning.
• 🌾 Legumes like peas, soybeans, peanuts, and lentils play a crucial role in the nitrogen cycle by fixing atmospheric nitrogen and making it available to other plants.
• 🌋 Geological processes, such as volcanic eruptions, also contribute to the carbon and nitrogen cycles by releasing stored gases into the atmosphere.
• 🌱 Crop rotation, particularly incorporating legumes, is a farming practice that enhances soil fertility by replenishing nitrogen, which is vital for plant growth.

Q & A

What are the four most abundant elements in living organisms?

The four most abundant elements in living organisms are oxygen, carbon, hydrogen, and nitrogen.

What is the law of conservation of mass, and how does it relate to the biosphere?

The law of conservation of mass states that matter and energy are never created nor destroyed. In the biosphere, this means that organisms cannot manufacture these elements, and they do not use them all up; instead, matter is recycled within ecosystems.

What are biogeochemical cycles, and why are they important for life?

Biogeochemical cycles are closed loops through which elements pass from one organism to another and to various parts of the biosphere. They are important for life because they allow for the recycling and reuse of essential elements like carbon, nitrogen, and phosphorus, which are necessary for the formation of life's most important compounds.

How does the availability of elements affect ecosystems?

The availability of elements affects ecosystems by influencing the cycling of matter. If certain elements are scarce, it can limit the growth and health of organisms, which in turn affects the entire ecosystem.

What are the main processes involved in the water cycle?

The main processes involved in the water cycle are evaporation, condensation, transpiration, percolation, and precipitation.

What is transpiration, and how does it relate to the water cycle?

Transpiration is the process by which water evaporates from the leaves of plants. It is a part of the water cycle as it contributes to the water vapor in the atmosphere, which can then condense to form clouds and lead to precipitation.

How does human activity affect the cycles of matter on a global scale?

Human activities such as mining, burning fossil fuels, clearing land for agriculture, and the use of fertilizers can significantly affect the cycles of matter. These activities can alter the natural balance of elements like carbon and nitrogen in the environment.

What is the role of photosynthesis and respiration in the carbon cycle?

Photosynthesis and respiration are reverse processes in the carbon cycle. Photosynthesis takes in carbon dioxide and uses it to make food for the plant, while respiration releases carbon dioxide back into the atmosphere.

Why is nitrogen fixation important in the nitrogen cycle?

Nitrogen fixation is important because it converts atmospheric nitrogen, which is unusable by most organisms, into ammonia or nitrates that can be used by plants. This process is carried out by certain bacteria and is essential for making nitrogen available in the soil for plant growth.

What are the two main processes in the nitrogen cycle that involve bacteria?

The two main processes in the nitrogen cycle that involve bacteria are nitrogen fixation and denitrification. Nitrogen fixation converts atmospheric nitrogen into a form usable by plants, while denitrification releases nitrogen gas back into the atmosphere.

Outlines

00:00

🌿 Biogeochemical Cycles and Conservation of Matter

This paragraph introduces the fundamental elements that make up living organisms: oxygen, carbon, hydrogen, nitrogen, and phosphorus. It emphasizes the law of conservation of mass and energy, stating that these elements are neither created nor destroyed but are recycled within ecosystems. The concept of biogeochemical cycles is introduced, explaining how elements move through the biosphere in closed loops, influenced by biological, geological, and chemical processes. Human activities, such as mining and burning fossil fuels, also impact these cycles on a global scale. The paragraph sets the stage for understanding how matter is recycled in nature, powered by the one-way flow of energy.

05:01

💧 The Water Cycle and Its Processes

The second paragraph delves into the water cycle, one of the most familiar biogeochemical cycles. It outlines the five main processes: evaporation, condensation, transpiration, percolation, and precipitation. Each process is described with examples, such as water evaporating from bodies of water and transpiration from plant leaves. The paragraph also touches on how water has been part of Earth's history, possibly existing in dinosaurs or historical figures like Julius Caesar, highlighting the recycling of matter. The importance of the water cycle for life is emphasized, as it demonstrates the continuous reuse of water through various stages.

10:01

♻️ The Nitrogen Cycle: Fixation, Utilization, and Denitrification

This paragraph explores the nitrogen cycle, which is crucial for life as nitrogen is a key component of amino acids and nucleotides. It explains that while the atmosphere is rich in nitrogen, most of it is unusable for living organisms. The process of nitrogen fixation, where unusable atmospheric nitrogen is converted into usable forms like ammonia and nitrates, is discussed. This can occur through natural processes like lightning or through the action of bacteria in the soil and water. The paragraph also mentions the role of legumes in nitrogen fixation and the practice of crop rotation to maintain soil fertility. Denitrification, where bacteria release nitrogen gas back into the atmosphere, is also highlighted as a key process in the cycle, showing the interplay between biological and geological processes.

Keywords

💡Biogeochemical Cycles

Biogeochemical cycles refer to the continuous movement and transformation of elements like carbon, nitrogen, and phosphorus through the biosphere. These cycles are powered by the one-way flow of energy and involve the interaction of biological, geological, and chemical processes. In the video, biogeochemical cycles are central to understanding how matter is recycled within ecosystems, as they illustrate the pathways through which elements pass from one organism to another and through various parts of the environment.

💡Conservation of Mass

The law of conservation of mass states that matter cannot be created or destroyed, only transformed. This principle is fundamental to the video's discussion of biogeochemical cycles, as it underscores the idea that while elements are recycled and rearranged within the biosphere, they are not lost or created anew. The script mentions this law as a key concept in biology, chemistry, and physics, highlighting its universality across scientific disciplines.

💡Evaporation

Evaporation is the process by which water changes from a liquid to a gaseous state. In the context of the video, evaporation is a critical component of the water cycle, where water from various sources, such as oceans and bodies of water, turns into vapor and enters the atmosphere. The script uses the example of a model over the ocean to illustrate this process, emphasizing its role in the continuous recycling of water within the biosphere.

💡Condensation

Condensation is the process where water vapor in the atmosphere cools and changes back into liquid form, often resulting in the formation of clouds. The video script describes condensation as a natural consequence of water vapor rising and cooling in the atmosphere, which is essential for the water cycle. It is also mentioned as a common occurrence, such as on a window when one side is cooler than the other.

💡Transpiration

Transpiration is the process by which water is released from the leaves of plants into the atmosphere as a vapor. The video script highlights transpiration as another form of evaporation, contributing to the water cycle. It is an important biological process that helps in the movement of water from the soil, through the plant, and back into the atmosphere.

💡Percolation

Percolation is the movement and filtering of water through layers of soil and rock. In the video, percolation is described as a geological process where water moves downward through the ground, being filtered as it goes. This process is essential for the water cycle, as it helps in the replenishment of groundwater and the filtration of water before it becomes part of other water bodies.

💡Precipitation

Precipitation refers to any form of water that falls from the atmosphere to the Earth's surface, including rain, snow, sleet, and hail. The video script mentions precipitation as a familiar part of the water cycle, where water that has evaporated and condensed in the atmosphere eventually falls back to the Earth. This process is crucial for replenishing water sources and continuing the cycle of water movement through the biosphere.

💡Photosynthesis

Photosynthesis is the process by which plants, algae, and some bacteria convert carbon dioxide and water into glucose and oxygen using sunlight. In the video, photosynthesis is presented as a key biological process in the carbon cycle, where plants take in carbon dioxide and produce organic compounds necessary for growth, while releasing oxygen back into the atmosphere.

💡Respiration

Respiration is the process by which living organisms, including plants and animals, convert glucose and oxygen into carbon dioxide, water, and energy. The video script explains that respiration is the reverse process of photosynthesis, where carbon dioxide is released back into the atmosphere, completing the carbon cycle and illustrating the continuous exchange of carbon within the biosphere.

💡Nitrogen Fixation

Nitrogen fixation is the process by which atmospheric nitrogen, which is largely unusable by most organisms, is converted into a form that can be used by plants, such as ammonia or nitrates. The video script discusses nitrogen fixation as a critical step in the nitrogen cycle, facilitated by certain bacteria and plants like legumes. This process makes nitrogen available for use in the synthesis of essential biological molecules like proteins and nucleic acids.

💡Denitrification

Denitrification is the process by which certain bacteria convert nitrates back into nitrogen gas, releasing it back into the atmosphere. In the video, denitrification is highlighted as an essential part of the nitrogen cycle, allowing for the recycling of nitrogen within the biosphere. This process is important for maintaining the balance of nitrogen compounds in the soil and water.

Highlights

Living organisms are composed mostly of oxygen, carbon, hydrogen, and nitrogen, with phosphorous in nucleic acids.

The law of conservation of mass and energy states that matter and energy are never created nor destroyed.

Organisms cannot manufacture elements; they must be obtained from the environment.

The availability of elements affects ecosystems, and organisms participate in biogeochemical cycles.

Matter moves through the biosphere differently than energy, which moves in one direction and dissipates as heat.

Earth receives a steady supply of energy from the sun but not a steady supply of new matter from space.

Matter is recycled within ecosystems in closed loops called biogeochemical cycles.

Biological processes include activities performed by living organisms, such as eating, breathing, and eliminating wastes.

Geological processes include volcanic eruptions, weathering, erosion, and movements within the Earth's surface.

Chemical and physical processes involve the formation of clouds, precipitation, and the action of lightning.

Human activity affects the cycles of matter on a global scale, including mining, burning fossil fuels, and land clearing.

The water cycle involves five main processes: evaporation, condensation, transpiration, percolation, and precipitation.

Carbon, nitrogen, and phosphorus recycle through biogeochemical cycles, essential for life.

Photosynthesis and respiration are reverse processes that take in or release carbon dioxide.

Decaying organisms and human activities, such as burning fossil fuels, contribute to the carbon cycle.

Volcanic activity is a geological part of the carbon cycle, releasing carbon dioxide into the atmosphere.

The nitrogen cycle is more complex, involving nitrogen fixation and denitrification by bacteria.

Legumes, such as peas and soybeans, play a crucial role in nitrogen fixation, making unusable nitrogen usable for other plants.

Crop rotation, including nitrogen-fixing plants, is a common agricultural practice to maintain soil fertility.

Bacteria in the soil help in the nitrogen cycle by obtaining energy from nitrates and nitrites, releasing nitrogen gas.

Transcripts

living organisms are composed mostly of

four elements oxygen carbon hydrogen and

nitrogen as we've just been talking

about in this whole unit with a little

bit of phosphorous thrown in there for

good measure in the nucleic acids these

are the basis for life's most important

compounds water carbohydrates lipids

proteins and nucleic acids but there's a

law in all of science it's about the

conference conservation of mass matter

and energy mass matter and energy are

never created nor are they ever

destroyed organisms cannot manufacture

these elements and they do not use them

all up so where do organisms get these

elements how does the availability of

these elements affect ecosystems guess

what get your papers ready because we're

gonna find out remember

wide right skinny left see on the next

slide on the first slide I mentioned the

law of conservation of mass matter and

energy okay this is a law that you're

going to hear repeated over and over in

biology as well as chemistry and physics

matter moves through the biosphere

differently than the way energy does

remember energy moves in one direction

from one trophic level to the next some

energy dissipates into the environment

as heat along the way but while the

Earth's receives a steady supply of

energy in the form of sunlight

constantly entering the biosphere Earth

does not receive a steady supply of new

matter from space instead matter is

recycled within in between all the

ecosystems if you take a look at the

picture on this slide and on page 79 in

your textbook it can help you remember

that these cycles of matter are powered

by this one-way flow of energy

matter moves through the cycles and is

transformed it's never created it's

never destroyed it's just changed or

rearranged

element's pass from one organism to

another and to various parts of the

biosphere in closed loops called bio geo

chemical cycles so that's one big word

that's got really three words crammed

together biological geological and

chemicals we call them biogeochemical

cycles and there are many ways they can

be classified biological processes

consist of any and all activities

performed by living organisms like the

bear catching the fish and the digestion

of the fish and all that kind of stuff

eating breathing burning food

eliminating eliminating wastes all of

these are biological processes

geological processes include things like

volcanic eruptions weathering erosion

movements within and below the surface

of the earth we see a beautiful picture

of Bryce Canyon here showing geological

processes and the island of Surtsey

erupting those are all geological

processes the formation of clouds

precipitation the flow running water and

the action of lightning are examples of

chemical and physical processes okay so

there's our bio geo chemical so we're

going to be talking about all three of

those as we go through this section

we're also going to be talking about

human activity because human activity

affects the cycles of matter on a global

scale

these can include activities such as

mining burning fossil fuels clearing

land to build a farm burning forests or

the manufacture and use of fertilizers

it even extends into our waters with

drilling rigs and production platforms

and barges and pipelines and all that

stuff these processes are vital to the

cycling of matter as you're going to see

in

classroom activities with the carbon and

the nitrogen cycle games the same atoms

and molecules are passed around again

and again and again but often in various

different compounds it's a never-ending

cycle so think about this the carbon or

nitrogen atoms or phosphorus atoms or

the water molecules in your body today

could have once been a part of a rock on

the ocean floor or they could have been

in the tail of a dinosaur or even a part

of someone like Julius Caesar

remember that matter is not created and

it's not destroyed it just keeps getting

reused and in order to get reused it has

to be recycled so in the next few slides

we're going to talk about those

processes we're gonna start with the

water cycle because it's probably the

most familiar to you and it's also the

first one they talked about in the book

so in the water cycle there are five

main processes that we're going to

consider the first one is evaporation

evaporation is the change of water from

a liquid to gaseous state we see an

example of evaporation here in this

model over the ocean and there's some

over the smaller body of body of water

as well water evaporates from all of

those places and goes into the

atmosphere as the gaseous water rises in

the atmosphere the temperatures become

cooler and when the temperatures become

cooler water vapor can't stay in the

gaseous state so it starts to condense

back into liquid and it forms bigger and

bigger droplets of water these bigger

and bigger droplets of water condense

and form clouds you see condensation on

windows when it's cooler on one side of

the window then then the other side okay

so water condenses so condensation we

see that happening where the clouds are

in this picture in the second little set

of red circles water can also evaporate

from the leaves of plants this is called

transpiration and you see that in the

fourth circle here so water evaporating

from the leaves of plants is called

transpiration water also moves down

through the ground it's filtered by

layers and layers of soil this process

is called percolation and you see

percolation all the way over there in

the right hand corner in our last circle

it's again water moving down through the

soil and being filtered by the layers

and layers of soil it's also a term

you're gonna hear in chemistry next year

because it means in general the movement

and filtering of a fluid in this case

water through layers of a porous

material in this case soil and rock

lastly another familiar part of the

process and something we've been seeing

quite a bit of lately is precipitation

yeah so everywhere here where you see

it's snowing or raining or sleeting we

see precipitation so the water that was

raining on us today might have been

water that was in a pool that dinosaurs

drink from millions of years ago pretty

cool I hear the dogs barking I gotta let

him go in water is not the only material

that recycles here in the biosphere

carbon nitrogen and phosphorus do as

well remember we don't have a new source

of elements coming in from outer space

like we do light energy so all matter is

just rearranged and used again and again

it's not created and it's not destroyed

nutrients pass through these

biogeochemical cycles moving carbon

nitrogen and phosphorus through the

biosphere without these life wouldn't

exist so let's take a look at the carbon

cycle photosynthesis and respiration are

reverse processes that either take in or

give off carbon dioxide and you might

already know plants do photosynthesis

but animals and plants do respiration

putting carbon dioxide into the air so

photosynthesis takes carbon dioxide out

and they use it to make their food which

is also a carbon compound but then at

night time they undergo respiration

which they take in oxygen and give off

carbon dioxide just like we do this is

the bio part of the biogeochemical

processes in the carbon cycle and you

see them circled in the two little

circles labeled photosynthesis and plant

respiration now decaying organisms also

put carbon

site back into the atmosphere as well so

we see that little circle there this is

where the detritivores and and

decomposers come in that we were just

talking about in the last section humans

have a part in this cycle as well as

they do in all cycles we burn fossil

fuels rerun automobiles we heat our

homes we generate electricity this is

the chemical part of the biogeochemical

process it's also human activity not

shown in this model but nonetheless

important is the geological part of this

cycle the geological part is volcanic

activity volcanic activity releases

tremendous amount of carbon dioxide into

the atmosphere this is carbon dioxide

that's been trapped in rock and magma

for millennia so yeah there's the carbon

cycle now the nitrogen cycle is a little

bit more complicated so we're gonna take

two slides to kind of sort it all out

here so just kind of stick with me on

this it is pretty interesting if you

asked me 78% of our atmosphere is

nitrogen but very little of it is any

use to living things as is all living

things need nitrogen do you remember why

we need it to make two things amino

acids for proteins and nucleotides for

nucleic acids nitrogen occurs naturally

in the soil as ammonia nh3 nitrate ions

no.3 - and nitrite ions no.2 - now you

don't need to remember the formula so

you just kinda need to be familiar with

the words that they're that they're

nitrogen compounds that occur in the

soil okay these compounds come from

animal wastes from dead decaying organic

matter some dissolved nitrogen exists in

the ocean and as we said nitrogen gases

in the atmosphere you see that noted

with the little three little black

arrows that we have here

okay now since 70% of the nitrogen is

unusable in order to recycle it it needs

to be made usable again okay so what do

you do if you have something that isn't

usable and you want to use it again you

fix it so nitrogen needs to be fixed it

gets fixed by reacting with hydrogen or

oxygen lightning fixes some atmospheric

nitrogen and bacteria in the soil and in

the water fix still more a third source

of nitrogen fixation is in plants called

legumes Peas soybeans peanuts and

lentils are examples of legumes now

farmers might plant these crops these

crops take the unusable nitrogen in the

soil and they make it usable again and

as I said farmers might plant these

crops this is actually pretty critical

because there are some crops like corn

that are nitrogen hogs they just deplete

the soil of all the usable nitrogen

stores in two or three crop cycles now

farmers usually don't want to spend

additional money on fertilizer so they

can do one of two things in a situation

if they have a field that doesn't have a

lot of nutrient as pretty poor soil they

can let the field sit fallow for one or

two crop cycles and let natural soil

bacteria work back up financially this

might not be a very good decision for

the farmer though so the farmer has

another option he can plant something

like soybeans or alfalfa or peanuts

because those crops put the nitrogen

back the good nitrogen back into the

soil this is called crop rotation and

it's very very common among farmers we

also have bacteria in the soil that

obtain energy from the nitrates and the

nitrites releasing nitrogen gas back

into the atmosphere so that the cycle

can start all over again

so if you study the diagram that we have

here which is also the same diagram

that's in the textbook you can see that

the nitrogen cycle is predominantly a

biological cycle you see the cycle of

nitrogen fixation and denitrification

shown in the purplish blue arrows here

fixation and denitrification by bacteria

are the two main processes in the

nitrogen cycle and those are the words

that I want you to be most most familiar

with this happens in both soil and water

and it goes from soil or water to the

air and back ok continually happening

geologically some nitrogen is put into

the air with volcanic activity but not

very significant amounts chemically some

of the nitrogen atmospheric nitrogen is