Biology Taxonomy

Hi, welcome back to www.educator.com, this is the lesson on taxonomy.0000

Taxonomy is all about categorizing groups for organisms, based on the evolutionary histories,0007

their body forms, genetics, and various other characteristics.0014

When it comes to taxonomy, it is really a system of classification.0019

You can classify anything in life.0023

You can classify types of music, types of shoes, types of buildings.0025

You can classify all kinds of things, that is a part of being a human.0032

We like to differentiate and compare and contrast things.0036

When it comes to life, humans are desire to classify what is life and how life is different,0040

and how other life forms are similar.0047

Ancient classification, very old as you would guess from the word ancient.0049

Classification systems pertaining to life, we started by Aristotle.0055

We are used and relied upon for over a thousand years, a very long time.0059

Aristotle had three main groups, depending on the textbook that you look in,0066

there will be slightly different phrasings of this.0070

I have seen this very often that he talked about animals with red blood, animals without red blood, and then plants.0073

Basically, according to Aristotle, according to his observations, every life form on earth was in one of these three groups.0082

You would imagine that humans and chickens and dogs, would be animals with blood.0089

Perhaps, you have an insect, or a worm, or maybe a squid, this one it is hard to say the entire list and0099

all the different animals that he would have been exposed in his lifetime.0111

Based on his observations, he separated all animals in these two groups, and everything else is plants.0115

The plant group, he would describe trees and bushes.0120

Probably he would have even put mushrooms in that group.0125

Now, we now know that mushrooms are not a plant, they are a fungus.0129

They are more closely related to animals than plants.0133

You got to cut stall and slack that, living about 2000 years ago,0137

even have all the tools we have today to figure out that a mushroom is in fact not a photosynthetic being like a plant.0143

There were some flaws to his system of classification.0152

Plants were split up based on type.0157

Further categorization underneath these little umbrella terms.0160

He would have split plants like that is a bush, that is a tree, etc.0166

Animals were split up based on where they were found, water, land, and air.0171

There is a problem with that because when you have very strict determining characteristics for that,0178

there is the water animals, there is the land animals, air animals.0185

What about a duck?0189

A duck can be in all three, they can fly, they can go to the water, and they can walk on land.0192

Yes, obviously some problems with his system.0201

However, up until the 1700’s approximately, this was a commonly use classification system in Europe and beyond.0204

Aristotle, you sir, definitely had a huge impact on classification.0210

Thanks to the scientific revolution and a little bit more kind of reliable thought,0217

in terms of like testing it out and figuring out for certain, it went beyond just theory.0223

Modern day classification is a little more precise.0229

Modern classifications, thanks to this gentleman Carolus Linnaeus, that was not his birth name.0234

He actually Latinized his own name, what I mean by Latinize is,0241

Latin is the basic language that he used to name species and categorize life.0252

It is almost a way to advertise the system that he invented.0261

He was born Carl Linnae.0264

You will also find it written as Carl Von Linnen in certain sources.0269

But Carl became known as Carolus Linnaeus because it almost sounds like a scientific name,0273

or ornithorhynchus anatinus that is the scientific name of the duck-billed platypus.0282

I can do it to my own name, I would be Briannus Cardellonis or Brianicus Cardillae.0286

He did it with Carl Linnae, and Carolus Linneaus, that name was born.0295

He was an 18th century Swedish biologist/botanist.0301

He knew a lot about animals, knew a lot about plants, and that certainly helped,0305

in him coming up of this really good way of categorizing life of different groups.0309

His system of classification is still used today, even though it dates back to the 1700’s.0314

It is known as taxonomy.0321

The different groups he came up with from broad to specific are called taxa.0323

You will see that on a slide in the future, in this lesson.0329

Taxonomy is the discipline of biology concerned with identifying, naming, and classifying species.0332

It is based on several different criteria.0338

We have the benefit of the evolutionary history, fossils, that inform us about different forms of life, we have DNA.0342

Carolus was not careless, but he did not rely on DNA because back then, he did not know about that.0352

He relied on some fossil evidence and then studying their bodily form,0364

which ones were similar to others and which ones were different.0372

Behavior can inform those things.0377

It is not just putting in different groups, it is naming them in the most specific way possible.0381

It is called a specific epithet.0388

Every organism has its own distinct name.0391

The cool thing about his system, regardless of whether or not a scientist knows Latin or speaks Swedish,0394

whether a scientist speaks English, Swahili, Japanese, Russian, Portuguese, it does not matter,0405

the same names are used around the world.0412

Here are the taxonomic groups.0418

From most broad to most specific, they are each called taxa.0420

Singular would be the term taxon.0424

A kingdom would be a taxon.0429

These are the taxa.0432

Domain, that is the largest group.0434

There are three domains and all life forms are in one of those three.0438

Domain, you think of it as a giant circle and that is domain.0441

A kingdom will be contained within the domain, like the animal kingdom.0449

Phylum, the class that we are in is actually called class mammalian.0459

That is c, I will do it in black because it is tough to see the c.0476

Order, like order carnivora, carnivorous mammals.0481

Family, let us do it in red, families are contained within orders.0489

Family hominidae,that would be the family that we are in.0499

Genus, like genus homo or genus canis, meaning it is of the dog family or phallus which is of the feline, the cat family.0505

Finally, within that we have got species, you can even go sub species.0523

The point is that, the broader groups contain smaller groups within them.0528

Within a kingdom, you could have 10 phyla, the different phylums, you could have 20.0533

It really depends on how scientists have decided to categorize, based on these different groups and the variety that there is.0540

I have seen in classrooms teachers talk about coming up with a mnemonic device,0550

meaning some kind of sentence that starts with all these letters so you can remember the order.0556

I have heard King Philip can only find green stools, or things like that.0563

If you include the D, did not King Philip crouch over fine green stations, I do not know, I’m just making up sentences.0570

If you come up with a sentence that even if it sounds silly, if you can remember it,0588

it will help you remember the order, from domain all the way down to species.0595

Quickly, I’m going to run through the names for our species.0601

Our domain is known as eukarya, more on that in the next slide coming up.0606

Kingdom, we are animals, animalia.0614

Phylum, this name might seem very strange at first but you will learn more about it in the future lesson in this course.0621

Chordata, we are chordates, all vertebrates are within that.0627

I had one little point here between phylum and class that, in here you have something called a sub phylum.0631

Scientists can feel free to do this, if they want to be a little bit more specific underneath a taxon,0641

but that is still more general than the next one down, you can talk about sub phylum vertebrata.0651

This would be all vertebrates, all animals with a spine.0658

Class, our class is mammalian.0662

There are definitely are sub classes of different kinds of mammals.0666

Our order, primates, sometimes called primata.0672

That would be all monkeys, apes, us, and our recent ancestors.0677

Family, hominidae, we are hominins, genus homo, species sapiens.0684

Our sub species is another sapiens, homo sapiens sapiens.0698

If you did this for a lion, African lion, it would be the same here, same here still animals,0703

still vertebrates, still mammals.0715

Once you get to order, there will be a separation.0717

With lions, they will be in order carnivore, family felidae because they are felines,0720

their genus species name would be different.0727

Binomial Nomenclature, this is the two main naming system, that is literally what this means.0732

Binomial two name, way of naming.0738

It is the scientific name of the species and is represented by having these two names back to back,0742

there is a certain way of writing it.0750

We are familiar with this, in a sense of homo sapiens or canis lupus would be the gray wolf.0752

When people hear canis or canine, they think it is dog.0760

Some of us are familiar with this, in terms of like hearing homo sapiens.0765

This applies to every single living organism.0769

They all have this scientific name.0772

Here are the rules for writing them out.0775

You capitalize the genus, lowercase the specific epithet.0777

Capitalize the genus, lowercase the specific epithet.0786

You have lowercased that.0792

By specific epithet, what we mean is that is the technical name for the second word.0794

It just means like, it is the most literally specific point.0802

It is the most specific end of this spectrum of naming.0808

Species comes from the word specific which makes sense, you are talking about a specific organism.0814

You italicize all of it when typed, like I did here.0819

Genus species, when its typed out, it is italicized, the letters do look slanted.0826

You underline all of it when it is handwritten.0833

If I were to handwrite this, it is not easy for people to italicize.0837

You would write genus species like Homo sapiens, like that.0841

But if I was typing it, I will write it like this.0858

See, this is not underlined.0861

This is the last kind of rule, the genus can be abbreviated with a single letter and period, it is implying that that is homo.0863

Also, you could see like this a lot, the e stands for escherichia,0871

that is the actual genus name for a really common bacterium that people are used to hearing about.0878

E coli is a commonly used abbreviation for the scientific name for this bacterial species.0883

Those are the rules with the binomial nomenclature that Carolus Linneaus came up with.0890

Advantages and disadvantages to taxonomy.0898

There are significant advantages to having the system in place.0900

Clarification of the relationships, close or distant between different organisms for all scientists worldwide.0904

Like I mentioned earlier, these names that most of them are derived from Latin and some of them scientific names0910

or the specific epithets are named after particular scientist who discovered them, in honor of them.0919

All of these names are used worldwide, regardless of what language is spoken.0925

That is awesome for international communication and sharing of data.0929

It is great that those things do not need to be translated.0934

Analysis of genetics in the fossil record relates to taxonomy so that we do not let appearances fool us.0937

Carolus Linneaus did a great job of categorizing beings.0944

There were occasional flaws in what he came up with because0948

he did not have the benefit of really advanced genetic analysis, in his favor.0951

These days, we can look it to animals and say that they were really closely related.0957

Let us say, you talk about the Roly-poly also known as an isopod.0964

Roly-poly look like this, they are kind of gray, they have their little feet.0971

And they can roll up to that cute little ball, when they get disturbed.0976

You find these in various places in the soil, in the dirt.0982

You might look at this and say that they are insects.0987

People will say they are not insects because they do not have 6 legs.0991

They definitely look like they are closely related.0995

Not as close as you might think, these are related to crustaceans.0999

But why are they not in the water?1007

There are giants isopods, relatives of wood lice, at the bottom of the ocean and they eat up dead carcasses of whales and such.1009

On land, these still do resemble crustaceans that are in the water, they have gills because1021

if these do not get enough water in the soil, they actually will suffocate.1028

I learned that the hard way when I ordered some of these roly-poly for a lab.1034

When the package of them arrived in the dirt, it told me to quickly open it and spray them with water.1038

I did not look at that notification.1043

By the time I open them, they were all dead, they have dried out because they were not given enough moisture to breathe.1045

They do still have this relationship to crustaceans.1053

Looking at them just base on appearances, you might not think of that relationship.1057

But analyzing their internal anatomy, their genetics, reveals a little bit more about what category of life they should be put in.1062

There are some disadvantages though to taxonomy and the system.1072

Occasionally, there is no category or group that adequately fits a species.1076

By virtue of making this set of determinant, to be in this group, A, B, and C have to be true.1082

What if only A and B are true, and A and B is not enough to get them in this category,1090

but now there is no other category that they belong in?1095

When it comes to these two, this is an example of the flaw of taxonomy.1099

The giant panda, it looks like a bear.1105

Bears are in order carnivora, they are carnivorous mammal and they are all related.1110

But there is plenty of species of bears now, within this order.1117

Are pandas carnivores?1122

No, they primarily depend on bamboo.1124

They tend to be herbivorous.1128

They tend to be herbivores.1133

Occasionally in the wild, pandas have been observed eating tiny animals, that is rare though.1140

They tend to rely on bamboo.1147

To put them in order carnivora is somewhat misleading.1149

Yes, there are genetic links and evolutionary links to a bear ancestor.1152

But putting them in this order is a little bit misleading.1159

Tardigrades, I have them pictured right here.1164

This is taken with a high powered microscope, they are very tiny.1166

At the largest, they will be like close to a millimeter in size.1171

They have their own phylum.1176

If you remember the order domain to kingdom to phylum, etc, phylum is a really broad group.1178

It is right below kingdom.1189

Kingdom animalia which has all animals, they have their own phylum.1190

When you look at the amount of species in each of the typical phyla, tens of thousands of species, if not more.1196

Phylum tardigrada has its own phylum named after it because1206

scientists have not discovered a living animal that resembles this at all.1211

They have theories about what it is more closely related to, like which worm or which other animal it has more in common with.1216

It is so weird that it is hard to put it in a category because it is so unique.1225

Domains, this is that broadest, the most broad category within our taxonomic system.1232

When I took biology, domains was first starting to appear in textbooks and1240

even a lot of textbooks at that time did not have the mention of domains.1245

But a lot of research into the kingdoms of life which is a little bit more specific,1249

has revealed some trends with three major groups of life, coming out of those kingdoms.1254

The three domains includes every life form an earth, every single life form you could possibly find,1262

could be put in one of these three domains.1268

There is domain archaea which includes all archaea bacteria, that is our little red part here.1270

Bacteria, includes all eubacteria, eu stands for true.1278

Archaea comes from the word archaic meaning ancient, very old.1290

I will explain more about that in a bit.1301

Domain eukarya, eukaryotes, you have seen what those are from the previous lesson.1304

That is all cells that actually have membrane bound organelles, nuclei, mitochondria, chloroplasts, etc..1311

The majority of species that have been discovered, they are definitely in this green region.1317

Down here, this is early on in time on earth and here is present day up on top.1324

There is a common ancestor right, the first official cell that get passed on its DNA.1332

We get to this point where there is a split.1337

This split is between what lead to eubacteria, the true bacteria that we are commonly exposed to, and archaea.1341

Archaebacteria, they tend to exist in really extreme environments.1349

I will tell you more about kingdom archaebacteria in a future lesson.1353

It is interesting that archaebacteria, they tend to be what are called extremophiles.1358

Extremophiles meaning they love extreme conditions, extreme temperatures, extreme salt level,1369

extreme amounts of certain gases, extreme acidity levels.1389

They like extremes.1393

It is interesting that these are modern day descendants of a very ancient form of bacteria that got by next to hydrothermal vents.1395

It got by in really harsh conditions.1405

You tend to not be exposed to these very much in your daily life.1408

Because right here right now, where you are watching this lesson, where it is room temperature,1411

it would be too darn cold for a lot of archabacteria to exist there.1418

You tend to find a lot of archaebacteria where it is really hot temperatures, even exceeding boiling.1421

The funny thing is that, notice that there was a split from archaea and what lead to us.1428

Analysis of those cells has revealed that, we actually have more in common as eukaryotes with archaea than with bacteria.1435

With bacteria, there still is plenty in common.1449

We still have ribosomes, we still have some genes in common with them.1455

When you compare what is going on in here, the ribosomes in archaebacteria,1461

certain proteins in archaebacteria, and DNA sequences, they are more in common.1467

This split right here, you can think endosymbiosis for that.1472

If you remember from earlier lesson, endosymbiosis was the point where you get this green line occurring.1485

You get membrane bound organelles inside of cells, what will become mitochondria and chloroplasts.1490

The success of eukarya and multicellularity on this planet,1497

is thanks to this green lineage that grew out of that separation from archaebacteria.1501

The kingdoms are within the domains.1510

Those three domains how these little kingdoms within them.1512

Archaebacteria and eubacteria, when we look at domain archaeaa, there is one kingdom, it is this one.1517

When you look at domain bacteria, there is one kingdom.1524

When I actually took biology, these were all considered monerans or monera.1527

If you ever come across this term moneran, it is basically talking about all forms of bacteria.1536

It is not as commonly used today because scientists differentiate between these.1541

There is enough differences to talk about them into different kingdoms, two different categories.1546

Kingdom protista, I wrote debatable here because certain textbooks will actually list several kingdoms for protists.1552

For right now, just know that protists are eukaryotic, they are in domain eukarya but they do not have organs.1561

You tend to see a lot of unicellular protists, single celled beings in lakes, ponds, the oceans, rivers, etc..1568

You see some on land as well.1577

Occasionally, you will come across multicellular protist.1580

They do not have highly developed organs that would make them plants or fungi or animals.1583

They are grouped to this category and that is why you have the lineage depicted it as it is.1589

You can see that down here, this would be the origin of life.1594

You got your eubacteria, your archaebacteria.1598

From out of that, you get a new symbiosis leading to single celled eukaryotes.1600

With a little bit more complexity from out of protist, you get the other three kingdoms here.1607

You can see in this protist category, you do have unicellular and multicellular.1613

Up here with plants, animals, and fungi, you do not have individuals that are single celled.1617

When you see single celled here, it is a sperm and egg that are temporary form to give rise to the new organism.1624

Notice that all of these are multicellular and they would have specialized tissues.1631

Plantae, fungi, mammalia, I will be going over them in this order, in future lessons in this course.1638

I wrote viruses with a question mark because viruses, they are technically not alive.1647

I put a question mark because in the taxonomic system that scientists tend to use,1657

the system that Carolus Linneaus started, there is no virus kingdom.1661

There are names for viruses, a lot of times they will be a letter and number sequence that viruses are given.1666

There are groupings of viruses, there are categories but they are not considered part of the taxonomic naming system,1675

because there are reasons why they are not alive.1682

If you watch the virus lesson, I will go over those reasons.1684

Next is cladograms, cladistics, involving the making of a cladogram which relates evolution to phylogeny.1688

Phylogeny is all about the grouping of organisms based on which one split from which,1697

why is this group considered in this category vs. this group, kind of steps in the evolutionary tree1704

that cause organisms to differentiate overtime.1711

It shows how various characteristics have led to the splitting off of groups of organisms in evolutionary history.1713

Here is a cladogram, right now I do not have all the species listed or the characteristics involved in which one got it,1720

which one did it, and how the splits happen.1729

We are going through it step by step.1731

This is going to be a vertebrate cladogram.1733

You can do it with all kinds of animals and plants.1736

We are going to say that here, there is a particular organism.1741

As time goes on, we go all the way up to here.1745

Each of these branches is a subsequent kind of splitting off.1748

This is a vertebrate ancestor.1754

Here we have what is known as a lamprey.1767

A lamprey is a jawless fish.1771

It is a fish with a spine, it would have to have a spine because from a vertebrate ancestor,1776

all the organisms we get along this lineage are also going to be vertebrates.1781

They are also going to have spines.1784

This is known as out group because right here, we are going to have a characteristic occurring.1786

Some adaptation, some change that caused the next one to have a characteristic that the previous one does not.1793

In here, we are going to have something developing that every other organism afterwards also has.1804

Here is the jaw, jaws develop and we get the tuna.1811

A fish with an actual bony jaw.1825

Lampreys have like a sucking face, they have eyes, they have mouth, but they do not have an actual jaw.1830

Next up, we would have another one, another splitting off.1839

It could be a leopard frog, it could be a tree frog, a frog.1849

What do frogs have that a tuna would not?1853

They have lungs.1858

And that means all the animals after this will have this lung characteristic.1864

Tuna, they have gills.1870

Frog has lungs, they are tinier than another organisms like the average reptile or mammal or bird.1873

Frogs they have lungs, that is why they can breathe air on land.1880

Next up, let us go with a lizard.1885

What is it that a lizard would have and these others will have, that a frog does not?1899

It is an amnion.1908

In a lizard or birds, it would be an amniotic egg meaning1912

you have this actual protective separation of the egg in the developing embryo from the outer environment.1918

In lizards and birds, reptiles and birds, you have a hard shell typically.1925

With frogs and fish, you have a very fragile, soft, delicate egg,1931

that does not have this amniotic sac or membrane, with some kind of extra barrier like a uterus or a hard shell.1938

An amnion, lizards, birds, mammals have that same characteristic demonstrated a little bit differently.1949

Next up, we have some mammals.1956

I’m going to say tree shrew, this is a rodent, something that the tree shrew has that,1961

among a lot of things that the lizard does not is hair, actual fur, lizards do not have that.1973

The rest of them, they are all going to have hair.1980

We can also say warm blooded, four chambered heart.1982

There is a lots of things that mammals have in comparison to the average reptile but when we say hair, here.1988

Tree shrew has hair.1997

Next up is chimpanzee.1999

Among other things, I mean we can say front facing eyes, a lot of different things.2007

We are going to say, let us go with front facing eyes.2013

Or binocular vision, stereoscopic vision is also ways to say this.2041

As discussed in the human evolution lesson, having eyes in the front, overlapping fields of vision gives you depth perception.2046

There are advantages having eyes in the side, you get more in the periphery.2053

Depth perception, when swinging to the trees definitely a good thing.2058

Last is going to be humans.2063

Something we have that they do not would be bipedalism, not being dependent on locomotion with our forelimbs as adults.2067

That is the norm for humans to walk on two legs.2084

Chimps, it might seem that they are dependent on just two legs, until they get running fast and then you see them on all fours.2090

They are naturally quadropedal, and we are bipedal.2099

It takes a lot more energy to be bipedal, to have that balance.2103

It certainly has its advantages, as discussed in the human evolution lesson.2109

This is a cladogram, a way that you can connect taxonomy or phylogeny to the evolutionary tree of life.2113

Thank you for watching www.educator.com.2120