Evolution Continues Bozeman Science English (auto-generated) English

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hi it's mr. Andersen and welcome to biology essentials video number nine

Hi. It's Mr. Andersen and welcome to biology essentials video number 9. This

this is on populations how they came to be through evolution how they continue

is on populations. How they came to be through evolution. How they continue to evolve every

to evolve every day one of my favorite theories in all of evolution is the idea

day. One of my favorite theories in all of evolution is the idea of the Red Queen

of the Red Queen theory and it essentially comes from Alice Through the

Theory. And it essentially comes from Alice Through the Looking Glass or Through the Looking

Looking Glass or through the looking-glass where Alice remember is running around with the Red Queen and she eventually stops and says well in my

Glass where Alice remembers running around with the red queen. And she eventually stops

country you generally get somewhere if you run as fast as you can like we've

and says "Well, in my country, you'd generally get somewhere if you run as fast as you can

been doing and the Red Queen says you live in a slow sort of country here it

like we've been doing." And the red queen says, "You live is a slow sort of country.

takes all you all the running you can do just to stay in the same place if you

Here it takes all the running you can do just to stay in the same place. If you want to

want to get somewhere else you must run at least twice as fast and so what's

get somewhere else you must run at least twice as fast." And so what's interesting about

interesting about that is it's a really good metaphor for how natural selection and evolution takes place species are

that is it's a really good metaphor for how natural selection and evolution takes place.

constantly in competition against all of the other organisms around them and they

Species are constantly in competition against all of the other organisms around them. And

may not look like they're changing but they continue to change and it's shaped

they may not look like they're changing but they continue to change and it's shaped the

the life that we have on our planet and so what am I going to talk about well

life that we have on our planet. And so what am I going to talk about? Well I'm going to

I'm going to start with evolution and the idea is that it's been around from day one so from day one until today all life on our planet has been created

start with evolution and the idea is that it's been around from day one. So from day one until today all life on our planet has been created through evolution or change.

through evolution or change and also it

continues on a daily basis species are evolving every day populations are

And also it continues on a daily basis. Species are evolving every day. Populations are evolving.

evolving because remember all evolution is is is a change in the allele

Because remember all evolution is is a change in the allele frequency of a gene pool. It

frequency of a gene pool can lead to speciation but it's constantly happening every day one of the mechanisms by which

can lead to speciation but it's constantly happening every day. What are the mechanisms

it occurs well we've already talked about a lot of these genetic drift

by which it occurs? Well we've already talked about a lot of these, genetic drift, mutations

mutations and we'll talk more about them in the next podcast but today I want to

and we'll talk more about them in the next pod cast. But today I want to specifically

specifically talk about selection and if you don't have a good understanding of

talk about selection. And if you don't have a good understanding of how natural selection

how natural selection occurs today you're going to get it and so natural selection is when nature selects which

occurs, today you're going to get it. And so natural selection is when nature selects

organisms are able to survive or die and the quintessential example is in the

which organisms are able to survive or die. And a quintessential example is in the beak

beak of the Finch and the work of Darwin but more importantly the work of the grant's sexual selection is a different

of the finch and the work of Darwin, but more importantly the work of the Grants. Sexual

type of natural selection and that's when mates are selecting based on the other gender example I'll give you as a peacock and then the one thing that I

selection is a different type of selection and that's when mates are selecting based on the other gender. An example I'll give you is a peacock. And then the one thing that

forgot to put here is our two fish selection which is another important one artificial selection is another type of selection and that's actually where

I forgot to put here is artificial selection, which is another important one. Artificial selection is another type of selection and that's actually where Darwin starts explaining

Darwin starts explaining the mechanisms

by which natural selection could occur

the mechanisms by which natural selection could occur. One thing that I want to drive

one thing that I want to drive home is the idea that all life evolves so once life shows up on our planet it's been

home is the idea that all life evolves. So once life shows up on our planet it's been

evolving ever since then and so our kea live here in the in the hot pots of

evolving ever since then. And so archaea live here in the hot pots of Yellowstone Park and

Yellowstone Park and they look very similar to what the first organisms on our planet probably look like but the

they look very similar to what the first organisms on our planet probably looked like. But the

archaea that live here and the animals that live in the savanna and the forest

archaea that live here and the animals that live in the savannah and the forest all of

all of these things all life came from one common ancestor and they got to be

these things all life came from one common ancestor and they got to be the way they are

the way they are through a process of evolution so let's talk specifically

through a process of evolution. So let's talk specifically about the mechanisms by which

about the mechanisms by which that occurs and when Darwin is explaining in the origin of the species he actually

that occurs. And when Darwin is explaining in the Origin of the Species he actually starts

starts with artificial selection because it really makes sense to us how that

with artificial selection. Cause it really makes sense to us how that might occur. If

might occur if we were to look at this great Great Dane and we were to look at this Chihuahua and if we were to look at

we were to look at this Great Dane and we were to look at this Chihuahua and if we were

a wolf the DNA of all of them is almost identical and the reason why is that

to look at a wolf, the DNA of all of them is almost identical. And the reason why is

these dog breeds that we have on our planet were created by humans

that these dog breeds that we have on our planet were created by humans, artificially

artificially choosing traits that they want and you can see the explosion of

choosing traits that they want. And you can see the explosion of tiny little breeds of

tiny little breeds of dogs that I'm seeing around right now it's humans making those choices selecting which

dogs that I am seeing around right now. It's humans making those choices, selecting which

offspring can pass on their traits in class this year we'll be using Brassica

offspring can pass on their traits. In class this year we will be using Brassica rapa which

Rapa which is a Wisconsin fast plant what you can do is you can actually do

is a Wisconsin fast plant. What you can do is, you can actually do the selecting, you

the selecting you can choose the traits that you want to pass on to the next generation and then you can see that

can choose the traits you want to pass on to the next generation. And then you can see

artificial selection taking place and actually Brassica is a type of plant

that artificial selection taking place. And actually Brassica is a type of plant that

that led to a lot of the different foods that we have today in fact a lot of the

led to a lot of the different foods that we have today. In fact a lot of the foods that you

foods that you eat were created through a process of artificial selection today

eat were created through a process of artificial selection. Today I want to spend a lot of

I want to spend a lot of time however talking about natural selection the mechanisms by which that occurs the most

time however talking about natural selection, the mechanisms by which that occurs. The most

famous studies on Galapagos were done by Peter and Rosemary grant and they

famous studies on Galapagos were done by a Peter and Rosemary Grant. And they studied

studied Joseph is afford Asst I hope I'm pronouncing that right and they studied

Geospiza fortis. Hope I am pronouncing that right. And they studied those on Daphne Major,

those on Daphne major which is this rock I've seen it from a distance it's just this rock in the Galapagos but it's a

which is this rock. I've seen it from a distance. It's just this rock in the Galapagos but it's

great natural laboratory so you can study the bird populations on it now natural selection is going to

a great natural laboratory. So you can study the bird populations on it. Now natural selection

select species to either survive or die and then the traits are passed on to the

is going to select species to either survive or die and then the traits are passed on to

next generation and so here's some data from Peter and Rosemary grant 1976 they

the next generation. And so here's some data from Peter and Rosemary Grant. In 1976 they

sampled all of the birds on Daphne major that they could find and they measured

sampled all of the birds on Daphne Major that they could find and they measured their beak

their beak depth in other words they measure this distance from here to here so they captured them probably nets they

depth. In other words they measured this distance from here to here. So they captured them probably

measured him with a calibre and they measured the beak depth all the way

in nets they measured them with a caliber and they measured the beak depth all the way

across in 1976 and they does study that 1977 and they studied the beaks for 30

across in 1976. And they studied that in 1977 and they studied the beaks for 30 years they've

years they've been studying the beaks of the the finches on the Galapagos but what they found is in 1977 there's a

been studying the beaks of the finches on the Galapagos. But what they found is in 1977

drought and so they go back in 1978 and so let me get the numbers right so you

there's a drought and so they go back in 1978, and so let me get the numbers right so you

can see him in 1976 they sampled 751 Birds so there were 751 Birds here but

can see them, in 1976 they sampled 751 birds. So there were 751 birds here, but they come

they come back in 1978 and they found they're only 90 Birds left and so lots

back in 1978 and they found there were only 90 birds left. And so lots of times when we

of times when we draw these graphs you have a tendency to not realize what the

draw these graphs you have a tendency to not realize what the end number or how many species,

N number how many species how many individuals were actually there and so what happened in that drought of 77 it's

how many individuals were actually there. And so what happened in that drought of '77?

like a bird apocalypse almost all the birds died from 751 down to 90 which

It's like a bird apocalypse. Almost all the birds died from 751 down to 90. Which ones

ones didn't die the ones that didn't die are ones that had a slightly bigger beak

didn't die? The ones that didn't die are ones that had a slightly bigger beak. And so why

and so why is that well what the grants found is that they were feeding on seeds

is that? Well, what the Grant's found is that they were feeding on seeds that were slightly

that were slightly bigger and harder to break and so the ones that were able to

bigger and harder to break. And so the ones that were able to break those seeds were able

break those seeds were able to survive not die and they were able to pass their genes on to the next generation and so

to survive, not die and they were able to pass their genes on to the next generation.

what happened to our bell-shaped curve our bell-shaped curve moved to the right

And so what happened to our bell shaped curve, our bell shaped curve moved to the right.

and so we call that directional selection now are they going to stay this way no because if you have a bird a

And so we call that directional selection. Now are they going to stay this way? No, because

big beak you have to make that beak you have to fly it around and so when the

if you have a big beak you have to make that beak, you have to fly it around and so when

when the weather gets good what we'll see is we'll actually see when there's

the weather gets good what we'll see is we'll actually see, when there's no drought, we're

no droughts we're actually going to see it move back in the others direction or

actually going to see it move back in the other direction or directional change. And

directional change and so there's moving over and over and over but that's the first type called directional selection

so this moving over and over and over, that's the first type called directional selection.

we can also have disruptive selection disruptive selection happens when you

We can also have disruptive selection. Disruptive selection happens when you have a bell shaped

have the bell-shaped curve of a trait and then it somehow gets split in the middle and so an example of that would

curve of a trait and then it somehow gets split in the middle. And so an example of

be the idea that all of the birds on the Galapagos

that would be the idea that all of the birds on the Galapagos, this is a picture that's

this is a picture that's actually from Darwin's book all of the finches on the Galapagos started from one and sensual

actually from Darwin's book, all of the finches on the Galapagos started from one ancestral

species in other words there is one Finch that flew there or a population

species. In other words there was one finch that flew there or population that flew there

that flew there maybe two to three million years ago and the 14 beaks for the 14 species that we now have on the

maybe 2-3 million years ago and the fourteen beaks, or the 14 species that we now have

Galapagos Islands are actually came through disruptive selection in other

on the Galapagos Islands actually came through disruptive selection. In other words if they

words if they start feeding on different seeds you eventually can have two different species and they quit

start feeding on different seeds you eventually can have two different species and they quit

interbreeding and then you can have different varieties and so even though

interbreeding and then you can have different varieties. And so even though these look quite

these look quite a bit different they all come from one common ancestor my

a bit different, they all come from one common ancestor. My favorite are the ones that are

favorite are the ones that are actually feeding on the the vampire Finch that feeds on they suck the blood off of the

actually feeding on the, the vampire finch, that feeds on the, they suck the blood off

blue footed boobies on the Galapagos pretty crazy last type is stabilizing

of the blue footed boobies in the Galapagos. Pretty crazy. Last type is stabilizing selection.

selection stabilizing selection occurs when you have here's our original bell-shaped curve it happens when you

Stabilizing selection occurs when you have, here's our original bell shaped curve, it

have selection on either side in other words you're squeezing that bell-shaped

happens when you have selection on either side. In other words you're squeezing that

a little bit closer I couldn't come up with great example of the finches on the

bell shape a little bit closer. I couldn't come up with great example of the finches on the

Galapagos of of that stabilizing selection however it would probably be what shows why one species stays the

Galapagos of that stabilizing selection, however, it would probably be what shows why one species

same but a great example of this would be in the birth of children in other

stays the same. But a great example of this would be in the birth of children. In other

words if you are a tiny baby let's say back in the day you weighed one pound

words if you were a tiny baby, let's say back in the day you weighed one pound when you

when you were born you probably were born premature and you died if you were like 18 pounds as a baby you probably

were born you probably were born premature and you died. If you were like eighteen pounds

didn't get out of your mother and you died and her genes died with you and so

as a baby you probably didn't get out of your mother and you died and her genes died with

that's going to push that bell-shaped curve together so that's artificial

you. And so that's going to push that bell shaped curve together. That's artificial selection

selection excuse me natural selection and then the last type is going to be sexual

excuse me, natural selection. And then the last type is going to be sexual selection.

selection sexual selection it was come up with by Darwin as well but not really tested until until the nineteenth

Sexual selection, it was come up with by Darwin was well, but not really tested until the

century or the 20th century in sexual selection the mate is actually doing the

19th century or the 20th century. In sexual selection the mate is actually doing the choice.

choice and lots of times we'll see sexual dimorphism in other words this is

And lots of times we'll see sexual dimorphism. In other words, this is a peahen and this

a peahen and this is a peacock and so we see a huge difference in their appearance and the reason why is that

is a peacock. And so we see a huge difference in their appearance and the reason why is

the female is making the choice it's not nature that's making the choice she's

that the female is making the choice. It's not nature that is making the choice she's

actually making the choice and so why does a peacock have this beautiful train

actually making the choice. And so why does a peacock have this beautiful train that it

that it does it's just going to get in the way it's doing that to impress the

does? It's just going to get in the way. It's doing that to impress the mate. In other words

mate in other words this female is only going to choose a peacock that has a really big train now why is

this female is only going to choose a peacock that has a really big train. Now why is she

she doing that she's looking for herself she's only going to choose a trait

doing that? She's looking for herself. She's only going to choose the trait that's going

that's going to pass on or it's a clear indication of the health of that mate

to pass on, or it's a clear indication of the health of that mate. And so if you can

and so if you can make a beautiful train like this you probably have good DNA and

make a beautiful train like this you probably have good DNA. And there were studies done

there were studies done where they would actually eliminate so they would cut off some of these eyes and they would find

where they would actually eliminate, so they would cut off some of these eyes and they

the female the peahens would actually ignore them they also found in the

would find the female, the peahens would actually ignore them. They also found in the studies

studies that if the mate if the males have a really beautiful train like this they actually produce offspring that are

that if the males have a really beautiful train like this, they actually produce offspring

more likely to survive and so in sexual selection the female is actually doing

that are more likely to survive. And so in sexual selection the female is actually doing

the choice not doing not nature and so if we ever see that sexual dimorphism so

the choice, not nature. And so if we ever see that sexual dimorphism, like in Montana

like a Montana way of elk and the elk have these huge antlers but they're doing that to impress their mate now

we have elk and the elk have these huge antlers but their doing that to impress their mate.

Geoffrey Miller has taken this to an extreme not to an extreme but he's

Now Geoffrey Miller has taken this to an extreme, not to an extreme, but he is saying that what

saying that what is it in humans that is like the Peacock's feathers what is it it's like that in us that's just it's

is it in humans that is like the peacock's feathers? What is it that's like that in us?

it's grossly in excess what we would see in humans is that it's our brain it's

It's grossly in excess. What you'd see in humans is that it's our brain. It's how smart

how smart we are and why are we so smart well we're trying to impress females and

we are. And why are we so smart? Well, we're trying to impress females and so it's interesting

so it's it's it's interesting when you look at males and ask them what what are they attracted to in females a lot of

when you look at males and ask them what are they attracted to in females, a lot of times

time it's physical characteristics but when you ask females it's more behavior

it's physical characteristics but when you ask females it's more behavior. He makes me

he makes me laugh or he makes me feel good and so those things are clear

laugh or he makes me feel good. And so those things are clear indications of brain and

indications of brain and Geoffrey Miller will go as far as to say that culture and all of those things are just made

Geoffrey Miller will go as far to say that culture and all of those things are just made

through process of sexual selection I think he's headed in the right direction

through a process of sexual selection. I think he's headed in the right direction.