listen to part of a conversation between a student and her biology Professor so the assignment is to reprod one of the animal camouflage experiments we read about in our textbook which experiment did you pick well I was wondering if I could try to reproduce an experiment that's kind of the opposite of what was discussed in the textbook so instead of how and why an animal might hide itself you want to do something about why an animal might want to be seen H tell me more well I got the idea from one of the journals you
said we should look at it's an experiment about uh they called them eye spots in the article ey spots sure the patterns on the wings of moths and butterflies that are generally believed to scare off Predators because they look like big eyes yeah except the article was about an experiment that disputes that theory well we know that the markings do scare the birds but the idea that the spots look like eyes is well that's just a commonly held belief so that's not even based on Research well this whole idea of moth or butterfly markings being
scary because they look like eyes rests on how we imagine that their predators like birds perceive the markings and we can never really know that all we can do is observe bird Behavior but tell me more about the experiment okay so the experiment looked at the shapes of the markings on moth Wings the researchers wanted to know if the markings that were round or eye-shaped were more effective at deterring predators than square or rectangular markings okay yeah so they attached food to paper models of moths with different shaped marks drawn on the wings to see
how birds reacted and what's interesting is they realized that the round marks were not more effective at scaring Birds than other shapes were they less effective no they were about the same but what researchers did determine is that larger markings are more effective than smaller markings at scaring off prey they called this phenomenon visual loudness visual loudness huh well I guess it's not all that shocking if you think about it so anyway is it okay can I repeat this experiment and write about it yes I think that'll work the problem I foresee is well where
this is an urban campus you'll have a hard time finding a good place to set up the experiment oh I wasn't planning on doing it on campus I'm going home for spring break and my family lives in the country far from the nearest city I can set it up in the backyard good idea except one week is not a lot of time so you'll need to make some adjustments to have enough data I'd set up the experiment near bird feeder and get in as much observation time as you can why does the student talk with
the professor what does the Professor say is a common assumption about certain markings on butterfly and moth wings what were the results of the experiment that the student describes why does the professor mention a bird feeder listen again to part of the conversation then answer the question the idea that the spots look like eyes is well that's just a commonly held belief so that's not even based on Research what can be inferred about the student when she says this so that's not even based on Research listen to part of a lecture in a botany class
so continuing with crop domestication and corn or um maze as it's often called obviously it's one of the world's most important crops today it's such a big part of the diet in so many countries and it's got so many different uses that it's hard to imagine a world without it but because it doesn't grow naturally without human cultivation and because there's no obvious wild relative of maze um well for the longest time researchers weren't able to find any clear link between Ma and other living plants and that's made it hard for them to trace the
history of ma now scientific theories about the origins of maze first started coming out in the 1930s one involved a plant called tein teosinte is a tall grass that grows wild in certain parts of Mexico and Guatemala when researchers first started looking at wild teosinte plants they thought there was a chance that the two plants um Ma and teosinte were related the young wild teosinte plant looks a lot like the corn plant and the plants continue to resemble each other at least superficially even when they're developed but when the scientists examined the fruits of the
two plants it was a different story when you look at ripe corn you see row upon row of Juicy kernels um all those tiny little yellow squares that people eat fully grown teosinte on the other hand has a skinny stock that holds only a dozen or so kernels behind a hard um almost stonik casing in fact based on the appearance of its fruit teos Cente was initially considered to be a closer relative to Rice than to maze but there was one geneticist named George Beetle who didn't give up so easily on the idea that teos
Cente might be well the parent of corn while still a student in the 1930s Beetle actually found that the two plants had very similar chromosomes very similar genetic information in fact he was even able to make fertile hybrids between the two plants in hybridization you remember the genes of two species of plants are mixed to produce a new third plant a hybrid and if this Offspring this hybrid is fertile then that suggests that the two species are closely related genetically this new hybrid plant looked like an intermediate right between Maize and teosinte so Beetle concluded
that Maize must have been developed over many years uh that it is a domesticated form of teos Cente many experts in the scientific Community however remained unconvinced by his conclusions they believed that with so many apparent differences between the two plants it would have been unlikely that ancient that prehistoric peoples could have domesticated maze from teosinte I mean when you think about it these people lived in small groups and they had to be on the Move constantly as the seasons changed so for them to selectively breed to have the patience to be able to pick
out just the right plants and gradually over Generations separate out the durable nutritious maze plant from the brittle teosinte that easily broke apart it's a pretty impressive feat and you can easily see why so many many experts would have been skeptical but as it turns out Beetle found even more evidence for his theory when he continued his experiments producing new hybrids to investigate the genetic relationship between teos Cente and Maize through these successive experiments he calculated that only about five specific genes were responsible for the main differences between tente and maiz the plants were otherwise
surprisingly similar genetically and more recently botanists have used modern DNA testing to scan plant samples collected from throughout the Western Hemisphere this has allowed them to pinpoint where the domestication of maze most likely took place and their research took them to a particular River Valley in southern Mexico they've also been able to estimate that the domestication of Mae most likely occurred about 9,000 years ago and subsequent archaeological digs have confirmed this estimate in one site archaeologists un covered a set of tools that were nearly 9,000 years old and these tools were covered with a Dusty
residue a residue of maze as it turns out thus making them the oldest physical evidence of maze that we found so far what is the lecture mainly about what evidence seemed to indicate that Mae and tail Cente are not related why does the professor discuss hybrids what was most researchers initial view of George Beetle's theory about Teo Cente what did Beetle conclude about mazee and T Cente according to the professor why was the discovery of stone tools important listen to part of a lecture in an art history class the professor has been discussing Illustrated books
I want to take a look at one particular book to give you an idea about what was involved in publishing Illustrated books in the 1800s the books called the birds of America and the illustrator was John James aabon so the birds of America four volumes which contained illustrations of nearly every bird in the United States over 400 birds all hand colored all painted lifesized the larger Birds printed on the largest printing paper available at that time this required a lot of dedication and aabon is best remembered as an incredibly meticulous accurate artist a very accomplished
illustrator of the natural world and while there were other artists working on similar projects at the same time aon's book Remains the most well-known and successful of its kind but uh let's talk a bit about aabon himself first first of all aabon was not a traditional painter and by this I mean that he didn't work in oils he preferred to use watercolor and pastel crayons and he worked on paper instead of on canvas the thing is utaban considered the illustrations in his book not the original watercolors to be the finished product his watercolors were merely
Preparatory studies most of which were painted while he was observing birds in the wild these watercolors were then sent to his printer who created the final prints for the book and aabon was so concerned with accuracy that he often scribbled notes to the printer around the edges of these original watercolors in fact you might question whether producing a work of art was even aon's goal now when I look at an oton illustration I see a work of art but it may make more sense to consider otoban first and foremost as a naturalist as a a
scientist see the early 19th century when aabon was painting was a time of major SCI scientific inquiry and an essential way of spreading scientific knowledge was through Illustrated books so what did aabon consider himself an artist or a scientist I'm not sure the distinction between the two was all that clear in the 1800s I think we can accurately state that that the driving force in his art was getting the science right and this was perhaps a point that critics of his artwork at the time just didn't appreciate aravan also studied birds in ways that didn't
directly inform his art uh you know what bird banding is Right a bird has a band attached to its foot so we can learn about things like migration patterns well the first recorded instance of anyone doing that it was aabon another example a common belief at the time was that vultures used their sense of smell to find food oton didn't believe that so he tested it he put a large painting of a dead sheep in a field and sure enough vultures found it and started pecking at it now aon's work was very accurate and we
know this because we can compare his illustrations to the birds around us but sometimes it's not possible to check there are actually several birds in his book that no one's ever seen these are sometimes called aon's mystery Birds because even though he drew them there's no evidence that they exist in the wild for someone who's respected as a naturalist isn't it strange to think that he drew some birds that don't appear to be real for example there's an illustration that appears to be a type of warbler a small bird it has a white ring around
its eyes and white bars on its wings no one's ever seen a warbler like this so some people wonder if aabon maybe forgot certain details about this bird when he painted it or that he copied another artist's work but considering that aabon was such a meticulous artist well there might be a better answer hybridization is something that's well known in birds and it definitely explains a rather unique looking dock ottobon painted he himself suggested that maybe it wasn't an unknown species but a hybrid born from two different species since then this particular Crossing of species
has actually been recorded both in the wild and in captivity so it turn turns out that aabon was right and this duck actually was a hybrid what does the professor mainly discuss according to the professor what were two steps aabon took in producing his illustrations what does the professor imply about critics of Autobon art why does the professor discuss autobond experiments with vultures and banding Birds what are aon's mystery Birds what does the professor believe is the most likely explanation for aon's warbler illustration listen to a conversation between a student and the director of the
Student Activities center hello Jack is everything set for the trip this Saturday everything's ready uh 15 people have signed up our train gets into New York City at noon which leaves plenty of time to get downtown to the art gallery for the reception it's great you could organ this what an honor having a painting by one of our students in that exhibit yeah my roommate's so modest if we weren't such good friends I'd have never realized his work was being exhibited so since I was going anyway for the opening and all I figured I might
as well make a student event out of it working here at the Student Activity Center has made me realize how popular our activities are I figured there'd be interest in it well you've done a super job organizing everything those posters look great and they went up in no time thanks and I'm glad you could approve the funding for us my pleasure by the way how are you getting to the gallery from the train station well there are buses that run downtown right you grew up in New York City didn't you yeah but the bus well
that's kind of what I wanted to talk to you about yes I realized it's last minute but well the weather for Saturday is supposed to be really nice sunny warm it'd be a great opportunity to walk the Highline the what haven't you oh I guess not everyone's heard of it it's this amazing it's like this this park in the sky a park in the sky yeah well see there was this old train line you know one of those elevated lines the kind that run high above the streets okay well this one was used for Freight
not passengers uhhuh but when it got cheaper to move Freight by trucks they stopped using it it was abandoned for a long time and then a few years back the city agreed to turn the tracks and surrounding area into a park it's not very wide but it's over a mile long and it goes from the train station all the way downtown near the gallery I've walked it before it's really cool there's grass and flowers everywhere and since you're high up you get these great views of the city sounds wonderful but have you considered not everybody
might be interested in walking that far they might prefer the bus couldn't we just split up you know have some of us walk and the others take the bus but remember Jack the poster advertises you as the tour leader not everybody's as adventurous about getting around the city you'd need to find someone to accompany people on the bus then you'd take the the Walkers yeah but who the trips in 2 days well I did my graduate work in New York of course it was a while ago but I still know how to get around the
city yeah and I'd love to see that exhibit you'd go oh that'd be great why does the student go to see the woman what point does the student make about his job in the Student Activities Center what two points does the student make about the history of The High Line why does the woman mention the information in the poster listen again to part of the conversation then answer the question the trips in 2 days well I did my graduate work in New York of course it was a while ago but I still know how to
get around the city what does the woman imply when she says this well I did my graduate work in New York of course it was a while ago but I still know how to get around the city listen to part of the discussion in a history of science class the class is discussing the heliocentric theory what I find really difficult to understand is why the heliocentric theory um why it wasn't like believed by everybody right away well one thing that's hard to do is to sort of see things from the perspective of someone who's hearing
that theory for the first time I mean today we tend to assume that the moment the heliocentric theory was laid out the idea that the Sun not the Earth was the center of the solar system that you know you'd have to be in denial not to accept it but it really wasn't that easy but the idea that the Earth wasn't the center of the universe that had been tossed around for like centuries right I mean lots of people had had the idea yes that's true going all the way back to the ancient Greeks but in
Europe when Galileo championed it in the 17th century due in part to his discoveries using a telescope there still was some major resistance to it but I still don't understand why I mean isn't it obvious well despite Galileo's ingenious arguments in support of the heliocentric theory there was still a lot of reasons why people of that period couldn't buy into it remember we're talking about 400 years ago so um let's think about a few of those reasons okay so first of all they could work out that if the Earth was going around the Sun then
it had to be traveling at many thousands of kilometers per hour and that was just beyond anything anyone could understand you know they could understand riding a horse or walking maybe they could get up to 30 32 km/ hour but tens of thousands of km/ hour that was just crazy so to many people whatever's going on it couldn't be that H so people didn't believe the heliocentric theory because it was so hard to believe exactly but there were more scientific kinds of re actions as well cuz look if you've ever been on a carousel or
you're on a ride at an amusement park and you're on something that is going round and round and round two things all right one you know you're moving there's no doubt and the other thing is you know that unless you hold on tight you're going to go flying out because of centrifugal force right so if I understand you for the average person 400 years ago there was no evidence that we were moving at high speed right since every everything was securely on the ground and no one was flying off into space yes and in particular
and this was one specific difficulty for people in the period even if they thought that there was some sort of force that maybe kept you and me and buildings and things on the surface of the Earth their theory about the nature of the atmosphere was that nothing was holding it down so if if you can understand that way of thinking then clearly if the Earth was moving at great speed we should have lost all our atmosphere a long time ago you know it would be like trailing away behind us and so I want to try
a little thought experiment because I I think that what we'll find is that some of us have ideas about motion that actually fit with anti-h heliocentrism anti-h heliocentrism no way this is the 21st century well then let's see so picture the following you're at the equator moving at, 1600 km hour okay and you drop something small and light like a match stick for example where is it going to land that's easy it'll be long gone the match stick is so light it'll fly right out of my hand and end up way behind me somewhere ah
actually that match stick you dropped it'll land right at your feet what well let's think think about it you forgot to consider that the Earth's rotating at, 1600 km hour at the equator and you me the air and that mat stick we're all moving together at the same speed even though it doesn't seem or look or feel like we're moving so class clearly even today we actually have some inclination to think that if the Earth were moving around at a great speed we ought to see signs of it perhaps now you're less inclined to dismiss
those who once found heliocentrism so hard to believe okay let's move on what is the professor's name purpose in the discussion what do the examples of riding a horse and walking represent what point does the professor make when he discusses a ride at an amusement park according to the professor 400 years ago what was believed to be true about Earth's atmosphere why does the professor talk about dropping a match stick listen again to part of the discussion then answer the question so people didn't believe the heliocentric theory because it was so hard to believe exactly
but there were more scientific kinds of reactions as well what does the professor mean when he says this but there were more scientific kinds of reactions as well e e for
