Extension #4 (Extra Credit)

View the video clip using the link below and read the article in the second link in order to answer the following question:

What is the evidence that modern-day whales are the descendants of ancient land mammals?

PBS Whale Evolution Video Clip

National Geographic Article on Whale Evolution

HW - 1/6/12

This weekend's homework is to complete the questions associated with CW 51 and get the permission slip for next week's field trip signed. See the space below for resources.

CW 51: "A Whale of a Tale" Analysis Questions

Answer ALL of the following questions to the best of your ability and in COMPLETE SENTENCES. Be SPECIFIC and EXPLAIN YOURSELF.

1. Review: What is natural selection?

2. Which whale ancestor (which card) do you think made the first ‘jump’ or transition from land to water? Explain your answer using evidence from the cards you observed.

3. What do you think happened to the species in cards B (basilosaurs) and M (mesonychids)? (You can see them on the “Whale Evolutionary Tree.”)

4. Which fossil organism in whale evolution do you think was the first to live mostly in water? Explain your reasoning using evidence from the cards.

5. Describe how natural selection explains the changes in the skeletons as they change their habitat from land to water. (There is a lot of space here because you are expected to write a lot for this answer . . . at least 3 – 5 sentences. Be specific and explain yourself.)

Challenge: 6. Examine the paraxonians at the bottom of the “Whale Evolutionary Tree.” What do you think are some examples of organisms that descended to the left from the ancestor paraxonians (hoofed land animals) on the diagram of the tree?


The link below connects to a .pdf file containing scanned images of fossil cards (M, T, O, B, K, A and D), the "Whale Fossil Chart" and the "Whale Evolutionary Tree."

Whale Fossil Cards and Charts

HW - 1/5/12

Tonight's homework is to complete the analysis questions for CW 50. Use the notes you took on the reading (which is also found below) to help you answer the questions.

1. How can fossils (for example, transitional fossils) provide evidence for evolution?

2. Describe the evolution of tetrapods (four-legged animals) in your own words.

3. Using details/examples describe how natural selection could have influenced the evolution of tetrapods. Feel free to discuss the traits of species as Eusthenopteron, Acanthostega, Tiktaalik, and/or Ichthyostega.

Link to "The Fossil Record" from class today











Link to video on Tetrapod Fossils (with the author of Your Inner Fish featured)

CW 48 Answers

1. Natural selection is how the environment can influence the changes in populations over time. Some traits are favorable for survival and reproduction in an environment, so organisms that possess those traits are more likely to survive and pass on those helpful traits to their offspring.

2. Typically, magical pinto and kidney beans survive longer than black beans, lentils and split peas. This is because pinto and kidney beans are usually too large to slip through the holes in the bowl and die.

3. The activity demonstrates natural selection because the environment (the bowl) is choosing for the favorable trait of a large diameter. Magical bean creatures with a large size see their population sizes increase across generations, while the opposite happened to smaller bean creatures.

4. Organisms change and evolve over time to best adapt to changing environments. Changes in climate, weather, predators, food sources, etc. alter what the best trait for an environment is and those organisms with the best traits survive and reproduce. As a result, the population evolves over time.

5. Peppered moths – The color of birch trees darkened which selected for darker color moths and against lighter moths
Antibacterial resistance – The overuse of antibiotics selected against bacteria that lacked the ability to survive in the presence of antibiotics, but selected for those bacteria with the mutations that offered protection from antibiotics

6. Natural selection both requires and produces biodiversity. Without a variety of traits in a population, favorable traits do not exist and so members have an advantage. Natural selection produces diverse populations of organisms each with favorable traits to aid survival and reproduction.

7. One’s traits are controlled by one’s genes, so basically the environment selects for organisms with genes that help survival and reproduction.

HW - 1/4/12

Tonight's homework is to complete the Analysis Questions about CW 49 (the "Beaks of Finches" activity).

1. Describe how today’s activity demonstrated natural selection.


2 – 5. The figure above, the outer ring shows the different species of finch found on the Galapagos Islands. The next two rings in show how the beak was used. The inner circle shows the types of food eaten by the finch.

2. What type or types of finch would best be able to survive if the weather changed on the Galapagos Islands and seeds suddenly became thicker and larger? Explain why.

3. One island is populated by two species – Small Ground Finches and Small Tree Finches. What two types of food do you expect to see on the island? Explain why.

4. Would you expect the two species to compete for food? Explain why or why not.

5. How would the two native finches species discussed above survive if a large group of Sharp-billed Ground Finches migrated to the island? Explain why.

6a. In order for natural selection and evolution to occur, what factors do you think need to be present?

6b. How can these factors work to produce changes in a population of organisms (such as finches). Provide an example to help explain your answer.

HW - 1/3/12

Welcome back! The first homework of the new year is to: 1. complete the graph of the data from CW 48's activity (by making a line graph of the population at the END of each generation for each type of magical bean creature) and 2. complete the CW 48 Analysis Questions (shown below).

Background Information

How does evolution work? What is it that actually causes populations to change with time?

These are questions to think about while we discuss natural selection. Natural selection is a way through which populations of organisms evolve. With natural selection, the environment (in other words, nature) determines the traits of an organism that are most fit for survival. Random mutations in the DNA of organisms provide new traits. The traits that make it easier to survive and reproduce stick around – those that hurt survival and reproduction do not (along with the organisms that carry them).

Analysis Questions

Answer all of the following questions to the best of your ability in COMPLETE SENTENCES on another sheet of paper. Explain yourself and be specific. (To earn 5’s, you need to answer the CHALLENGE questions.)

1. In your own words, what is natural selection?

2a. Which types of magical bean creatures were able to survive and reproduce for all 5 generations? Why do you think this was the case?

2b. Which were not able to survive all 5 generations? Why do you think they were unable to survive?

3. How did the activity you completed show natural selection?

4. Why do you think organisms evolve and change over time?

5. Explain an example of natural selection causing a population to change. (HINT: Think about previous activities/classworks that you have completed.)

CHALLENGE: 6. How are biodiversity and natural selection related to each other?

CHALLENGE: 7. How are genetics and natural selection related to each other?

Furaha in NRC again, but in English this time!

In June of this year, the Dutch newspaper NRC Handelsblad devoted a satisfyingly large section of their science section to the Furaha project. You will find the post on that subject here. As the text was in Dutch, the majority of the readers of this blog were unable to understand it. Mind you, I displayed the images at such a small scale to make it unreadable regardless of language; newspaper texts are not free, after all. But as time passes things change, so I asked Lucas Brouwers, the journalist who wrote the article, whether he would mind if I translated his text into English, and he in turn asked those in charge of such matters at the newspaper whether they would mind having the article republished in this form. The short answer was that no-one minded, so I went ahead and translated it into English. I tried to stay fairly close to the text, but at the same time wished to avoid the stilted style you often get in translations (it is much easier to write directly in a foreign language than it is to translate something from your own language into that language).

Click to enlarge; copyright NRC / Gert van Dijk

Hairy shufflers and radial flyers

BIOLOGY Professor of neurophysiology Gert van Dijk designs the flora and fauna of the fictive planet Furaha in his spare time.

Lucas Brouwers

At first glance the woolly-haired shuffler looks familiar. The animal looks quite a bit like a large mammal. It might just be a close relative of a rhinoceros, or a bison. But a closer look reveals that it is standing on six legs and that its upper jaw has grown into a grotesque shovel. Its more distant relatives are no less odd than the shuffler itself. There are six-legged predators, using their two front legs to knock their prey unconscious with. Or how about water animals, gliding solemnly through the oceans with hardly any moving parts visible from the outside. They are ingeniously designed: a hollow tube runs through their body, displacing water by pulsating continuously.

None of these animals are real. They are creations of Gert van Dijk, professor of neurophysiology in Leiden. In his spare time he designs the flora and fauna of the fictive planet Furaha, home to the woolly-haired shuffler. Van Dijk designed the workings of his planet in minute detail. From the evolution of life on Furaha to the place of the planet and its star in our galaxy: it is all there.

As a student Van Dijk used to paint extraterrestrial scenes for book covers for a publisher of what he now labels as "atrociously poor science fiction" The work did not make him exactly happy." That publisher asked me questions like the following: 'There is an empty corner in your painting; couldn't you fit in an exploding planet there?' ", he recollects.

Van Dijk therefore decided to start painting for his own pleasure. The first painting showing life on Furaha dates from 1979. It showed an exotic tree with an odd four-winged beast. That was only the beginning. Van Dijk: "Having painted a landscape with lots of grass in it, there obviously had to be something to eat all that grass. That was the start of the second painting. Well, once you have a animal eating plants, you are bound to need something to eat that animal in turn. That is how Furaha grew, and continued to grow."

A series of paintings followed. Later on Van Dijk started elaborating Furaha in other ways than using a painter's canvas. He writes essays on the biological background of his creations and simulates their anatomy using a computer. An astrophysics friend helped him to find a suitable spot in our galaxy for Furaha: in orbit around the star Nu Phoenicis IV. This star is of the same type as our sun and could therefore in principle support life.

Now, over thirty years after that first painting, the oceans and continents of Furaha are filled with life, there are detailed maps of the planet as well as descriptions of its climate. While there is a serious scientific background to the work, shaping the world flows from Van Dijk's fantasy.

This unusual hobby is known as 'speculative biology'. There aren't many speculative biologists. Van Dijk is familiar with most of the worlds they created. "There is the planet Nereus by Evan Black, there's Snaiad by Mehmet Kösemen and Epona, a collective project. There are a few projects dealing with the evolution of life on Earth in case the dinosaurs would not have gone extinct. That's largely it."

"There are certainly more people who wish to start a similar project", Van Dijk says, "but most do not combine a scientific background with artistic talent. Moreover, most projects stop after a few years' such as Snaiad, for the simple reason that they take up so much time. In fact, I stopped working on Furaha for years on end, but kept getting back to it. Fuaraha allows me to paint, write design and program. It meets to many of my needs to let it go."

Click to enlarge; copyright NRC / Gert van Dijk

How the woolly-haired shuffler came into being he no longer remembers in detail. "It's possible I had recently been looking at pictures of a rhinoceros. Things may just click together in my head. The inside of the skin folds of rhinos could well be covered in hairs, I may have thought."

That was the basic concept around which the animal took shape. "A skin fold covered in fur would be able to trap more warm air than one without hair. A fur coat, turned inside out, would have the same effect. That is in fact how the Inuit put their fur coats together", he explains. An animal with such furry folds would be able to deal with below-zero temperatures. And its shovel for a snout? "That evolved by itself".

In the end, Van Dijk painted the woolly-haired shuffler while it was upturning snow or soil in a search for plant roots or anything edible (see the cover). Its biology and ecology have been described in detail on Van Dijk's weblog. For instance, that says that the animal lives in small herds, and that that are small parasites living in the fur of its skin folds (trichophages).

Van Dijk does not use any fixed recipe to come up with a new life form. Sometime an animal crystallises around an interesting biological principle. The 'radial flyers', small creatures with four wings, came into being while he was sketching. Their wings are placed at an angle of 90 degrees to their body, like the blades of an helicopter rotor. The first sketches of these 'tetropters' showed a bilaterally symmetrical body , like a bird's, hanging under the wings. "That did not feel altogether right. I then thought it better to make the entire animal radially symmetrical, such as starfish or jellyfish."

In flight, the animals look a bit like helicopters as well. "Thanks to their design they have excellent manoeuvrability, but they aren't that fast in horizontal flight", Van Dijk explains. "The wings move in a figure eight-like pattern. A wing briefly beats against another one twice in every movement cycle. This creates additional lift". He explains calmly how this works. "Pigeons taking off do the same thing. Their two wings beat against one another above their backs. The contact between the wings does not only cause the characteristic sounds of pigeons taking off, but also causes extra air to be sucked in, and that generates an upwards force."

Van Dijk visualised the flight of these four-winged little creatures with computer simulations. The resulting flight of these radial flyers look looks organic. Their wings swing gracefully to and fro, rather like flags in the hands of a flagthrower. This mode of flight actually makes sense, as was proven by engineers a few years ago. With some pride Van Dijk wrote on his blog that they built a flying robot with four wings, flying in exactly the same manner as Furahan tetropters.

Another source of inspiration is nature on Earth. This is most apparent in those creation he labels as 'supercharged Earth designs'. One example of supercharging was his take on the undulating membranes of squids. "I started sketching animals with not two, but four of such membranes: two at the top and bottom, and two at the sides. From that design an animal emerged with a screw-like propulsion system."

There is no place on Furaha for unrealistic creatures. Ballonts, creatures that float by virtue of being lighter than air, may be struck from the record soon. Van Dijk: "I am beginning to think that balloon-like organism are not going to work. To keep them in I already increased the density of the atmosphere, but I do not really think that that is enough. That is a pity, because that would mean I have to abolish them."

No matter how exotic the Furahan fauna may be, most animals still look plausible and familiar. Why is that? Van Dijk: "That is an interesting question. Is the resemblance with life on Earth the result of a workable biomechanical design, or because many design models are simply prewired in my imagination?" He does not have the answer. One thing is certain, and that the resemblance is not introduced on purpose to make Furaha more palatable to his audience. Van Dijk: "I do not make any concessions to what people might like".

Making too many concessions is something he blames James Ccameron for, the director of the science fiction movie Avatar. Avarar takes place on the moon Pandora where there are six-legged animals, just like on Furaha. Wolves, horses and monkeys all have six-legged analogues on Pandora.

Van Dijk criticises their 'awkward' anatomy. "The horse analogues in Avatar have one pair of hind legs and two pairs of front legs, placed very close together. If you look carefully you will see that the two pairs of front legs move in synchrony. The designers simply doubled the front legs, so the animal looks in exactly the same way as a four-legged animal. At first glance they look cool, but essentially they are just horses with added frills."

The fact that Avatar is a science fiction movie is no excuse, Van Dijk thinks. "Of course, enjoying science fiction requires a degree of suspension of disbelief. But no-one ever claimed plausibility for the aliens of Star Wars or the sand worms of Dune, in contrast to what happened with Avatar. Cameron and scientists he hired claimed to have developed an accurate and biologically plausible world, and they simply did not.", Van Dijk says.

Obviously, Furaha reaches a fraction of the people of a Hollywood blockbuster. Van Dijk supposes that Furaha mainly attracts people with a higher education, interested, like he is, in what happens in the intersection of science and the arts. Still, he would definitely like to widen the readership of Furaha, for instance by publishing a book. In fact, he already posted a fake encyclopaedia of life on Furaha, including illustrations and infographics. He doesn't think there is a good chance of it getting published: "I do not know much about publishing books, but I guess that the market for such a work is very small."

You would expect professional biologists to be interested in a hobby that is so closely allied to their area of interest. Astrobiologists, dealing with the science of life on other planets, in particular might show an interest. But, apart from a rare exception, cross pollination between biologists and those working in speculative biology seems not to happen. Van Dijk: "They ought to like it in their heart of hearts. But perhaps astrobiologists do not wish to be associated with speculative biology. They are dealing with serious science and may prefer not to be to be portrayed as believers in little green men. Neither do I, by the way. I regard what I am doing as an intellectual and artistic game."

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Legends
- (Left bottom pen drawing) Furahan fish developed variable numbers of jaws and fins
- (Underneath the block of six paintings) Top row, from left to right: many-legged grouillards, honeysucker, mowers. Bottom row, from left to right: landscape, phleph and worryw. All images: copyright Gert van Dijk
- (Right top) Tetropters generate extra lift by clapping their wings together in the same way insects and pigeons do.
- (Far right) Tetropters are very manoeuvrable and can let themselves drop very quickly. They cannot fly fast.

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Click to enlarge; copyright Gert van Dijk

It is quite possible that some of the images are new to the readers. The one above, a phleph, has featured on the front page of the site at one time. Its formal name is Vanitas sursumvergenspropterpenuriaponderis, and yes, that does mean something...