Organic molecules in smoke
Burning wood produces a wide array of organic compounds. Each type of wood makes many unique compounds, and the specific compounds formed depend on the amount of oxygen available. Here are a few of them.
Description: nutty roasted hazelnut
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nutty nut flesh roasted hazelnut toasted grain
sigmaaldrich.com
Learning Standards
2016 Massachusetts Science and Technology/Engineering Curriculum Framework
HS-LS1-6. Construct an explanation based on evidence that organic molecules are primarily composed of six elements, where carbon, hydrogen, and oxygen atoms may combine with nitrogen, sulfur, and phosphorus to form monomers that can further combine to form large carbon-based macromolecules.
Mollusk family tree
Cladograms and Evolution
Molluscs are invertebrate animals with a three part body plan that includes
(a) mantle = large body mass, with internal organs. Mantle is usually wholly or partly enclosed in a calcium carbonate shell.
(b) radula = fleshy structure used for feeding, sometimes compared to a tongue. Covered in very tiny denticles (miniature teeth.) Only found in molluscs. In all molluscs (except the bivalves.)
(c) a nervous system (almost all animals have a nervous system)
Several categories
Gastropods- “stomach foot”. Includes snails, slugs, limpets, and sea cucumbers.
Cephalopods- “head foot”. Includes octopi, squid, cuttlefish, and nautilus.
Bivalves- foot projects from shell. Includes clams, oysters, scallops, mussels
(there are a few other smaller categories)
Image from Phylogenomics reveals deep molluscan relationships, by Kocot et al.
Nature volume 477, pages 452–456 (22 September 2011) doi:10.1038/nature10382
Learning Standards
Massachusetts Science and Technology/Engineering Curriculum FrameworkLife
Science (Biology), Grades 6–8.
Classify organisms into the currently recognized kingdoms according to characteristics that they share. Be familiar with organisms from each kingdom.
Biology, High School
5.2 Describe species as reproductively distinct groups of organisms. Recognize that species are further classified into a hierarchical taxonomic system (kingdom, phylum, class, order, family, genus, species) based on morphological, behavioral, and molecular similarities.
Benchmarks for Science Literacy, American Association for the Advancement of Science
Students should begin to extend their attention from external anatomy to internal structures and functions. Patterns of development may be brought in to further illustrate similarities and differences among organisms. Also, they should move from their invented classification systems to those used in modern biology… A classification system is a framework created by scientists for describing the vast diversity of organisms, indicating the degree of relatedness between organisms, and framing research questions.
Evolution and diversity: Origin of life, evidence of evolution, patterns of evolution, natural selection, speciation, classification and diversity of organisms.
Teaching About Evolution and the Nature of Science, National Academy Press (1998)
Biological classifications are based on how organisms are related. Organisms are classified into a hierarchy of groups and subgroups based on similarities which reflect their evolutionary relationships. Species is the most fundamental unit of classification.
Prof Devel log NGSS Science discussion group
Sample prof development log for teachers in a NGSS Science Facebook discussion group.
Prof Development Log for FB Science teachers group (MS Doc format)
Prof Development Log for FB Science teachers group, PDF format
Miniaturization
Many sci-fi stories depend upon a technology called miniaturization. Isaac Asimov’s classic Fantastic Voyage; his more scientifically rigorous sequel, Fantastic Voyage II; DC Comics featuring The Atom, and Marvel Comics featuring Antman and The Wasp.
Is miniaturization real? Could it be real? What would be the results if it was real?
Scene from the 1966 movie Fantastic Voyage. The medical ship, inside in a blood vessel, is under attack from antibodies!
Miniaturization in movies and TV
1940’s movie – Dr. Cyclops. People are reduced to less than a foot in size by the titular mad scientist, and are subjugated to his whims.
1957 movie – The Incredible Shrinking Man inspired a boom in science fiction films that made use of size-alteration.
1961 The Atom, a Silver Age comic book character, the Atom, Dr. Ray Palmer, created by DC Comics.
1960’s Ant-Man, Marvel Comics superhero.
1966 Fantastic Voyage
1976 Dr. Shrinker, from the ABC network’s The Krofft Supershow
1987 Innerspace starring stars Dennis Quaid, Martin Short and Meg Ryan.
1989 Honey, I Shrunk the Kids, 1997 Honey, We Shrunk Ourselves
2015 Ant-Man, and 2018 Ant-Man and the Wasp
2016 – DC’s Legends of Tomorrow (featuring The Atom)
What would happen if we compressed someone?
Neil deGrasse Tyson shows us the real physics.
Although he probably shouldn’t write any more comics 😉
By Clay Yount, Hamlet’s Danish, 12/9/2014
Physics: How would one try to do this?
There are no practical ways to actually do this. However, science fiction stories speculate on how this could be done.
Interestingly, sustained thought and speculation on science fiction technologies has allowed scientists to develop real-world technologies.
A. Compression / increasing density
“Why are you so certain miniaturization is impossible?”
“If you reduce a man to the dimensions of a fly, then all the mass of a man would be crowded into the volume of a fly. You’d end up with a density of something like -” he paused to think – “a hundred and fifty thousand times that of platinum. “
From Fantastic Voyage II
B. Removing atoms
“But what if the mass were reduced in proportion?” – “Then you end up with one atom in the miniaturized man for every three million in the original. The miniaturized man would not only have the size of a fly but the brainpower of a fly as well. “
From Fantastic Voyage II:
C. Changing Planck’s constant
This is a major science-plot point in Fantastic Voyage II (1988)
“And if the atoms are reduced, too?”
“If it is miniaturized atoms you are speaking of, then Planck’s constant, which is an absolutely fundamental quantity in our Universe, forbids it. Miniaturized atoms would be too small to fit into the graininess of the Universe. “
“And if I told you that Planck’s constant was reduced as well, so that a miniaturized man would be encased in a field in which the graininess of the Universe was incredibly finer than it is under normal conditions?”
“Then I wouldn’t believe you. “
“Without examining the matter? You would refuse to believe it as a result of preconceived convictions, as your colleagues refuse to believe you?”
And at this, Morrison was, for a moment, silent….
…Well over half an hour had passed before Morrison felt convinced that the objects he could see outside the ship were shrinking and were receding perceptibly toward their normal size.
Morrison said, “I am thinking of a paradox.”
“What’s that?” said Kalinin, yawning. She had obviously taken her own advice about the advisability of relaxing.
“The objects outside the ship seemed to grow larger as we shrink. Ought not the wavelengths of light outside the ship also grow larger, becoming longer in wavelength, as we shrink? Should we not see everything outside turn reddish, since there can scarcely be enough ultraviolet outside to expand and replace the shorter-wave visible light?”
Kalinin said, “If you could see the light waves outside, that would indeed be how they would appear to you. But you don’t. You see the light waves only after they’ve entered the ship and impinged upon your retina. And as they enter the ship, they come under the influence of the miniaturization field and automatically shrink in wavelength, so that you see those wavelengths inside the ship exactly as you would see them outside.”
“If they shrink in wavelength, they must gain energy.”
“Yes, if Planck’s constant were the same size inside the miniaturization field as it is outside. But Planck’s constant decreases inside the miniaturization field — that is the essence of miniaturization. The wavelengths, in shrinking, maintain their relationship to the shrunken Planck’s constant and do not gain energy. An analogous case is that of the atoms. They also shrink and yet the interrelationships among atoms and among the subatomic particles that make them up remain the same to us inside the ship as they would seem to us outside the ship.”
“But gravity changes. It becomes weaker in here.”
“The strong interaction and the electroweak interaction come under the umbrella of the quantum theory. They depend on Planck’s constant. As for gravitation?” Kalinin shrugged. “Despite two centuries of effort, gravitation has never been quantized. Frankly, I think the gravitational change with miniaturization is evidence enough that gravitation cannot be quanitzed, that it is fundamentally nonquantum in nature.”
“I can’t believe that,” said Morrison. “Two centuries of failure can merely mean we haven’t managed to get deep enough into the problem yet. Superstring theory nearly gave us out unified field at last.” (It relieved him to discuss the matter. Surely he couldn’t do so if his brain were heating in the least.)
“Nearly doesn’t count,” said Kalinin. “Still, Shapirov aagreed with you, I think. It was his notion that once we tied Planck’s constant to the speed of light, we would not only have the practical effect of miniaturizing and deminiaturizing in an essentially energy-free manner, but that we would have the theoretical effect of being able to work out the connection between quantum theory and relativity and finally have a good unified field theory. And probably a simpler one than we could have imagined possible, he would say.”
“Maybe,” said Morrison. He didn’t know enough to comment beyond that.
Surely this is complete fantasy, correct? Well, probably. But there is some room in physics to believe that the constants of nature, even Planck’s constant, may quite be constant:
Could Fundamental Constants Be Neither Fundamental nor Constant?
Are Nature’s Laws Really Universal? Dr. Michael Murphy, Centre for Astrophysics and Supercomputing,
Swinburne University of Technology
The Variability of the ‘Fundamental Constants’
The Constants of Nature: From Alpha to Omega – The Numbers That Encode the Deepest Secrets of the Universe (book,) John D. Barrow
D. Nanotechnology as miniaturization
“…The ideas and concepts behind nanoscience and nanotechnology started with a talk entitled “There’s Plenty of Room at the Bottom” by physicist Richard Feynman at an American Physical Society meeting at the California Institute of Technology (CalTech) on December 29, 1959, long before the term nanotechnology was used.
In his talk, Feynman described a process in which scientists would be able to manipulate and control individual atoms and molecules. Over a decade later, in his explorations of ultraprecision machining, Professor Norio Taniguchi coined the term nanotechnology. It wasn’t until 1981, with the development of the scanning tunneling microscope that could “see” individual atoms, that modern nanotechnology began.”
Nano.gov What is nanotechnology?
Nanotechnology isn’t so impossible. We already have developed techniques to image and pick atoms. one atom at a time, through technologies such as atomic force microscopy and Scanning tunneling microscopy.
References
Miniaturization: Technovelgy article
Excerpt from Fantastic Voyage: II A Novel By Isaac Asimov, 1988
Learning Standards
Next Generation Science Standards: Science & Engineering Practices
● Ask questions that arise from careful observation of phenomena, or unexpected results, to clarify and/or seek additional information.
● Ask questions that arise from examining models or a theory, to clarify and/or seek additional information and relationships.
● Ask questions to determine relationships, including quantitative relationships, between independent and dependent variables.
● Ask questions to clarify and refine a model, an explanation, or an engineering problem.
● Evaluate a question to determine if it is testable and relevant.
● Ask questions that can be investigated within the scope of the school laboratory, research facilities, or field (e.g., outdoor environment) with available resources and, when appropriate, frame a hypothesis based on a model or theory.
● Ask and/or evaluate questions that challenge the premise(s) of an argument, the interpretation of a data set, or the suitability of the design
MA 2016 Science and technology
Appendix I Science and Engineering Practices Progression Matrix
Science and engineering practices include the skills necessary to engage in scientific inquiry and engineering design. It is necessary to teach these so students develop an understanding and facility with the practices in appropriate contexts. The Framework for K-12 Science Education (NRC, 2012) identifies eight essential science and engineering practices:
1. Asking questions (for science) and defining problems (for engineering).
2. Developing and using models.
3. Planning and carrying out investigations.
4. Analyzing and interpreting data.
5. Using mathematics and computational thinking.
6. Constructing explanations (for science) and designing solutions (for engineering).
7. Engaging in argument from evidence.
8. Obtaining, evaluating, and communicating information.
Scientific inquiry and engineering design are dynamic and complex processes. Each requires engaging in a range of science and engineering practices to analyze and understand the natural and designed world. They are not defined by a linear, step-by-step approach. While students may learn and engage in distinct practices through their education, they should have periodic opportunities at each grade level to experience the holistic and dynamic processes represented below and described in the subsequent two pages… http://www.doe.mass.edu/frameworks/scitech/2016-04.pdf
Facts and Fiction of the Schumann Resonance
This has been excerpted from Facts and Fiction of the Schumann Resonance,by Brian Dunning, Skeptoid Podcast #352
It’s increasingly hard to find a web page dedicated to the sales of alternative medicine products or New Age spirituality that does not cite the Schumann resonances as proof that some product or service is rooted in science. … Today we’re going to see what the Schumann resonances actually are, how they formed and what they do, and see if we can determine whether they are, in fact, related to human health.
In physics, Schumann resonances are the name given to the resonant frequency of the Earth’s atmosphere, between the surface and the densest part of the ionosphere.
Image from nasa.gov/mission_pages/sunearth/news/gallery
They’re named for the German physicist Winfried Otto Schumann (1888-1974) who worked briefly in the United States after WWII, and predicted that the Earth’s atmosphere would resonate certain electromagnetic frequencies.
[What is a resonant frequency? Here is a common example. When you blow on a glass bottle at a certain frequency, you can get the bottle to vibrate at the same frequency]
from acs.psu.edu/drussell/Demos/BeerBottle/beerbottle.html
This glass bottle has a resonant frequency of about 196 Hz.
That’s the frequency of sound waves that most efficiently bounce back and forth between the sides of the bottle, at the speed of sound, propagating via the air molecules.
Electromagnetic radiation – like light, and radio waves – is similar, except the waves travel at the speed of light, and do not require a medium like air molecules.
The speed of light is a lot faster than the speed of sound, but the electromagnetic waves have a lot further to go between the ground and the ionosphere than do the sound waves between the sides of the bottle.
This atmospheric electromagnetic resonant frequency is 7.83 Hz, which is near the bottom of the ELF frequency range, or Extremely Low Frequency.
The atmosphere has its own radio equivalent of someone blowing across the top of the bottle: lightning.
Lightning is constantly flashing all around the world, many times per second; and each bolt is a radio source. This means our atmosphere is continuously resonating with a radio frequency of 7.83 Hz, along with progressively weaker harmonics at 14.3, 20.8, 27.3 and 33.8 Hz.
These are the Schumann resonances.
It’s nothing to do with the Earth itself, or with life, or with any spiritual phenomenon;
it’s merely an artifact of the physical dimensions of the space between the surface of the Earth and the ionosphere.
Every planet and moon that has an ionosphere has its own set of Schumann resonances defined by the planet’s size.
Biggest point: this resonated radio from lightning is a vanishingly small component of the electromagnetic spectrum to which we’re all naturally exposed.
The overwhelming source is the sun, blasting the Earth with infrared, visible light, and ultraviolet radiation.
All natural sources from outer space, and even radioactive decay of naturally occurring elements on Earth, produce wide-spectrum radio noise. Those resonating in the Schumann cavity are only a tiny, tiny part of the spectrum.
Nevertheless, because the Schumann resonance frequencies are defined by the dimensions of the Earth, many New Age proponents and alternative medicine advocates have come to regard 7.83 Hz as some sort of Mother Earth frequency, asserting the belief that it’s related to life on Earth.
The most pervasive of all the popular fictions surrounding the Schumann resonance is that it is correlated with the health of the human body.
There are a huge number of products and services sold to enhance health or mood, citing the Schumann resonance as the foundational science.
A notable example is the Power Balance bracelets. Tom O’Dowd, formerly the Australian distributor, said that the mylar hologram resonated at 7.83 Hz.
When the bracelet was placed within the body’s natural energy field, the resonance would [supposedly] “reset” your energy field to that frequency.
Well, there were a lot of problems with that claim.
First of all, 7.83 Hz has a wavelength of about 38,000 kilometers. This is about the circumference of the Earth, which is why its atmospheric cavity resonates at that frequency. 38,000 kilometers is WAY bigger than a bracelet!
There’s no way that something that tiny could resonate such an enormous wavelength. O’Dowd’s sales pitch was implausible, by a factor of billions, to anyone who understood resonance.
This same fact also applies to the human body. Human beings are so small, relative to a radio wavelength of 38,000 kilometers, that there’s no way our anatomy could detect or interact with such a radio signal in any way.
Proponents of binaural beats cite the Schumann frequency as well. These are audio recordings which combine two slightly offset frequencies to produce a third phantom beat frequency that is perceived from the interference of the two.
Some claim to change your brain’s encephalogram, which they say is a beneficial thing to do. Brain waves range from near zero up to about 100 Hz during normal activity, with a typical reading near the lower end of the scale.
This happens to overlap 7.83 — suggesting the aforementioned pseudoscientific connection between humans and the Schumann resonance — but with a critical difference. An audio recording is audio, not radio. It’s the physical oscillation of air molecules, not the propagation of electromagnetic waves. The two have virtually nothing to do with each other.
[Other salespeople claim] that our bodies’ energy fields need to interact with the Schumann resonance, but can’t because of all the interference from modern society [and so they try to sell devices that supposedly connect our body to the Schumann resonance.]
It’s all complete and utter nonsense. Human bodies do not have an energy field: in fact there’s not even any such thing as an energy field. Fields are constructs in which some direction or intensity is measured at every point: gravity, wind, magnetism, some expression of energy.
Energy is just a measurement; it doesn’t exist on its own as a cloud or a field or some other entity. The notion that frequencies can interact with the body’s energy field is, as the saying goes, so wrong it’s not even wrong.
Another really common New Age misconception about the Schumann resonance is that it is the resonant frequency of the Earth. But there’s no reason to expect the Earth’s electromagnetic resonant frequency to bear any similarity to the Schumann resonance.
Furthermore, the Earth probably doesn’t even have a resonant electromagnetic frequency. Each of the Earth’s many layers is a very poor conductor of radio; combined all together, the Earth easily absorbs just about every frequency it’s exposed to. If you’ve ever noticed that your car radio cuts out when you drive through a tunnel, you’ve seen an example of this.
Now the Earth does, of course, conduct low-frequency waves of other types. Earthquakes are the prime example of this. The Earth’s various layers propagate seismic waves differently, but all quite well. Seismic waves are shockwaves, a physical oscillation of the medium. Like audio waves, these are unrelated to electromagnetic radio waves.
Each and every major structure within the Earth — such as a mass of rock within a continent, a particular layer of magma, etc. — does have its own resonant frequency for seismic shockwaves, but there is (definitively) no resonant electromagnetic frequency for the Earth as a whole.
So our major point today is that you should be very skeptical of any product that uses the Schumann resonance as part of a sales pitch.
The Earth does not have any particular frequency. Life on Earth is neither dependent upon, nor enhanced by, any specific frequency.
Source: skeptoid.com/episodes/4352
Resonance
Resonance: The increase in the amplitude of an oscillation of a system under the influence of a periodic force whose frequency is close to that of the system’s natural frequency.
There are several types of resonance
Mechanical resonance
tendency of a mechanical system to respond at greater amplitude when the frequency of its oscillations matches the system’s natural frequency of vibration (its resonance frequency or resonant frequency) than it does at other frequencies.
This may cause violent swaying motions and potentially catastrophic failure in improperly constructed structures including bridges, buildings and airplanes.
Examples include:
Musical instruments (acoustic resonance)
Musical instruments are set into vibrational motion at their natural frequency when a person hits, strikes, strums, plucks or somehow disturbs the object.
Each natural frequency of the object is associated with one of the many standing wave patterns by which that object could vibrate. The natural frequencies of a musical instrument are sometimes referred to as the harmonics of the instrument.
Physics Classroom – Sounds – Lesson 5 – Resonance
Clocks
Most clocks keep time by mechanical resonance in a balance wheel, pendulum, or quartz crystal.
Tidal resonance
Seen at the Bay of Fundy in Canada.
Objects can shatter at resonant frequencies
A wineglass breaking when someone sings a loud note at exactly the right pitch.
Resonance in weather systems
Rossby waves, also known as planetary waves, are a type of wave naturally occurring in rotating fluids (gas or liquid.) Here on Earth are they are giant meanders in high-altitude winds; they have a major influence on weather.
It has been proposed that a number of regional weather extremes in the Northern Hemisphere associated with blocked atmospheric circulation patterns may have been caused by quasiresonant amplification of Rossby waves.
Examples include the 2013 European floods, the 2012 China floods, the 2010 Russian heat wave, the 2010 Pakistan floods and the 2003 European heat wave.
Rossyby Wave, Wikipedia
Orbital resonance
The motion of one object orbiting a star, or planet, can influence the motion of another object. Eventually, over time the motions of the objects can become in resonance with each other.
Orbital resonance can occur in many ways:
Here we see an asteroid sometimes called a quasi-satellite. It has its own orbit around the Sun, but over time this has developed a 1:1 resonance with Earth’s orbit.
The most well known quasi-satellite of Earth is the asteroid Cruithne, discovered in 1986. It is 5 KM in diameter. If you were “above” our Sun, looking down into the solar system then you would see it’s orbit and Earth’s orbit like this:
IMAGE FROM WIKIPEDIA
But from the point of view of people here on Earth, it appears to be trailing us, making a horseshoe-shaped orbit.
That’s not a moon as such, and it doesn’t even orbit us. But due to the oddities of orbital mechanics it appears to be behind us in space, orbiting empty space!
IMAGE FROM WIKIPEDIA
Resonance in the rings of Saturn
TBA
Ring dynamics, Stars and Planets, ASTR 221
The Forces that Sculpt Saturn’s Rings….
Resonance Moon and Rings, NASA Science
Staggering Structure, NASA Science
Planetary Rings, Lumen Learning
Resonance in electrical circuits
Circuits involving capacitors and inductors can demonstrate resonance.
A collapsing magnetic field from the inductor generates an electric current in its windings;
this current charges the capacitor,
hen the discharging capacitor provides an electric current that builds the magnetic field in the inductor.
This process is repeated continually. An analogy is a mechanical pendulum, and both are a form of simple harmonic oscillator.
Symbols: resistor – R, inductor – L, capacitor – C
Resonance in RLC circuits
An RLC circuit consists of a resistor, an inductor, and a capacitor.
The circuit forms a harmonic oscillator for current; it resonates similarly to an LC circuit.
The main difference (due to the presence of the resistor) is that any oscillation induced in the circuit decays over time if it is not kept going by a source.
This effect of the resistor is called damping.
The presence of the resistance reduces the peak resonant frequency of damped oscillation, although the resonant frequency for driven oscillations remains the same as an LC circuit.
Some resistance is always unavoidable in real circuits, even if a resistor is not specifically included as a separate component.
A pure LC circuit is an ideal that exists only in theory.
An important application for this type of circuit is tuning, such as in radio receivers or television sets. They are used to select a narrow range of frequencies from the ambient radio waves.
Intuitor.com The Physics of Resonance
Video LC Inductor-Capacitor Resonating Circuits by by Eugene Khutoryansky
Mechanical structure susceptible to damage from resonance
RedGrittyBrick, a physicist writing on skeptics.stackexchange.com, notes that a bridge can be susceptible to mechanical resonance:
Mechanical structures usually have one or more frequencies at which some part of the structure oscillates. A tuning fork has a well-defined natural frequency of oscillation. More complex structures may have a dominant natural frequency of oscillation.
If some mechanical inputs (such as the pressure of feet walking in unison) have a frequency that is close to a natural frequency of the structure, these inputs will tend to initiate and, over a short time, increase the oscillating movements of the structure. Like pushing a child’s swing at the right time.
One example is London’s Millennium Bridge which was closed shortly after opening because low-frequency vibrations in the bridge were causing large groups of pedestrians to simultaneously shift their weight and reinforcing the oscillation. Dampers were fitted.
Skeptics.stackexchange Does a column of marching soldiers have to break their rhythm while crossing a bridge to prevent its collapse?
Related topics (local)
Nikola Tesla and wireless power transmission
Facts and Fiction of the Schumann Resonance: On this website
Learning Standards
2016 Massachusetts Science and Technology/Engineering Curriculum Framework
HS-PS4-5. Communicate technical information about how some technological devices use the principles of wave behavior and wave interactions with matter to transmit and capture information and energy. Examples of principles of wave behavior include resonance, photoelectric effect, and constructive and destructive interference.
MCAS Science and Technology
MCAS Science and Technology 8th grade. Spring 2017. Based on learning standards in the four major content strands of the Massachusetts Science and Technology/Engineering Curriculum Framework.
MCAS Science and Tech 8th grade
• Earth and Space Science
• Life Science (Biology)
• Physical Sciences (Chemistry and Physics)
• Technology/Engineering
MCAS Evolution
MCAS Evolution
Feb 2016 MCAS. Scientists often compare fossils of extinct organisms with living organisms to help determine evolutionary relationships. What is the primary information that scientists use when comparing fossils with living organisms?
A. the types of minerals that formed the fossils
B. the size of the rocks that contained the fossils
C. the cause of death for the fossilized organisms
D. the physical characteristics of the fossilized organisms
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Feb 2016 MCAS .
The pictures below show the shells of some species of land snails found on a Pacific island. Each species was found on a different hill on the island. Based on the snails’ shell shapes, scientists made hypotheses about the evolutionary relationships among the snails. Which of the following would be the best characteristic to compare in order to test these hypotheses?
A. the size of the snails
B. the diet of the snails
C. the DNA of the snails
D. the average age of the snails
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Scientists hypothesized that several species of frogs called tiger frogs evolved from a recent common ancestor. The hypothesis was based on fossil evidence and on physical similarities among living species.
Which of the following provides the best additional support for the scientists’ hypothesis?
A. Tiger frogs have longer life spans than other frog species.
B. Tiger frogs have the same diet and all use enzymes to digest food.
C. Tiger frogs live near each other and are all preyed upon by the same predator species.
D. Tiger frogs have similarities in their mitochondrial DNA that are not shared by other frog species.
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Spring 2017
Some populations of Atlantic tomcod fish have an allele that makes the fish resistant to toxic pollutants called PCBs. Tomcod populations in several rivers were analyzed for the presence of this allele. Each river had varying levels of PCB pollution. Which of the following results would best support the conclusion that natural selection is influencing the presence of this allele in the tomcod populations?
A. All of the tomcod in each of the rivers have this allele.
B. The percentage of tomcod with this allele remains the same from year to year in each river.
C. The rivers with high PCB levels have larger percentages of tomcod with this allele than the rivers without PCBs.
D. Eggs from tomcod without this allele can hatch in rivers with or without PCBs, and eggs from tomcod with this allele can only hatch in rivers without PCBs.
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Spring 2017.
A researcher observed army ants, which form colonies with one queen ant and many worker ants. The researcher observed worker ants moving from place to place to hunt and collect a variety of food for the colony. The queen ant was observed mating with a male ant from another ant colony. The queen produced many eggs after this mating. Which of the following could help increase the genetic diversity in the colony of army ants?
A. the queen ant mating with the ant from a different colony
B. the worker ants collecting the food for the colony to eat
C. the worker ants moving from place to place
D. the queen ant eating a variety of food
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Scientists discovered a 375-million-year old fossil in Canada. The diagram below shows the top and side views of the fossil.
Which observation would best support the hypothesis that this organism was
a transitional form between amphibians and fish?
A. The fossil has a long body, which both modern amphibians and modern fish have.
B. The fossil is larger than most modern amphibians, but smaller than most ancient fish.
C. The fossil has some body structures that are similar to amphibians and some body structures that are similar to fish.
D. The fossil was discovered near a lake, which shows that the organism
needed water to reproduce, as do amphibians and fish.
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Some plants in an area produce a toxin that protects them from being eaten by a variety of insect species. The toxin decreases reproductive rates in insects. Because of a genetic mutation, some fruit flies can detect the plant toxin and therefore avoid eating the plant.
a. Describe how the number of fruit flies in the population that can detect the toxin will most likely change over the next 25 years.
b. According to the mechanism of natural selection, explain how the change you described in part (a) will occur.
c. Based on the changes in the fruit fly population, describe what will most likely happen to the plants’ production of the toxin. Explain your answer.
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Sperm whales have vestigial hip bones, and a small percentage of sperm whales
also have vestigial hind limbs. Which of the following statements best explains
the presence of these vestigial structures in sperm whales?
A. Sperm whales evolved from ancestors that walked on land.
B. Sperm whales are in the process of evolving into land mammals.
C. These structures are acquired by each individual sperm whale during its lifetime.
D. These structures resulted from sperm whales having a long period of embryonic development.
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2014 MCAS Open response question
An elephant shrew and a shrew are pictured below.
For many years, scientists had classified elephant shrews in the same family as shrews. In the 1990s, however, scientists gathered evidence for the evolutionary tree below and reclassified elephant shrews into a different family from shrews.
a. Describe the most likely reason why scientists originally classified elephant shrews with shrews.
b. Using the evolutionary tree, identify the groups to which elephant shrews are most closely related.
c. Identify and explain the evidence scientists most likely used to build the evolutionary tree and reclassify elephant shrews.
d. Identify one other type of evidence that scientists use to determine evolutionary relationships and build evolutionary trees.
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Scientists measured and recorded the average body size in a bird population over time. One year, a period of cold weather killed many of the birds. A few generations later, the scientists observed that the average body size in the population was larger than it had been before the cold weather. The scientists concluded that the population had evolved through natural selection. Which of the following would provide the best evidence to support the scientists’ conclusion?
A. The size of the bird eggs also increased over time.
B. The birds with the largest body size were the males.
C. The frequency of alleles for body size changed in the bird population.
D. The number of birds in the population had decreased by 50% or more.
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The three-spined stickleback is a species of fish. It lives in the ocean and in streams that flow into the ocean. Some scientists think that the ocean populations and stream populations may be evolving into separate species. Which of the following statements describes how speciation of these fish would most likely occur?
A. Fish from stream populations would start to reach maturity at the same time as fish from ocean populations.
B. Fish from stream populations would sometimes swim into the ocean but fish from ocean populations would stop swimming into streams.
C. Ocean populations and stream populations would each mate fewer times per year and would have decreased birth rates over time.
D. Ocean populations and stream populations would each adapt differently to their environments and would accumulate enough differences over time to prevent interbreeding
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In a certain insect species, body color varies from very light gray to very dark gray. These insects are eaten by birds that find their prey by sight. A brush fire occurs, blackening the ground where one population of this insect species lives. Which of the following is most likely to occur over the next few years?
A. The body color in the population will mutate to black.
B. The percentage of very dark gray individuals will increase.
C. The distribution of body color in the population will not change.
D. The very light gray individuals will learn how to reproduce at a later age.
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MCAS Cell biology, mitosis, meiosis, fertilization
Different types of cells in the human body undergo mitosis at different rates. Which of the following statements best explains why skin cells frequently undergo mitosis?
A. Skin cells contain molecules of DNA.
B. Skin cells constantly need to be replaced or repaired.
C. Skin cells have large numbers of sensory nerve receptors.
D. Skin cells constantly need to produce antibodies to fight off infections.
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Mice with the same parents can have different traits. Which of the following
best explains how most of these differences occur?
A. Gametes join by binary fission.
B. Cells divide by asexual reproduction.
C. Genes assort independently during meiosis.
D. Spontaneous mutations occur during mitosis.
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Which of the following is always part of normal sexual reproduction?
A. The male produces gametes by mitosis.
B. An offspring looks identical to the parents at birth.
C. The female carries only one fertilized egg at a time.
D. An offspring receives half its chromosomes from each parent.
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Various MCAS questions may be related to bacteria.
a. Identify the process that bacteria cells use to reproduce.
b. Describe two similarities between the process that skin cells use for cell division and the process that you identified in part (a).
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2015 MCAS
The illustration below shows one chromosome pair in a zygote. The zygote was produced by sexual reproduction.
Assuming normal meiosis and fertilization occurred, which illustration shows the egg and sperm that produced this zygote?
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The diagram below shows a plant cell at a particular stage in the cell cycle. This stage occurs immediately after which cellular process?
A. crossing over
B. DNA replication
C. fertilization
D. mitosis
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2016 MCAS
Which of the following must occur before mitosis can begin?
A. DNA must be replicated in the nucleus.
B. RNA must move to the center of the nucleus.
C. Chromosomes must attach to the cell membrane.
D. Ribosomes must move to opposite sides of the cell.
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Each summer, up to 40% of the lobsters in a certain area lose one of their claws due to injury. By late fall, the missing claw usually begins to grow back. Which of the following describes the process by which lobsters grow new claws?
A. Lysosomes fuse together to recycle matter to build a new claw.
B. Mitotic cell division adds new cells to rebuild the lobster’s claw.
C. Facilitated diffusion moves body cells from the remaining claw to the new claw.
D. Cellular respiration creates nutrients to enlarge existing cells in the lobster’s claw.
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2014 MCAS
Sharks typically reproduce sexually. A particular female shark, however, gave birth in a zoo despite having no recent contact with a male shark.
a. Identify the type of cell division that produces eggs and sperm in animals such as sharks.
b. Describe what normally happens during fertilization in animals such as sharks. Be sure to identify the end product of fertilization.
Female sharks can store sperm after mating and then wait to fertilize their eggs.
Scientists investigated whether the female shark in the zoo did this.
c. Describe how DNA analysis can determine if the shark reproduced using stored sperm or if she reproduced asexually. Be sure to include the source(s) of DNA being analyzed and the results of the analysis in your answer.
d. Explain why sexual reproduction is important for the long-term survival of shark species.
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2016 MCAS open response question
The diagram below represents a plant cell with three structures labeled X, Y, and Z.
Plant cells and fungal cells have many of the same types of organelles. Structures X and Y are found in both plant cells and fungal cells. Structure Z is found in plant cells, but not in fungal cells.
a. Identify structure Y and describe its main function.
b. Identify structure Z and explain how plants use this structure to survive.
c. Explain how fungi can survive without structure Z
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Each summer, up to 40% of the lobsters in a certain area lose one of their claws due to injury. By late fall, the missing claw usually begins to grow back. Which of the following describes the process by which lobsters grow new claws?
A. Lysosomes fuse together to recycle matter to build a new claw.
B. Mitotic cell division adds new cells to rebuild the lobster’s claw.
C. Facilitated diffusion moves body cells from the remaining claw to the new claw.
D. Cellular respiration creates nutrients to enlarge existing cells in the
lobster’s claw.
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2017 MCAS
The diagram below shows a chloroplast and some of the components of the reactions that occur in chloroplasts.
Which of the following is a product of the reactions that take place in a chloroplast?
A. hydrogen gas B. nitrate C. oxygen gas D. protein
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In which of the following ways does the plasma membrane regulate the entry of molecules into a cell?
A. The membrane allows only certain molecules to move into the cell.
B. The membrane destroys most molecules so that they do not enter the cell.
C. The membrane changes only certain molecules into ions before they move into the cell.
D. The membrane allows most molecules to transfer energy to the cell without entering the cell.
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Many animals have either internal or external skeletons that provide support and structure. Which of the following parts of plant cells play a similar role?
A. cell membranes
B. cell walls
C. chloroplasts
D. cytoplasm
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Sample response: Sharks typically reproduce sexually.
Concept Maps
We’re teaching our students how to translate articles into concept maps: these are graphical tool that depict relationships between concepts. They are used by students, engineers, and technical writers, to organize and structure knowledge.
Here’s an example of how one could take ideas related to energy and electricity, and show how they are related:
A concept map typically represents ideas and information as boxes or circles.
They are connected with labeled arrows.
The relationship between concepts often shows us cause-and-effect, with terms like: causes, requires, or “contributes to.”
Below I have given students an article on how some insects have evolved resistance to insecticides due to gut bacteria they carry within them. For many students the original article was quite challenging. This is how I scaffolded it:
I copied & pasted the article into a word processor.
I broke up long paragraphs into shorter ones; broke up some of the longer sentences into two shorter ones.
Used bold font to call attention to important vocabular words or concepts.
Added a photograph or graphic after each bolded word to help the students better understand the word.
After we went through this article together they were then able to draw concept maps, showing relationships between various topics in the article.
Here we did the same thing for another article. This was about the role of honeybees in agriculture.
How to create a concept map
Read the article
Identify the main concepts
How are the concepts related to each other?
Draw a rough map: draw each concept inside a square or circle
Draw arrows showing how one action or event affects another
You can use symbols “+” for increase, and ” – ” for decrease.
Here’s an example of an astronomy concept map
Learning Standards
Why should teachers use concept maps? According to the National Research Council, experts differ from novices in that experts notice features and patterns of information, have acquired a great deal of content knowledge that is organized in ways that reflect deep understanding. Their knowledge cannot be reduced to a set of isolated facts or propositions but, instead, reflects contexts of applicability (Bransford, Brown, and Cocking 2000).
More important, experts have efficiently coded and organized this information into well-connected schemas that help experts interpret new information and notice features and meaningful patterns of information that might be overlooked by less competent learners (Pellegrino, Chudowshy, and Glaser 2001).
As students gain mastery of concept maps, they develop an understanding of relationships among elements of a concept, ultimately making incremental gains in moving from novice to expert-level learners. Furthermore, by constructing concept maps, students enhance a metacognitive approach to learning by negotiating their ideas, taking control of their own learning, and monitoring their progress. As the learner physically draws the connection between two subtopics, he/she reinforces that same connection mentally.
From “Making the Most of Concept Maps”, Douglas Llewellyn, National Science Teachers Association
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