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Teaching about evolution
So, we’re supposed to teach our students about evolution – but where to start? What topics to cover? And in what order should we cover them? And for each topic, what are the relevant learning standards? This sequence works for me:
Abiogenesis & spontaneous generation
Abiogenesis – modern discoveries
Charles Darwin’s Voyage of Discovery and Darwin’s notebook
Fossils: Evidence of evolution over time and Dating of fossils
Convergent evolution and Homologous and analogous structures
clades rotate = equivalent phylogenies
Gradualism vs. Punctuated Equilibrium
Examples of evolution
Where did the idea of evolution develop? How has the idea of evolution changed over time?
Advanced topics
Evolution of the first animals
Ontogeny and Phylogeny: Addressing misconceptions
Horizontal Gene Transfer and Kleptoplasty
Teaching about cells
So, we’re supposed to teach our students biology – but where to start? What topics to cover? And in what order should we cover them? And for each topic, what are the relevant learning standards? This sequence works for me:
Characteristics of Life
Organelles, an introduction
Organelles: In more depth
What is the role of enzymes in cells?
Then we move on to types of cells
Now the nitty-gritty: Cell reproduction
For those teaching Honors Biology
Active transport across cell membranes
Psychiatry
Psychiatry is a medical field devoted to the diagnosis, study, and treatment of mental disorders.
The following intro has been adapted from Wikipedia:

Psychiatric assessment of a person typically begins with a case history and mental status examination.
Physical examinations and psychological tests may be conducted.
On occasion, neuroimaging or other neurophysiological techniques are used.
Mental disorders are often diagnosed in accordance with criteria listed in diagnostic manuals. Examples include:
Diagnostic and Statistical Manual of Mental Disorders (DSM),
by the American Psychiatric Association (APA),
and the International Classification of Diseases (ICD),
by the World Health Organization (WHO).
Psychopharmacology became important starting with Otto Loewi‘s discovery of the neuromodulatory properties of acetylcholine. This is the first-known neurotransmitter.
Neuroimaging was first utilized as a tool for psychiatry in the 1980s.

The discovery of chlorpromazine‘s effectiveness in treating schizophrenia in 1952 revolutionized treatment of the disorder.
Another major discovery (1948) was the chemical lithium carbonate. This molecule can stabilize mood highs and lows in bipolar disorder.
Biopsychiatric research – This has shown us how biology is related to psychiatry.
We have discovered that there are relationships between certain mental illnesses, and certain abnormalities of brain structure. This includes schizophrenia.
We have also discovered that some genetic mutations are related to psychiatric disorders. This includes schizophrenia, bipolar disorder, and autism.
In general, though, science has not progressed to the stage that we can identify clear biomarkers of these disorders.
In other words, we don’t have specific biochemical tests for mental disorders.
Mental disorders don’t exist on their own
From The hidden links between mental disorders
Psychiatrists have a dizzying array of diagnoses and not enough treatments.
Hunting for the hidden biology underlying mental disorders could help.
Michael Marshall, Nature 581, 19-21 (2020). doi: 10.1038/d41586-020-00922-8
In 2018, psychiatrist Oleguer Plana-Ripoll was wrestling with a puzzling fact about mental disorders. He knew that many individuals have multiple conditions — anxiety and depression, say, or schizophrenia and bipolar disorder. He wanted to know how common it was to have more than one diagnosis, so he got his hands on a database containing the medical details of around 5.9 million Danish citizens.
He was taken aback by what he found. Every single mental disorder predisposed the patient to every other mental disorder — no matter how distinct the symptoms. “We knew that comorbidity was important, but we didn’t expect to find associations for all pairs,” says Plana-Ripoll, who is based at Aarhus University in Denmark.
The study tackles a fundamental question that has bothered researchers for more than a century. What are the roots of mental illness? In the hope of finding an answer, scientists have piled up an enormous amount of data over the past decade, through studies of genes, brain activity and neuroanatomy. They have found evidence that many of the same genes underlie seemingly distinct disorders, such as schizophrenia and autism, and that changes in the brain’s decision-making systems could be involved in many conditions.
They have a few theories. Perhaps there are several dimensions of mental illness — so, depending on how a person scores on each dimension, they might be more prone to some disorders than to others. An alternative, more radical idea is that there is a single factor that makes people prone to mental illness in general: which disorder they develop is then determined by other factors. Both ideas are being taken seriously, although the concept of multiple dimensions is more widely accepted by researchers.
The details are still fuzzy, but most psychiatrists agree that one thing is clear: the old system of categorizing mental disorders into neat boxes does not work. They are also hopeful that, in the long run, replacing this framework with one that is grounded in biology will lead to new drugs and treatments. Researchers aim to reveal, for instance, the key genes, brain regions and neurological processes involved in psychopathology, and target them with therapies. Although it might take a while to get there, says Steven Hyman of the Broad Institute of MIT and Harvard in Cambridge, Massachusetts, “I am long-term optimistic if the field really does its work.”
Related articles
Neuroscientist argues that addiction is not a disease
Is a ‘Spectrum’ the Best Way to Talk About Autism?
Learning styles and multiple intelligences
Psychopathy
Psychopaths Don’t Care If They Hurt You. This Is Why. New research shows why the psychopathic are so likely to harm others.
Detecting genetic disorders with 3d face scans
Link between marijuana and pyschosis, and depression, hyperactivity, and inattention in children.
Mysterious link between immune system and mental illness – He Got Schizophrenia. He Got Cancer. And Then He Got Cured.
Article on mental health disorders
NIMH Disruptive Mood Dysregulation Disorder
Learning Standards
Massachusetts Comprehensive Health Curriculum Framework
PreK–12 STANDARD 5: Mental Health. Students will acquire knowledge about emotions and physical health, the management of emotions, personality and character development, and social awareness; and will learn skills to promote self-acceptance, make decisions, and cope with stress, including suicide prevention.
Benchmarks: American Association for the Advancement of Science
Stresses are especially difficult for children to deal with and may have long-lasting effects. 6F/H1
Biological abnormalities, such as brain injuries or chemical imbalances, can cause or increase susceptability to psychological disturbances. 6F/H2
Reactions of other people to an individual’s emotional disturbance may increase its effects. 6F/H3
Human beings differ greatly in how they cope with emotions and may therefore puzzle one another. 6F/H4
Ideas about what constitutes good mental health and proper treatment for abnormal mental states vary from one culture to another and from one time period to another. 6F/H5
Psychological distress may also affect an individual’s vulnerability to biological disease. 6F/H6** (SFAA)
According to some theories of mental disturbance, anger, fear, or depression may result from exceptionally upsetting thoughts or memories that are blocked from becoming conscious. 6F/H7** (SFAA)
Organelles in depth
Cell membrane
Made of 2 layers of lipids (fats); aka lipid bilayer.
We sometimes see simplified 2D drawings of this.
This drawing shows a small section of the lipid bilayer: 2 layers of lipids and some proteins floating in these lipids.

Cell membrane lipid bilayer Regents diagram http://www.hobart.k12.in.us/jkousen/Biology/cell.htm#plcell_dia_ans
A more accurate visualization would be to show this in three dimensions:

We sometimes see simplified 2D drawings of this. This drawing shows a small section of the lipid bilayer: 2 layers of lipids and some proteins floating in these lipids.

Cell membrane lipid bilayer Regents diagram http://www.hobart.k12.in.us/jkousen/Biology/cell.htm#plcell_dia_ans
Cytoplasm
A thick viscous liquid filling the cell.
All the organelles float in it.
Filled with millions of enzymes, dissolved salt ions, and other chemicals.

Here is a (false color) visualization of proteins floating in a cell’s cytoplasm. Densely packed!

Nucleus
The command-and-control center of the cell.
Chromosomes (made of DNA) are stored in here. In this animation we see DNA in the nucleus, and a copy of it (RNA) leaving the nucleus and going out into the rest of the cell.

Here we see a more realistic image of the nucleus (lower left); we see mRNA copies of DNA coming out of the nucleus through nuclear pores.

Nucleus to ribosomes to ER GIF from NPR: Protein synthesis
Chromosomes
If we magnify a cell we see chunks floating in the nucleus called chromosomes. They are made of a chemical called DNA.

Here we see a cell nucleus being lysed (broken open) and all the chromosomes are spilling out on the right.
The color was added by hand to make it easier to tell them apart. We cut-and-paste each of the chromosomes, number them, and line them up (lower left.)
In humans we find 23 pairs of chromosomes in every cell.
These X shaped chromosomes are not solid; they are like objects made of wound-up yarn.
A chromosome could be unwound into a long, thing string.
This string is made of DNA molecules.

Each section of the chromosome has difference sequences of DNA.
A complete sequence of DNA is called a gene; it is an instruction on how to build a protein.
Mitochondrion
Plural is mitochondria.
Converts energy from food molecules into a form usable by the cell.

Jay Swan http://www.slideshare.net/jayswan http://www.slideshare.net/jayswan/honors-biology-cellular-respiration
and

Jay Swan http://www.slideshare.net/jayswan http://www.slideshare.net/jayswan/honors-biology-cellular-respiration
Ribosomes
Little organic machines that take in amino acids (from our food) and turn them into proteins.
They are very tiny compared to the size of a cell – often seen as mere dots.

Here we see the ribosomes picking up RNA, and using that instruction to build a protein.

Nucleus to ribosomes to ER GIF from NPR: Protein synthesis
Ribosomes struck on an organelle
On the right we can just barely see the ribosomes as small dots stuck to the ER (endoplasmic reticulum.)
On the left we see the ER magnified.
The ribosomes are a bit clearer here (although we still don’t see their details.)
When the ER is covered with ribosomes we call it the “rough ER.”

Darryl Leja, NHGRI Rough endoplasmic reticulum and ribosomes
Other ribosomes float freely in the cytoplasm.
Here we see mRNA copies of DNA coming out of a cell nucleus, and moving to a ribosome floating nearby.
Here’s how we remember this:
ER (endoplasmic reticulum)
This manufactures lipids and proteins.
Like an assembly line which makes our products.

Next, molecules from the ER are packaged into vesicles, and transported to the Golgi apparatus.

Golgi body
This organelle packages proteins into vesicles, tags them with an “address” and send them to their destination.

another image will be here:
Details of Golgi bodies function and organization

From The Cell: A Molecular Approach, 5th ed. Cooper & Hausman. 2009
The Endomembrane system
Here we see the while system, from products leaving the nucleus, going to the ER, then to the Golgi, and then secreted as a vesicle.
In this case the products are going out to the cell membrane (“plasma membrane.)

From Biotech Review YouTube channel.
More details: The endomembrane system is composed of the different membranes that are suspended in the cytoplasm within a eukaryotic cell.

Endomembrane system by Mariana Ruiz Villarreal, LadyofHats
Cytoskeleton
These thin protein tubes give the cell its shape and mechanical resistance to deformation.
With the right stains, one can take a beautiful photo of the cytoskeleton.
Lysosome
Contain enzymes that can break down virtually all kinds of biomolecules. Garbage disposal.

Vacuoles
A lipid bag that can store organic molecules.

Chloroplasts
In this movie of plant cells, we some small, green discs moving around: these are chloroplasts.

They contain a light-absorbing pigment (colored molecule), chlorophyll.
This molecules captures the energy from some wavelengths of light.
The plant cell stores this energy in chemical bonds. The plant builds ATP and sugar molecules which store this energy.
In this image we see some chloroplasts floating within a plant cell.
Here we see a single chloroplast, vastly magnified with a TEM (transmission electron microscope.)
We see that there is quite a bit of detail within them.

Cell wall
Note that animal cells don’t have this organelle. Only plants and bacteria have it.
Made of cellulose – a special sugar used to provide structure, and not used for energy.
If the cell membrane is like a balloon, then the cell wall is like a cardboard box around the balloon, protecting it.
Gives strength and support. Allows plants like bamboo and trees to grow tall.

Here we see a typical boxy shaped plant cell, clearly showing the cell wall (green) and the lipid bilayer (yellow, aka plasma membrane.)

Plant cell has a wall adapaproject
Large central vacuole
A membrane that stores watery bags of food or waste molecules.
How do we know what these organelles really look like?
Visualizing cells and organelles in 3D
Sample questions
Feb 2016 MCAS: Which of the following types of organisms have cell walls composed of cellulose?
A. amoebas B. birds C. grasses D. worms
==========
Feb 2016 MCAS. Antibiotics are medicines used to treat bacterial infections in humans. Some antibiotics work by interfering with the bacteria’s ribosomes. Other antibiotics work by interfering with the bacteria’s plasma membrane.
a. Describe the function of the ribosomes and explain why interfering with the ribosomes would kill the bacteria.
b. Describe the function of the plasma membrane and explain why interfering with the plasma membrane [lipid bilayer] would kill the bacteria.
Medicines called antifungals are used to treat infections caused by fungi. One way antifungals work is by targeting cell parts that are present in fungal cells but not in human cells.
c. Identify one cell part other than a ribosome or a plasma membrane that human cells and fungal cells have in common.
d. Describe what would happen to a human cell if the cell part you identified in part (c) were affected by an antifungal. Explain your answer based on the function of the cell part.
==========
External resources
Biology MCAS exams
Previous MCAS exams from the Massachusetts Department of Elementary and Secondary Education
Below you will find each released short-response question, open-response question, and writing prompt that was included on High School Biology MCAS tests; the scoring guide for each question; and a sample of student work at each score point for that question. Taken together, these provide a picture of the expectations for student performance on the MCAS tests.
Special Education accommodations
February 2018 MCAS Biology Test Administration Resources
MCAS Accessibility and Accommodations
SAMPLE MCAS High School Biology Reference Sheet For Students with Accommodation 20
]MCAS Access & Accommodations Manual Spring 2018
MCAS TEST ACCOMMODATIONS FOR STUDENTS WITH DISABILITIES (PDF document)
MCAS Standard Accommodations
Frequent Breaks: The test is administered in short periods with frequent breaks
Time of Day: The test is administered at a time of day that takes into account the student’s medical or learning needs (IEP or 504 plan must specify time of day)
Small Group: The test is administered in a small group setting (no more than 10 students)
Separate Setting: The test is administered in a room other than the one used by the rest of the class
Individual: The test is administered to the student individually
Specified Area: The test is administered with the student seated at the front or other specified area of the room, in a study carrel, or in another enclosed area (IEP or 504 plan must specify where)
Familiar Test Administrator: The test is administered by a test administrator familiar to the student
Noise Buffers: The student wears noise buffers, after test administration instructions have been read (headphones with music playing are not allowed)
Magnification or Overlays: The student uses magnifying equipment, enlargement devices, colored visual overlays, or specially tinted lenses (IEP or 504 plan must specify which)
Test Directions: The test administrator clarifies general administration instructions No portion of the test items themselves (eg, the introduction to a reading selection) may be read or signed
Large-Print: The student uses a large-print version of the test
Braille: The student uses a Braille version of the test
Place Marker: The student uses a place marker
Track Test Items: The test administrator assists the student in tracking test items (eg, moving from one test question to the next) or by redirecting the student’s attention to the test
Amplification: The student uses sound amplification equipment
Test Administrator Reads Test Aloud (except ELA Reading Comprehension test): Test Administrator reads entire test session word-for-word exactly as written
Test Administrator Reads Test Aloud (except ELA Reading Comprehension test): Test administrator reads selected words, phrases, and/or sentences as directed by the student. The student points to the word, phrase, or sentence that he or she needs read aloud.
Test Administrator Signs Test (except ELA Reading Comprehension test): The test administrator signs the ELA Composition writing prompt or the Mathematics, Science and Technology/Engineering, and/or History and Social Science passages and test items to a student who is deaf or hard of hearing
Electronic Text Reader (except ELA Reading Comprehension test): The student uses an electronic text reader for the ELA Composition writing prompt or the Mathematics and Science and Technology/Engineering tests
Scribe Test (except ELA Composition): For open-response test items (and multiple-choice items if needed), the student dictates responses to a scribe or uses a speech-to-text conversion device to record responses
Organizer, Checklist, Reference Sheet, or Abacus: The student uses a graphic organizer, checklist, individualized mathematics reference sheet, or abacus
Student Signs or Reads Test Aloud: The student reads the test aloud to himself or herself, or student reads the test and records answers on audiotape, then writes responses to test items while playing back the tape; a student who is deaf or hard of hearing signs test items/responses onto video, then writes answers while playing back the tape
Monitor Placement of Responses: The test administrator monitors placement of student responses in the student’s answer booklet
Word Processor: The student uses a word processor, Alpha-Smart, or similar electronic keyboard to type the ELA Composition and/or answers to open-response questions
Answers Recorded in Test Booklet: The student records answers directly in the test booklet
Other Standard Accommodation: Other standard accommodation that is identified by the IEP Team or team, documented in the student’s IEP, and not on this list
Alternate Assessment (Portfolio)
MCAS Nonstandard
Test Administrator Reads Aloud ELA Reading Comprehension Test: The test administrator reads the ELA Reading Comprehension test to a student
Test Administrator Signs ELA Reading Comprehension Test for a Student Who Is Deaf or Hard of Hearing
Electronic Text Reader for the ELA Reading Comprehension Test: The student uses an electronic text reader for the ELA Reading Comprehension test
Scribe ELA Composition: The student dictates the ELA Composition to a scribe or uses a speech-to-text conversion device to record the ELA Composition
Calculation Devices: The student uses a calculator, arithmetic table (including multiplication and division charts), or manipulatives on all sections of the Mathematics or Science and Technology/Engineering test
Spell- or Grammar-Checking Function on Word Processor, Spell-Checking Device, or Word Prediction Software for the ELA Composition: The student uses a spell- or grammar-checking function, spelling device (including hand-held electronic spellers), or word prediction software (IEP must specify which device) for the ELA Composition
Other Nonstandard Accommodation: Other nonstandard accommodation that is identified by the IEP Team or team, documented on the student’s IEP, and not on this list
.
Organelles
A car is a working machine – made from smaller systems working together.
A cell is an organic, living machine – made from organelles working together.
No part of a car, by itself, is functioning.
No part of a cell, by itself, is alive.
What we a “functioning car” is the way that parts work together.
What we call “life” is the way that organelles work together.
Let’s compare the parts of a car with the parts of a cell
Consider: The transmission, the axles and the engine.
Yet disconnect just one of these systems, and we effectively no longer have a car.
We’d just have an inert 2000 pound block of metal and plastic.
A car is not a car unless the parts are connected and working together.
The same is true for cells.

Inside the engine, what would happen if we removed or froze the pistons?
We’d effectively no longer have an engine.
The same is true for organelles inside cells.

Similarly, consider the ways that organelles and organic molecules are interacting within our cells.
This is mitochondrial ATP synthase. See how it is just like a machine? This is a machine with organic parts.

All parts of the body, when examined in detail, turn out to work in the same way: Like a simple machine, with parts that move against other parts, and objects that move from one place to another.

Nucleus to ribosomes to ER GIF from NPR: Protein synthesis
What would happen if we removed some of these parts?
We’d effectively no longer have a living cell.
You’ve seen parts inside cars. Now let’s look at the organelles (parts inside cells)
First, a note of caution about artwork: Many books simplify what a cell looks like, with a 2D black & white drawing, like this. This picture is “true” – but simplified.
In reality cells are 3D.
Organelles are suspended in cytoplasm throughout the cell.

Now let’s learn the job of each organelle using analogies:

Organelle |
Function |
Analogy |
|---|---|---|
lipid bilayer |
Controls which molecules go in/out of the cell |
Walls and doors |
cytoplasm |
Suspends and holds all the organelles |
the factory floor, where all the work is done. |
nucleus |
Chromosome (DNA) storage |
Control center |
chromosomes(made of DNA) |
Instructions for building and running the cell |
blueprints and instructions |
mitochondrion |
Converts energy from food molecules into a form usable by the cell |
Powerhouse |
ribosomes |
biological protein synthesis (translation) |
Workers on the assembly line, building our product. |
cytoskeleton |
gives the cell its shape and mechanical resistance to deformation |
Walls & studs, support and structure |
golgi body |
Packages proteins into vesicles inside the cell, and send them to their destination. |
Receives product from ER. Like UPS, its packages and distributes the products. |
endoplasmic reticulum(ER) |
Manufactures lipids and proteins |
Assembly line which makes our products |
lysosome |
Contain enzymes that can break down virtually all kinds of biomolecules. |
garbage disposal |
vacuoles |
Multiple uses, often related to storing molecules. |
Storage |
Organelles unique to plants

Click here to read about the organelles in more depth.
Endomembrane system
More details here: The endomembrane system

Endomembrane system by Mariana Ruiz Villarreal, LadyofHats
Learning Standards
2016 Massachusetts Science and Technology/Engineering Curriculum Framework
6.MS-LS1-2. Develop and use a model to describe how parts of cells contribute to the cellular functions of obtaining food, water, and other nutrients from its environment,
disposing of wastes, and providing energy for cellular processes.
2006 Massachusetts Science and Technology/Engineering Curriculum Framework
Biology High School Standards: Cells have specific structures and functions that make them distinctive. Processes in a cell can be classified broadly as growth, maintenance, and reproduction.
2.1 Relate cell parts/organelles (plasma membrane, nuclear envelope, nucleus, nucleolus, cytoplasm, mitochondrion, endoplasmic reticulum, Golgi apparatus, lysosome, ribosome, vacuole, cell wall, chloroplast, cytoskeleton, centriole, cilium, flagellum, pseudopod) to their functions. Explain the role of cell membranes as a highly selective barrier (diffusion, osmosis, facilitated diffusion, active transport).
Benchmarks for Science Literacy, AAAS
By the end of the 12th grade, students should know that
- Every cell is covered by a membrane that controls what can enter and leave the cell. 5C/H1a
- In all but quite primitive cells, a complex network of proteins provides organization and shape and, for animal cells, movement. 5C/H1b
- Within the cells are specialized parts for the transport of materials, energy capture and release, protein building, waste disposal, passing information, and even movement. 5C/H2a
Cellular and molecular biology: Cell structure and organization, mitosis, photosynthesis, cellular respiration, enzymes, biosynthesis, biological chemistry
External links
Evolution of the first animals
Animals probably evolved from marine protists, although no group of protists has been identified from an at-best sketchy fossil record for early animals.
Cells in primitive animals (sponges in particular) show similarities to collared choanoflagellates as well as pseudopod-producing amoeboid cells.
Multicellular animal fossils and burrows (presumably made by multicellular animals) first appear nearly 700 million years ago, during the late precambrian time….
All known Vendian animal fossils had soft body parts: no shells or hard (and hence preservable as fossils) parts.
Animals in numerous phyla appear at (or in many cases before) the beginning of the Cambrian Period ( 540 million years ago)
from http://www2.estrellamountain.edu/faculty/farabee/BIOBK/BioBookDiversity_7.html
Nicole King explains “All animals, from sponges to jellyfish to vertebrates [animals with a backbone], can be traced to a common ancestor. So far, molecular and fossil evidence indicate that animals evolved at least 600 million years ago. The fossil record does not reveal what the first animals looked like or how they lived. Therefore, my lab and other research groups around the world are investigating the nature of the first animals by studying diverse living organisms….. Choanoflagellates are a window on early animal evolution. Both cell biological and molecular evidence indicate that choanoflagellates are the closest living relatives of multicellular animals.
http://www.actionbioscience.org/evolution/king.html
————————————–
http://www.wired.com/2014/08/where-animals-come-from/
Between 620 and 550 million years ago (during the Vendian Period) relatively large, complex, soft-bodied multicellular animals appear in the fossil record for the first time. While found in several localities around the world, this particular group of animals is generally known as the Ediacaran fauna, after the site in Australia where they were first discovered.
The Ediacaran animals are puzzling in that there is little or no evidence of any skeletal hard parts i.e. they were soft-bodied organisms, and while some of them may have belonged to groups that survive today others don’t seem to bear any relationship to animals we know. Although many of the Ediacaran organisms have been compared to modern-day jellyfish or worms, they have also been described as resembling a mattress, with tough outer walls around fluid-filled internal cavities – rather like a sponge.
http://sci.waikato.ac.nz/evolution/AnimalEvolution.shtml
A new study mapping the evolutionary history of animals indicates that Earth’s first animal–a mysterious creature whose characteristics can only be inferred from fossils and studies of living animals–was probably significantly more complex than previously believed… the comb jelly split off from other animals and diverged onto its own evolutionary path before the sponge. This finding challenges the traditional view of the base of the tree of life, which honored the lowly sponge as the earliest diverging animal. “This was a complete shocker,” says Dunn. “So shocking that we initially thought something had gone very wrong.”
But even after Dunn’s team checked and rechecked their results and added more data to their study, their results still suggested that the comb jelly, which has tissues and a nervous system, split off from other animals before the tissue-less, nerve-less sponge.
The presence of the relatively complex comb jelly at the base of the tree of life suggests that the first animal was probably more complex than previously believed, says Dunn.
http://www.astrobio.net/topic/origins/origin-and-evolution-of-life/earths-first-animal/
Is this possible? for this to be true, it would seem that complex structures – neurons – have evolved twice! Independently? See here for more amazing details:
What kinds of radiation cause cancer
For most people the biggest cancer risk from radiation hovers in the sky above us giving us all warmth and light. There is no cancer risk from Wi-Fi or microwaves.
Wear sunscreen, but use WiFi without fear. (Image: Spazturtle/SMS (CC))
What is radiation, and where does it come from? nuclear chemistry
What is cancer? How is caused? Cancer
Microwaves, Radio Waves, and Other Types of Radiofrequency Radiation: American Cancer Society

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Organic food and farming
Organic food
“People got in their head, well, if it’s man-made somehow it’s potentially dangerous, but if it’s natural, it isn’t. That doesn’t really fit with anything we know about toxicology. When we understand how animals are resistant to chemicals, the mechanisms are all independent of whether it’s natural or synthetic. And in fact, when you look at natural chemicals, half of those tested came out positive [for toxicity in humans].” –Bruce Ames
Organic food is food produced by organic farming, a set of techniques that mixes scientific knowledge of soil depletion and enrichment with anti-scientific beliefs and myths about nature and the natural.
A key belief of groups like the International Federation of Organic Agriculture Movements (IFOAM) and the Soil Association, which oppose conventional farming in favor of organic farming, is that pesticides and fertilizers are so harmful that they should be avoided unless they are “natural.”
This belief is contradicted by the vast majority of scientific studies that have been done on these subjects (Morris and Bate 1999; Taverne 2006; NCPA study). The United States Department of Agriculture (USDA) has put in place a set of national standards that food labeled “organic” must meet, whether it is grown in the United States or imported from other countries.
“USDA makes no claims that organically produced food is safer or more nutritious than conventionally produced food. Organic food differs from conventionally produced food in the way it is grown, handled, and processed.”*
Harm from bacterial contamination is a much greater possibility from natural fertilizers (Stossel 2005: 194). (For those of you who hate John Stossel, read the newspaper. The most dangerous bacteria in America’s food supply is E. coli, which is found in abundance in cattle manure, a favorite “natural” fertilizer of organic farming.)
The residues from pesticides on food, natural or synthetic, are not likely to cause harm to consumers because they occur in minute quantities.* (This fact does not make either kind of pesticide safe for those who work with them and are exposed to large quantities on a regular basis. I refer to residues on foods you and I are likely to find on fruits and vegetable we buy at the store or market.)
Using natural biological controls rather than synthetic pesticides is more dangerous to the environment (Morris and Bate 1999). The amounts of pesticide residue produced by plants themselves or introduced by organic farmers are significantly greater than the amounts of synthetic pesticide residues.
Almost all of the pesticides we ingest in food are naturally produced by plants to defend themselves against insects, fungi, and animal predators (Ames and Gold 1997). The bottom line is that fresh fruits and vegetables are good for you and it doesn’t matter whether they’re organic.
Over 30 separate investigations of about 500,000 people have shown that farmers, millers, pesticide-users, and foresters, occupationally exposed to much higher levels of pesticide than the general public, have much lower rates of cancer overall (Taverne 2006: 73.)
Groups like IFOAM refer to synthetic pesticides as “toxic,” even though the amount of pesticides people are likely to ingest through food are always in non-toxic amounts.
Many toxic substances occur naturally in foods, e.g.,arsenic in meat, poultry, dairy products, cereals, fish, and shellfish, but usually in doses so small as not to be worthy of concern. On the IFOAM website you will find the following message:
Although IFOAM has no official position on the quality of organic food, it’s easy to conclude that the overall nutritional and health-promoting value of food is compromised by farming methods that utilize synthetic fertilizers and toxic pesticides.
It’s easy to conclude—as long as you ignore the bulk of the scientific evidence that is available.
the myth of organic superiority
The evidence for the superiority of organic food is mostly anecdotal and based more on irrational assumptions and wishful thinking than on hard scientific evidence. There is no significant difference between a natural molecule and one created in the laboratory. Being natural or organic does not make a substance safe* nor does being synthetic make a substance unsafe.
Organic food does not offer special protection against cancer or any other disease. Organic food is not “healthier” than food produced by conventional farming, using synthetic pesticides and herbicides. Organic farming is not necessarily better for the environment than conventional farming. There is scant scientific evidence that most people can tell the difference in taste between organic and conventional foods. The bottom line is: fresher is better. Organic produce that travels thousands of miles to market is generally inferior to the same produce from local farmers, organic or not.
Is there any difference between organic and conventional fruits and vegetables? According to one scientific paper, there are several differences:
Based on the results of our literature review and experiment we conclude that there are substantial differences between organic and conventional fruits and vegetables. They differ with respect to production method, labeling, marketing, price and potentially other parameters.
You don’t need to do a scientific study to know that organic foods are produced differently from conventionally farmed foods. Anyone who has been to the market knows that you will pay substantially more for food labeled “organic.”
… The aforementioned scientific study did find that the literature provides evidence for one nutritional difference between organic and conventional foods: vitamin C was found to be higher for organic food.
coddling by the media
The way the media treat “green” issues accounts for one reason that the organic-is-better myth is pervasive. Here’s an example from BBC News:
Growing apples organically is not only better for the environment than other methods but makes them taste better than normal apples, US scientists say.
The study is among the first to give scientific credence to the claim that organic farming really is the better option.
The researchers found organic cultivation was more sustainable than either conventional or integrated farming, which cuts the use of chemicals.
The scientists, from Washington State University in Pullman, found the organic apples were rated highest for sweetness by amateur tasting panels.
They reported: “Escalating production costs, heavy reliance on non-renewable resources, reduced biodiversity, water contamination, chemical residues in food, soil degradation and health risks to farm workers handling pesticides all bring into question the sustainability of conventional farming systems.”
The headline for the story reads: Organic apples tickle tastebuds.
Most people might stop reading the story after five paragraphs of nothing but positive statements about organic farming and the mention of a number of problems ahead for conventional farming. For those who persevere, however, the following bits of information are also provided:
…organic farming systems were “less efficient, pose greater health risks and produce half the yields of conventional farming”.
…the tests “found no differences among organic, conventional and integrated apples in texture or overall acceptance”.
…Growers of more sustainable systems may be unable to maintain profitable enterprises without economic incentives, such as price premiums or subsidies for organic and integrated products.
Apparently, the measure used to determine that organic farming was “better for the environment” was based on physical, chemical, and biological soil properties. The scientists created their own index and found that organic was better mainly because of the addition of compost and mulch.
Certainly, there are going to be some organic farms that use methods of composting and mulching that improve growing conditions. But there are also methods conventional farmers can use to accomplish the same thing.
Finally, there are some organic farmers who used methods of composting and mulching that don’t improve anything except the chances of bacterial infection. Only a “green” journalist or scientist could turn being less efficient, posing greater health risks, no different in texture or appearance, and producing half the yields of conventional farming into “better than conventional farming.”
I’ll provide just one more example of how the media and scientists with agendas distort the results of scientific studies that compare organic with conventional agricultural practices. In 2003, Alyson Mitchell, Ph.D., a food scientist at the University of California, Davis, co-authored a paper with the formidable title of “Comparison of the Total Phenolic and Ascorbic Acid Content of Freeze-Dried and Air-Dried Marionberry, Strawberry, and Corn Grown Using Conventional, Organic, and Sustainable Agricultural Practices.”
The article was published in the Journal of Agricultural and Food Chemistry, a peer-reviewed journal of the American Chemical Society. The article got some good press from “green” journalists, who proclaimed that the study showed that organic foods have significantly higher levels of antioxidants than conventional foods.
(Examples of glowing press reports can be found here and here.) There is a strong belief among promoters of organic foods that there is good scientific support for the claim that diets rich in antioxidants contribute to significantly lower cancer rates.
The data, however, do not support this belief. “Study after study has shown no benefit of antioxidants for heart disease, cancer, Parkinson’s disease, Alzheimer’s disease, or longevity” (Hall 2011).
The study compared total phenolic metabolites and ascorbic acid in only two crops, marionberries and corn. Both crops were grown organically and conventionally on different farms. The organic berries were grown on land that had been used for growing berries for four years; the conventional berries were grown on land that had been used to grow conventional berries for 21-22 years.
The crops were grown on different soil types: the organic soil was “sandy, clay, loam”; the conventional was “sandy, Ritzville loam.” The soil for the conventional corn had been used before for wheat; the soil for the organic corn had been used for green beans. The conventional farm used well water; the organic farm used a combination of well and creek water. (I don’t mention the strawberry listed in the title of the article because no organic strawberries were tested.)
As you can tell from the title of the article, the metabolites measured were not taken from fresh berries or corn but from samples that had been freeze-dried and air-dried. Though not mentioned in the title, the scientists also compared samples that were simply frozen.
The data provided by the authors in their published study shows clearly that there was not enough measurable ascorbic acid (AA) in either of the marionberry samples to compare the organic to the conventional. As already noted, no organic strawberries were studied. There was not enough measurable AA for the freeze-dried or air-dried corn to be compared.
So, the only data on AA is for the frozen corn: organic had a value of 3.2 and conventional had a value of 2.1. You can read the study yourself to find out what these numbers represent, but whatever they represent they do not merit the conclusion drawn by the authors of the study: “Levels of AA in organically grown … samples were consistently higher than the levels for the conventionally grown crops.”
The study also compared what it calls “sustainable agricultural practices” to organic and conventional practices. Sustainable practices in this study included the use of synthetic fertilizers.
“Our results indicate,” the authors write, “that TPs [total phenolics] were highest in the crops grown by sustainable agricultural methods as compared to organic methods.” Dr. Mitchell is quoted in the press as saying that their study “helps explain why the level of antioxidants is so much higher in organically grown food.” Yet, her study clearly states that the evidence for this claim is anecdotal. In fact, the authors write of the comparative studies that have been done:
These data demonstrate inconsistent differences in the nutritional quality of conventionally and organically produced vegetables with the exception of nitrate and ascorbic acid (AA) in vegetables.
distortion of evidence by scientists
One thing these “green” advocates are good at is distorting data to make lead appear to be gold. Another study led by Mitchell claims that organic tomatoes have “statistically higher levels (P < 0.05) of quercetin and kaempferol aglycones” than conventional tomatoes. The increase of these flavonoids corresponds “with reduced manure application rates once soils in the organic systems had reached equilibrium levels of organic matter.”
In fact, the study suggests that it is the nitrogen “in the organic and conventional systems that most strongly influence these differences.” The authors suggest that “overfertilization (conventional or organic) might reduce health benefits from tomatoes.” The argument is that the flavonoids are a protective response by the plants and one of the things they respond to is the amount of nitrogen in the soil.
In any case, the thrust of these and similar studies is that both organic and conventional crops can be manipulated to yield higher levels of antioxidants. At least one study has found “organic food products have a higher total antioxidant activity and bioactivity than the conventional foods.”* That study, however, involved only ten Italian men, aged 30-65 years.
I have to say that I am underwhelmed by the studies I have reviewed that claim to have found organic foods are more nourishing or healthy than conventional fruits and vegetables. At present, there is no strong body of scientific evidence that supports the contention that organic fruits and vegetables are superior to conventional produce.
A best case scenario for the organic folks would be that to achieve the recommended nutrients from five helpings a day of fruits or vegetables you might have to eat four or five more conventionally grown strawberries or two or three more baby carrots to get the same amount of vitamins, minerals, or antioxidants as provided by organic fruits and vegetables. But I’m not sure the evidence supports even that weak position.
History of the term “organic”
The term ‘organic’ as a descriptor for certain sustainable agriculture systems appears to have been used first by Lord Northbourn in his book Look to the Land (1940).
“Northbourn used the term to describe farming systems that focused on the farm as a dynamic, living, balanced, organic whole, or an organism.”* T
he term ‘organic’ was first widely used in the U.S. by J. I. Rodale, founder of Rodale Press, in the 1950s. “Rodale failed to convince scientists of the validity of his approach because of his reliance on what were perceived to be outrageous unscientific claims of organic farming’s benefits.”*
The USDA standards for organic food state:
Organic food is produced without using most conventional pesticides; fertilizers made with synthetic ingredients or sewage sludge; bioengineering; or ionizing radiation.
These standards capture the essence of the organic mythology:
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Conventional pesticides should be avoided.
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Synthetic fertilizers should be avoided.
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Food should not be genetically altered.
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Food should not be subjected to ionizing radiation.
The bit about sewage sludge is there because some organic farmers follow the “law of return” as proposed by Sir Albert Howard (1873-1947), a founder and pioneer of the organic movement. He advocated recycling all organic waste materials, including sewage sludge, in farmland compost. The practice of adding human and animal feces to the soil is an ancient practice found in many cultures even today.
The fact that these cultures developed their practices without benefit of modern knowledge of such things as bacteria or heavy metals is trumped by the romantic notion that farm life was idyllic in those times and places when life expectancy was half that of today.
Rudolf Steiner, the founder of a set of superstitious agricultural practices known as biodynamics, also advocated using manure as fertilizer but it had to be prepared according to a magical formula based on his belief that cosmic forces entered animals through their horns. Steiner also romanticized farming. Commenting on some peasants stirring up manure, he said:
“I have always had the opinion … that [the peasants’] alleged stupidity or foolishness is wisdom before God [sic], that is to say, before the Spirit. I have always considered what the peasants and farmers thought about their things far wiser than what the scientists were thinking.”*
Steiner gave lectures on farming, but did no scientific research to test his ideas.
A central concept of these lectures was to “individualize” the farm by bringing no or few outside materials onto the farm, but producing all needed materials such as manure and animal feed from within what he called the “farm organism.”
Other aspects of biodynamic farming inspired by Steiner’s lectures include timing activities such as planting in relation to the movement patterns of the moon and planets and applying “preparations,” which consist of natural materials which have been processed in specific ways, to soil, compost piles, and plants with the intention of engaging non-physical beings and elemental forces. Steiner, in his lectures, encouraged his listeners to verify his suggestions scientifically, as he had not yet done.*
Steiner opposed the use of synthetic fertilizers and pesticides, not on scientific grounds but on spiritual grounds. He claimed there were “spiritual shortcomings in the whole chemical approach to farming.”* He had a mystical idea of the farm as an organism, “a closed self-nourishing system.”*
This article has been excerpted from The Skeptic’s Dictionary, http://skepdic.com/organic.html
Possible habitat for life on Enceladus, a moon of Saturn

– This graphic illustrates how Cassini scientists think water interacts with rock at the bottom of the ocean of Saturn’s icy moon Enceladus, producing hydrogen gas. Credit: NASA/JPL-Caltech
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Two veteran NASA missions are providing new details about icy, ocean-bearing moons of Jupiter and Saturn, further heightening the scientific interest of these and other “ocean worlds” in our solar system and beyond. The findings are presented in papers published Thursday by researchers with NASA’s Cassini mission to Saturn and Hubble Space Telescope.
In the papers, Cassini scientists announce that a form of chemical energy that life can feed on appears to exist on Saturn’s moon Enceladus, and Hubble researchers report additional evidence of plumes erupting from Jupiter’s moon Europa.
“This is the closest we’ve come, so far, to identifying a place with some of the ingredients needed for a habitable environment,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at Headquarters in Washington. ”These results demonstrate the interconnected nature of NASA’s science missions that are getting us closer to answering whether we are indeed alone or not.”
The paper from researchers with the Cassini mission, published in the journal Science, indicates hydrogen gas, which could potentially provide a chemical energy source for life, is pouring into the subsurface ocean of Enceladus from hydrothermal activity on the seafloor.
The presence of ample hydrogen in the moon’s ocean means that microbes – if any exist there – could use it to obtain energy by combining the hydrogen with carbon dioxide dissolved in the water. This chemical reaction, known as “methanogenesis” because it produces methane as a byproduct, is at the root of the tree of life on Earth, and could even have been critical to the origin of life on our planet.
Life as we know it requires three primary ingredients: liquid water; a source of energy for metabolism; and the right chemical ingredients, primarily carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.
With this finding, Cassini has shown that Enceladus – a small, icy moon a billion miles farther from the sun than Earth – has nearly all of these ingredients for habitability. Cassini has not yet shown phosphorus and sulfur are present in the ocean, but scientists suspect them to be, since the rocky core of Enceladus is thought to be chemically similar to meteorites that contain the two elements.
“Confirmation that the chemical energy for life exists within the ocean of a small moon of Saturn is an important milestone in our search for habitable worlds beyond Earth,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California.
The Cassini spacecraft detected the hydrogen in the plume of gas and icy material spraying from Enceladus during its last, and deepest, dive through the plume on Oct. 28, 2015. Cassini also sampled the plume’s composition during flybys earlier in the mission. From these observations scientists have determined that nearly 98 percent of the gas in the plume is water, about 1 percent is hydrogen and the rest is a mixture of other molecules including carbon dioxide, methane and ammonia.
The measurement was made using Cassini’s Ion and Neutral Mass Spectrometer (INMS) instrument, which sniffs gases to determine their composition. INMS was designed to sample the upper atmosphere of Saturn’s moon Titan. After Cassini’s surprising discovery of a towering plume of icy spray in 2005, emanating from hot cracks near the south pole, scientists turned its detectors toward the small moon.
Cassini wasn’t designed to detect signs of life in the Enceladus plume – indeed, scientists didn’t know the plume existed until after the spacecraft arrived at Saturn.
“Although we can’t detect life, we’ve found that there’s a food source there for it. It would be like a candy store for microbes,” said Hunter Waite, lead author of the Cassini study.
The new findings are an independent line of evidence that hydrothermal activity is taking place in the Enceladus ocean. Previous results, published in March 2015, suggested hot water is interacting with rock beneath the sea; the new findings support that conclusion and add that the rock appears to be reacting chemically to produce the hydrogen.







