Name: DNA Evidence That Humans & Chimps Share A Common Ancestor: Endogenous Retroviruses @StatedClearly
Uploaded: 2024-10-11T08:17:00-05:00
Duration: 8 min 17 s
Description: DNA Evidence That Humans & Chimps Share A Common Ancestor: Endogenous Retroviruses

DNA Evidence That Humans & Chimps Share A Common Ancestor: Endogenous Retroviruses

Stated Clearly 2024-10-11 | DNA Evidence That Humans & Chimps Share A Common Ancestor: Endogenous Retroviruses

The greatest unsolved mystery in biology

Stated Clearly 2024-07-05 | Some would say consciousness is the greatest unsolved mystery in biology... maybe, but in my mind there's a bigger one:

I put the origin of life as "the greatest unsolved mystery in biology" because, despite many breakthroughs, scientists have yet to develop a complete model of how non-living materials can transition into living organisms on a previously lifeless planet. This fundamental question involves figuring out how simple organic molecules organized into complex structures capable of metabolism, reproduction, and evolution—the defining characteristics of life.

This clip is from our video "What is the metabolism-first hypothesis, an angle of study on the origin of life that's seldom talked about but deeply fascinating.

The first drawings of molecules

Stated Clearly 2024-07-01 | patreon.com/statedclearly
Full video: youtu.be/LhveTGblGHY?si=2DL2fTAv71-LjlDp

John Dalton, a school teacher who studied chemistry in his free time, was a pioneering figure in the development of modern atomic theory. He was also among the first to attempt drawing molecules to represent his ideas. In 1808, Dalton published a book titled A New System of Chemical Philosophy, where he introduced these molecular drawings.

Key Features of Dalton’s Drawings:
Symbolic Representation: Dalton used circles to represent atoms of different elements. Each type of atom was designated by a unique symbol or shading, which was a novel way of visually distinguishing between different elements.

Molecular Formulas: Alongside the drawings, Dalton provided explanations of how atoms of different elements combine to form compounds. He used his symbols to illustrate the composition of various compounds, effectively creating an early form of what we now know as molecular formulas.

Dalton’s molecular drawings were crucial for visualizing what used to be very abstract concepts of atoms and molecules. His drawings and equations helped lay the groundwork for later developments in chemical notation and molecular modeling, even though they were relatively simple and not entirely accurate by today’s standards. His work marked a significant step forward in the visual representation of chemical structures, facilitating a better understanding of chemical reactions and molecular composition.

You are not an individual

Stated Clearly 2024-06-28 | You are a colony of cells... trillions of them! Theodor Schwann, a German physiologist, was crucial in developing the cell theory, which fundamentally changed the understanding of biological life.

His work, particularly his 1839 book "Microscopical Researches into the Accordance in the Structure and Growth of Animals and Plants," proposed that all organisms, including humans, are made up of cells. This was a pivotal step in recognizing that humans and other multicellular organisms are composed of many cells, not just a singular entity. His contributions laid foundational concepts for modern biology, helping to shift scientific thought towards understanding the cellular basis of life.

What is Consciousness?

Stated Clearly 2024-06-26 | Consider supporting my work on patreon.com/statedclearly

The Hard Problem of Consciousness:

The "hard problem" of consciousness is about figuring out why we have experiences that feel like something. For instance, why is eating a strawberry an experience, rather than just triggering an robotic "this food is nourishing must eat more" message inside the brain. Why must the "lights be on" when our brains process information? We don't think computers personally experience their existence.

While science can explain what happens in our brain when we do things, it can’t yet explain why those actions come with specific feelings, or what it feels like to be you experiencing them.

Why Does It Matter today more than ever?
Now that we’re building advanced artificial intelligences, this question gets even trickier and more important. If we make machines that think and process information like us, should we consider the possibility they might also 'feel' like us? Why or why not? How we answer this affects how we handle AI, ethically and legally—like deciding whether AI can suffer, or if it has rights.

What if we assume consciousness where there is none?
People have a knack for seeing sentience/consciousness where it doesn't exist. The shadow on the wall is demon. The whistling wind is a ghost. This means there's a real risk that we could mistakenly attribute consciousness to AI, thinking machines have feelings or awareness when they actually don't. Imagine the chaos that could be caused by a social justice movement for robots founded on bad info? We’re wired to humanize things—so much so that simply sticking googly eyes on a toaster might make you apologize to it if bumped on the counter.

The Implications: If we’re not careful, this tendency could lead us to believe that AI systems, especially those designed to mimic human behavior, possess a form of consciousness. This could push us towards granting them rights or ethical considerations akin to those we provide humans, based on our mistaken assumptions.

Different Ways People Think About Consciousness:
Just a Side Effect: Some experts think consciousness might just be a side effect of our brains doing their complex work. It’s like the whistle of a teapot isn’t necessary for boiling water, but it happens because of the design.

A Helpful Tool: Others believe our ability to be aware and feel things helps us survive better, making decisions and working with others easier, which would mean it evolved for a reason.

Something Totally New: Then, there are those who say consciousness is something totally different and new, something we might not yet fully understand, maybe even requiring new laws of physics or ideas we haven’t discovered.

As we dive deeper into making and integrating AI, understanding consciousness isn’t just academic—it’s a must to see that we handle the future of AI in a fair and responsible way. Whether it’s an accident, a survival tool, or something mind-blowingly new, figuring out this piece of the puzzle has more practical value now than ever.

How many atoms are in a molecule? #chemistry

Stated Clearly 2024-06-24 | patreon.com/statedclearly

Full video here: youtu.be/C0Qaf-UJ2XQ?si=Wj9ba8fXSickES0U

A molecule is a group of atoms stuck together. They can vary greatly in size.

1. Hydrogen Molecules: Table for two (H₂)
The smallest molecule is two hydrogen atoms stuck together. Hydrogen is the lightest element. It pairs up with just one buddy to form a hydrogen molecule (H₂). That's just two atoms sticking together.

2. Water: The Popular Trio (H₂O)
Water is a molecule you know super well—it's everywhere! In every water molecule, there are three atoms: two hydrogen atoms (those same guys from the hydrogen molecule) and one oxygen atom. Together, they make every splash, drip, and drop!

3. Carbon Dioxide: The Bubble Maker (CO₂)
This molecule is famous for putting the fizz in your soda! Carbon dioxide has three atoms—one carbon and two oxygen atoms. They work together to make those bubbles that tickle your nose when you drink a soda.

4. Sugar: The Sweet Team (C₆H₁₂O₆)
Sugar molecules are like a little sports team. A sugar molecule, like glucose, has 24 atoms: 6 carbon, 12 hydrogen, and 6 oxygen atoms.

5. DNA: The Blueprint of Life
Now, here’s a giant! While single nucleotides of DNA are made of only about 40 atoms, millions of nucleotides are linked together to make a DNA chain. This means a full chain of DNA in one of your cells is made up of billions of atoms!

Proof of Evolution?

Stated Clearly 2024-06-21 | patreon.com/statedclearly

Full video "What is the Evidence for Evolution?" youtu.be/lIEoO5KdPvg?si=wUcr323hf3zD0JUD

I'm often asked for the "proof" of evolution. The term 'proof' isn't usually used in science. It's more common in math and philosophy where a conclusion is demonstrated or "proved" via a string of deductive arguments. That said, in common language, people asking for scientific 'proof' of a claim are usually meaning to ask is "what's the evidence supporting the claim".

Evolution is one of the most well-supported concepts in science, backed by extensive evidence from multiple fields, including genetics, paleontology, and comparative anatomy.

1. Fossil Records: Show the historical lineage of organisms and transitional species.
2. Genetic Similarities: Demonstrate shared DNA sequences among diverse species, suggesting common ancestry.
3. Observable Changes: Documented instances of species evolving in response to environmental pressures.

These and many other branches of evidence all paint the same picture from very different starting points: Life on earth evolved from a common ancestor.

Ovipositor: Mystery Adaptation

Stated Clearly 2024-06-19 | Insect ovipositors are specialized egg-laying structures. "Ovi" as in "egg", "positor" as in "depositor. They are used by female insects of many species to deposit their eggs in specific environments.

Ovipositors vary greatly in shape and function among different insect species, adapting to unique ecological niches. For example, parasitic wasps use their ovipositors to lay eggs inside host insects, while grasshoppers and crickets have digging ovipositors for embedding eggs in soil. The honeybee’s ovipositor no longer serves for eggs to travel through, but has been modified into a stinger serving mostly as a defense weapon. It can also aid in egg placement.

In cicadas and sawflies, the ovipositor has evolved into a drilling blade letting them place eggs precisely in host plant tissue, ensuring both protection and immediate access to food for emerging larvae.

This remarkable diversity in ovipositor structure showcases the evolutionary adaptability of insects, enabling them to successfully reproduce and thrive in a wide range of habitats.

Einstein and Atomic Theory

Stated Clearly 2024-06-17 | patreon.com/statedclearly
Full video: youtu.be/LhveTGblGHY?si=2DL2fTAv71-LjlDp

A young Albert Einstein, aside from everything else he did, made significant contributions to our understanding of the atom.

Brownian Motion (1905):
In his 1905 paper, Einstein theoretically described Brownian motion, which is the random movement of particles suspended in a fluid. He proposed that this motion resulted from collisions with atoms, suggesting a way to observe and measure atomic activity indirectly. While he didn’t conduct the experiments himself, his predictions laid the groundwork for experimental verification by others, such as Jean Perrin in 1908, which provided empirical support for the existence of atoms.

Photoelectric Effect (1905):
Einstein's explanation of the photoelectric effect was groundbreaking for quantum theory. He theorized that light could be considered as consisting of discrete packets of energy, or photons, which could eject electrons from a metal surface if the photons had enough energy. This hypothesis challenged the classical wave theory of light and was crucial in the development of quantum mechanics. Einstein received the Nobel Prize in Physics in 1921 for this work, specifically for his discovery of the law of the photoelectric effect.

Evolution directly observed

Stated Clearly 2024-06-14 | The paper is free to read here: Experimental evolution of multicellularity pnas.org/doi/full/10.1073/pnas.1115323109

Here's the abstract: Multicellularity was one of the most significant innovations in the history of life, but its initial evolution remains poorly understood. Using experimental evolution, we show that key steps in this transition could have occurred quickly. We subjected the unicellular yeast Saccharomyces cerevisiae to an environment in which we expected multicellularity to be adaptive. We observed the rapid evolution of clustering genotypes that display a novel multicellular life history characterized by reproduction via multicellular propagules, a juvenile phase, and determinate growth. The multicellular clusters are uniclonal, minimizing within-cluster genetic conflicts of interest. Simple among-cell division of labor rapidly evolved. Early multicellular strains were composed of physiologically similar cells, but these subsequently evolved higher rates of programmed cell death (apoptosis), an adaptation that increases propagule production. These results show that key aspects of multicellular complexity, a subject of central importance to biology, can readily evolve from unicellular eukaryotes.

The Struggle Is Real! #evidencesofevolution

Stated Clearly 2024-06-12 | Humans, thanks to our technology and large cooperative societies, live safely near the top of the food chain and some of us even live comfy lives. This, however, is not the norm in nature, nor can the privileged among us expect that privilege to last.

Organisms are in a near constant battle to survive and reproduce. Darwin called this the "struggle for existence." Here's the gist:

Resources Are Limited: There's only so much food, water, and space to go around. Plants, animals, and even microorganisms are all vying for these limited resources.

Competition Is Fierce: Every creature has to compete with others to get what it needs. This isn't just between different species but within the same species too. Think of it like a game of musical chairs—too many players, not enough chairs.

Survival of the Fittest: Those best suited to their environment get to live longer and have more offspring. This means the next generation is a bit better adapted to the environment. The weak, sickly, or less adapted ones? They fall by the wayside.

Nature’s Filters: Over time, this struggle weeds out the less adapted individuals. The ones that survive pass on their traits, making future generations more fit for survival.

Cooperation Counts Too: It's not all doom and gloom. Many species thrive through cooperation. Wolves hunt in packs, bees work together to build hives, and humans form societies to share resources and protect each other. Cooperation can be just as crucial for survival as competition.

In short, Darwin’s struggle for existence is nature’s way of keeping life on its toes, constantly pushing species to adapt, evolve, and improve. It’s a relentless, never-ending battle, but cooperation and teamwork play a big part in who comes out on top

How to split a molecule

Stated Clearly 2024-06-10 | patreon.com/statedclearly

Full video here: youtu.be/C0Qaf-UJ2XQ?si=Wj9ba8fXSickES0U

Molecules are made of atoms connected by bonds, which can be thought of as tiny springs or rubber bands holding these atoms together. These springs have a certain strength, but they're not unbreakable.

If you heat a molecule, the atoms wiggle, stretch, and bend their bonds more violently. If the energy given to these bonds is enough, they can stretch too far and snap, much like if you overstretch a rubber band. When these bonds break, the molecule splits into smaller parts. This can lead to chemical reactions, forming new substances.

Heating up a molecule increases the energy within it, causing the atoms to move so vigorously that their bonds can break. This leads to the molecule changing, either breaking down into simpler molecules or reacting to form new products. It's a fundamental concept in chemistry that explains a lot about how substances change under different conditions.

Evolution: Sorry folks, its real.

Stated Clearly 2024-06-07 | patreon.com/statedclearly

Full video "What is the Evidence for Evolution?" youtu.be/lIEoO5KdPvg?si=wUcr323hf3zD0JUD

The chimps might not be happy but it's true: We are related.

This little clip is from the end of my longer video: What is the evidence for evolution? It follows whale evolution to understand common ancestry:

youtu.be/lIEoO5KdPvg?si=QX6CWkDQLXY4kzZj

1 x 1 = 2?

Stated Clearly 2024-06-06 | ...

Aggressive Mimicry #evolution

Stated Clearly 2024-06-05 | Aggressive mimicry is when an aggressor evolves to mimic an object that its victims find attractive. There are many really cool examples of this, but few as spectacular as the tongue of a snapping turtle!

How were elements discovered? #chemistry #atomictheory

Stated Clearly 2024-06-03 | patreon.com/statedclearly
Full video: youtu.be/LhveTGblGHY?si=2DL2fTAv71-LjlDp

Antoine Lavoisier and Marie-Anne Pierrette Paulze: Foundational Figures in Modern Chemistry

Antoine Lavoisier, often called the "Father of Modern Chemistry," fundamentally transformed chemistry from a qualitative to a quantitative science. His work laid the foundation for many of the principles and practices that define the field today.

Marie-Anne Lavoisier's Contributions:
Marie-Anne Pierrette Paulze, Lavoisier's wife, was indispensable to his scientific career. She managed his laboratory, translated English and Latin scientific texts (providing Lavoisier with access to crucial developments), and skillfully illustrated his experiments. Her precise illustrations were vital for the clear communication of Lavoisier's methods and findings, greatly aiding in the dissemination of his revolutionary ideas.

Lavoisier’s Scientific Achievements:

1. Quantitative Approach: Lavoisier introduced precise measurement in chemical experimentation, notably using the balance to demonstrate that mass is conserved in chemical reactions.
2. Nomenclature and Theory: He systematized chemical nomenclature, which helped standardize the language of chemistry. Most famously, he debunked the phlogiston theory—a prevalent theory that posited a fire-like element released during combustion.
3. Role of Oxygen: Building on the work of others, such as Joseph Priestley who first isolated oxygen (which he called "dephlogisticated air"), Lavoisier conducted experiments that demonstrated oxygen’s essential role in combustion. He was the first to correctly explain combustion as a reaction with oxygen, and he named this element based on its ability to form acids—a misconception, as not all oxides are acidic.

Downfall and Legacy:
Despite his monumental contributions to science, Lavoisier's life ended tragically; he was executed by guillotine in 1794 during the French Revolution, largely because of his association with the unpopular Ferme Générale, a tax collection agency. Nonetheless, his and Marie-Anne's work profoundly impacted the development of chemistry, transforming it into a systematic and empirical science. Their legacy in advancing the methodology and understanding of chemical reactions remains a cornerstone of modern chemistry.

The Tar Paradox and the Origin of Life

Stated Clearly 2024-05-31 | As researchers simulate early Earth conditions in an attempt to witness the synthesis of complex organic molecules like RNA or proteins from simpler compounds, they often encounter a hurdle: Along with the desired biological monomers, the reactions produce a sticky, inert tar - a mishmash of organic materials that are not biologically useful and gum up further chemical reactions.

Here's how scientists are working on the puzzle:

1. Mineral Assistance: In nature, minerals like clays could have acted as catalysts, promoting the right chemical reactions and preventing unwanted ones that lead to tar. Laboratory experiments have shown that minerals can, in deed, stabilize necessary molecules and encourage their formation, mimicking natural processes that could have occurred on early Earth.
2. Creating Compartments: By forming vesicles and micelles, which are like tiny bubbles or pockets, scientists simulate how early cell membranes might have worked. These structures can isolate important molecules, protecting them from the chaotic external environment and helping them to react correctly. Experiments confirm that these compartments can form under prebiotic conditions, and can act (minimally), to sort compounds out of tar-like mixtures.
3. Cyclical Reaction Processes: Nick Hud's research into depsipeptides provides a compelling example of how cyclic environmental conditions, similar to day/night cycles, could influence the formation of complex organic molecules. By simulating these cycles in the lab, Hud explores how alternating periods of wet and dry conditions could facilitate the polymerization of depsipeptides, which are chains consisting of both amino acids and hydroxy acids. This approach highlights the potential for natural rhythms to promote the chemical evolution necessary for life's origins. Hud's work demonstrates that depsipeptides can form under such cyclic conditions, offering insights into how early life might have developed molecular complexity through natural processes.

These laboratory strategies are not about artificially creating life, but rather about understanding and eventually replicating the natural conditions that might have allowed life to form spontaneously on the primitive Earth. By simulating these environments, scientists gain insights into what natural paths could have led to the complex chemistry of life amid a world prone to producing tar.

Evolutions Mystery Paw

Stated Clearly 2024-05-29 | You might be upset that I didn't reveal what animal this actually belongs to. If you can't figure it out but really want to know, go to the subreddit "r/mildlyinteresting" and find the post by verdachteaugurk

How does chemistry work: Stated Clearly

Stated Clearly 2024-05-27 | patreon.com/statedclearly

Full video here: youtu.be/C0Qaf-UJ2XQ?si=Wj9ba8fXSickES0U

Atoms bond with different numbers of other atoms based on the number of electrons in their outermost shell, also known as the valence shell. These electrons are the ones involved in bonding, and each atom seeks to either gain, lose, or share electrons to achieve a stable configuration similar to that of noble gases, which have complete outer shells.

The rule of thumb here is the octet rule, which suggests that atoms are most stable when they have eight electrons in their valence shell. However, the number of electrons currently in the valence shell determines how many additional electrons an atom needs to reach this stable state:

Atoms like oxygen have six electrons in their valence shell and need two more to complete the octet. Therefore, they typically form two bonds.
Atoms like carbon have four electrons in their valence shell. To reach an octet, they need four more electrons, allowing them to form up to four bonds.

This difference in the number of required electrons to achieve a full outer shell is what causes some atoms to bond with more or fewer atoms than others.

Endosymbiosis has been directly observed!

Stated Clearly 2024-05-24 | The Paper:
Auto-/heterotrophic endosymbiosis evolves in a mature stage of ecosystem development in a microcosm composed of an alga, a bacterium and a ciliate

Abstract
We investigate an ecological mechanism by which endosymbiotic associations evolve, with a particular focus on the relationship between the evolution of endosymbiosis between auto- and heterotrophic organisms, and the stages of ecosystem development. For this purpose we conducted a long-term microcosm culture composed of three species, a green alga (Chlorella vulgaris), a bacterium (Escherichia coli), and a ciliated protozoan (Tetrahymena thermophila) for 3 years. During this culture T. thermophila cells harboring Chlorella cells emerged by phagocytotic uptake, and increased in frequency, reaching ca. 80-90%. This level was maintained in the late stage of ecosystem dynamics. Analysis of the ecosystem dynamics in the microcosm revealed that a complex causal process through direct/indirect interactions among ecosystem components led to reduction in dissolved O2 and food (E. coli) available to the T. thermophila, which gave a selective advantage to the organisms in the endosymbiotic association. This result suggests that the endosymbiosis evolves in a mature stage of ecosystem development, where reproduction and survival of prospective partner organisms is highly resource-limited and density-dependent, favoring efficient matter/energy transfers among participating organisms due to physical proximity. Consequently, a complex web of interactions and pathways of matter/energy flow in ecosystem evolves from an initially simple one.

Read the entire paper for free here: researchgate.net/publication/23931293_Auto-heterotrophic_endosymbiosis_evolves_in_a_mature_stage_of_ecosystem_development_in_a_microcosm_composed_of_an_alga_a_bacterium_and_a_ciliate

Atomic Theory In Ancient Greece #chemistry #history

Stated Clearly 2024-05-20 | patreon.com/statedclearly
Full video: youtu.be/LhveTGblGHY?si=2DL2fTAv71-LjlDp

We're zipping back over 2,400 years to ancient Greece, where the philosopher Democritus had a big idea about tiny things. He and his teacher, Leucippus are among the first thinkers to argue for the existence of atoms—those incredibly small building blocks of matter.

Democritus looked around and thought, "What if everything is made up of tiny, indivisible pieces?" He called these pieces "atomos," which means "uncuttable" or "indivisible" in Greek. His reasoning? If you keep cutting a piece of matter into smaller and smaller pieces, you'd eventually reach a point where you couldn't cut it anymore, but it would still have the properties of the original material.

Democritus's theory was more of a thought experiment than based on experiments—back then, they didn’t have the tools to see atoms. He believed everything in the universe, including us, is made up of these atoms, moving through empty space. They come together in different combinations and arrangements to form all the materials and objects we see.

So why did he argue this way? Democritus was trying to answer a big question: "What is the simplest explanation for the diversity and complexity of the material world?" His answer was atoms, the smallest bits of matter, combining and recombining in various ways.

BUT WAIT THERE'S MORE
Democritus gets the spotlight because early modern chemists knew his concepts well, but he was not really the first thinker, in recorded history, to have argued the case of the atom:

Before Democritus in Greece, there was a philosopher in India who also played with the idea of atoms. His name was Kanada, a sage and philosopher who founded the Vaisheshika school of philosophy around the 6th century BCE.

Kanada proposed that everything in the universe is made up of particles he called “anu,” or atoms, which are eternal and indivisible. He theorized that these atoms combine in various ways to form more complex objects, which can be seen and experienced. According to Kanada, these combinations happen under the influence of nature’s forces, which govern how they combine, break up, and interact.

This was a revolutionary idea because it suggested a systematic and natural order to the universe, all based on these tiny, unseen building blocks. Kanada’s work is the earliest known atomic theories. It is not clear if his ideas made it to Greece or if Democritus came to his ideas independently but next time you study atoms in chemistry class, remember, the roots of these ideas are both deep and wide, spanning continents and civilizations!

Dolphin embryos give clues about evolution

Stated Clearly 2024-05-17 | patreon.com/statedclearly

Full video "What is the Evidence for Evolution?" youtu.be/lIEoO5KdPvg?si=wUcr323hf3zD0JUD

I've noticed that when embryo photos are shown, it's common for creationists to get upset and tell me that Ernst Haeckel embellished his embryo drawings that used to be used in text books. For examples, just look at the comment section on the full length video here: youtu.be/lIEoO5KdPvg?si=ydPCdtjlVoFkt532

Okay... um... I'm not showing you drawings. These are photographs. That said, it is worth talking about Haeckel as his story has had a huge impact:

Ernst Haeckel lived in Germany during the mid 1800s. He was a biologist and artist, who profoundly influenced both scientific and public perceptions of biology with his spectacular artwork or rare and sometimes microscopic life forms. Even if you don't know his name, you've almost surely seen his hauntingly beautiful prints.

Haeckel's most influential embryonic illustrations were published in the 1870s, particularly in his book Anthropogenie (1874), where he presented drawings that compared the embryos of different species. His work was intended to provide visual evidence for Darwinian evolution, showing that embryos of different vertebrates—humans, chickens, turtles, etc.—appear remarkably similar in early stages, suggesting a common ancestry.

Criticism and Controversy
Haeckel's embryo drawings have been criticized on several grounds:

Accuracy: Critics, both contemporary and modern, have accused Haeckel of embellishing or inaccurately rendering some embryos to fit his theories. In the early 1900s, his drawings were scrutinized and found to be exaggerated in their similarities, leading to accusations of fraud. This criticism was notably led by embryologist Wilhelm His, who argued that Haeckel had intentionally misrepresented the embryos. While it's normal for artists to simplify a subject, making it easier for the viewer to understand what they're looking at, it is clearly unethical to exaggerate traits you're using as scientific evidence.

Scientific Impact: The controversy surrounding Haeckel's drawings has had a lasting impact on his reputation and the public understanding of evolution. While his goal was to support Darwin's theory (and, by the way, embryology actually does support Darwin's theory), the inaccuracies in his work provided fodder for opponents of evolution, who used the errors to argue against the theory’s validity and the character of those who teach evolution.

Ethical Implications: The debate also touches on the ethics of scientific illustration and communication. Haeckel’s case is often used as an example of how scientific data should not be manipulated for advocacy purposes, emphasizing the importance of accuracy in scientific illustrations.

So where does his legacy stand:
Despite the controversies, Haeckel's work, in general, has been significant! His art and writings continue to be studied not only for their artistic merit but also for his role in the historical development of scientific thought and its cautionary tale about the handling of scientific evidence.

Spandrels: This is NOT an evolutionary adaptation #Evolution #Adaptation #Biology

Stated Clearly 2024-05-15 | Visit patreon.com/statedclearly to support my work and see videos early.

Here I share with you a really neat example of a non-adaptive trait I found in giant, wild agave plants of Ecuador. Normally when I teach evolution, I focus on adaptations because they're so fun to think about, but many traits that organisms have are not directly selected for. They're often called "spandrels". In many cases, it's hard to tell if a trait is an adaptation or a spandrel, but in the case I show here in the agave plant, things are pretty clear.

Here's a bit of background:
"Adaptive evolution", or what Charles Darwin called "evolution by natural selection", happens when some mechanism (usually a mutation) generates a heritable trait that happens to help an organism survive better and/or reproduce more effectively than its neighbors, causing the trait to become more common in the population over generations.

"Evolutionary drift" (often called "genetic drift") is when a mutation changes an old trait in a neutral way or produces a new trait of no particular value. Sometimes neutral mutations become more common in a population by chance, despite their lack of value. This happens most often in small populations.

"Evolutionary Spandrels" are features that weren't directly shaped by natural selection; they just happen as side-effects of development or of the evolution of linked traits. If you do the math, you see that when a new spandrel pops up, if it is to stick around, it can't have a negative effect on those who inherit it, or if it does, that negative effect can't outweigh the beneficial effects of traits that were packaged with the spandrel. Your bellybutton, for example, might not be your prettiest feature, but having an umbilical chord was a huge plus when you were a fetus!

Genetic drift and spandrels show that sometimes, evolution can be random. There is plenty of functionless noise in our phenotypes.

Chemical Reactions Stated Clearly

Stated Clearly 2024-05-13 | You can support Jon Perry's work on patreon.com/statedclearly

Full video: youtu.be/C0Qaf-UJ2XQ?si=Wj9ba8fXSickES0U

Let's zoom into the microscopic world where atoms bond to form everything around us. We’re talking about chemical bonding, the glue of the universe!

Ionic Bonds: Picture a transfer of valentines—this happens when one atom gives up one or more electrons to another, creating ions. These oppositely charged ions attract each other like magnets. Typical in salts, like sodium chloride (table salt), ionic bonds are all about give and take!

Covalent Bonds: This is more about sharing than giving. Atoms share pairs of electrons to get that stable, cozy feel. Water (H2O) is a classic example, where hydrogen and oxygen share electrons tightly. It's like a strong handshake that holds molecules together.

Metallic Bonds: Imagine a sea of electrons shared among a lattice of metal atoms. These free-flowing electrons give metals their characteristic properties like conductivity and malleability. It’s like a communal pool of electrons where every metal atom gets to swim.

Each type of bond has its unique properties and uses, from the salt in your food to the water you drink and the gold in your electronics. Understanding these bonds helps us manipulate the world on an atomic level, crafting everything from medicines to man-made materials. So next time you snap a selfie or season your fries, think of the incredible bonds at work!

Evolution of the Whales blowhole

Stated Clearly 2024-05-10 | patreon.com/statedclearly

Full video "What is the Evidence for Evolution?" youtu.be/lIEoO5KdPvg?si=wUcr323hf3zD0JUD

Whales evolved from terrestrial mammals that gradually adapted to aquatic life around 50 million years ago. The ancestors of modern whales were artiodactyls, a group of hoofed mammals. Over millions of years, these ancestors transitioned from land-dwellers to water inhabitants, leading to significant anatomical changes. One of the most notable adaptations is the evolution of the blowhole, the nasal opening that allows whales to breathe efficiently on the water's surface.

How did evolution build this?

Stated Clearly 2024-05-08 | Visit patreon.com/statedclearly to support my work and see videos early.

The pink orchid praying mantis, Hymenopus coronatus, is one of the most striking examples of aggressive mimicry on earth! To understand how it evolved, it helps to understand the diversity of mantis species, and the types of selection pressures they're under as they hunt while avoiding being hunted.

In this short, I give a very simple outline of one of several possible routes to the evolution of orchid mantises from more typical ancestors. Early members of the lineage may have started down their trajectory due to an albino mutation. This is not mere conjecture, but is based on field observations showing that, even though their closest relatives are often deep yellow or green, H. coronatus is most often white, or pink/purple. On rare occasions they are pale yellow.

Once starting down the flower mimic path, mutations enlarging leg-petal ornamentation could have happened slowly, helping them better trick prey and other predators.

While not mentioned in the short (due to time constraints in YouTube Shorts), details on the specific mutations that allowed the evolution of pink pigment and the gene duplications that led the extreme leg-petal enlargement are now known. For details, see the free paper in Nature: Evolutionary genomics of camouflage innovation in the orchid mantis.

For behavior in the wild, and observed color variations, see: The orchid mantis exhibits high ontogenetic colouration variety and intersexual life history differences (preprint is available for free on researchgate.net)

From chemistry to life: Hints in the lab

Stated Clearly 2024-05-07 | patreon.com/statedclearly
See the full video: youtu.be/K1xnYFCZ9Yg?si=x4wdMR7taNrIiTQy

The paper: Isolation of Fast Purine Nucleotide Synthase Ribozymes
sfu.ca/~punrau/pdfs/Lau_JACS_2004.pdf

Abstract: Here we report the in vitro selection of fast ribozymes capable of promoting the synthesis of a purine nucleotide (6-thioguanosine monophosphate) from tethered 5-phosphoribosyl 1-pyrophosphate
(PRPP) and 6-thioguanine (6SGua). The two most proficient purine synthases have apparent efficiencies of 284 and 230 M-1 min-1 and are both significantly more efficient than pyrimidine nucleotide synthase ribozymes selected previously by a similar approach. Interestingly, while both ribozymes showed good substrate discrimination, one ribozyme had no detectable affinity for 6-thioguanine while the second had a Km of ∼80 µM, indicating that these ribozymes use considerably different modes of substrate recognition. The purine synthases were isolated after 10 rounds of selection from two high-diversity RNA pools. The first pool contained a long random sequence region. The second pool contained random sequence elements interspersed with the mutagenized helical elements of a previously characterized 4-thiouridine synthase ribozyme. While nearly all of the ribozymes isolated from this biased pool population appeared to have
benefited from utilizing one of the progenitor’s helical elements, little evidence for more complicated secondary structure preservation was evident. The discovery of purine synthases, in addition to pyrimidine
synthases, demonstrates the potential for nucleotide synthesis in an ‘RNA World’ and provides a context from which to study small molecule RNA catalysis.

From Alchemy to Chemistry

Stated Clearly 2024-05-06 | patreon.com/statedclearly
Full video: youtu.be/LhveTGblGHY?si=2DL2fTAv71-LjlDp

When you hear "alchemy," you might think of wizards trying to turn lead into gold, right? Sounds like a pseudoscience today, but hold on, don't dismiss it just yet. Alchemy, woo-woo and all, was actually crucial in kick-starting modern chemistry!

Back in the day, alchemists were the ones mixing things up, experimenting with all sorts of materials, and documenting results to teach apprentices to follow in their steps. They were really into perfecting distillation, which is basically a fancy way of saying "boiling and condensing" to separate stuff. This wasn't just magical mumbo-jumbo; these techniques are why we can make everything from pure water to strong spirits today.

And the stars of the show? Folks like Jabir ibn Hayyan—this guy could be called the father of chemistry. He tinkered with the alembic still, a tool that’s pretty much a medieval chemistry set. Then you've got Paracelsus and even Isaac Newton, dabbling in alchemy, laying down the groundwork for the science labs we know and love.

So, next time you think about alchemy, remember it's not just old-timey potion-making. It's the trailblazer for the chemistry that powers our world today!

Cicada molts and grows his wings: Time-Lapse

Stated Clearly 2024-05-05 | If you're feeling generous, you can support my work on Patreon: patreon.com/statedclearly

Cicadas develop underground feeding on liquid from plant roots and growing slowly for many years. When ready to leave their nymph life behind, they crawl out of the ground and look for a safe spot to transform into adults. They usually pick the rough bark of a tree or a sturdy plant. Here, they use their claws to grab on tightly, hooking claws into the plant as well as possible. This step is important because they need to be very stable for what comes next.

The Molt: Breaking Free
Once anchored, cicadas start the molting process. They split their old, tight skin along the back and slowly wriggle out. The process is one of the most dangerous things they do. Molting can take hours and their new exoskeleton is soft and vulnerable until crosslinking chemistry is able to help it harden and dry. During this time, they’re easy targets for any predator looking for a meal, and they are extremely vulnerable to injury bumps and falls.

Wing Inflation
With their old skin left behind, it’s time for the cicadas to "grow" their wings (in reality, they've already grown, but need to be inflated).

After molting, the new wings are small and wrinkly. Cicadas pump a special fluid into them, which stretches and unfolds the wings until they're full-sized. This fluid, called hemolymph, works a bit like air inflating a balloon, pushing out into the wings through tiny veins. The wings then dry and harden, preparing the cicada for flight and the new mission in life: Find a little love, make some babies.

This is a Sea Apple

Stated Clearly 2024-05-01 | Visit patreon.com/statedclearly to support my work and see videos early.

The evolution of metabolism is fun to think about. Just look at all the crazy ways there are to make a living on this planet? For example, here we see a sea apple - a round, colorful type of sea cucumber that sits around all day just filter feeding.

At first glance it seems he’s really stuffing his fat little face but he actually gets next to nothing per mouthful. Just a few white specs it caught, drifting in the water.

Think on this: each bite needs to have enough calories, on average, to justify the energy spent moving his arm, scraping it clean, and digesting the particles. After all that, there must be extra calories left over for maintenance and growth. Thinking about the mathematics of this metabolism is wild!

The Origin of Life: Metabolic Fossils

Stated Clearly 2024-04-30 | You can Support Jon's work on patreon.com/statedclearly

See full video here: youtu.be/K1xnYFCZ9Yg?si=fIFn4f9YK4gp2lOx

In origin of life research, "metabolic fossils" refers to the idea that some of the chemical reactions and processes found in modern organisms might have originated very early in life's history. These processes have been preserved through billions of years because they were effective and essential for life. They are like "fossils" because they give us clues about what life was like on the early Earth.

Researchers study these processes to understand how life could have started from non-living materials. For example, simple chemical reactions that occur in cells today might be similar to reactions that occurred spontaneously on the early Earth, using basic chemicals available in the environment back then. By examining these, scientists hope to piece together the puzzle of how increasingly complex life forms developed from basic chemistry.

Evolution: Its a fact

Stated Clearly 2024-04-29 | In the media recently, a guy named Tucker Carlson claimed that evolution is rejected by scientists and that it's "just a theory". There is a thing called evolutionary theory (the math and concepts we use to make sense of biology) and then there's the fact of evolution: That which we can directly observe with our own eyes.

Here I cover two experiments of observed evolution from single celled to multicellular life. Researchers used theory to guide them as they set up their experiments, they then observed and documented the fact of evolution unfolding before their eyes. This is how real science works.

To support Jon's work, go to patreon.com/statedclearly

Papers:
1. Phagotrophy by flagellate selects for colonial prey: A possible origin of multicellularity
2. Experimental evolution of multicellularity

This short clip comes from the longer video "What caused life's major evolutionary transitions". You can find direct links to downloadable versions of papers in the video description of the longer video, or on the website statedclearly.com

The Dire Wolf Paradox - Stated Clearly

Stated Clearly 2024-04-24 | Visit patreon.com/statedclearly to support my work and see videos early.

It's well known that in any ecosystem, prey animals far outnumber predators and scavengers. This is because each predator must eat several prey items per year to survive. So why then, are Dire Wolves, the most common fossils found in California’s La Brea Tar Pits pits?

The cleanest theory is that when large mammals got stuck in a tar pit, they would panic and flail. The noise attracted wolves. Entire groups would try to kill trapped animals or scavenge a carcass. In the process they often ended up getting stuck as well.

The tar pits are what biologists call a natural ecological trap! When new or uncommon environmental conditions lead organisms to perform maladaptive behaviors.

Luna Moth Inflates Wings (x200 speed)

Stated Clearly 2024-03-30 | This Luna Moth just emerged from her cocoon and is searching for a place to inflate her wings with hemolymph.

Footage of inflation is sped up, sometimes the first part is x10, the later stage (it slows at it grows) is x200 speed.

The Portuguese man o war #evolution #bluebottle #florida

Stated Clearly 2024-01-27 | The bluebottle or Portuguese man o' war is not a jellyfish but a siphonophore – a complex colony of specialized organisms, each with its own unique role.

Floating on the ocean surface is its most visible part, a gas-filled bladder that looks like a translucent, blue-purple balloon. This acts like a sail, helping the Man o' War drift across the sea.

But here's where it gets really interesting. Dangling below are long, menacing tentacles, loaded with tiny, venomous cells called nematocysts. When a fish or unsuspecting swimmer brushes against them, these cells explode, delivering a powerful sting that can paralyze small marine animals and cause immense pain to humans.

Despite its dangerous tentacles, the Portuguese Man o' War is a beautiful and mesmerizing creature, often seen in warm waters.

That's it for today's oceanic insight. Stay curious, and keep exploring the wonders of our natural world. And don't forget to like, share, and subscribe for more 'Stated Clearly' science!"

How were the Mexico Aliens made?

Stated Clearly 2024-01-25 | Many people were interested in little supposed "alien mummies" presented to the Mexican government last year. Some people thought they were real. It turns out that researchers in Peru had seen these 5 years ago and found they were made from animal and human bones, some of which the scam artists had collected from ancient Peruvian burial sites. See their full video of this here: youtu.be/PqxNJH4Gztg?si=RGk8GhLDyN9WVdNZ

How did a whale get in the jungle? #animals #amazonjungle #evolution

Stated Clearly 2023-12-16 | How did a whale end up in the Amazon Jungle? Turns out it's in the part of the jungle that floods during high tide. This whale was found 15 meters from the beach, in a tidal river bed within the coastal mangrove forest of the Marajó Bay in Soure, Brazil.

Evolution of... well, I dont want to spoil the surprise, but its manatees and dugongs. #evolution

Stated Clearly 2023-12-08 | That amazing photo of the manatee foot was by Fritz Geller-Grimm, en.wikipedia.org/wiki/Evolution_of_sirenians#/media/File:Trichechus_manatus_fg01.JPG

Dugongs and Manatees, often called sea-cows, are members of the group called Sirenia, an order of herbivorous mammals that evolved from a common ancestor with Elephants.

To be clear, manatees and dugongs (sirenians) did not evolve from elephants, elephants and sirenians both evolved, down separate paths, from a common relative. Researchers now think that common ancestor was a medium sized, semiaquatic creature similar to the fossil genus, Moeritherium.

Elephants are no longer considered "aquatic mammals" but it's well known that they still love swimming! A family of elephants once famously swam across the Johor Strait (about a mile of sea water) and tried to settle on Tekong Island, a military base in Singapore. This caused all sorts drama for soldiers who had to get the protected animals safely off their base.

Interestingly, modern elephants have several traits usually associated with aquatic life that help them swim, including internal testis, and a muscle inside the ear canal that closes tightly shut when swimming. journals.physiology.org/doi/full/10.1152/physiol.00008.2007

The earhole in manatees still exists but is small pinched closed all the time by surrounding fat and muscle. It clogs with cellular debris as they mature. https://diginole.lib.fsu.edu/islandora/object/fsu:254627/datastream/PDF/view

Amazon River Dolphin #amazonjungle #evolution

Stated Clearly 2023-12-04 | Want to join me on the Evolution tour? Go to evotour.scibugs.info to sign up

Evolution of Beetle Wings

Stated Clearly 2023-11-17 | Beetle forewings are modified into hardened structures called elytra. A recent study indicates that the evolution of elytra involved co-opting genes for exoskeleton formation into the wing development gene network of beetles.

For Tour info, go to evotour.scibugs.info

Scientific Papers: Tip #3 Avoid Jargon

Stated Clearly 2023-11-03 | It's refreshing to find this tip in Oxford's new writing guide for scientists. I hope this has a real impact in the community!

For your copy of Scientific Paper's Made Easy: amazon.com/Scientific-Papers-Made-Easy-Sciences/dp/0192862790/ref=pd_ci_mcx_mh_mcx_views_0?pd_rd_w=rGR54&%3Bcontent-id=amzn1.sym.225b4624-972d-4629-9040-f1bf9923dd95%253Aamzn1.symc.40e6a10e-cbc4-4fa5-81e3-4435ff64d03b&%3Bpf_rd_p=225b4624-972d-4629-9040-f1bf9923dd95&%3Bpf_rd_r=CM69PCYXRQWBMC88J1KE&%3Bpd_rd_wg=hLa89&%3Bpd_rd_r=aa9e82d8-8d56-486d-8813-b9ca5a978883&%3Bpd_rd_i=0192862790&_encoding=UTF8&tag=statedclear00-20&linkCode=ur2&linkId=261d5d255e2bf31d010c25392d2c8e09&camp=1789&creative=9325

Writing Tip 7: Be Precise!

Stated Clearly 2023-10-27 | In technical writing, extreme clarity is key! Get a copy of Oxford's new writing guide here: amazon.com/Scientific-Papers-Made-Easy-Sciences/dp/0192862790/ref=pd_ci_mcx_mh_mcx_views_0?pd_rd_w=rGR54&%3Bcontent-id=amzn1.sym.225b4624-972d-4629-9040-f1bf9923dd95%253Aamzn1.symc.40e6a10e-cbc4-4fa5-81e3-4435ff64d03b&%3Bpf_rd_p=225b4624-972d-4629-9040-f1bf9923dd95&%3Bpf_rd_r=CM69PCYXRQWBMC88J1KE&%3Bpd_rd_wg=hLa89&%3Bpd_rd_r=aa9e82d8-8d56-486d-8813-b9ca5a978883&%3Bpd_rd_i=0192862790&_encoding=UTF8&tag=statedclear00-20&linkCode=ur2&linkId=261d5d255e2bf31d010c25392d2c8e09&camp=1789&creative=9325

Scientific Writing - Top 10 Tips

Stated Clearly 2023-10-20 | For more about Oxford's new writing guide, check out the associated video. For the book, get your copy here: amazon.com/Scientific-Papers-Made-Easy-Sciences/dp/0192862790/ref=pd_ci_mcx_mh_mcx_views_0?pd_rd_w=rGR54&%3Bcontent-id=amzn1.sym.225b4624-972d-4629-9040-f1bf9923dd95%253Aamzn1.symc.40e6a10e-cbc4-4fa5-81e3-4435ff64d03b&%3Bpf_rd_p=225b4624-972d-4629-9040-f1bf9923dd95&%3Bpf_rd_r=CM69PCYXRQWBMC88J1KE&%3Bpd_rd_wg=hLa89&%3Bpd_rd_r=aa9e82d8-8d56-486d-8813-b9ca5a978883&%3Bpd_rd_i=0192862790&_encoding=UTF8&tag=statedclear00-20&linkCode=ur2&linkId=261d5d255e2bf31d010c25392d2c8e09&camp=1789&creative=9325

Birds Evolved From Dinosaurs! #science

Stated Clearly 2023-10-13 | If you want to meet a Hoatzin, join me on the Evolution tour of the Amazon jungle, July 17th to 25th, 2024: evotour.scibugs.info

DNA - Do Not Acronym!

Stated Clearly 2023-10-13 | I'm so happy Oxford's new writing guide takes a stand against this silly cultural habit. DOWN WITH THE ACRONYMS! You can get your copy here: amazon.com/Scientific-Papers-Made-Easy-Sciences/dp/0192862790/ref=pd_ci_mcx_mh_mcx_views_0?pd_rd_w=rGR54&%3Bcontent-id=amzn1.sym.225b4624-972d-4629-9040-f1bf9923dd95%253Aamzn1.symc.40e6a10e-cbc4-4fa5-81e3-4435ff64d03b&%3Bpf_rd_p=225b4624-972d-4629-9040-f1bf9923dd95&%3Bpf_rd_r=CM69PCYXRQWBMC88J1KE&%3Bpd_rd_wg=hLa89&%3Bpd_rd_r=aa9e82d8-8d56-486d-8813-b9ca5a978883&%3Bpd_rd_i=0192862790&_encoding=UTF8&tag=statedclear00-20&linkCode=ur2&linkId=261d5d255e2bf31d010c25392d2c8e09&camp=1789&creative=9325

The Curse of Knowledge

Stated Clearly 2023-10-06 | This is a mini lesson from Oxford's new science writing guide, Scientific Papers Made Easy: amazon.com/Scientific-Papers-Made-Easy-Sciences/dp/0192862790/ref=pd_ci_mcx_mh_mcx_views_0?pd_rd_w=rGR54&%3Bcontent-id=amzn1.sym.225b4624-972d-4629-9040-f1bf9923dd95%253Aamzn1.symc.40e6a10e-cbc4-4fa5-81e3-4435ff64d03b&%3Bpf_rd_p=225b4624-972d-4629-9040-f1bf9923dd95&%3Bpf_rd_r=CM69PCYXRQWBMC88J1KE&%3Bpd_rd_wg=hLa89&%3Bpd_rd_r=aa9e82d8-8d56-486d-8813-b9ca5a978883&%3Bpd_rd_i=0192862790&_encoding=UTF8&tag=statedclear00-20&linkCode=ur2&linkId=261d5d255e2bf31d010c25392d2c8e09&camp=1789&creative=9325

Spider Stomach!

Stated Clearly 2023-10-06 | I found this spider in the woods behind my house and was so surprised to witness her amazing hunting techniques. What a fantastic world we live in!

Oxfords Golden Rule in Scientific Writing

Stated Clearly 2023-09-29 | "The reader must come first" is golden rule in Oxford's new writing guide: Scientific Papers Made Easy

Get a copy here: amazon.com/Scientific-Papers-Made-Easy-Sciences/dp/0192862790/ref=pd_ci_mcx_mh_mcx_views_0?pd_rd_w=rGR54&%3Bcontent-id=amzn1.sym.225b4624-972d-4629-9040-f1bf9923dd95%253Aamzn1.symc.40e6a10e-cbc4-4fa5-81e3-4435ff64d03b&%3Bpf_rd_p=225b4624-972d-4629-9040-f1bf9923dd95&%3Bpf_rd_r=CM69PCYXRQWBMC88J1KE&%3Bpd_rd_wg=hLa89&%3Bpd_rd_r=aa9e82d8-8d56-486d-8813-b9ca5a978883&%3Bpd_rd_i=0192862790&_encoding=UTF8&tag=statedclear00-20&linkCode=ur2&linkId=261d5d255e2bf31d010c25392d2c8e09&camp=1789&creative=9325

Origin of Life #evolution #chemistry

Stated Clearly 2023-09-29 | The origin of life is a mystery, but it's currently being worked on by persistent scientists such as my friend, Ram Krishnamurthy, at Scripps: https://www.scripps.edu/krishnamurthy/ #originoflife #evolution #chemistry #chemicalevolution #scripps

Huge thanks to Cogito of cogitosjournalclub.com, for the excellent photo of Ram!

Scientific Papers Made Easy | Stated Clearly Review

Stated Clearly 2023-09-26 | If you want to do the science, you'll want to read this book: amazon.com/Scientific-Papers-Made-Easy-Sciences/dp/0192862790/ref=pd_ci_mcx_mh_mcx_views_0?pd_rd_w=rGR54&content-id=amzn1.sym.225b4624-972d-4629-9040-f1bf9923dd95%253Aamzn1.symc.40e6a10e-cbc4-4fa5-81e3-4435ff64d03b&pf_rd_p=225b4624-972d-4629-9040-f1bf9923dd95&pf_rd_r=CM69PCYXRQWBMC88J1KE&pd_rd_wg=hLa89&pd_rd_r=aa9e82d8-8d56-486d-8813-b9ca5a978883&pd_rd_i=0192862790&_encoding=UTF8&tag=statedclear00-20&linkCode=ur2&linkId=261d5d255e2bf31d010c25392d2c8e09&camp=1789&creative=9325"

And here's the UK version: amazon.co.uk/Scientific-Papers-Made-Easy-Sciences/dp/0192862790/ref=sr_1_1?crid=F5VWOQ21I4ZQ&keywords=scientific+papers+made+easy&qid=1695721920&s=books&sprefix=scientific+papers+made+easy%2Cstripbooks%2C149&sr=1-1

Neoteny - When evolution causes certain juvenile features to be retained in adults

Stated Clearly 2023-08-29 | ...