Latest Posts by csmsdust - Page 4
Morphological differences between thorns, spines, and prickles
my watery friend... are you too brushed with the pattern of the dappled light...?
Slime Molds and Intelligence
Okay, despite going into a biology related field, I only just learned about slime molds, and hang on, because it gets WILD.
This guy in the picture is called Physarum polycephalum, one of the more commonly studied types of slime mold. It was originally thought to be a fungus, though we now know it to actually be a type of protist (a sort of catch-all group for any eukaryotic organism that isn't a plant, animal, or a fungus). As protists go, it's pretty smart. It is very good at finding the most efficient way to get to a food source, or multiple food sources. In fact, placing a slime mold on a map with food sources at all of the major cities can give a pretty good idea of an efficient transportation system. Here is a slime mold growing over a map of Tokyo compared to the actual Tokyo railway system:
Pretty good, right? Though they don't have eyes, ears, or noses, the slime molds are able to sense objects at a distance kind of like a spider using tiny differences in tension and vibrations to sense a fly caught in its web. Instead of a spiderweb, though, this organism relies on proteins called TRP channels. The slime mold can then make decisions about where it wants to grow. In one experiment, a slime mold was put in a petri dish with one glass disk on one side and 3 glass disks on the other side. Even though the disks weren't a food source, the slime mold chose to grow towards and investigate the side with 3 disks over 70% of the time.
Even more impressive is that these organisms have some sense of time. If you blow cold air on them every hour on the hour, they'll start to shrink away in anticipation when before the air hits after only 3 hours.
Now, I hear you say, this is cool and all, but like, I can do all those things too. The slime mold isn't special...
To which I would like to point out that you have a significant advantage over the slime mold, seeing as you have a brain.
Yeah, these protists can accomplish all of the things I just talked about, and they just... don't have any sort of neural architecture whatsoever? They don't even have brain cells, let alone the structures that should allow them to process sensory information and make decisions because of it. Nothing that should give them a sense of time. Scientists literally have no idea how this thing is able to "think'. But however it does, it is sure to be a form of cognition that is completely and utterly different from anything that we're familiar with.
Today I found a good video about merging tubes with different angles, ellipses, phase shift of sine waves, featuring sculptures by Frank Smullin.
This video is exceptionally comprehensive.
[Shared by hardm.ix on instagram: Text says: "A little more on the analytic constructivist sculpture of Frank Smullin, a professor of mine at Duke University who combined art and engineering in a way that reminded me a little of Kenneth Snelson and Tensegrity or Buckminster Fuller and geodesic domes."]
Eukaryotic cell gang!! We love women in STEM.
The organelles of the cells have been translated into human anatomy, so the nucleus is the brain, the vacuole function as the lungs, and the mitochondria is the heart since it’s the… you already know, I don’t have to say it ;)
‘Wrinkles’ in time experience linked to heartbeat
How long is the present? The answer, Cornell researchers suggest in a new study, depends on your heart.
They found that our momentary perception of time is not continuous but may stretch or shrink with each heartbeat.
The research builds evidence that the heart is one of the brain’s important timekeepers and plays a fundamental role in our sense of time passing – an idea contemplated since ancient times, said Adam K. Anderson, professor in the Department of Psychology and in the College of Human Ecology (CHE).
“Time is a dimension of the universe and a core basis for our experience of self,” Anderson said. “Our research shows that the moment-to-moment experience of time is synchronized with, and changes with, the length of a heartbeat.”
Saeedeh Sadeghi, M.S. ’19, a doctoral student in the field of psychology, is the lead author of “Wrinkles in Subsecond Time Perception are Synchronized to the Heart,” published in the journal Psychophysiology. Anderson is a co-author with Eve De Rosa, the Mibs Martin Follett Professor in Human Ecology (CHE) and dean of faculty at Cornell, and Marc Wittmann, senior researcher at the Institute for Frontier Areas of Psychology and Mental Health in Germany.
Time perception typically has been tested over longer intervals, when research has shown that thoughts and emotions may distort our sense time, perhaps making it fly or crawl. Sadeghi and Anderson recently reported, for example, that crowding made a simulated train ride seem to pass more slowly.
Such findings, Anderson said, tend to reflect how we think about or estimate time, rather than our direct experience of it in the present moment.
To investigate that more direct experience, the researchers asked if our perception of time is related to physiological rhythms, focusing on natural variability in heart rates. The cardiac pacemaker “ticks” steadily on average, but each interval between beats is a tiny bit longer or shorter than the preceding one, like a second hand clicking at different intervals.
The team harnessed that variability in a novel experiment. Forty-five study participants – ages 18 to 21, with no history of heart trouble – were monitored with electrocardiography, or ECG, measuring heart electrical activity at millisecond resolution. The ECG was linked to a computer, which enabled brief tones lasting 80-180 milliseconds to be triggered by heartbeats. Study participants reported whether tones were longer or shorter relative to others.
The results revealed what the researchers called “temporal wrinkles.” When the heartbeat preceding a tone was shorter, the tone was perceived as longer. When the preceding heartbeat was longer, the sound’s duration seemed shorter.
“These observations systematically demonstrate that the cardiac dynamics, even within a few heartbeats, is related to the temporal decision-making process,” the authors wrote.
The study also showed the brain influencing the heart. After hearing tones, study participants focused attention on the sounds. That “orienting response” changed their heart rate, affecting their experience of time.
“The heartbeat is a rhythm that our brain is using to give us our sense of time passing,” Anderson said. “And that is not linear – it is constantly contracting and expanding.”
The scholars said the connection between time perception and the heart suggests our momentary perception of time is rooted in bioenergetics, helping the brain manage effort and resources based on changing body states including heart rate.
The research shows, Anderson said, that in subsecond intervals too brief for conscious thoughts or feelings, the heart regulates our experience of the present.
“Even at these moment-to-moment intervals, our sense of time is fluctuating,” he said. “A pure influence of the heart, from beat to beat, helps create a sense of time.”
Ammonite fossil, 45 - 60 mm
Mouse embryo (day 12.5) stained for motor (red) and sensory (magenta) nerves and nerve endings (cyan)
By Dr. Gist F. Croft, Lauren Pietila, Dr. Ali H. Brivanlou (The Rockefeller University - Laboratory of Stem Cell Biology and Molecular Embryology)
Technique: Light Sheet Microscopy and Tissue Clearing (iDISCO)
Magnification 1.8x (objective lens magnification)
no gods no masters
The incredibly stunning Port Jackson Shark, which lives on coastal reefs in Australia
Though it can be solitary it prefers to stay in small groups and explore the sea floor with its friends
What I love most about this shark is how surreal it looks due to the patterns of its skin
It is friendly and curious of people
An oviparous shark, it lays spiral eggs to keep the current from dragging babies into the open ocean
Probably the coolest shark jaw I’ve ever seen, most of its teeth are round and flat in order to crush clams and mollusks
Hello! Why did penguins evolve to have black feathers if they live in icy (mostly white?) locations? I understand them having a white tummy because when swimming they could be more difficult to identify by a predator swimming below them? Thanks!
Love your blog!
Hello! So, here's what I learned at uni:
the widely-accepted reason penguins have black feathers is the same reason they have white tummies, but backwards. When swimming, they are more difficult to identify by a predator swimming above them! You can see similar countershading in sharks and dolphins, and also on land animals like mountain goats and lizards. Overall, it helps to make animals less obvious when viewing from the side, because it reduces the obviousness of their shadow.
As to why penguins have black feathers in icy, mostly white, locations (on LAND), you need to consider why it would be good to be white in an icy, white location in the first place!
Mostly, it would provide camouflage, which would protect from land predators! However, penguins don't really have any significant land predators in Antarctica. There are no polar bears, or big snakes, or even foxes or coyotes in Antarctica, so the penguin won't benefit from being camouflaged on land. Basically, there's no "selective pressure" for them to be all white!
some penguin chicks, however, do have to worry about a few predators, so they have a little more camouflage than the adult penguins:
What's more, there are likely advantages to black feathers in a cold environment like Antarctica! For example, in the sun, dark feathers absorb more thermal energy, helping to warm the penguin and maintain their body heat.
There may also be some stuff with black feathers being more resistant to wear/ friction drag in the water, but that's entering the realm of ongoing research, which I won't get into here.
Let me know if there's anything that needs clarifying!
(some citations if anyone wants further reading:)
Bonser, R. H. (1995). Melanin and the abrasion resistance of feathers. The Condor, 97(2), 590-591.
Ksepka, D. T. (2016). The penguin's palette--more than black and white: this stereotypically tuxedo-clad bird shows that evolution certainly can accessorize. American Scientist, 104(1), 36-44.
Rowland, H. M. (2009). From Abbott Thayer to the present day: what have we learned about the function of countershading?. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1516), 519-527.
Zagrai, A., & Hassanalian, M. (2020, July). Penguin coloration affects skin friction drag. In 2020 Gulf Southwest Section Conference.
What are Phytoplankton and Why Are They Important?
Breathe deep… and thank phytoplankton.
Why? Like plants on land, these microscopic creatures capture energy from the sun and carbon from the atmosphere to produce oxygen.
Phytoplankton are microscopic organisms that live in watery environments, both salty and fresh. Though tiny, these creatures are the foundation of the aquatic food chain. They not only sustain healthy aquatic ecosystems, they also provide important clues on climate change.
Let’s explore what these creatures are and why they are important for NASA research.
Phytoplankton are diverse
Phytoplankton are an extremely diversified group of organisms, varying from photosynthesizing bacteria, e.g. cyanobacteria, to diatoms, to chalk-coated coccolithophores. Studying this incredibly diverse group is key to understanding the health - and future - of our ocean and life on earth.
Their growth depends on the availability of carbon dioxide, sunlight and nutrients. Like land plants, these creatures require nutrients such as nitrate, phosphate, silicate, and calcium at various levels. When conditions are right, populations can grow explosively, a phenomenon known as a bloom.
Phytoplankton blooms in the South Pacific Ocean with sediment re-suspended from the ocean floor by waves and tides along much of the New Zealand coastline.
Phytoplankton are Foundational
Phytoplankton are the foundation of the aquatic food web, feeding everything from microscopic, animal-like zooplankton to multi-ton whales. Certain species of phytoplankton produce powerful biotoxins that can kill marine life and people who eat contaminated seafood.
Phytoplankton are Part of the Carbon Cycle
Phytoplankton play an important part in the flow of carbon dioxide from the atmosphere into the ocean. Carbon dioxide is consumed during photosynthesis, with carbon being incorporated in the phytoplankton, and as phytoplankton sink a portion of that carbon makes its way into the deep ocean (far away from the atmosphere).
Changes in the growth of phytoplankton may affect atmospheric carbon dioxide concentrations, which impact climate and global surface temperatures. NASA field campaigns like EXPORTS are helping to understand the ocean's impact in terms of storing carbon dioxide.
Phytoplankton are Key to Understanding a Changing Ocean
NASA studies phytoplankton in different ways with satellites, instruments, and ships. Upcoming missions like Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) - set to launch Jan. 2024 - will reveal interactions between the ocean and atmosphere. This includes how they exchange carbon dioxide and how atmospheric aerosols might fuel phytoplankton growth in the ocean.
Information collected by PACE, especially about changes in plankton populations, will be available to researchers all over the world. See how this data will be used.
The Ocean Color Instrument (OCI) is integrated onto the PACE spacecraft in the cleanroom at Goddard Space Flight Center. Credit: NASA
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Radiolaria, a type of protozoa known for its complex shell structure, from Marvels of the Universe v.2.
Full text here.
