study-astronomy-biology-ref
This is a studyblr for everyone have some passion for science, especially astronomy and biology
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Latest Posts by study-astronomy-biology-ref
The solar eclipse that occurred in Chile on July 2, 2019 photographed by Dan Marker-Moore. Great job!
Via Colossal
How to Escape a Hair Grab or a Neck Grab ? Look at them, carefully.
tai chi pants on http://www.icnbuys.com/tai-chi-pants give you surprise at the new year.
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Researchers find proteins that might restore damaged sound-detecting cells in the ear
Using genetic tools in mice, researchers at Johns Hopkins Medicine say they have identified a pair of proteins that precisely control when sound-detecting cells, known as hair cells, are born in the mammalian inner ear. The proteins, described in a report published June 12 in eLife, may hold a key to future therapies to restore hearing in people with irreversible deafness.
“Scientists in our field have long been looking for the molecular signals that trigger the formation of the hair cells that sense and transmit sound,” says Angelika Doetzlhofer, Ph.D., associate professor of neuroscience at the Johns Hopkins University School of Medicine. “These hair cells are a major player in hearing loss, and knowing more about how they develop will help us figure out ways to replace hair cells that are damaged.”
Keep reading
Colourised footage of Benjamin, the last know Tasmanian Tiger (Thylacine).
Benjamin died on September 7th, 1936 in Hobart zoo. It is believed that he died out of neglect, as he was locked out of his shelter and was exposed to the searing hot sun and freezing cold night of Tasmania.
The Thylacine was one of the last large marsupials left on Australia (the other being the Kangaroo) after a great extinction event occurred around 40 thousand years ago. This extinction event, caused mainly by the arrival of humans, wiped out 90% of Australia’s terrestrial vertebrates, including the famous Megafauna.
The Thylacine was around 15-30kg (33-66lbs), were carnivorous, and had numerous similarities to other species like dogs, despite not being related and purely by chance, in a phenomenon known as convergent evolution (just like the ability to fly of bats and birds, despite following different evolutionary paths). Not only that, they could open their jaws up to 120 degrees, could hop around on two legs like a kangaroo, and both males and females had pouches.
Lastly in a cruel twist, the Tasmanian government decided to protect the Thylacine - just 59 days before the last one died, in a very notable case case of “Too little too late”. To date, many biologists believe that there are still Thylacine roaming the wild plains of Australia.
This is a 392 year old shark that was recently discovered in the Arctic Ocean.
This guy was wandering the oceans back in 1627 🦈
Tardigrades: ‘Water bears’ stuck on the moon after crash
The moon might now be home to thousands of planet Earth’s most indestructible animals.
Tardigrades - often called water bears - are creatures under a millimetre long that can survive being heated to 150C and frozen to almost absolute zero.
They were travelling on an Israeli spacecraft that crash-landed on the moon in April.
And the co-founder of the organisation that put them there thinks they’re almost definitely still alive.
The water bears had been dehydrated to place them in suspended animation and then encased in artificial amber.
“We believe the chances of survival for the tardigrades… are extremely high.”
Guide to DIY Designing It Yourself Wedding Dress from storymixmedia
Writers continue to reblog these infographics for their useful terminology.
If you’ve missed any infographics, here they are:
Know Your Shoes Part 1 Lobster Claws anyone? Know Your Shoes Part 2 Know You Heels Fashion Pattern Vocabulary Part 1 Fashion Pattern Vocabulary Part 2 Know Your Check Fabrics Know Your Animal Prints Know Your Hosiery Know Your Gloves History of Hairstyles Part 1 History of Hairstyles Part 2 Know Your Braids Know Your Scarves Know Your Belts Part 1 Know Your Belts Part 2 Know Your Sleeve Lengths Know Your jacket length Know Your Skirt Lengths Know Your Pant Lengths Know Your Front and Back Yokes Know Your Yokes and Hems Know Your Pleats Know Your Darts Know Your Denim Pockets Part 1 Know Your Patch Pockets Part 2 Know Your Pockets Part 3 Know Your Sleeves Know Your Bras Know Your Collars Know Your Hair Buns Know Your Sunglasses Infographic Know Your Necklines Sleeves and Necklines Know Your Hats Know Your Collars and Cuffs Know Your Necklines Know Your Skirts Know Your Nail Shapes and What’s Popular on Instagram Know Your Eye Liners Know Your Wedding Dresses History of Swimwear Know Your Vintage Sleeves here Know Your Vintage Collars and Necklines Know Your Zippers and Zipper Pulls
An asteroid the size of a skyscraper should pass near the Earth on August 10th
Asteroid Watch logo. August 5, 2019
Near Earth Asteroid
An asteroid 570 meters in diameter is expected to approach 8 million kilometers from our planet on August 10. The situation is of no concern to NASA specialists, who stress the large number of similar celestial objects that are spotted each year near the Earth. The space agency says it fears more those who are not listed.
Artist’s impression of 2006 QQ23 asteroid
According to NASA, an asteroid the size of a skyscraper will pass near the Earth on Saturday, August 10. Called “2006 QQ23”, the celestial object is approximately 570 meters in diameter and its trajectory will place it at a distance of 8 million kilometers from our planet, closer to home, says CNN. A “more or less benign” situation for experts from the American Space Agency. This asteroid is of a “moderate size” Lindley Johnson of NASA’s Global Coordinating Office for Defense says the asteroid is “of moderate size” and explains that half a dozen similar-sized aerolites are approaching each year. Not to mention that the solar system includes nearly 900 of a volume greater than that which advances towards the Earth. The specialists are therefore reassuring.
2006 QQ23 orbit
They explain having already studied the movements of “2006 QQ23” since the year 1901 and until 2200. Because a possible impact between the Earth and a foreign body of this size would cause significant damage over a large area . Even if this scenario occurred, NASA would then be able to launch a space mission to deflect the celestial object. When it comes to asteroids, “it’s the ones we do not know about that worry us,” says Kelly Fast, also a member of the Coordination Office. Related article: Asteroid’s surprise close approach illustrates need for more eyes on the sky https://orbiterchspacenews.blogspot.com/2019/08/asteroids-surprise-close-approach.html Additional information: Asteroid Watch: For more information about asteroids and near-Earth objects, visit: http://www.jpl.nasa.gov/asteroidwatch and http://www.nasa.gov/asteroid . Updates about near-Earth objects are also available by following AsteroidWatch on Twitter at http://www.twitter.com/asteroidwatch . Near-Earth Object Program Office: http://neo.jpl.nasa.gov/ Images, Text, Credits: AFP/NASA/ESA/Orbiter.ch Aerospace/Roland Berga. Best regards, Orbiter.ch Full article
Skull of a woman with monocephalus diprosopus. This is a form of conjoined twinning characterized by a single head and two faces. From the Museum of Anatomy in Montpellier, France.
Wow this is really cool! Love the amount of efforts put into this!
Animal/Bio-Diversity Facts!
I combined these two topics because there’s a lot of overlap, and I decided that taking notes on both really helped me understand what the other is trying to say. This will be a long post, strap yourself in.
Organisms are organized and classified via a system known as Taxonomy. This system was developed by a scientist named Carl Linnaeus. To identify individual organisms, binomial nomenclature is used. What this means is each organism is called by their genus and species name. For example, Homo sapien, Pyrrhura molinae, (Green cheek conure), and Betta splendens.
There were originally 6 taxa or levels of organization developed by Linnaeus; kingdom, phylum, class, order, family, genus, and species. The 20th century saw many changes to Linnaeus’ original system of organization. The 3 original kingdoms were expanded to 5; Monera, Protista, Fungi, Plantae, and Animalia, a 6th, Archaebacteria was added to represent extremophiles that were so intense they had to be separated from bacteria to give their coolness more merit.
Today’s scientists added a 7th level, domain. We use a 3-domain system based on DNA analysis. These domains are eukarya, bacteria, and archaea. Monera stopped being used as the prokaryotes were split between bacteria and archaea. Archaea are in fact, not bacteria, and so were given their own domain.
Here are some characteristics shared among members of the same domain:
Bacteria
All members of this domain are unicellular prokaryotes. This means that they lack internal membranes, like a nucleus, mitochondria, or chloroplasts)
Some are anaerobic (metabolize without oxygen) some are aerobic (metabolize with oxygen)
In the environment, some are decomposers, meaning they decompose and recycle dead organic material.
Some are pathogens, such as some strains of E.coli.
Speaking of E.coli, they also play a vital role in genetic engineering. E.coli is used to manufacture human insulin
Some reproduce using conjugation. This is a primitive process, where individuals exchange genetic material
They have a thick and rigid cell wall
Some, like blue-green algae, are autotrophic (make their own food) others are heterotropic (depend on complex organic substances for food)
Have no introns (noncoding segments of DNA)
Archaea
Also unicellular prokaryotes
Include extremophiles, which are organisms that live in extreme environments. Some examples are Methanogens (obtain energy by producing methane from hydrogen) Halophiles (thrive in extremely salty environments, such as the Dead Sea) and Thermophiles (thrive in extremely high temperatures, like Yellowstone’s hot springs)
Have introns present in some of their genes
Eukarya
Have a nucleus and internal, membrane-bound organelles
Include: Protista, Fungi, Plantae, and Animalia
Moving into kingdoms, there are 4. These are the 4 mentioned above, fungi, Protista, Plantae, and Animalia. Here are some traits for each:
Protista
Most are unicellular, however, some are primitive multicellular organisms.
Include both heterotrophs (like amoeba, and paramecium) and autotrophs (like euglenas)
Move using different structures, such as pseudopods in amoeba, cilia in paramecium, and flagella in euglenas.
Include organisms not cool enough to sit with the fungi or Plantae kingdoms, like seaweed and slime mould.
Some, like algae and paramecium, carry out conjugation
Some can cause serious diseases like amoebic dysentery and malaria
Fungi
All are heterotrophic
Include unicellular and multicellular organisms
Able to digest extracellularly by secreting hydrolytic enzymes, and absorbing the nutrients via diffusion.
Are essential to the environment, as they are decomposers. They are saprobes, which mean they eat decaying organic matter.
They have cell walls, however, unlike plants whose cell walls are made of cellulose, their cell walls are made of chitin.
Lichens are fungi and algae living in a mutualistic, symbiotic relationship. Lichens are strong enough to withstand harsh, unforgiving environments, thus are often the pioneer organisms (the first to colonize a new environment).
They reproduce asexually by budding, like yeast, spore formation, like bread mould, or fragmentation (aka 1 parent breaks itself into several, living pieces), however, some can reproduce sexually.
Plantae
All are multicellular, nonmotile, and autotrophic.
Their cell walls, as mentioned above, are made of cellulose.
Plants can create their own food by photosynthesis, which uses chlorophyll a and b.
Their carbohydrates are stored as starch
They reproduce sexually by alternating between the gametophyte and sporophyte generations.
Some (tracheophytes) have vascular tissue while others (bryophytes) do not.
Animalia
All are heterotrophic, multicellular, and motile
Most reproduce sexually with a dominant diploid (2n) stage
In most, a sperm with a flagellum fertilizes a large, nonmotile egg.
Animals are classified, traditionally based on anatomical features (homologous structures) and embryonic development.
There are 35 phyla. Since I want to eat something today, I’ll go over the 9 the Barron’s SAT book describes, which are Porifera, cnidarians, Platyhelminthes, nematodes, annelids, molluscs, arthropods, echinoderms, and chordates.
Each animal phylum represents the evolution of a new, successful body plan. Some of these trends include specialisation of tissues, germ layers, body symmetry, the development of a head end, and body cavity formation.
Specialized cells, tissues, and organs
The cell is the basic unit of all life, for example, fat cells. Tissue is the next block up and is a collection of tissues performing a function, such as adipose tissue. An organ is a group of tissues working together to perform a similar function. For example, the brain.
Organisms making up the phylum Porifera, like sponges are made of a loose confederation of cells. Since those cells are not specialized, they are not considered tissue. These cells can react to stimuli, however, lack muscle or nerve tissue.
Organisms making up the phylum cnidaria possess tissue, however the most primitive and simple form of tissue. However, no organs. Flatworms do have organs, however, lack an organ system. Annelids, however, possess a full organ system.
Germ Layers
Germ layers make up the tissues and organs of the body. They form early in embryonic development. There are 3 kinds, however, not all organisms have all 3.
Ectoderm- outermost layer, makes up skin and nervous system
Mesoderm- middle layer, becomes blood, muscles, and bones
Endoderm- innermost layer, makes up the viscera (guts)
Porifera and cnidarians only have 2 layers. They lack mesoderm and instead have mesoglea or middle glue which holds the 2 layers together. Organisms that have 3 true germ layers are called triploblastic.
Body Symmetry
Most primitive animals exhibit radial symmetry. More complex animals exhibit bilateral symmetry. This is displayed in the drawings below. Echinoderms are a key exception to this rule. They develop with bilateral symmetry, however, as an adult, they exhibit radial symmetry. In bilateral symmetry, the body mirrors itself along the left and right on the longitudinal axis.
This also means that Patrick Star is not drawn biologically accurate. Shame.
Body Cavity Formation
The coelom is a fluid-filled body cavity, completely surrounded by mesoderm tissue. It is found only in more evolutionarily advanced organisms. Organisms like flatworms, who lack a coelom are known as acoelomates. Organisms, like nematodes or roundworms, who have a fluid-filled tube between the endoderm and mesoderm, functioning as a hydrostatic skeleton, are known as pseudocoelomates. Coelomates are organisms with a true coelom. Annelida, Mollusca, Arthropoda, and Chordata are all phyla that have this structure.
Development of a Head (Cephilization)
Organisms that developed bilateral symmetry also have an anterior and posterior end. (The head and rear end). The sensory apparatus and brain, or ganglia in less developed organisms are organized on the anterior end, while digestion, excretion, and reproduction all keep their organs on the posterior end. Cephilization began with flatworms.
Here is a cladogram to help visualize when different traits developed.
Traits of 9 different phyla:
Porifera:
No symmetry at all
No nerve or muscle tissue, sessile (nonmotile)
Filter nutrients from water drawn into a central cavity
Like many other primitive organisms, they only have 2 cell layers, ectoderm and endoderm, with the noncellular mesoglea holding them together
They have specialized cells, however, there is no organization to the cells, therefore they do not have tissue or organs.
Evolved from colonial organisms: fun fact, you can push a sponge through a cheesecloth, which will separate into individual cells, all and become a sponge. This is related to how a sponge reproduces
They reproduce asexually via fragmentation, meaning each piece that is separated has the necessary cells to become an individual organism. This means that technically,
Spongebob is reproducing here. Good on him.
They also reproduce sexually. They are hermaphrodites, meaning that they have characteristics of both males and females.
Cnidarians
Include organisms like hydra and jellyfish
Radial symmetry
Body plan is a polyp (vase-shaped, like hydra) which is mostly sessile or medusa (upside-down bowl-shaped, like jellyfish) which is mostly motile.
Life cycle- although there are exceptions, some go through a planula larva (free-swimming) stage, then proceed to their reproductive stage, that being asexual (polyps, ) or sexual (medusas)
Only have ectoderm and endoderm cell layers
Have a gastrovascular cavity where extracellular digestion occurs. They only have one opening to this cavity, so waste and food both go through the mouth.
Have lysosomes where intracellular digestion occurs.
No transport system, since each cell is in contact with the outside environment.
All have stinging cells (cnidocytes) for protection, with nematocysts, which are stingers.
Platyhelminthes
Include organisms like flatworms like tapeworms
These are the most simple organisms with bilateral symmetry, an anterior end, and 3 distinct cell layers (ectoderm, endoderm, and mesoderm… yay bones muscle and blood!)
The digestive cavity has only 1 opening for egestion and ingestion, like cnidaria, so food can’t be continuously processed.
Their body is solid and has no room for a true digestive and respiratory system to circulate food or oxygen. The solution to this problem was to develop an extremely flat and thin body that allowed most of their body cells to have contact with the outside and thus exchange nutrients and waste via diffusion.
Nematodes
Include roundworms like pinworms
Unsegmented worms with bilateral symmetry, but very little sensory apparatus.
A large majority of them are parasitic. Trichinosis is caused by the worm Trichinella, which is often found in uncooked pork.
C. elegans is often used as an animal model when studying genes and embryonic development.
Digestive tract is two way, meaning they have a mouth and an anus
Annelids
Include earthworms and leeches
Segmented worms with bilateral symmetry, and very little sensory apparatus.
Two-way digestive tract, and a tube within a tube, consisting of a crop, gizzard, and intestine.
They have a nephridium, which is a tubule responsible for the excretion of nitrogen waste, urea.
They have a closed circulatory system and a heart with 5 pairs of aortic arches
Diffuse oxygen and carbon dioxide through their moist skin
Hermaphrodites
Mollusca
Include squids, octopi, slugs, clams and snails.
Have soft bodies, protected by hard calcium shells
They have open circulatory systems. This means they don’t have capillaries, however, have blood-filled spaces called hemocoels, or sinuses.
Have bilateral symmetry and 3 distinct body zones: The head-foot, with sensory and motor organs, Visceral mass, with organs of digestion, excretion, and reproduction, and the mantle, a specialized tissue that surrounds the visceral mass and produces the shell.
They have something known as a radula, which is moveable and has teeth, that behaves like a tongue.
Many have gills and nephridia
Arthropods
Include insecta (like grasshoppers), crustacea (like shrimp and crabs), and arachnida (like spiders and scorpions
Have jointed appendages
Segmented into head, thorax, and abdomen
Contain more sensory apparatuses than annelids which means they can move much more freely
Have an exoskeleton made of a polysaccharide known as chitin.
They also have an open circulatory system, with a tubular hard and hemocoels
For excretion, they have structures known as Malpighian tubules, which remove the nitrogenous waste; uric acid.
They have air ducts known as trachea which bring air from the environment into hemocoels.
Echinoderms
Include sea stars and sea urchins.
Most are sessile, or slow-moving (so stop judging Patrick. It’s just how he was born)
They are an exception to the bilateral symmetry rule. As embryos, they have bilateral symmetry, however, as they develop, they develop radial symmetry. This evolved for their sedentary lifestyle.
They have a water vascular system, which creates hydrostatic support for their tube feet which allow for locomotion
They reproduce sexually via external fertilization
They also have the ability to reproduce asexually via fragmentation, and regeneration. As long as the new sea star has part of the central canal, it will become a new organism.
They have an endoskeleton with calcium plates. Endoskeletons grow with the body, as opposed to exoskeletons that have to be shed
Chordates
Include vertebrae (like us!)
Chordates have a notochord which is a rod that extends the length of the body and is a flexible axis.
They have a dorsal, hollow nerve cord
The tail is responsible for movement and balance. We, humans, have a coccyx, which is a vestige of what was once our tail. Hence the name, tailbone.
Birds and mammals are homeotherms, meaning they are able to maintain consistent body temperature. The other chordates, like fish, reptiles, and amphibians are cold-blooded.
Let’s get specific, with mammals (because mammals are a superior class of animals. I would know, I am one.)
Mammals are named after their mammary glands. These glands let mothers provide milk to their babies.
They all have hair or fur
They are endotherms, meaning they generate their hair from within
Most are placental mammals, also known as eutherians. The embryo develops internally in a uterus connected to the mother via a placenta. Since the embryo is unable to perform essential functions such as digestion and excretion by itself, until late into the pregnancy, the placenta diffuses nutrients in and waste out for the baby.
Marsupials are an interesting class of animals. Their babies are born extremely early in development (after about 36 days), however, the mother has a pouch, where the baby will nurse until around 9 months.
Most mammals give birth to live young. There are exceptions to this rule, as our favourite egg-laying mammal of action’s theme explained to us. (Dooby dooby dooa dooby dooby dooaa AGENT P!)
Platypi and spiny anteaters derive their nutrients from a shelled egg.
Getting even more specific, let’s talk about primates. These are the least superior mammals. I should know. I am one.
Primates were descendants of insectivores. They have dexterous hands, and opposable thumbs, which allow their hands to perform fine motor tasks. Instead of claws, they have nails
Their hands contain many nerve endings, making them very sensitive (which is why papercuts are so agonizingly painful.) Their eyes are forward-facing and close together. This allows face to face communication. Close eyes allow for overlapping fields of vision, increasing depth perception and hand-eye coordination.)
Primates engage in the most intensive parenting out of any mammal. They tend to have single births and build strong bonds with their young.
The book organized 3 different organisms based on their taxonomy. I put that down and added rats because rats are cool. Don’t @ me.
Cladograms
Cladograms are an extremely useful tool to show how organisms evolved different traits over time. There is a more complicated one above, however, the book included an extremely simplified one also that helped me understand how these graphs are made, so I will include that here as well.
First, like any graph, a table is made detailing the data that will be graphed. In this case, this data will be the specific organisms (cats, lizards, salmons, and earthworms) and the existence of specific traits (backbone, legs, and hair.)
Then a line is drawn, showing each trait as it developed, following by the organism with that trait.
What this graph shows is that cats and lizards are more related than lizards and earthworms, etc. Tldr; a cladogram/phylogenetic tree draws distinctions between shared traits (traits different organisms have in common) and derived traits (traits that the ancestor did not have) displayed in such a way so as to show the evolutionary history of a group of organisms.
So what qualifies an animal? Animals are multicellular eukaryotes. They are all heterotrophs, meaning they acquire nutrients via ingestion. (Unlike plants, which manage to get nutrients through photosynthesis, such as the Calvin Cycle which produces a plants sugar.) All animals can move in some form.
Movement is a broad term. Beating cilia, and waving tentacles both count as movement. The movement that often comes to peoples minds, however, is locomotion, which is the movement from place to place. Some animals are sessile, which means they lack the capability to move from place to place. Hydra can still wave their tentacles (in the air like they just don’t care). Sponges are an interesting case, as many legitimately, cannot move.
Above, I mentioned terms like endoskeletons, exoskeletons, and hydrostatic skeletons. Hydrostatic skeletons are closed body compartments filled with fluid, that provide support. Exoskeletons are external, nongrowing skeletons, made of chitin (which also makes up the cell walls of fungi). Endoskeletons are internal skeletons made of bone and cartilage that grow with the organism. They are connected to each other at joints via ligaments, and to skeletal muscles (voluntary muscles) via the tendons.
All life has the ability to maintain homeostasis. Life survives within a narrow temperature range, from around 0 degrees Celsius to around 50 degrees celsius. In the ocean, this was not a massive problem, as it is the most stable environment temperature-wise, as water is able to absorb a lot of heat. However, the land is a lot more crazy. Different organisms found different ways to adapt and survive.
For example, a jackrabbit’s ears are a major tell about what climate they live in. Jackrabbits that survive in the cold have small ears to minimize heat loss. Jackrabbits living in the heat have large ears that allow heat to dissipate, filled with small capillaries making the ears appear pink.
Huddling, basking, panting and sweating, swarming, and shivering are all examples of adaptations different organisms use to survive in extreme temperature. Depending on whether an organism is an ectotherm or endotherm, their temperature regulation will be different. An ectotherm is heated from the outside. For example, crocodiles bask in the warm sun to heat their bodies up. Endotherms or homeotherms generate their heat from the inside by using large quantities of energy. For example, a litter of cold puppies will huddle together and with their mother, as their warmth, and their mothers warmth help heat them up.
Excretion refers to the removal of metabolic waste, such as excess water, carbon dioxide, and nitrogenous waste. There are 3 different kinds produced by different organisms
Ammonia
Ammonia is soluble in water and extremely toxic. Anybody who takes proper care of a fish tank is aware that cleaning the ammonia from their tank is essential in keeping their fish healthy.
Excreted mainly by marine life, like hydra and fish.
Urea
Not as toxic as ammonia
Excreted by earthworms and humans (urine contains urea and water)
In mammals, the liver is responsible for turning ammonia into urea.
Uric Acid
A paste-like substance that isn’t soluble, and not very toxic
Excreted by insects, many reptiles, and birds, and allow for the preservation of water.
Different organisms have different structures that allow for excretion.
Hydra excretes ammonia with no aid from any excess structure.
Platyhelminthes have flame cells that help them excrete ammonia
Earthworms have nephridia (metanephridia) to excrete Urea
Insects have Malpighian tubules to excrete uric acid
Humans have nephrons to excrete urea.
Following up, let’s look at 3 different organisms and the characteristics that make them unique!
Hydra (from Cnidaria)
Hyrda digest their food in the gastrovascular cavity. They, unfortunately only have one hole, where food goes in and waste comes out. The gastrodermis (gastrovascular cavity lining, or gastrocoel) secrete digestive enzymes to help extracellular digestion progress. Lysosomes, which are found in animal cells are responsible for intracellular digestion.
Hydra reproduces asexually by budding. A bud is a genetically identical, but tiny little hydra that grows within or on the parent.
Earthworms (From Annelida)
The digestive system of earthworms is much more complex than that of the hydra. Luckily, they have a mouth and an anus. The mouth ingests decaying organic matter along with the soil. The food travels down the oesophagus into the crop. The crop stores the food until it is ready to be digested. The food then moves into the gizzard, with thick muscular walls that digest the food mechanically, with the aid of the ingested sand and soil. The food moves into the intestines, where chemical digestion occurs. The intestine has a large fold, called the typhlosole, which increases the surface area.
Worms don’t have a traditional respiratory system. Instead, gas is exchanged by diffusion, through moist skin. This type of respiratory system is called an external respiratory system. Their hearts have 5 aortic arches that pump blood. Worms have capillaries, giving them a closed circulatory system. Their blood contains haemoglobin, making it red. Earthworms have nephridia, excreting urea, and are hermaphrodites. A worms brain is made of two dorsal, solid, fused ganglia, with a solid, ventral, nerve cord.
Grasshoppers (From Arthropoda)
Grasshoppers also have a digestive tract consisting of a crop and gizzard. They also have mouthparts specialized for tasting, biting, and crushing food, and their gizzard has chitin plates that aid in mechanical digestion. Their digestive tract contains Malpighian tubules that remove nitrogenous waste in the form of uric acid. (No, I did not draw a grasshopper. I know when I am defeated.)
Grasshoppers have a similar nervous system to worms, however, they have an open circulatory system. They lack capillaries, and blood moves through hemocoels instead. Arthropod blood has no haemoglobin. They have an internal respiratory surface because gas exchange occurs on the inside. They have a system of tracheal tubes that lead to the hemocoels. Oxygen is carried by hemocyanin, with copper as the core atom. This is why molluscs and insects have blue blood.
The circulatory system: dissection of the stomach and intestines, with the arteries and veins indicated in red and blue. Coloured lithograph by Joseph Maclise, 1841/1844.
ELISA
Enzyme-linked immunosorbent assay is a plate-based assay technique used to detect substances such as proteins, peptides and hormones.
An antigen is immobilized on a solid surface
It is complexed with an antibody that is linked to an enzyme.
The conjugated enzyme activity is assessed via incubation with a substrate.
Which produces a product that can be measured.
Direct ELISA
Antigen is coated directly to wells of microtitre plate
an enzyme-labelled primary antibody that detects the antigen is added.
Advantages
Fast and minimal steps needed.
Minimum precursor requirement makes it less error prone.
Disadvantages
The immobilization of the antigen is not specific - background interference.
Less flexibility of primary antibody.
No signal amplification –> less sensitivity.
Indirect ELISA
An enzyme labelled secondary antibody interacts with a primary antibody to increase sensitivity.
Advantages
Offers high sensitivity and flexibility as a secondary antibody can label different primary antibodies
It is cheap (fewer labelled antibodies needed)
Disadvantages
Increased background noise from the secondary antibody.
Extra labour.
Sandwich ELISA
Capture antibody bound to surface.
Antigen-containing sample is applied and captured.
A specific antibody is added, and binds to antigen (sandwiching the antigen between 2 antibodies).
Enzyme-linked secondary antibodies are used as detection antibodies.
Advantages
Offers high sensitivity and a highly specific reaction due to 2 antibodies (both have to bind to the antigen).
Disadvantages
For recognition of a specific epitope, only monoclonal antibodies can be applied as matched pairs.
Procuring monoclonal antibodies is difficult and expensive.
Strap in for a Tour of the Milky Way
The night sky isn’t flat. If you traveled deep into this part of the sky at the speed of the radio waves leaving this tower, here are some places you could reach.
Jupiter: Travel time – 35 minutes, 49 seconds.
The closest object in this view is the planet Jupiter, brilliant now in the evening sky…and gorgeous when seen up close by our Juno spacecraft. Distance on the night this picture was taken: 400 million miles (644 million kilometers).
Saturn: Travel time – one hour and 15 minutes.
The next closest is Saturn, another bright “star” in this summer’s sky. On the right, one of the Cassini spacecraft’s last looks. Distance: 843 million miles (1.3 billion kilometers).
Pluto: Light-speed travel time from the radio tower – four hours, 33 minutes.
It’s not visible to the unaided eye, but Pluto is currently found roughly in this direction. Our New Horizons space mission was the first to show us what it looks like. Distance: more than 3 billion miles.
F-type star, HD 1698330: Light-speed travel time from the radio tower – 123 years.
Within this patch of sky, there’s an F-type star called HD 169830. At this speed, it would take you 123 years to get there. We now know it has at least two planets (one of which is imagined here) — just two of more than 4,000 we’ve found…so far.
The Lagoon Nebula: Light-speed travel time from the radio tower – 4,000 years.
If you look closely, you’ll see a fuzzy patch of light and color here. If you look *really* closely, as our Hubble Space Telescope did, you’ll see the Lagoon Nebula, churning with stellar winds from newborn stars.
Black hole, Sagittarius A*: Light-speed travel time from the radio tower – 26,000 years.
In 26,000 years, after passing millions of stars, you could reach the center of our galaxy. Hidden there behind clouds of dust is a massive black hole. It’s hidden, that is, unless you use our Chandra X-ray Observatory which captured the x-ray flare seen here.
The next time you’re under a deep, dark sky, don’t forget to look up…and wonder what else might be out there.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
If someone is attractive and charming, you’re more likely to assume they’re intelligent and hard working- even if they’re not.
Known as the ‘Halo Effect’, it’s a theory that our generalized judgements of people can bleed over into the more specific judgements we make about them. Studies show that even though we understand the Halo Effect intellectually, it’s almost impossible for us to recognize when it’s actually happening.
(Source, Source 2)
Dirty thunderstorm
A dirty thunderstorm (also volcanic lightning, thunder volcano) is a weather phenomenon that is related to the production of lightning in a volcanic plume.
A study in the journal Science indicated that electrical charges are generated when rock fragments, ash, and ice particles in a volcanic plume collide and produce static charges, just as ice particles collide in regular thunderstorms.
Volcanic eruptions are sometimes accompanied by flashes of lightning. However, this lightning doesn’t descend from storm clouds in the sky. It is generated within the ash cloud spewing from the volcano, in a process called charge separation.
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It’s a baby bat ray brunch! Using plate-like teeth to grind and chew their sustainable seafood, these youngsters will grow quickly into their role as majestic sea flap flaps.
Sleep is your superpower | Matt Walker
Sleep is your life-support system and Mother Nature’s best effort yet at immortality, says sleep scientist Matt Walker. In this deep dive into the science of slumber, Walker shares the wonderfully good things that happen when you get sleep – and the alarmingly bad things that happen when you don’t, for both your brain and body. Learn more about sleep’s impact on your learning, memory, immune system and even your genetic code – as well as some helpful tips for getting some shut-eye.
Chandra X-Ray Observatory, We Appreciate You
On July 23, 1999, the Space Shuttle Columbia blasted off from the Kennedy Space Center carrying the Chandra X-ray Observatory. In the two decades that have passed, Chandra’s powerful and unique X-ray eyes have contributed to a revolution in our understanding of the cosmos.
Since its launch 20 years ago, Chandra’s unrivaled X-ray vision has changed the way we see the universe.
Chandra has captured galaxy clusters – the largest gravitationally bound objects in the universe – in the process of merging.
Chandra has shown us the powerful wind and shock fronts that rumble through star-forming systems.
And a star school, so to speak – home to thousands of the Milky Way’s biggest and brightest.
Carl Sagan said, “We are made of star-stuff.“ It’s true. Most of the elements necessary for life are forged inside stars and blasted into interstellar space by supernovas. Chandra has tracked them.
Thank you Chandra X-Ray! To more adventures with you!
Check out Chandra’s 20th anniversary page to see how they are celebrating.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.
▪︎Copernican armillary sphere.
Date: 1807-1846
Place of origin: Paris
From the source: Copernican armillary sphere from set of two armillary spheres and a celestial globe constructed in paper on pasteboard with metal fitments supported on a decorative mahogany baluster base. Shows planets out to Uranus, plus four asteroids, Ceres, Pallas, Juno & Vesta, first quarter 19th century.
How do you observe that the Universe is expanding?
In 2011, the Nobel Prize in Physics was awarded to Saul Perlmutter, Brian Schmidt and Adam Riess for discovering that the Universe is expanding at an accelerating rate. We’d known for a while that the Universe has been expanding ever since its birth - but we didn’t know whether the expansion was slowing down, staying the same, or speeding up.
So, how exactly do you discover something like this?
Perlmutter, Schmidt, and Riess did it by observing a special type of supernovae: Type Ia supernovae. Supernovae are the explosive deaths of large stars, and they usually occur when a star runs out of fuel and collapses under its own weight, generating a shockwave that blasts its material out into space. However, this only happens when a star is big enough - the initial star has to have a critical, threshold mass, called the Chandrasekhar limit. Our sun, for example, won’t go supernova because the Chandrasekhar limit happens to be around 1.4 solar masses. When it runs out of fuel, our sun will instead gently blow off its outer layers and quietly become a dense core of carbon and oxygen, called a white dwarf.
But here’s the kicker: not all white dwarfs stay white dwarfs.
Some white dwarfs exist as one half of a binary system, where two stars orbit each other in a perpetual celestial dance. In some situations, the white dwarfs can actually “steal” matter from their partner star, siphoning it off and guzzling it up to grow more and more massive. Eventually, when their mass hits the Chandrasekhar limit, the white dwarf is ripped apart in a supernova.
Image Credit
This happens in binary systems all across the Universe, and because these white dwarfs all go supernova at exactly the same mass, this means we know exactly how bright the supernovae are. When they’re observed through telescopes, some look brighter and some look fainter depending on their distance - but because we know their actual intrinsic brightness, we can work out how far away they really are. (You could do this yourself using a more earthly standard candle.) For this reason, Type Ia supernovae are called “standard candles”.
In their observations, Perlmutter, Schmidt, and Riess realised that far away supernovae were more redshifted than the supernovae close by. “Redshift” is essentially a measure of how much the Universe has expanded since the light left the supernovae, so by comparing the distance and the redshift of the supernovae, they could create an “expansion history” of the Universe.
This showed pretty clearly that the universe isn’t just expanding, it’s accelerating - i..e, everything’s flying apart more quickly than it was yesterday, or a century, or a billion years ago. Why? Dark energy.
FAMOUS AUTHORS
Classic Bookshelf: This site has put classic novels online, from Charles Dickens to Charlotte Bronte.
The Online Books Page: The University of Pennsylvania hosts this book search and database.
Project Gutenberg: This famous site has over 27,000 free books online.
Page by Page Books: Find books by Sir Arthur Conan Doyle and H.G. Wells, as well as speeches from George W. Bush on this site.
Classic Book Library: Genres here include historical fiction, history, science fiction, mystery, romance and children’s literature, but they’re all classics.
Classic Reader: Here you can read Shakespeare, young adult fiction and more.
Read Print: From George Orwell to Alexandre Dumas to George Eliot to Charles Darwin, this online library is stocked with the best classics.
Planet eBook: Download free classic literature titles here, from Dostoevsky to D.H. Lawrence to Joseph Conrad.
The Spectator Project: Montclair State University’s project features full-text, online versions of The Spectator and The Tatler.
Bibliomania: This site has more than 2,000 classic texts, plus study guides and reference books.
Online Library of Literature: Find full and unabridged texts of classic literature, including the Bronte sisters, Mark Twain and more.
Bartleby: Bartleby has much more than just the classics, but its collection of anthologies and other important novels made it famous.
Fiction.us: Fiction.us has a huge selection of novels, including works by Lewis Carroll, Willa Cather, Sherwood Anderson, Flaubert, George Eliot, F. Scott Fitzgerald and others.
Free Classic Literature: Find British authors like Shakespeare and Sir Arthur Conan Doyle, plus other authors like Jules Verne, Mark Twain, and more.
TEXTBOOKS
Textbook Revolution: Find biology, business, engineering, mathematics and world history textbooks here.
Wikibooks: From cookbooks to the computing department, find instructional and educational materials here.
KnowThis Free Online Textbooks: Get directed to stats textbooks and more.
Online Medical Textbooks: Find books about plastic surgery, anatomy and more here.
Online Science and Math Textbooks: Access biochemistry, chemistry, aeronautics, medical manuals and other textbooks here.
MIT Open Courseware Supplemental Resources: Find free videos, textbooks and more on the subjects of mechanical engineering, mathematics, chemistry and more.
Flat World Knowledge: This innovative site has created an open college textbooks platform that will launch in January 2009.
Free Business Textbooks: Find free books to go along with accounting, economics and other business classes.
Light and Matter: Here you can access open source physics textbooks.
eMedicine: This project from WebMD is continuously updated and has articles and references on surgery, pediatrics and more.
MATH AND SCIENCE
FullBooks.com: This site has “thousands of full-text free books,” including a large amount of scientific essays and books.
Free online textbooks, lecture notes, tutorials and videos on mathematics: NYU links to several free resources for math students.
Online Mathematics Texts: Here you can find online textbooks likeElementary Linear Algebra and Complex Variables.
Science and Engineering Books for free download: These books range in topics from nanotechnology to compressible flow.
FreeScience.info: Find over 1800 math, engineering and science books here.
Free Tech Books: Computer programmers and computer science enthusiasts can find helpful books here.
CHILDREN’S BOOKS
byGosh: Find free illustrated children’s books and stories here.
Munseys: Munseys has nearly 2,000 children’s titles, plus books about religion, biographies and more.
International Children’s Digital Library: Find award-winning books and search by categories like age group, make believe books, true books or picture books.
Lookybook: Access children’s picture books here.
PHILOSOPHY AND RELIGION
Bored.com: Bored.com has music ebooks, cooking ebooks, and over 150 philosophy titles and over 1,000 religion titles.
Ideology.us: Here you’ll find works by Rene Descartes, Sigmund Freud, Karl Marx, David Hume and others.
Free Books on Yoga, Religion and Philosophy: Recent uploads to this site include Practical Lessons in Yoga and Philosophy of Dreams.
The Sociology of Religion: Read this book by Max Weber, here.
Religion eBooks: Read books about the Bible, Christian books, and more.
PLAYS
ReadBookOnline.net: Here you can read plays by Chekhov, Thomas Hardy, Ben Jonson, Shakespeare, Edgar Allan Poe and others.
Plays: Read Pygmalion, Uncle Vanya or The Playboy of the Western World here.
The Complete Works of William Shakespeare: MIT has made available all of Shakespeare’s comedies, tragedies, and histories.
Plays Online: This site catalogs “all the plays [they] know about that are available in full text versions online for free.”
ProPlay: This site has children’s plays, comedies, dramas and musicals.
MODERN FICTION, FANTASY AND ROMANCE
Public Bookshelf: Find romance novels, mysteries and more.
The Internet Book Database of Fiction: This forum features fantasy and graphic novels, anime, J.K. Rowling and more.
Free Online Novels: Here you can find Christian novels, fantasy and graphic novels, adventure books, horror books and more.
Foxglove: This British site has free novels, satire and short stories.
Baen Free Library: Find books by Scott Gier, Keith Laumer and others.
The Road to Romance: This website has books by Patricia Cornwell and other romance novelists.
Get Free Ebooks: This site’s largest collection includes fiction books.
John T. Cullen: Read short stories from John T. Cullen here.
SF and Fantasy Books Online: Books here include Arabian Nights,Aesop’s Fables and more.
Free Novels Online and Free Online Cyber-Books: This list contains mostly fantasy books.
FOREIGN LANGUAGE
Project Laurens Jz Coster: Find Dutch literature here.
ATHENA Textes Francais: Search by author’s name, French books, or books written by other authors but translated into French.
Liber Liber: Download Italian books here. Browse by author, title, or subject.
Biblioteca romaneasca: Find Romanian books on this site.
Bibliolteca Virtual Miguel de Cervantes: Look up authors to find a catalog of their available works on this Spanish site.
KEIMENA: This page is entirely in Greek, but if you’re looking for modern Greek literature, this is the place to access books online.
Proyecto Cervantes: Texas A&M’s Proyecto Cervantes has cataloged Cervantes’ work online.
Corpus Scriptorum Latinorum: Access many Latin texts here.
Project Runeberg: Find Scandinavian literature online here.
Italian Women Writers: This site provides information about Italian women authors and features full-text titles too.
Biblioteca Valenciana: Register to use this database of Catalan and Valencian books.
Ketab Farsi: Access literature and publications in Farsi from this site.
Afghanistan Digital Library: Powered by NYU, the Afghanistan Digital Library has works published between 1870 and 1930.
CELT: CELT stands for “the Corpus of Electronic Texts” features important historical literature and documents.
Projekt Gutenberg-DE: This easy-to-use database of German language texts lets you search by genres and author.
HISTORY AND CULTURE
LibriVox: LibriVox has a good selection of historical fiction.
The Perseus Project: Tufts’ Perseus Digital Library features titles from Ancient Rome and Greece, published in English and original languages.
Access Genealogy: Find literature about Native American history, the Scotch-Irish immigration in the 19th and 20th centuries, and more.
Free History Books: This collection features U.S. history books, including works by Paul Jennings, Sarah Morgan Dawson, Josiah Quincy and others.
Most Popular History Books: Free titles include Seven Days and Seven Nights by Alexander Szegedy and Autobiography of a Female Slave by Martha G. Browne.
RARE BOOKS
Questia: Questia has 5,000 books available for free, including rare books and classics.
ARTS AND ENTERTAINMENT
Books-On-Line: This large collection includes movie scripts, newer works, cookbooks and more.
Chest of Books: This site has a wide range of free books, including gardening and cooking books, home improvement books, craft and hobby books, art books and more.
Free e-Books: Find titles related to beauty and fashion, games, health, drama and more.
2020ok: Categories here include art, graphic design, performing arts, ethnic and national, careers, business and a lot more.
Free Art Books: Find artist books and art books in PDF format here.
Free Web design books: OnlineComputerBooks.com directs you to free web design books.
Free Music Books: Find sheet music, lyrics and books about music here.
Free Fashion Books: Costume and fashion books are linked to the Google Books page.
MYSTERY
MysteryNet: Read free short mystery stories on this site.
TopMystery.com: Read books by Edgar Allan Poe, Sir Arthur Conan Doyle, GK Chesterton and other mystery writers here.
Mystery Books: Read books by Sue Grafton and others.
POETRY
The Literature Network: This site features forums, a copy of The King James Bible, and over 3,000 short stories and poems.
Poetry: This list includes “The Raven,” “O Captain! My Captain!” and “The Ballad of Bonnie and Clyde.”
Poem Hunter: Find free poems, lyrics and quotations on this site.
Famous Poetry Online: Read limericks, love poetry, and poems by Robert Browning, Emily Dickinson, John Donne, Lord Byron and others.
Google Poetry: Google Books has a large selection of poetry, fromThe Canterbury Tales to Beowulf to Walt Whitman.
QuotesandPoem.com: Read poems by Maya Angelou, William Blake, Sylvia Plath and more.
CompleteClassics.com: Rudyard Kipling, Allen Ginsberg and Alfred Lord Tennyson are all featured here.
PinkPoem.com: On this site, you can download free poetry ebooks.
MISC
Banned Books: Here you can follow links of banned books to their full text online.
World eBook Library: This monstrous collection includes classics, encyclopedias, children’s books and a lot more.
DailyLit: DailyLit has everything from Moby Dick to the recent phenomenon, Skinny Bitch.
A Celebration of Women Writers: The University of Pennsylvania’s page for women writers includes Newbery winners.
Free Online Novels: These novels are fully online and range from romance to religious fiction to historical fiction.
ManyBooks.net: Download mysteries and other books for your iPhone or eBook reader here.
Authorama: Books here are pulled from Google Books and more. You’ll find history books, novels and more.
Prize-winning books online: Use this directory to connect to full-text copies of Newbery winners, Nobel Prize winners and Pulitzer winners.
Festo’s Bionic Flying Fox, as an example of Bio-mimicry.
German automation company Festo has created a Flying Fox (Fruit Bat) made of a 580g foam body with a carbon fibre skeleton and a membrane like material for the wings.
This robot imitates the exact body and wing movements of an actual bad in order for it to fly. This idea of bio-mimicry is one that is paving the way for a host of natural moving, nature inspired machines.
How To Help Your Anxious Partner — And Yourself
Living with anxiety can be tough — your thoughts might race, you might dread tasks others find simple (like driving to work) and your worries might feel inescapable. But loving someone with anxiety can be hard too. You might feel powerless to help or overwhelmed by how your partner’s feelings affect your daily life.
If so, you’re not alone: Multiple studies have shown that anxiety disorders may contribute to marital dissatisfaction.
“We often find that our patients’ … partners are somehow intertwined in their anxiety,” says Sandy Capaldi, associate director at the Center for the Treatment and Study of Anxiety at the University of Pennsylvania.
Anxiety is experienced at many different levels and in different forms — from moderate to debilitating, from generalized anxiety to phobias — and its impacts can vary. But psychiatrists and therapists say there are ways to help your partner navigate challenges while you also take care of yourself.
Read the full story here
I’ve been receiving tonnes of questions on Note - Taking recently, so I’d thought I make a post. Plus, I had fun making these graphics.
There are three different methods that I prefer when it comes to note taking:
Notes written During the Lecture
I highly recommend taking notes during the lecture.
I also use abbreviations for quicker and more efficient note taking. Some examples of abbreviation that I use are:
w/ - With
w/o - Without
e.g. - For example
Notes written After the Lecture
As for notes written after the lecture, I tend to seek the help of Google Spreadsheets or Microsoft Excel. This way I am able to organise information learnt. I do this by dividing the information provided into two columns, one for keywords or questions and the other for definitions and answers.
*Note: This method was adapted from the note taking method I’ve used during college.
Rewritten Notes
I also rewrite my notes. My rewritten notes are arranged based on the order they appear in the syllabus unless there are pieces of information that are related to more than one topic.
I use a black pen or pencil for my written notes, as well as coloured pens and highlighters to highlight the key words and terminologies for emphasise.
Before writing them down, I tend to visualise the layout - alternating between words and pictures/diagram. This definitely helps me with remembering for exams. All I have to do is imagine that I’m looking at that page and I can remember where everything is.
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Please click on the images for a much clearer view.
Well, that’s all from me! I hope that you found this information helpful. And, don’t hesitate to ask me questions if you’re confused about this method of note-taking, or any other problems you might have. For more information of how to survive university, follow this page. And, for more medical school chronicles, follow me on IG. Follow my studygram/medgram for more content.
How a blobfish looks with and without extreme water pressure. Blobfish live in water pressures 60-120 times greater than sea level.
wait what
…
turns out that pack rats (Neotoma sp.) creates these big middens which they urinate on. The urine then crystallizes over time, creating amber-like deposits. Some of the ones found in caves are 50.000 years old and contains intact plant material, allowing scientists to analyse the prehistoric flora.
the dark deposits in the middle are 10.000+ year old crystallized rat piss
what a world