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For a long time, scientists have assumed that plants became more complex as seeds and flowers made their way. A new study has revealed that this actually happened in two bursts with a long period stasis in between.

The study, led by researchers at Stanford University, reveals that evolution in land plants didn't take place gradually over hundreds of millions of years. Instead, land plants had two dramatic bursts nearly 250 million years apart. After the first one occurred early in plant history and gave rise to the development of seeds, there was a long lull in between before the second burst, which saw the diversification of flowering plants.

The difference in complexity between flowering plants and non-flowering plants is so stark that botanists have long focussed on characteristics within these groups and studying their evolution separately. This is because flowers are more diverse and intricate than anything else in plants.

A flowery problem

To overcome these differences, the researchers in this study designed a system that classified the number of different parts in the plants reproductive structures. This was done based on observation alone and then each species was scored based on how many types of parts it has and the degree to which it exhibited clustering. The researchers were able to categorise 1.300 land species from about 420 million years ago until the present.

250-million-year hiatus

Based on this technique, the researchers were able to show that land plants first diversified about 420 million to 360 million years ago with the onset of early seed plants. And even though insect pollination and animal seed dispersal might have appeared as early as 300 million years ago, it was only about 100 million years ago that the complexity of flowering plants came about The unique nature of flowering plants meant that the second burst of evolution was much more dramatic than the first.

Thus, by using a simple but novel metric, plants were classified based on the arrangement and number of parts in their reproductive system. Once that was achieved, the researchers were able to show that between the initial evolution of seeds and the total change that happened with flowering plants, there was a period of stasis that extended for nearly 250 million years when there was hardly any change. These findings were published in Science in September 2021 and offer insights into the timing and magnitude of these changes.

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October 6, 2021, marks a historic day in humanity's fight against malaria, as the World Health Organization (WHO) approved the rollout of the malaria vaccine, RTS.S/AS01 (RTS.S) among children living in sub-Saharan Africa and other at-risk regions.

Malaria is a deadly infectious disease that claims more than 4 lakh lives every year around the world. It is caused by Plasmodium parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes, called the malaria vector. Among the five parasite species that cause malaria in humans, Plasmodium falciparum and Plasmodium vivax pose the greatest threat.

Who will get the vaccines and how efficient is it in preventing the spread of malaria?

WHAT is RTS,S/AS01?

RTS,S/AS01 or Mosquirix (trade name) has been developed by British drug manufacturer GlaxoSmithKline in collaboration with Seattle-based health non-profit PATH and a network of African research centres, with partial funding from the Bill and Melinda Gates Foundation. The vaccine is the result of 30 years of research and it targets Plasmodium falciparum, the most common parasite causing malaria in Africa. The vaccine offers no protection against the other four species such as P vivax, P ovale, P knowlesi and P malariae which are prevalent in Southeast Asia, Americas and Europe.

RTS,S was created in 1987 by scientists working in GlaxoSmithKline laboratories. The European Medicines Agency issued a positive scientific opinion on the vaccine in July 2015, concluding that the benefits of the vaccine outweigh the risks

RTS.S has been rigorously tested through a series of clinical trials since 2019 in seven African countries (Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique, and Tanzania).

Who is it for?

The WHO has recommended that the RTS,S/AS01 malaria vaccine be used for the prevention of P. falciparum malaria in children living in regions with moderate to high transmission as defined by it. The vaccine has been recommended to be provided in a schedule of four doses in children from 5 months of age.

What is its efficacy?

The current approval of the vaccine is based on the results of the ongoing pilot programme in Ghana, Kenya and Malawi. More than 2.3 million doses of the vaccine have been administered in these countries so far as part of the pilot. The following observations have been made since:

• The vaccine offers 39% protection against malaria in children between the ages of five and 17 months.
• The vaccine prevents approximately 4 in 10 (39%) cases of malaria and about 3 in 10 (29%) cases of severe malaria.
• There is significant reductions in overall malaria admissions as well as malaria-induced anaemia.
• The vaccine also reduced the need for blood transfusions, which are required to treat life-threatening malaria anaemia by 29%.

How does the vaccine work?

RTS,S works by introducing the immune system to a fragment of a protein that is naturally present on the surface of Plasmodium parasite when it enters the bloodstream through an infected mosquito. The protein in the vaccine stimulates the production of antibodies, and allows the body to mount a swift response to the parasite the next time it is encountered. The vaccine is designed to prevent the parasite from infecting the liver, where it can mature, multiply, re-enter the bloodstream, and infect red blood cells, which can lead to disease symptoms.

Why is developing a vaccine against malaria tough?

Malaria vaccines have been in development since the 1960s, with substantial progress only in the last decade.

• Developing a vaccine against malaria parasite has been a difficult task, chiefly because of the parasite's complex lifecycle and genetical make-up. It has a multistage lifecycle occurring within two living beings, the vector mosquitoes and the vertebrate hosts (humans for instance). The survival and development of the parasite within the invertebrate and vertebrate hosts, in intracellular and extracellular environments, is made possible by more than 5,000 genes and their specialised proteins that help the parasite to invade and grow within multiple cell types and to evade host immune responses. The surface proteins and metabolic pathways keep changing during these different stages, that help the parasite to evade the immune clearance, while also creating problems for the development of drugs and vaccines.
• The technical complexity of developing any vaccine against a parasite is another obstacle.
• With no real market for a malaria vaccine in resource-rich countries like the U.S., pharmaceutical companies did not have a strong financial incentive to accelerate vaccine development. Hence there are a few malaria vaccine developers.

What are the symptoms and consequences of malaria?

Symptoms usually appear 10-15 days after the infective mosquito bite. According to the WHO, the first symptoms-fever, headache, and chills - may be mild and difficult to recognise as malaria. In no time, it can progress into severe illness and possible death.

Children may develop severe anaemia, respiratory distress or cerebral malaria, while adults can face multi-organ failure. Children under 5 years of age are the most vulnerable group affected by malaria.

Some facts about malaria

• There are more than 400 species of Anopheles mosquito, of which around 30 are malaria vectors. All the important vector species bite between dusk and dawn.
• Anopheles mosquitoes lay their eggs in water, usually shallow pools of fresh water, such as puddles, which are abundant during the rainy season in tropical countries. .
• Vector control is the main way to prevent and reduce malaria transmission. The two WHO-recommended methods are - insecticide-treated mosquito nets and indoor residual spraying. Early diagnosis and treatment of malaria reduces disease and prevents deaths.
• Exposure to malaria parasites does not confer lifelong protection.

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The skin is the soft outer cover/organ that forms the outer surface of the body. There are over 4 million pores in the skin. In 1 square inch of skin there lies 4 yards of nerve fibers, 1300 nerve cells, 100 sweat glands, 3 million cells, and 3 yards of blood vessels. Every square inch of the human body has an average of 32 million bacteria on it. Humans shed about 600,000 particles of skin every hour - about 1.5 pounds a year. Most dust particles in your house are made from dead skin. By 70 years of age, an average person will have lost 105 pounds of skin.

Skin shields the body against infection, dehydration, injuries, parasites, and temperature changes. It provides sensory information about the environment, manufactures vitamin D; and excretes salts and small amounts of urea. Skin provides a relatively dry and semi-impermeable barrier to fluid loss. The skin acts as a water resistant barrier so essential nutrients aren't washed out of the body.

Like a big bag of grain that takes shape on what is inside it. The largest human organ is the skin, with a surface area of about 25 square feet.

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The elbow is a complex joint formed by the articulation of three bones –the humerus, radius and ulna. The elbow joint helps in bending or straightening of the arm to 180 degrees and assists in lifting or moving objects.

The elbow can move in three ways based on slight variations in the positions of the heads of the three bones. The first is the large hinge action that is used in most movements of the arms, such as holding bags of groceries or doing bicep curls. The other movements are so small that the untrained eye rarely notices the changes in position, but they are important for motor function of the hand and wrist. Inside and outside the elbow joint, there are points where tendons attach. These tendons allow for wrist and hand movements. For example, they allow the hand to rotate.  The elbow bones are held together primarily by fibrous tissue known as ligaments. The ulnar collateral ligament, or UCL, on the inner side of the joint closest to the body is the primary stabilizer. This thick triangle-shaped band connects the head of the humerus to the heads of the ulna and radius.

The UCL can be torn or completely ruptured, which would cause severe pain on the inside of the elbow, a popping noise, swelling, and bruising. Injuries to the UCL are common among baseball pitchers, football quarterbacks, ice hockey players, and racquet sport players due to the type of motion these sports involve.

The other ligament in the elbow is the radial collateral ligament. Located on the outside of the elbow, it prevents excessive extension of the elbow.

Credit :  Healthline 

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Sloths are the slowest animals in the world. They also happen to be the cutest animals. Sloths are so slow that their name itself means sluggishness or laziness. The top speed of a sloth is 0.003 miles per hour. Also, they are so slow in movement that algae grow on them.

Native to Central America, the three-toed sloth (Bradypodidae bradypus) is the slowest mammal in the world, moving at the hair raising speed of up to 2.4 meters per minute on the ground. When they’re up in their favored canopy these rainforest animals are able to pick up their speed to around a 4.6 meters per minute.

In fact, their top speed is so slow that it’s algae growing on their coats that gives them a greenish tinge. They also have the accolade that their name is a synonym of slow movement!.

Sloths have an incredibly low metabolic rate and need only a few leaves and twigs for nutrition, along with a very slow digestive system leading to their sluggish pace. In combination, the sloth’s anatomical structure differs from other mammals in having very long arms with very short shoulder-blades, which allows them a large reach without the effort of too much movement, and adds to their languid style of movement.

Credit : Safaris 

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If you want to dream up an alien species for the next big sci-fi blockbuster, start with slug anatomy. First, check out the tentacles. Slugs have four, and they’re retractable. Two are for seeing and smelling, and they can be operated independently: a slug can gaze at you (or smell you) and a friend simultaneously. The other two are for touching and tasting.

Slugs also have thousands and thousands of teeth. These tiny chompers are part of a rasping structure called a radula that’s unique to mollusks. And in case that doesn't seem weird enough, slugs essentially breathe through a blowhole that opens up on one side of their bodies. This round pore is called a pneumostome.

But that’s just the anatomy of land-living slugs. Sea slugs have their own incredible features. For example, some breathe using delicate feather-like gills that surround their butt holes, and they smell with neon-colored, bizarrely shaped protrusions called rhinophores.

Credit : Mental Floss

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