What are subtle fluids?

Jean Baptiste Lamarck believed that all bodies had ‘subtle fluids’. These were weightless fluids pervading all space and bodies. Two good examples of eighteenth – century subtle fluids were electricity and heat. Lamarck believed that subtle fluids were responsible for both movement and change. For example, Lamarck pointed out that snails have poor vision because the feelers on their heads acted as their eyes. According to him, the ancestors of snails did not have feelers. They groped about with their heads to find their way around. This groping sent subtle fluids to the front of the head, and the constant presences of moving subtle fluids eventually brought about the development of feelers, and these feelers were passed from generation to generatio 

Butterfly Evidence

         Lamarck supported his theory of evolution with the example of butterflies. According to him, you find different species of butterflies in different places because butterflies in one place acquire certain characteristics to survive in their environment, and pass on these characteristics to the next generation.




Lost Worlds

        The duck billed platypus of Australia is a strange looking bird that was discovered only in 1799. This made several people believe that there might be many other weird animals alive in some remote corner of our planet and that animals that were thought to be extinct might still exist in some unknown place.


Why Apollo 17 is considered the last moon mission?


The Apollo 11 was the first manned mission that successfully landed on the Moon. Manned by three American astronauts, Apollo’s lunar module, the Eagle, landed on the face of the Moon on July 20th, 1969. Neil Armstrong and Edwin Aldrin were the first men to walk on the Moon. Three years later, Apollo 17 was the last Apollo Mission to land men on the Moon. It carried the only trained geologist to walk on the lunar surface – Harrison Schmitt. The Apollo 17 astronauts traversed the greatest distance on the Moon, using the lunar roving vehicle. They also returned the greatest amount of samples of rock and soil. The last human being to walk on the Moon was the Commander of Apollo 17, Eugene Cernan. No humans have visited the Moon since December 14th 1972.

Why is Jean Baptiste de Lamarck a key figure in the history of evolution?

Jean Baptiste Lamarck was a French scientist who developed a theory of evolution at the beginning of the 19th century. His theory involved two ideas. The first was the law of use and disuse, which stated that a characteristic which is used more and more by an organism becomes bigger and stronger, and one that is not used, eventually disappears. The second law was the law of inheritance of acquired characteristics. It stated that any feature of an organism that is improved through use, is passed to its offspring. However, Lamarck’s theory cannot account for all the observations made about life on Earth. For instance, his theory would predict that all organisms gradually become complex and simple organisms disappear. But we know that this is not the case, and that simple organisms still exist. So today, Lamarck’s theory is largely ignored.

What are the evolutionary findings from the Cambrian Period?

The Cambrian explosion is a brief time when most major groups of animals that have bilateral symmetry first appear in the fossil record. Do you know what a bilateral animal is? It is one whose body has two mirror-image halves. Modern examples are lobsters, people, dogs, and butterflies. The event is referred to as an ‘explosion’, because a rich diversity of species appeared in a relatively short amount of time. There is growing evidence that these different groups had a common ancestor that lived during the Cambrian Period. Evidence is growing to support this theory, at least from the fossils that date back to this period. After the Cambrian Period, very few additional animal phyla, or large animal categories, arose.


Why was there an explosion of life during the Cambrian Period?

The Cambrian Period marks an important point in the history of life on Earth. It is the time when most of the major groups of animals first appear in the fossil record. This event is sometimes called the ‘Cambrian Explosion’, because of the relatively short time over which many life forms appeared. Many reasons have been suggested for this explosion. The first is that the increase in oxygen levels in the atmosphere led to the evolution of more complex body structures. Moreover, many species became extinct at the end of the Vendian Period, and this allowed new life forms to develop. It is also thought that a change in the ocean chemistry made possible the development of hard body parts such as teeth and skeletons. Animals could now swim, burrow, defend themselves, hide, and hunt. However, the sea was still the centre of activity.

Why Neptune is considered the last planet to be discovered in our solar system?

neptuneOur solar system consists of the sun, planets, moons, dwarf planets, asteroids, comets, meteors, and others. Of all the planets in our solar system, the six nearest the Sun can be seen with the naked eye. So these planets – Mercury, Venus, Earth, Mars, Jupiter, and Saturn- have been observed since ancient times. The first planet to be discovered using a telescope was Uranus, in 1781. Neptune, the eighth planet was discovered only in 1846. Pluto was discovered in 1930, but it is now not classified as a planet, and so Neptune is considered to be the last planet to be discovered in our solar system


Astronomers have detected what could be a new planet in our solar system. It was first seen by astronomers at California’s Palomar Observatory, and has been given the name ‘Sedna’. Sedna, or 2003 VB 12, as it was originally designated, is the most distant object yet found orbiting our Sun. however, there is some debate as to whether it is a true planet, or a planetoid like Pluto.

What is the Cambrian period?

The Cambrian Period lasted for nearly 53 million years, from about 543 million years ago, until 490 million years ago. The continents were still forming, but were mostly barren rocks. The land had no plant or animal life on it yet. During the Cambrian Period, there was an explosion of life forms. Most of these were in the water. Many animals with no backbones lived in the shallow seas. The most plentiful species during this period were trilobites. The species got its name from the three lobes in the hard skin. The trilobite was also one of the first animals to have eyesight. There were plenty of other species living during the Cambrian Period also. Molluscs, worms, sponges and echinoderms filled the Cambrian seas. The plants of the Cambrian were mostly simple, one-celled algae.The Cambrian period ended in a mass extinction. Advancing glaciers would have lowered the temperature of the shallow seas where so many species lived. Changes in the temperature and the amount of oxygen in the water would have meant the end for any species that could not adapt.

Rarely Fossilized

       Did you know that there are very few fossils of lizards, insects and other land animals? Most of the fossils that have been discovered are of animals that lived in the sea.

Secret Author

        Robert Chambers was a well-know literary and intellectual figure who is primarily remembered today as the author of ‘Vestiges of Natural History of Creation’ in 1844. This work caused a great sensation in Victorian Britain. However, Robert kept the fact that he had written the book a secret.

What are metazoans?

Metazoans were the first multi -cellular animals. They could move, respond to their environment, and feed on other organisms. They developed organs, a nervous system, sensory organs, and a brain which led to the development of intelligence. The earliest forms were flat bodied, like today's flat-worms. Direct fossils of metazoans from later periods have been found. These are fossils of animals that lived in the sea and the seabed, 680 to 570 million years ago. These fossils bear some resemblance to the bodies of some of today's invertebrates, including some types of jellyfish. These fossils are amongst the earliest discovered of distinct forms of animal life.


Dawn of Life

            Stanley Miller, a scientist, devised an experiment to discover the origin of life. He removed all oxygen from his apparatus, which contained the gases that mimic the Earth’s atmosphere. He then mimicked lightening flashes by providing an electrical spark. At the end of the experiment, the apparatus contained complex molecules of the kind that are found only in living things.

How did oxygen make its appearance in the atmosphere?

In the beginning, the Earth's atmosphere was made up of only nitrogen, carbon dioxide, and some hydrogen. There was very little oxygen present, and it was produced by stromatolites- which are rocks formed by the growth of blue green algae- strewn in the sea. Whatever oxygen was present was quickly absorbed by rocks and minerals. Gradually however, excess oxygen began to accumulate in the atmosphere. This excess oxygen had a dramatic effect on the living cells present. It triggered the evolution of a higher form of life. These were nucleus-containing eukaryotic cells. Thus, the simple blue green algae that were the first form of life became stepping stones to higher life forms, thanks to rising oxygen levels in the atmosphere.

Why is the Precambrian Period extremely significant?

The Precambrian Period spans a long period of the Earth's history. It starts with the planet's creation about 4.5 billion years ago, and ends with the emergence of complex, multicelled life-forms almost four billion years later. It is extremely significant, because it is the earliest of the geologic ages which are marked by different layers of sedimentary rock. Laid down over millions of years, these rock layers contain a permanent record of the Earth's past, including the fossilized remains of plants and animals buried when the sediments were formed.The Precambrian is divided into two parts- the Archaean time, and the Proterozoic Era. There may not have been many different forms of life, but very important changes were taking place during the Precambrian. The Earth was formed, and its outer covering cooled and hardened into a crust. The hot molten insides of the Earth leaked out at weak places in the crust to form volcanoes. The clouds formed by the volcanoes caused huge amounts of rain to fall, and the oceans were created.The first life formed. The oceans were like a thick soup, and their chemistry made them the perfect place for life to begin. The first one-celled organisms formed during the Precambrian Era. They had an important job to do. They helped make the air and water around the Earth full of oxygen. Once there was plenty of oxygen, new life could form. This life would have many cells which would evolve into different kinds of animals. All of the important work of the Precambrian period made the Earth ready for what would come next.

Which Way Up?

            Hallucigenia was a bizarre looking fossil which appeared to have tentacles on its back. For a long time, scientists were baffled by it, and unable to determine what kind of creature it was. Finally, they realized that they were looking at it upside down! The tentacles were in fact, legs that resembled the tubular legs of today’s velvet worms!

Which was the last major asteroid impact?

Asteroids, comets, and meteorites are the debris left over after a meteoroid has burned up in the outer atmosphere. Whenever any of these collide with the Earth, the result is devastating. The last such impact occurred in the year 1930. On February 17th, 1930, a meteorite hit Paragould, in Northeast Arkansas. At that time, it was the largest stony meteorite in the world to be seen falling and recovered.

 Another famous asteroid impact happened on Earth on 13th August of the same year, when an asteroid exploded in the sky above the River Curuca in Brazil. At about eight o’ clock, the sun became blood-res, and darkness fell over the region. Three mighty explosions were heard in rapid succession. Immediately after the explosions, the whole forest became a blazing inferno, which lasted for several months.

Asteroid Hit

 There are a number of stories of people being injured, and even killed, by meteorites. On 30th November 1954, Mrs. Hewlett Hodges of the USA was hit by an asteroid. A four kilogramme asteroid crashed through the roof of her home, and she was struck as she slept in the living room. Fortunately, her injury was not serious.

When was the last day the Morse code was used?

Morse code was a system of communication in which letters and numbers were represented by dots and dashes that could be transmitted by telegraph in the form of sound, and also as flashes of light. The code was invented by Samuel Morse. The Morse code was used extensively by ships at sea. It was used in emergencies throughout the world. However, as technology advanced, the Morse code became obsolete.

The last official day of Morse code for distress signals at sea was January 31st, 1999. On July 12th of the same year, the last commercial Morse transmission was made by Globe Wireless in USA, and it was the same as the very first Morse code message – ‘What hath God wrought?’ The Morse code, the language which has saved countless sailors’ lives, was being consigned to history, a victim of technology.


Why is the Vendian Period important?

The Vendian Period began about 650 billion years ago, and ended about 543 million years ago with the beginning of the Cambrian Period. The Vendian is when the earliest known animals evolved. These included soft-bodied multi cellular animals, like sponges and worms. During the Vendian, the continents had merged into a single supercontinent called Rodinia. In the 20th century, macroscopic fossils of soft-bodied animals, algae, and fossil bacteria have been found in rocks attributed to the Vendian Period in a few localities around the world. The Vendian is also known as the Ediacaran or as the Proterozoic.

Rock of Ages      

            Did you know that chalk is almost entirely made up of tiny shells? These shells once belonged to microscopic animals that floated on the ocean’s surface. They can form layers that over the ages become towering chalk cliffs!

When was the last day of the Vietnam War?

 Vietnam is a small country in Southeast Asia. In 1954, it was divided into communist-ruled North Vietnam, and non communist South Vietnam. North Vietnam wanted to end US support of South Vietnam, and to unite the north and south into a single nation. Over the next ten years, tensions in the area increased as the conflict between North and South Vietnam grew. When North   Vietnam attacked a US destroyer on August 2nd 1964, USA officially entered the Vietnam War.

The Vietnam War was the longest war in which the United States took part. The first U.S. troops entered Vietnam in March 1965. Until 1969, North Vietnam and the United States did most of the fighting. By 1969, the Vietnam War seemed endless, and many Americans opposed American involvement in the war. As a result, United States slowly began to withdraw troops. On 29th April 1975, the US began a massive helicopter evacuation, airlifting 1000 Americans and 6000 South Vietnamese from the capital city of Saigon. The official last day of the war was 30th April 1975, when South Vietnam surrendered to North Vietnam.

Why does World War II have many last days?

World War II started when Germany, led by Adolf Hitler, launched an unprovoked attack on Poland. Britain and France then declared war on Germany. It soon developed into a total war that involved 61 countries, and 1.7 billion people. The Axis countries consisting of Germany, Italy, and Japan were on one side. The other side was made up of the Allies, and included the USA, UK, France, and Russia among other European nations. Fifty million people lost their lives in this war, and hundreds of millions were injured.

 World War II ended with the unconditional surrender of the Axis powers. On May 8th 1945, the Allies accepted Germany’s unconditional surrender, and this day marks the end of World War II in Europe. However, though the war had officially ended, it raged on in the Far East, for Japan refused to surrender. The Japanese held on for some more months until atomic bombs were dropped on Hiroshima and Nagasaki on August 6th and 9th. Japan surrendered to the Allies only on 15th August 1945, and the surrender was officially signed on September 2nd 1945, abroad the battleship USS Missouri. That is why we say that World War II had not one, but many ‘last days’!

Last Soldier

 The last soldier to surrender in World War II was Hiroo Onoda, a Japanese soldier. He surrendered only in 1974, 29 years after the Japanese surrendered. He had been living on a remote island, and did not know that the war had ended!