Tag Archives: Plants

Why are fungi considered neither plant nor animal?

Like plants, they have a cell wall, which is a durable framework that supports the cell, which animal cells do not have. Unlike plants, this cell wall is made of chitin rather than cellulose. Animals though use chitin to make hard shells, which is what insect exoskeletons are made of.

Fungi reproduce similar to how simple plants do, by spores. Yet they cannot synthesize their own food like plants can. Like animals, they have to take in food. However, they are also immobile for the most part, like plants. They rely on the environment to move around, where as even simple animal cells can move on their own power.

So they have attributes of both, but are not quite one or the other.

What determines if a plant is a fruit or a vegetable?

It depends on the context since different words mean different things in different contexts.

In botany, fruit refers the part of a flowering plant that has seeds. Things like apples and pears are botanical fruits, but so are tomatoes, cucumbers, legumes, and eggplant. The thing that makes them all fruit is they come from flowering plants and are contain seeds from that plant.

Vegetable is not a botanical term.

In cooking, fruit usually refers to any part of a plant that tastes sweet and is often eaten uncooked. A vegetable is usually any part of a plant that is savory and is often eaten cooked.

There are some legal classifications for foods too that may be different than the above definitions. For example, imported vegetables might be taxed differently from imported fruits and the law would just have to have a list of what counts as a fruit and what counts as a vegetable. Or it might matter for meeting nutritional guidelines.

So tomato is a fruit botanically speaking, but a vegetable in terms of cooking. On the other hand, jicama is not a botanical fruit, but it is a culinary fruit.

How was the Moon formed?

Even though it is lit up by thousands of stars, the night sky would seem vacant to most of us without the presence of Moon. The only natural satellite of Earth, the Moon has been the subject of interest of man forever. Moon had a position of reverence in ancient civilizations and has a great stature in various mythologies.
Myths and stories aside, the cosmic body has been one of the favorites of scientific world. The scientists are more interested in Moon now than ever, even so far as researching about the possibility of living there. As long as they have been mulling over the formation of the universe and solar system and Earth, the scientists have been after Moon as well.
There are a number of theories regarding the origin of Moon. Each one has its merits and faults. One of the earliest modern theories about Moon’s formation was the Fission Theory proposed by George Darwin, son of Charles Darwin. He argued that Moon was a piece expelled from Earth while the latter was still in its rapidly spinning molten state. This theory was popular in late 1800s.
Other notable hypotheses are the Capture theory which states that the Moon was captured by Earth and the Accretion theory stating Earth and Moon were formed together. However, the most widely accepted theory of Moon’s formation is the Giant Impact Hypothesis. It was first put forward by Canadian professor Reginald Daly in 1940s. Later many scientists gathered evidence in support of this hypothesis.
According to GIH, the Moon originated as a result of collision between the Earth and a Mars-sized body named Theia billions of years ago. This collision produced a large amount of debris around the Earth, some of which accumulated to form the Moon. The Moon rotated about one tenth of the distance today, and gradually became tidally locked with Earth.
The Giant Impact Hypothesis has been able to explain some of the aspects of the Moon, like its angular momentum, the difference between the cores of two bodies. However, a number of conflicts have arisen challenging the Giant Hypothesis. One of them is the isotopic comparison between Earth and Moon. The lunar isotope samples show great similarities with Earth. It is against the belief that much of Moon’s mass came from Theia. Also the volatile elements in Moon are not being depleted as fast as they are supposed to be, considering the energy unleashed during the collision. More and more research is being conducted on the subject, and one day we might have the sufficient explanation.

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Why do we only see one side of the moon?

Moon, the natural satellite of Earth, is also the planet’s closest neighbor in space. About a quarter of Earth’s size, the Moon rotates around Earth with a velocity of 1.03 km/s.
Click to enlarge
When we look from Earth, we always see the same side of the moon, about 59% of its surface. We call this side ‘near side’. The other one, which we call the ‘dark side’, is not actually dark, but permanently turned away from us. Moon, just like Earth, also goes through the cycle of day and night.
The reason for the far side of the moon being never visible from Earth is the uniformity between the periods of Moon’s rotation on its axis and around Earth. The phenomenon is known as synchronous rotation or tidal locking. The Moon takes same amount of time, 27.3 ‘Earth days’, to spin about its axis and to complete a revolution around the Earth. If they were even slightly different, we could see the entire surface of the satellite. But, these two periods have been same for all of the known history, and is likely to remain so for millions of years in future.
The reason for this phenomenon is called tidal friction. It can be explained in regard to the effects created by gravitation. The Earth and Moon exert gravitational force on each other. This mutual force creates tidal bulges on each other. One bulge faces in the direction of the other body, and one faces away. Over time, they siphon energy away from the rotational momentum of both bodies, producing a breaking effect.
Since the gravitational force of the Earth on Moon is considerably greater than that of Moon on Earth (about six times), the Moon experiences a greater breaking effect. While it attempts to go on a straight line, the Earth attracts it towards it. Millions of years ago, Moon used to rotate at much faster rate than now. Over time, Moon’s rotation has gradually slowed until the rate of rotation matches the rate at which the tidal bulges move around the body; that is tidally locked. At present, lunar tidal bulges are located at a constant position with respect to the rotation of the Moon, forming a sort of equilibrium. Now the Moon is locked into this period, with the same hemisphere always turned towards Earth.
Even though we should only be able to see half of the surface according to this theory, we get to see 59%, as said earlier. This discrepancy is because the moon orbits around Earth in an elliptical trajectory rather than a perfectly circular one, and it creates differences in angular and linear velocities.

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Why is the center of the Earth still hot?

4.6 billion years into its existence the lava at the core of the Earth is still not freezing. The internal heat of the Earth is due mainly to four sources. 1) About 10,000º Celsius of heat generated at the time of Earth’s formation is still not discharged in the space. 2) A few crore years after the Earth’s formation a space object the size of Mars collided with Earth and the impact generated immense heat. Our moon is formed of debris resulted out of this massive collision. 3) Internal flow of liquids in the Earth generate heat out of friction with substances they come in contact with. 4) The core of the Earth is rich with radioactive substances like uranium, thorium and potassium-40 which generate heat while decaying.
On one hand the already cooled down 6 to 40 kilometers thick external crust blocks internal heat from coming out, and on the other hand the flows of liquids and decay of radioactive substances below the crust constantly generate heat. As a result the core heats up all the more. This situation is favorable to the life on Earth though. If the Earth went the same way of the now cold Mars then it would lose electrical flows at the core and in turn magnetic fields. Once the protective shield vanishes, Sun’s intense radiation would kill the life on Earth.

Why is Jupiter’s moon Europa believed to have life under its surface?

Europa, only slightly smaller than the Earth’s Moon, is one of Jupiter’s four natural satellites discovered by Galileo in 1610. (Jupiter has 64 moons in all — more than any other planet). If life does exist elsewhere in the solar system, many scientists would put their money on Europa, though Saturn’s moon Titan is also a promising candidate.
Surface of Jupiter’s moon Europa
Europa’s surface is made of ice, which may have an ocean of water beneath it. Indeed, faint cracks visible on the surface are very much like the rifts in our own Arctic ice. (See the photo above.) Also like the Arctic, Europa may only be frozen on the top, with the ice layer just a few kilometers thick. The interior, especially near the bottom, is hotter than the surface. The interior flexes due to the gravitational forces of Jupiter and other neighboring moon lo, which is the hottest moon in our solar system. This produces heat in a process called tidal heating and keeps the bottom of Europa above freezing point. Studies of Earth’s deep oceans have discovered hot volcanic vents where bacteria and other primitive creatures live. It is possible that such life forms could exist on Europa as well.

Additional reading:
Europa (moon) (Wikipedia)

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Why pulses and beans contain protein and vegetables don’t?

Carbohydrates are the main constituents of most of the vegetation. While stems and branches of the plants and trees contain cellulose, seeds and fruits are storehouses of starch and glucose respectively. Thus all three substances — cellulose, starch and glucose — are carbohydrates.
Plants of pulses and beans of legumes as they are also called, are different from the plants of other vegetables and fruits. The roots of pulses and beans bear nodules in which a kind of bacteria known as ‘Rhizobium’ thrives. There is a close relationship of interdependence known as ‘symbiosis’ between the plants of pulses and these bacteria. Colonies of Rhizobium bacteria get sustenance from the roots of pulses and beans plants and provide nutritious fertilizer to the host plants in return. They do this by a process called ‘nitrogen fixing’, i.e. converting nitrogen in the atmosphere into nutritious fertilizer which can be assimilated by the plants. The plants of pulses and beans process the nitrogen provided by Rhizobium bacteria into amino acid and thereafter convert it into protein.

Additional reading:
Pulse (legume) (Wikipedia)
Protein (Wikipedia)

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What is the raw material of menthol?

Menthol is used in a wide variety of products such as pain balm, toothpaste, cough syrup and peppermint etc.
Leaves of some varieties out of about 25 varieties of plants bearing the genetic name ‘mentha’ form the raw material of menthol. Mentha oil is extracted from the leaves of these plants and crystallized. The crystal form is known as menthol. India is a leading producer of mentha and menthol, and nearly 70% of total production is exported.

Additional reading:
Menthol (Wikipedia)

Where does the flavoring agent vanilla come from? Is it sourced from plants?


It is. Used in earlier times to flavor the chocolate beverages of the Aztecs of Mexico, vanilla is extracted from the beans of a tropical vine which attaches its little rootless stem to trees (see photo). Incidentally, fresh vanilla beans have no aroma, though it contains basic components of the chemical vanillin which ultimately provides the characteristic flavor associated with vanilla. To derive this extract, the beans have to be cured. The time-honored method is to expose the harvested beans to sunshine and keeping them in sweat-boxes at night. The process, lasting about 10 days, brings about fermentation in the beans and they become chocolate brown in color. The curing leads to the formation of the volatile oil vanillin. The beans are then dried for about four months. The proportion of vanillin is seldom more then 2%, but it is highly concentrated form. After the dried beans are crushed the vanillin is extracted by alcohol. The eventual flavoring-vanilla-is 35% ethyl alcohol and is used in a variety of sweet foods and beverages such as ice-cream, milk-shakes, chocolate and cakes.

Worldwide, it is the most preferred flavoring and a large quantity of vanilla is made nowadays from commercially synthesized vanillin.

Additional reading:
Vanillin (Wikipedia)
Vanilla (Wikipedia)

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Are there any plants without flowers, fruits, seeds or even roots?

Giant Kelps
Yes there are! The plant kingdom is divided into four sub-kingdoms out of which one, made up of very simple plants, called thallus plants or thallophytes. Thallophytes have no flowers, fruits or seeds, and no leaves, roots or stems corresponding to those of higher plants. The two main divisions of the thallophytes are the algae and the fungi. The most primitive of all plants are the bacteria, which are one of the divisions of the fungi. Each bacterium consists of a single, very small cell. Among the thallophytes that are familiar to many people are those that coat tree trunks and old wooden fences with green moss that after rain, turn so bright that they look like fresh green paint.

The giant kelps (see photo, above) of the Pacific Ocean and the Sargasso Sea, the ‘reindeer moss’ of northern Canada and many other lichens; and the true Fungi, which include yeasts, moulds, mildews, puffballs, mushrooms, toadstools and the bracket fungi, which grow like shelves from the side of trees are also thallophytes.

Additional reading:
Thallus (Wikipedia)
Thallophyte (Wikipedia)

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