Category Plants & Animals

CAN TREES CAUSE WEATHERING?

Yes, trees can break up large rocks. Seeds may be deposited in the cracks and gaps of rock clusters and they germinate there. As the plant grows, the roots crack the rock further and may even break it into many pieces.

Plants can cause mechanical and chemical weathering. When plants cause mechanical weathering, their roots grow into rocks and crack them.It can also happen in streets or sidewalks. When plants cause chemical weathering, there roots release acid or other chemicals, onto rocks, which then forms cracks, and breaks apart.

Plants can cause physical weathering as their roots grow. Seeds of plants or trees can grow inside rock cracks where soil has collected. The roots then put pressure on the cracks, making them wider and eventually splitting the rock. Even small plants can cause this kind of weathering over time.

Biological Weathering – This type of weathering is caused by plants and animals. The plants and animals have acids inside them and when they release their acid it converts into chemicals that further results in weathering and breaking down of rocks and minerals and other types of landforms.

Credit: SidmartinBio

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What ant actually explodes to protect the entire colony?

Found in the remote rainforests of Borneo, Colobopsis explodens ants have developed extreme abilities to protect their colony. When threatened by other insects, these ‘exploding ants’ rupture their own body walls, releasing a toxic, sticky liquid which kills or immobilizes their attacker.  Outside the kitchen door at the Kuala Belalong Field Studies Center in Brunei, on a number of trees near the balcony, there is a nest of very special ants. Workers of C. explodens have a distinctive, rather foul talent. When their nest is invaded, they rupture their own abdomens, releasing a sticky, bright yellow fluid laced with toxins on their attackers. Similar to honey bees that die after stinging, the exploded ants do not survive, but their sacrifice can help save the colony. Scientists call this suicidal behaviour “autothysis”.

Some ants (called door-keepers) have even developed plug-shaped heads used to physically barricade the nest entrances against intruders. These ants explode, but their nests live to see another day.

Credit : The Newyork Times

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WHEN DID PLANTS START TO GROW ON LAND?

The first land plants appeared during the Silurian period, around 440 million years ago. These simple plants reproduced by releasing spores. Plants produced oxygen and provided food for the first land animals – amphibians. Amphibians first developed in the Devonian period, 420 million years ago, from fish whose fins evolved into limbs.

Botanists now believe that plants evolved from the algae; the development of the plant kingdom may have resulted from evolutionary changes that occurred when photosynthetic multicellular organisms invaded the continents. The earliest fossil evidence for land plants consists of isolated spores, tracheid-like tubes, and sheets of cells found in Ordovician rocks. The abundance and diversity of these fossils increase into the Silurian Period (about 443.8 million to 419.2 million years ago), where the first macroscopic (megafossil) evidence for land plants has been found. These megafossils consist of slender forking axes that are only a few centimetres long. Some of the axes terminate in sporangia that bear trilete spores (i.e., spores that divide meiotically to form a tetrad). Because a trilete mark indicates that the spores are the product of meiosis, the fertile axes may be interpreted as the sporophyte phase of the life cycle.

Fossils of this type could represent either vascular plants or bryophytes. Another possibility is that they are neither but include ancestors of vascular plants, bryophytes, or both. The earliest fossils also include at least one or more additional plant groups that became extinct early in the colonization of the land and therefore have no living descendants. By the early Devonian Period (about 419.2 million to 393.3 million years ago), some of the fossils that consist of forking axes with terminal sporangia also produced a central strand of tracheids, the specialized water-conducting cells of the xylem. Tracheids are a diagnostic feature of vascular plants and are the basis for the division name, Tracheophyta.

Credit: Britannica

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Can seaweed clean your teeth?

NEWCASTLE University scientists claim that an enzyme isolated from marine bacterium Bacillus licheniformis cuts through plaque on teeth and cleans hard-to-reach areas. Dr Nicholas Jakubovics of the university’s School of Dental Sciences said: “Plaque is made up of bacteria which join together to colonize an area in a bid to push out any potential competitors. Traditional toothpastes work by scrubbing off the plaque containing the bacteria. But that’s not always effective which is why people who religiously clean their teeth can still develop cavities.” When bacterial cells die, the DNA inside leaks out and creates a biofilm that sticks to teeth, protecting the bacteria from brushing, chemicals or even antibiotics. Bacillus licheniformis, found on the surface of seaweed, releases an enzyme which breaks up the biofilm and strips away harmful bacteria.

Researcher Prof. Burgess said: “The zyme breaks up and removes the bacteria esent in plaque and importantly, prevents build-up of plaque too. If we can contain it with’n toothpaste we would be creating a product which could prevent tooth decay. The enzyme also has huge potential in he ping keep clean medical implants such as artificial hips and speech valves which also suffer from biofilm infection.”

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