Why does the Earth rotate clockwise?
Actually, we can’t determine the direction of Earth’s rotation on its axis and there is no correct answer to this question. We can’t determine its direction because it depends on our reference point and from where we see it. If we observe earth’s rotation from above the North Pole, we will see that its direction in counter-clockwise. If we observe the rotation from above the South Pole, it will appear to be a clockwise motion. As to why the earth rotates, many believe that its motion is due to how it came to be. The Big Bang theory states that earth, like other celestial bodies, was formed when a huge cloud collapsed. The earth started spinning thereafter at a given speed, and, since according to Newton’s first law of motion “A body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by an external force,” the earth remains spinning as no external force is present to stop it.
Why don’t the oceans freeze during winters while the rivers do even though they have high speed water currents?
Even though the oceans seem calmer than the rivers, the water is constantly moving at greater depths at a very high speed and at a greater volume. This is a pretty complex thing to understand if you are not familiar with the geographical water currents and their direction of flow. The water currents from warmer regions also flow in the direction of colder regions; this is based on the theory of transfer of energy. Energy flows from a high concentration region to a lower concentration region. Heat energy from warm water regions thrusts the currents to flow to colder regions. This plays a key role in keeping the oceans warmer because rivers don’t come in contact with these currents.
Also, the presence of high salt concentrations lowers the freezing temperature for the oceans. Oceans are very deep and the ocean beds are several metres below the Earth’s outer crust. As we know that Earth’s inner layers radiate Earth’s internal heat, deeper is warmer (past a point). So it is actually quite cozy and warm near the ocean beds and thus, prevents the freezing of the water.
Rivers, on the other hand, are shallower with fresh water and generally freeze at zero degrees Celsius (or below). They have a lesser volume of water which loses heat energy much faster.
One more thing to keep in mind is that oceans do freeze in regions like the Arctic and Antarctica. Icebergs and ice caps are formed but the whole ocean doesn’t freeze. This is because of a number of reasons: enough warm water currents don’t reach these regions, the top ice crust forms as insulation for the water below, and water is saltier as we go deeper.
What are gene banks and why do we need them?
Biosciences for Farming in Africa, a non-profit initiative to improve farming conditions in African countries defines gene banks as biological repositories—collections of samples of DNA or genes of plants and animals produced by preserving their reproductive tissues, which can used for breeding purposes in future. Seeds, parts of plants that can propagate, and sperm and eggs of animals are stored in artificial environments and kept viable for reproduction. The samples are often periodically checked and replaced if needed.
Robert Lamb—a writer at HowStuffWorks and a blogger—in his article on gene banks compared the gene banks with Noah’s efforts to preserve the diversity of life. We know that human activities pose a great threat to wildlife and plant life on Earth. Lamb mentioned that according to the US Fish and Wildlife Service, more than 900 species of animals are currently endangered. He further stated that to avoid their extinction, scientists want to preserve their genes for cloning and artificial breeding in future. According to the above mentioned sources, gene banks are useful for ensuring the conservation of animal and bird species that are on the verge of extinction and for ensuring healthy breeding of plants or crops. These also provide an insight to the natural world and its functioning.