Саният Меджидовна

Саният Меджидовна

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четверг, 29 ноября 2018 г.

Laboratory of Evolution

The Galápagos Islands archipelago is home to a complex ecosystem with a fascinating geological history, as well as unique examples of plant and animal life. The islands' flora and fauna inspired renowned naturalist Charles Darwin to formulate his theory of evolution, and thousands of tourists and scientists flock to the islands every year to further study the wildlife.
Credited as the father of evolution, Darwin was actually a trained geologist. Darwin had been traveling around South America for about four years before landing in the Galápagos in 1835, J. Bret Bennington, chair of the Department of Geology, Environment, and Sustainability at Hofstra University, told Live Science. During that time, Darwin became familiar with the plant and animal life that lived in various climates around the mainland as well as with some of the islands the ship visited in the Atlantic Ocean on its way to South America from England, said Bennington, who also directs a study abroad program to the Galápagos Islands.

Darwin was a creationist when he began his journey on the HMS Beagle, but he slowly changed his mind during the voyage, especially when he studied life on and around the Galápagos. Darwin saw many islands of various sizes, close together and geologically young inhabited by similar yet different species of plant and animal life. Darwin concluded that life in the Galápagos didn't make sense with the current views of creationism.
It took Darwin 23 years after returning home from his voyage to put together the jigsaw puzzle that fully supported evolution and natural selection, which is one of bases of evolution that explains why certain traits get passed on to the following generations, according to the University of California at Berkeley. Published in 1859, Darwin's famous "On the Origin of Species" took the foundations for the theories of evolution that had already been placed before him and built upon them, providing the evidence that definitively supported evolution. Within a decade of the theories' publication, according to Cornell, scientists favored Darwin's theories of evolution and natural selection over creationism, and these transformational ideas still hold today, about 160 years later.
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четверг, 22 ноября 2018 г.

What Is CRISPR?

CRISPR technology is a simple yet powerful tool for editing genomes. It allows researchers to easily alter DNA sequences and modify gene function. Its many potential applications include correcting genetic defects, treating and preventing the spread of diseases and improving crops. However, its promise also raises ethical concerns.
In popular usage, "CRISPR" (pronounced "crisper") is shorthand for "CRISPR-Cas9." CRISPRs are specialized stretches of DNA. The protein Cas9 (or "CRISPR-associated") is an enzyme that acts like a pair of molecular scissors, capable of cutting strands of DNA.

CRISPR technology was adapted from the natural defense mechanisms of bacteria and archaea (the domain of single-celled microorganisms). These organisms use CRISPR-derived RNA and various Cas proteins, including Cas9, to foil attacks by viruses and other foreign bodies. They do so primarily by chopping up and destroying the DNA of a foreign invader. When these components are transferred into other, more complex, organisms, it allows for the manipulation of genes, or "editing."
Until 2017, no one really knew what this process looked like. In a paper published Nov. 10, 2017, in the journal Nature Communications, a team of researchers led by Mikihiro Shibata of Kanazawa University and Hiroshi Nishimasu of the University of Tokyo showed what it looks like when a CRISPR is in action for the very first time. [A Breathtaking New GIF Shows CRISPR Chewing Up DNA]
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четверг, 15 ноября 2018 г.

History of biology

Our fascination with biology has a long history. Even early humans had to study the animals they hunted and know where to find the plants they gathered for food. The invention of agriculture was the first great advance of human civilization. Medicine has been important to us from earliest history as well. The earliest known medical texts are from China (2500 B.C.), Mesopotamia (2112 B.C.), and Egypt (1800 B.C.).
In classical times, Aristotle is often considered to be the first to practice scientific zoology. He is known to have performed extensive studies of marine life and plants. His student, Theophrastus, wrote one of the West's earliest known botanical texts in 300 B.C. on the structure, life cycle and uses of plants. The Roman physician Galen used his experience in patching up gladiators for the arena to write texts on surgical procedures in A.D. 158.
During the Renaissance, Leonardo da Vinci risked censure by participating in human dissection and making detailed anatomical drawings that are still considered among the most beautiful ever made. Invention of the printing press and the ability to reproduce woodcut illustrations meant that information was much easier to record and disseminate. One of the first illustrated biology books is a botanical text written by German botanist Leonhard Fuchs in 1542. Binomial classification was inaugurated by Carolus Linnaeus in 1735, using Latin names to group species according to their characteristics.
Microscopes opened up new worlds for scientists. In 1665, Robert Hooke, used a simple compound microscope to examine a thin sliver of cork. He observed that the plant tissue consisted of rectangular units that reminded him of the tiny rooms used by monks. He called these units "cells." In 1676, Anton von Leeuwenhoek published the first drawings of living single celled organisms. Theodore Schwann added the information that animal tissue is also composed of cells in 1839.
During the Victorian era, and throughout the 19th century, "Natural Science" became something of a mania. Thousands of new species were discovered and described by intrepid adventurers and by backyard botanists and entomologists alike. In 1812, Georges Cuvier described fossils and hypothesized that Earth had undergone "successive bouts of Creation and destruction" over long periods of time. On Nov. 24, 1859, Charles Darwin published "On the Origin of Species," the text that forever changed the world by showing that all living things are interrelated and that species were not separately created but arise from ancestral forms that are changed and shaped by adaptation to their environment.

While much of the world's attention was captured by biology questions at the macroscopic organism level, a quiet monk was investigating how living things pass traits from one generation to the next. Gregor Mendel is now known as the father of genetics although is papers on inheritance, published in 1866, went largely unnoticed at the time. His work was rediscovered in 1900 and further understanding of inheritance rapidly followed. 
The 20th and 21st centuries may be known to future generations as the beginning of the "Biological Revolution." Beginning with Watson and Crick explaining the structure and function of DNA in 1953, all fields of biology have expanded exponentially and touch every aspect of our lives. Medicine will be changed by development of therapies tailored to a patient's genetic blueprint or by combining biology and technology with brain-controlled prosthetics. Economies hinge on the proper management of ecological resources, balancing human needs with conservation. We may discover ways to save our oceans while using them to produce enough food to feed the nations. We may "grow" batteries from bacteria or light buildings with bioluminescent fungi. The possibilities are endless; biology is just coming into its own.
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четверг, 8 ноября 2018 г.

What is Biology?

Biology is the science of life. Its name is derived from the Greek words "bios" (life) and "logos" (study). Biologists study the structure, function, growth, origin, evolution and distribution of living organisms. There are generally considered to be at least nine "umbrella" fields of biology, each of which consists of multiple subfields.
  • Biochemistry: the study of the material substances that make up living things
  • Botany: the study of plants, including agriculture
  • Cellular biology: the study of the basic cellular units of living things
  • Ecology: the study of how organisms interact with their environment
  • Evolutionary biology: the study of the origins and changes in the diversity of life over time
  • Genetics: the study of heredity
  • Molecular biology: the study of biological molecules
  • Physiology: the study of the functions of organisms and their parts
  • Zoology: the study of animals, including animal behavior
Adding to the complexity of this enormous idea is the fact that these fields overlap. It is impossible to study zoology without knowing a great deal about evolution, physiology and ecology. You can't study cellular biology without knowing biochemistry and molecular biology as well.
Framework of understanding.


All the branches of biology can be unified within a framework of five basic understandings about living things. Studying the details of these five ideas provides the endless fascination of biological research:
  • Cell Theory: There are three parts to cell theory — the cell is the basic unit of life, all living things are composed of cells, and all cells arise from pre-existing cells.
  • Energy: All living things require energy, and energy flows between organisms and between organisms and the environment.
  • Heredity: All living things have DNA and genetic information codes the structure and function of all cells.
  • Equilibrium: All living things must maintain homeostasis, a state of balanced equilibrium between the organism and its environment.
  • Evolution: This is the overall unifying concept of biology. Evolution is the change over time that is the engine of biological diversity.

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четверг, 1 ноября 2018 г.

Science and Change

 If scientists are constantly trying to make new discoveries or to develop new concepts and theories, then the body of knowledge produced by science should undergo constant change. Such change is progress toward a better understanding of nature. It is achieved by constantly questioning whether our current ideas are correct. As the famous American astronomer Maria Mitchell (1818-1889) put it, "Question everything".
     The result is that theories come and go, or at least are modified through time, as old ideas are questioned and new evidence is discovered. In the words of Karl Popper, "Science is a history of corrected mistakes", and even Albert Einstein remarked of himself "That fellow Einstein . . . every year retracts what he wrote the year before". Many scientists have remarked that they would like to return to life in a few centuries to see what new knowledge and new ideas have been developed by then - and to see which of their own century's ideas have been discarded. Our ideas today should be compatible with all the evidence we have, and we hope that our ideas will survive the tests of the future. However, any look at history forces us to realize that the future is likely to provide new evidence that will lead to at least somewhat different interpretations.
     Some scientists become sufficiently ego-involved that they refuse to accept new evidence and new ideas. In that case, in the words of one pundit, "science advances funeral by funeral". However, most scientists realize that today's theories are probably the future's outmoded ideas, and the best we can hope is that our theories will survive with some tinkering and fine-tuning by future generations.
     We can go back to Copernicus to illustrate this. Most of us today, if asked on a street corner, would say that we accept Copernicus's idea that the earth moves around the sun - we would say that the heliocentric theory seems correct. However, Copernicus himself maintained that the orbits of the planets around the sun were perfectly circular. A couple of centuries later, in Newton's time, it became apparent that those orbits are ellipses. The heliocentric theory wasn't discarded; it was just modified to account for more detailed new observations. In the twentieth century, we've additionally found that the exact shapes of the ellipses aren't constant (hence the Milankovitch cycles that may have influenced the periodicity of glaciation). However, we haven't gone back to the idea of an earth-centered universe. Instead, we still accept a heliocentric theory - it's just one that's been modified through time as new data have emerged.

     The notion that scientific ideas change, and should be expected to change, is sometimes lost on the more vociferous critics of science. One good example is the Big Bang theory. Every new astronomical discovery seems to prompt someone to say "See, the Big Bang theory didn't predict that, so the whole thing must be wrong". Instead, the discovery prompts a change, usually a minor one, in the theory. However, once the astrophysicists have tinkered with the theory's details enough to account for the new discovery, the critics then say "See, the Big Bang theory has been discarded". Instead, it's just been modified to account for new data, which is exactly what we've said ought to happen through time to any scientific idea.

     Try an analogy: Imagine that your favorite fictional detective (Sherlock Holmes, Miss Marple, Nancy Drew, or whoever) is working on a difficult case in which the clues only come by fits and starts. Most detectives keep their working hypotheses to themselves until they've solved the case. However, let's assume that our detective decides this time to think out loud as the story unfolds, revealing their current prime suspect and hypothesized chronology of the crime as they go along. Now introduce a character who accompanies the detective and who, as each clue is uncovered, exclaims "See, this changes what you thought before - you must be all wrong about everything!" Our detective will think, but probably have the grace to not say, "No, the new evidence just helps me sharpen the cloudy picture I had before". The same is true in science, except that nature never breaks down in the last scene and explains how she done it. 
From science
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