How the properties of organism are affected due to gene mutation? How ecosystem changes due to climate? What can human genetic variation tell us about the history of human evolution and migration?
Evolution is the change in heritable traits of biological populations over successive generations. Evolutionary processes give rise to diversity at every biological organization level. All life on earth shares a common ancestor known as the last universal ancestor. Evolution is a cornerstone of modern science, accepted as one of the most reliably established of all facts and theories of science, based on evidence not just from the biological sciences but also from anthropology, psychology, astrophysics, chemistry, geology, physics, mathematics, and other scientific disciplines, as well as behavioral and social sciences.
Today life diversity on earth is the result of evolution. On Earth life began at least 4 billion years ago and it has been evolving every year.
In the beginning all living things on earth were single celled organism, after several years multicellular organism evolved after that diversity in life on earth increased day by day. Here in the figure shows the history of life on earth Fig. DNA deoxyribonucleic acid is the double helix structure shown in Fig. Its duplicate copies have coded information coiled up in almost all of the ,,,, one hundred trillion cells in your body. In human DNA has 46 segments; 23 segments received from father and 23 from mother.
Each DNA contains exclusive information that determines what you look like, your personality and how your body cell is to function throughout your life. If one cell whole DNA was uncoiled and stretched out then it would be six feet long. Its detailed structure could not be seen due to its thin structure even under electron microscope. If all the coded information from one cell of one person were printed on books then it would fill a library of four thousand books and if the whole body DNA were positioned continuously, it would extend from here to Moon more than , times.
If one set of DNA from each individual who still lived were placed in a pile, the final pile would weigh less than an aspirin. About cubic miles have been worn from the Grand Canyon. From earth the moon is , miles. If the human cell DNA were prolonged out and linked, it would be more than 7 feet long.
The weight of DNA in human cell is 6. According to Hoyle and Wickramasinghe, biochemical systems are exceptionally composite, so much so that the possibility of their being shaped from side to side haphazard shuffling of simple organic molecules is remarkably small, to a position certainly where it is inertly different from zero Hoyle and Wickramasinghe, For the realistic cause entire visible universe is not vast adequate to hold the essential monkey hordes, essential typewriters, and surely the baskets for waste paper required for the deposition of wrong attempts.
The same is true for the living matter. In the same way, a small number of correct amino acids sequences would decay long before a protein was completed, not to point out that thousands of proteins must be at their proper place in a living cell. At last the most composite condition of all is the occurrence of working DNA Vogel, They also state that our intelligence must reflect a vastly superior intelligence, even the tremendous idealized limit of God. They also believe that life was created by some intelligence somewhere in outer space and latter was transported to the Earth.
All point mutations that have been studied on the molecular level turn out to reduce the genetic information and not to increase it Storz, This study made an insightful point that if all the DNAs of human, mice and other organisms were useful then after so many mutations that build up in hundreds of millions of years then those species become extinct.
Any science topic can be taught in an inquiry-oriented manner, and evolution is particularly amenable to this approach. At the core of inquiry-oriented instruction is the provision for students to collect data or be given data when collection is not possible and to analyze the data to derive patterns, conclusions, and hypotheses, rather than just learning facts.
Students can use many data sets from evolution such as diagrams of anatomical differences in organisms to derive patterns or draw connections between morphological forms and environmental conditions. They then can use their data sets to test their hypotheses. Students also can collect data in real time.
For example, they can complete extended projects involving crossbreeding of fruit flies or plants to illustrate the genetic patterns of inheritance and the influence of the environment on survival. In this way, students can develop an understanding of evolution, scientific inquiry, and the nature of science. Today many school students are shielded from one of the most important concepts in modern science: evolution.
In engaging and conversational style, Teaching About Evolution and the Nature of Science provides a well-structured framework for understanding and teaching evolution. Written for teachers, parents, and community officials as well as scientists and educators, this book describes how evolution reveals both the great diversity and similarity among the Earth's organisms; it explores how scientists approach the question of evolution; and it illustrates the nature of science as a way of knowing about the natural world.
In addition, the book provides answers to frequently asked questions to help readers understand many of the issues and misconceptions about evolution. The book includes sample activities for teaching about evolution and the nature of science. For example, the book includes activities that investigate fossil footprints and population growth that teachers of science can use to introduce principles of evolution.
Background information, materials, and step-by-step presentations are provided for each activity. In addition, this volume:. Teaching About Evolution and the Nature of Science builds on the National Science Education Standards released by the National Research Council—and offers detailed guidance on how to evaluate and choose instructional materials that support the standards. Comprehensive and practical, this book brings one of today's educational challenges into focus in a balanced and reasoned discussion.
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Get This Book. Visit NAP. Looking for other ways to read this? No thanks. Teaching About Evolution and the Nature of Science. Page 56 Share Cite. Is evolution a fact or a theory? Why isn't evolution called a law? Don't many famous scientists reject evolution? Page 57 Share Cite. Gould defines punctuated equilibrium as follows: Punctuated equilibrium is neither a creationist idea nor even a non-Darwinian evolutionary theory about sudden change that produces a new species all at once in a single generation.
Page 58 Share Cite. Religious Issues. Page 59 Share Cite. Educational Issues. Page 60 Share Cite. Page 55 Share Cite. Login or Register to save! In addition, this volume: Presents the evidence for evolution, including how evolution can be observed today. Explains the nature of science through a variety of examples.
Describes how science differs from other human endeavors and why evolution is one of the best avenues for helping students understand this distinction. Answers frequently asked questions about evolution. Stay Connected! At the Earth Summit in Rio de Janeiro, world leaders agreed on a comprehensive strategy for "sustainable development" -- meeting our needs while ensuring that we leave a healthy and viable world for future generations.
One of the key agreements adopted at Rio was the Convention on Biological Diversity. This pact among the vast majority of the world's governments sets out commitments for maintaining the world's ecological underpinnings as we go about the business of economic development. The Convention establishes three main goals: the conservation of biological diversity, the sustainable use of its components, and the fair and equitable sharing of the benefits from the use of genetic resources.
Even more revealingly, the supposedly irreducibly complex bacterial flagellum turns out not to be irreducible after all.
For example, there is a protein at the base of the flagellum, an ATPase, that drives the key structural subunit flagellin of the long hollow tube through its inner core, causing the flagellum to grow in length.
Yet, it has been shown that flagellin can be transported to the end of a flagellum without this ATPase. This illustrates a fourth principle of building a complex structure: redundancy. One of these redundant mechanisms may become more specialized, and even perfected, as time goes by. Another system that is often held up as an example of irreducible complexity is the eye.
People often ask: What good is a partly assembled eye? Is there any logical series of steps that could result in the creation—through the process of natural selection—of a structure so elegant as the eye of an eagle? What would be the starting point, anyway? All light-sensing devices in the animal world make use of a single light-sensitive molecule, retinal, which is derived from Vitamin A.
Retinal can change its shape when it absorbs a photon of light. This molecule is always complexed with a protein known as an opsin. The two work together to sense light.
Circadian rhythms function throughout the living world, including single-cell organisms. It seems likely, then, that the simplest light-detecting device arose through exaptation of a molecular device that was used to detect light—not so that an organism might move toward or away from the light, but so it could reset its molecular clock.
Even the origin of opsin illustrates a basic principle of building complexity, co-option. Opsin is one of many G-protein receptors, which have come to take on many different functions through the history of life.
When coupled with the light-sensitive molecule retinal, a G-protein receptor allows the cell to be sensitized to the presence and absence of light. Although we have no fossilized transitions that allow us to trace the various eye intermediates that have occurred in animal history, as we do with the middle ear, we do have a myriad of light-sensing devices in the animal kingdom that allow us to piece together how sophisticated eyes could have been created through a gradual process driven by natural selection.
You can read more about the prospective intermediates that exist in the animal world in a wonderful paper by Ryan Gregory. If you choose to explore eye development in detail, be watching for examples of exaptation, co-option, step-by-step adaptation and redundancy. For example, you will note that the evolution of the lens illustrates co-option and redundancy. There are two ways to focus the image on the light-receiving cells at the back of an eye.
One way is through an independent lens. The other way is through the transparent cornea in front of the lens. The lens is simply transparent crystallized protein molecules that are assembled in such a manner that they bring the image into sharp focus.
There are a variety of proteins that can be crystallized to serve as an effective lens. It turns out that, depending on the evolutionary lineage, various proteins—including enzymes such as alcohol dehydrogenase an enzyme for breaking down ethanol , glutathione S transferase and protein chaperones—are used for this purpose. This is a simple example of co-option and redundancy functioning together as part of the tinkering mechanism used for building a complex structure like the eye.
Two-thirds of animal phyla have some sort of light-sensing device. Although all of these light-sensing devices make use of retinal and opsins, there are differences in structure that we can trace to differences in evolutionary origin.
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