15 Best Documentaries About Evolution Site
The Berkeley Evolution Site
The Berkeley site offers resources that can help students and educators understand and teach evolution. The resources are organized into optional learning paths, such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection describes how species that are better equipped to adapt biologically to changing environment survive over time and those that don't become extinct. This process of biological evolution is what science is all about.
What is Evolution?
The term "evolution" could have many nonscientific meanings. For example it could mean "progress" and "descent with modifications." It is an academic term that is used to describe the process of changing traits over time in organisms or species. In biological terms, this change is based on natural selection and genetic drift.
Evolution is one of the fundamental tenets of modern biology. It is a theory that has been confirmed by thousands of scientific tests. Evolution doesn't deal with God's presence or spiritual beliefs, unlike many other theories of science, such as the Copernican or germ theory of diseases.
Early evolutionists, including Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical traits were predetermined to change, in a gradual way, over time. This was referred to as the "Ladder of Nature", or scala Naturae. Charles Lyell used the term to describe this idea in his Principles of Geology, first published in 1833.
In the early 1800s, Darwin formulated his theory of evolution and published it in his book On the Origin of Species. It states that all species of organisms share an ancestry that can be traced using fossils and other evidence. This is the current understanding of evolution that is supported by a variety of lines of scientific research which includes molecular genetics.
Although scientists aren't able to determine exactly how organisms evolved, they are confident that the evolution of life on earth is the result of natural selection and genetic drift. Individuals with advantageous characteristics are more likely to survive and reproduce. They then pass their genes to the next generation. As time passes the gene pool gradually changes and evolves into new species.
Some scientists also employ the term evolution to refer to large-scale changes in evolutionary processes, such as the formation of an entirely new species from an ancestral species. Some scientists, like population geneticists, define the term "evolution" in a broader sense by referring to the net change in allele frequency over generations. Both definitions are accurate and palatable, but some scientists argue that allele-frequency definitions miss important aspects of the evolutionary process.
Origins of Life
The development of life is a key stage in evolution. The beginning of life takes place when living systems begin to develop at a micro level, such as within individual cells.
The origins of life are an issue in a variety of disciplines such as biology, chemistry, and geology. The question of how living organisms began has a special place in science because it is an important challenge to the theory of evolution. It is sometimes referred to "the mystery" of life or "abiogenesis."
Traditionally, the notion that life could emerge from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's experiments proved that it was impossible for the creation of life to be a result of the natural process.
Many scientists believe that it is possible to make the transition from nonliving substances to living. However, the conditions required are extremely difficult to reproduce in labs. This is why scientists studying the nature of life are also keen to understand the physical properties of the early Earth and other planets.
Additionally, the evolution of life is dependent on the sequence of extremely complex chemical reactions that cannot be predicted from basic physical laws alone. These include the reading of long, information-rich molecules (DNA or RNA) into proteins that perform a function, and the replication of these complex molecules to generate new DNA or sequences of RNA. These chemical reactions are comparable to the chicken-and-egg issue that is the emergence and growth of DNA/RNA, protein-based cell machinery, is necessary for the beginning of life. However without life, the chemistry that is required to make it possible is working.
Research in the area of abiogenesis requires collaboration among scientists from many different disciplines. This includes prebiotic scientists, astrobiologists, and planetary scientists.
Evolutionary Changes
The term "evolution" is typically used today to describe the cumulative changes in the genetic traits of a population over time. These changes can result from adaptation to environmental pressures, as described in the entry on Darwinism (see the entry on Charles Darwin for background), or from natural selection.
This latter mechanism increases the number of genes that offer an advantage for survival in a species, resulting in an overall change in the appearance of the group. The specific mechanisms behind these changes in evolutionary process include mutation and reshuffling of genes in sexual reproduction, and gene flow between populations.
Natural selection is the process that makes beneficial mutations more common. All organisms undergo mutations and reshuffles in their genes. As noted above, individuals who possess the desirable trait have a higher reproduction rate than those who don't. Over many generations, this difference in the number of offspring born can result in an inclination towards a shift in the amount of desirable characteristics in a particular population.
An excellent example is the increase in beak size on various species of finches found on the Galapagos Islands, which have developed beaks with different shapes to allow them to more easily access food in their new home. These changes in the shape and appearance of living organisms may also aid in the creation of new species.
The majority of the changes that occur are caused by one mutation, but occasionally several will happen at the same time. Most of these changes may be neutral or even harmful however, a few may have a positive effect on the survival of the species and reproduce with increasing frequency as time passes. Natural selection is a mechanism that causes the accumulating change over time that leads to the creation of a new species.
Some people think that evolution is a form of soft inheritance, which is the idea that inherited traits can be changed by conscious choice or by abuse. 에볼루션 바카라사이트 is a misunderstanding of the biological processes that lead to the process of evolution. It is more accurate to say that the process of evolution is a two-step, separate process, which involves the forces of natural selection and mutation.
Origins of Humans
Humans of today (Homo sapiens) evolved from primates - a species of mammals that includes chimpanzees and gorillas and bonobos. Our predecessors walked on two legs, as shown by the first fossils. Biological and genetic similarities indicate that we share an intimate relationship with chimpanzees. In actual fact, our closest relatives are the chimpanzees from the Pan genus. This includes pygmy, as well as bonobos. The last common human ancestor and chimpanzees lived between 8 and 6 million years ago.
Over time, humans have developed a range of characteristics, such as bipedalism and the use fire. They also created advanced tools. It is only in the last 100,000 years or so that the majority of the essential traits that distinguish us from other species have emerged. These include language, a large brain, the capacity to build and use sophisticated tools, and a the diversity of our culture.
Evolution occurs when genetic changes allow members of a group to better adapt to the environment. Natural selection is the mechanism that drives this adaptation. Certain characteristics are more desirable than others. The ones with the best adaptations are more likely to pass on their genes to the next generation. This is the way that all species evolve and forms the basis of the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states that species which have a common ancestor, tend to develop similar traits over time. This is because the traits allow them to survive and reproduce in their environment.
All organisms have a DNA molecule, which contains the information needed to control their growth and development. The DNA structure is composed of base pairs that are arranged in a spiral around sugar and phosphate molecules. The sequence of bases within each strand determines phenotype, or the individual's characteristic appearance and behavior. Variations in a population can be caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils from the earliest human species Homo erectus, and Homo neanderthalensis have been found in Africa, Asia and Europe. Although there are some differences they all support the hypothesis that modern humans first came into existence in Africa. The evidence from fossils and genetics suggests that the first humans left Africa and migrated to Asia and Europe.