The Berkeley Evolution Site
The Berkeley site has resources that can assist students and teachers to understand and teach about evolution. The resources are arranged into different learning paths such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains that in time, creatures more adaptable to changing environments survive and those that do not become extinct. This process of biological evolution is what science is all about.
What is Evolution?
The term "evolution" has a variety of nonscientific meanings, including "progress" or "descent with modification." It is a scientific term that refers to the process of changing characteristics over time in organisms or species. The reason for this change is biological terms on natural selection and drift.
Evolution is one of the fundamental tenets of modern biology. It is a theory that has been tested and verified by thousands of scientific tests. Contrary to other theories of science such as the Copernican theory or the germ theory of disease, evolution does not address issues of religious belief or the existence of God.
Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to change in a stepped-like manner over time. They referred to this as the "Ladder of Nature" or the scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology.
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 have a common ancestry, which can be traced through fossils and other evidence. This is the current perspective on evolution, and is supported by a variety of disciplines which include molecular biology.
While scientists don't know exactly how organisms developed however they are sure that the evolution of life on earth is a result of natural selection and genetic drift. Individuals with advantageous traits are more likely to live and reproduce, and they transmit their genes to the next generation. As time passes this leads to an accumulation of changes in the gene pool that gradually lead to new species and types.
Certain scientists use the term"evolution" in reference to large-scale change, such as the formation of an animal from an ancestral one. Others, like population geneticists, define evolution more broadly by referring an overall change in the frequency of alleles across generations. Both definitions are valid and reliable however, some scientists claim that the definition of allele frequency is lacking important features of the evolutionary process.
Origins of Life
One of the most crucial steps in evolution is the development of life. This occurs when living systems begin to evolve at the micro level, within individual cells, for example.
The origins of life are an important issue in a variety of disciplines that include biology and chemistry. The question of how living organisms began is of particular importance in science since it poses an enormous challenge to the theory of evolution. It is often called "the mystery of life" or "abiogenesis."
Traditionally, the belief that life can emerge from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a popular view before Louis Pasteur's experiments showed that it was impossible for the creation of life to occur by the natural process.
Many scientists believe it is possible to transition from nonliving substances to living ones. However, the conditions needed are extremely difficult to reproduce in labs. Researchers interested in the origins and development of life are also eager to understand the physical properties of the early Earth as well as other planets.
The life-cycle of a living organism is dependent on a variety of complex chemical reactions, which are not predicted by the basic physical laws. These include the reading and replication of complex molecules, like DNA or RNA, to create proteins that perform a particular function. These chemical reactions are often compared with the chicken-and-egg problem of how life began with the emergence of DNA/RNA and protein-based cell machinery is essential to the birth of life, however, without the development of life, the chemical reaction that is the basis for it does not appear to work.
Abiogenesis research requires collaboration with scientists from various fields. This includes prebiotic chemists astrobiologists, planetary scientists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The word evolution is usually used to describe the accumulated changes in the genetic traits of an entire population over time. These changes may result from adaptation to environmental pressures, as discussed in the entry on Darwinism (see the entry on Charles Darwin for background) or natural selection.
The latter is a mechanism that increases the frequency of genes in a species which confer an advantage in survival over other species and causes an ongoing change in the appearance of a particular population. The specific mechanisms that cause these changes in evolutionary process include mutation or reshuffling genes during sexual reproduction, and gene flow between populations.
Natural selection is the process that makes beneficial mutations more frequent. All organisms undergo changes and reshuffles of their genes. As mentioned above, those with the beneficial trait have a higher reproduction rate than those that do not. Over the course of many generations, this variation in the number of offspring produced can result in gradual changes in the average amount of desirable traits within a group of.
A good example of this is the growth of beak size on various species of finches in the Galapagos Islands, which have developed different beak shapes to allow them to more easily access food in their new environment. These changes in the shape and form of organisms can also aid in the creation of new species.
Most of the changes that occur are the result of one mutation, however occasionally several will happen at once. Most of these changes can be harmful or neutral however, a small percentage could have a positive impact on survival and reproduce, increasing their frequency over time. Natural selection is a process that causes the accumulating changes over time that lead to the creation of a new species.
에볼루션 게이밍 confuse the idea of evolution with the idea that the traits inherited from parents can be altered through conscious choice or use and abuse, a notion known as soft inheritance. This is a misinterpretation of the biological processes that lead up to evolution. A more precise description is that evolution involves a two-step process, involving the independent and often conflicting forces of mutation and natural selection.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a group of mammal species which includes chimpanzees as well as gorillas. Our ancestral ancestors were walking on two legs, as demonstrated by the oldest fossils. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In reality our closest relatives are chimpanzees of the Pan genus. This includes pygmy and bonobos. The last common human ancestor as well as chimpanzees was between 8 and 6 million years ago.
Humans have evolved a variety of traits throughout time such as bipedalism, use of fire and advanced tools. But it's only in the last 100,000 years or so that most of the essential characteristics that differentiate us from other species have been developed. They include a huge, complex brain, the ability of humans to construct and use tools, and cultural variety.
Evolution occurs when genetic changes allow individuals in a group to better adapt to their environment. This adaptation is triggered by natural selection, a process whereby certain traits are preferred over other traits. The ones who are better adjusted are more likely to pass on their genes to the next generation. This is the way that all species evolve and is the basis of the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states that species which share a common ancestor tend to develop similar traits over time. It is because these traits allow them to survive and reproduce within their environment.
Every living thing has DNA molecules, which is the source of information that helps control their growth and development. The DNA structure is composed of base pairs arranged in a spiral around phosphate and sugar molecules. The sequence of bases found in each strand determines the phenotype - the characteristic appearance and behavior of an individual. Variations in a population can be caused by reshufflings and mutations of genetic material (known collectively as alleles).
Fossils from the earliest human species Homo erectus, as well as Homo neanderthalensis have been discovered in Africa, Asia and Europe. These fossils, despite a few differences in their appearance, all support the idea of the origins of modern humans in Africa. The evidence from fossils and genetics suggests that early humans left Africa and migrated to Asia and Europe.