The Berkeley Evolution Site
The Berkeley site contains resources that can help students and educators understand and teach evolution. The materials are organized in optional learning paths like "What does T. rex look like?"
Charles Darwin's theory of natural selection explains how creatures who are better able to adapt biologically to changing environments survive longer and those who do not disappear. Science is all about the process of biological evolutionary change.
What is Evolution?
The term "evolution" can be used to refer to a variety of nonscientific meanings. For example it could refer to "progress" and "descent with modifications." Scientifically it is a term used to describe a changing the characteristics of living things (or species) over time. In terms of biology, this change is based on natural selection and genetic drift.
Evolution is one of the fundamental tenets of modern biology. It is an accepted theory that has stood up to the test of time and thousands of scientific experiments. It does not address spiritual beliefs or God's presence like other scientific theories such as the Copernican or germ theory of disease.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to evolve in a step-like fashion over time. They called this the "Ladder of Nature" or the scala naturae. Charles Lyell used the term to describe this concept in his Principles of Geology, first published in 1833.
Darwin published his theory of evolution in his book On the Origin of Species published in the early 1800s. click through the next webpage asserts that different species of organisms have an ancestry that can be traced through fossils and other lines of evidence. This is the modern view on evolution, which is supported in many scientific fields, including molecular biology.
While scientists don't know exactly how organisms developed, they are confident that the evolution of life on earth is a result of natural selection and genetic drift. People with desirable traits are more likely to survive and reproduce. They transmit their genes on to the next generation. As time passes the gene pool gradually changes and evolves into new species.
Some scientists also use the term"evolution" to refer to large-scale evolutionary changes, such as the formation of a 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 the frequency of alleles across generations. Both definitions are valid and palatable, but some scientists believe that allele-frequency definitions omit important features of evolutionary process.
Origins of Life
The birth of life is a crucial stage in evolution. This occurs when living systems begin to evolve at the micro level - within cells, for instance.
The origins of life are an issue in a variety of disciplines such as biology, chemistry and geology. The nature of life is an area of interest in science, as it is a challenge to the theory of evolution. It is often described as "the mystery of life" or "abiogenesis."
The notion that life could be born from non-living things was called "spontaneous generation" or "spontaneous evolutionary". It was a common belief prior to Louis Pasteur's tests proved that the emergence of living organisms was not achievable through the natural process.
Many scientists believe that it is possible to make the transition from nonliving substances to life. The conditions necessary for the creation of life are difficult to reproduce in a lab. Researchers interested in the evolution and origins of life are also keen 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 number of complex chemical reactions, that are not predicted by simple physical laws. These include the reading and replication of complex molecules, such as DNA or RNA, to create proteins that perform a particular function. These chemical reactions are often compared with the chicken-and-egg dilemma of how life first appeared with the development of DNA/RNA as well as protein-based cell machinery is essential to the birth of life, however, without the development of life, the chemical process that allows it does not appear to work.
Info in the area of abiogenesis requires collaboration between scientists from many different disciplines. This includes prebiotic scientists, astrobiologists and planetary scientists.
Evolutionary Changes
The word evolution is usually used to refer to the accumulated changes in genetic characteristics of a population over time. 에볼루션 코리아 could result from adaptation to environmental pressures as discussed in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This is a method that increases the frequency of genes in a species that offer a survival advantage over others and causes gradual changes in the overall appearance of a group. These changes in evolutionary patterns are caused by mutations, reshuffling genes in the process of sexual reproduction, and also by gene flow.
While mutation and reshuffling of genes are common in all living things, the process by which beneficial mutations are more prevalent is referred to as natural selection. As previously mentioned, those who have the advantageous characteristic have a higher reproduction rate than those who don't. Over many generations, this difference in the number of offspring born could result in a gradual shift in the number of advantageous traits within a group of.
This can be seen in the evolution of different beak shapes for finches from the Galapagos Islands. They have created these beaks to ensure that they can eat more easily in their new environment. These changes in the form and shape of living organisms may also help create new species.
The majority of changes are caused by a single mutation, although sometimes multiple occur at the same time. The majority of these changes are not harmful or even harmful to the organism however a small portion of them could have an advantageous impact on the longevity and reproduction of the species, thus increasing the frequency of these changes in the population over time. Natural selection is a mechanism that can produce the accumulating change over time that leads to the creation of a new species.
Many people confuse the concept of evolution with the notion that the traits inherited from parents can be changed through conscious choice or by use and abuse, a concept called soft inheritance. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that cause it. A more accurate description of evolution is that it involves a two-step process, involving the independent and often conflicting forces of natural selection and mutation.
Origins of Humans
Humans of today (Homo Sapiens) evolved from primates, which is a group of mammal species which includes chimpanzees and gorillas. The earliest human fossils prove that our ancestors were bipeds, walking on two legs. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In fact, our closest relatives are chimpanzees from the Pan genus. This includes pygmy and bonobos. The last common ancestor of modern humans and chimpanzees was between 8 and 6 million years old.
Humans have evolved a variety of traits over time including bipedalism, the use of fire and advanced tools. It is only within the last 100,000 years that we've developed the majority of our key characteristics. These include a big brain that is sophisticated and the capacity of humans to create and use tools, and cultural variety.
Evolution occurs when genetic changes allow individuals of a population to better adapt to their surroundings. Natural selection is the mechanism that triggers this adaptation. Certain traits are preferred over others. The more adaptable are more likely to pass on their genes to the next generation. This is how 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 that have a common ancestor are likely to acquire similar traits in the course of time. This is because the traits allow them to survive and reproduce in their natural environment.
Every living thing has the DNA molecule, which contains the information needed to guide their growth. The structure of DNA is made of base pairs that are arranged in a spiral around sugar and phosphate molecules. The sequence of bases within each strand determines the phenotype - the characteristic appearance and behavior of an individual. The variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils of the first human species, Homo erectus and Homo neanderthalensis, have been found in Africa, Asia, and Europe. Although there are some differences, these fossils all support the idea that modern humans first came into existence in Africa. The fossil evidence and genetic evidence suggest that early humans migrated from Africa into Asia and then Europe.