The Berkeley Evolution Site
The Berkeley site contains resources that can help students and teachers understand and teach evolution. The resources are organized into optional learning paths such as "What did T. rex taste like?"
Charles Darwin's theory on natural selection explains how animals that are better equipped to adapt biologically to a changing environments over time, and those who do not end up becoming extinct. Science is about this process of biological evolution.
What is Evolution?
The term "evolution" can have a variety of meanings that are not scientific. For example it could refer to "progress" and "descent with modifications." Scientifically it refers to a process of change in the characteristics of living things (or species) over time. This change is based in biological terms on natural drift and selection.
Evolution is one of the fundamental tenets of modern biology. It is a concept that has been tested and confirmed by a myriad of scientific tests. Unlike many other scientific theories, such as the Copernican theory or the germ theory of disease, evolution does not address questions of religion or the existence of God.
Early evolutionists, such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to change in a step-like fashion over time. This was referred to as the "Ladder of Nature", or 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 claims that different species of organisms share an ancestry that can be proven through fossils and other evidence. This is the current perspective on evolution, and is supported by a variety of disciplines, including molecular biology.
Scientists do not know how organisms evolved but they are sure that natural selection and genetic drift are the primary reason for the evolution of life. People with traits that are advantageous are more likely to live and reproduce, and these individuals transmit their genes to the next generation. As time passes the gene pool slowly changes and evolves into new species.
Some scientists employ the term"evolution" in reference to large-scale change, such as the formation of one species from an ancestral one. Others, like population geneticists, define it more broadly by referring an overall change in allele frequencies over generations. Both definitions are acceptable and precise, although some scientists argue that the allele-frequency definition omits important features of the evolutionary process.
Origins of Life
The emergence of life is a crucial stage in evolution. This occurs when living systems begin to evolve at a micro-level - within individual cells, for example.
The origins of life are an important issue in many fields that include biology and the field of chemistry. The question of how living organisms began is a major topic in science since it poses a major challenge to the theory of evolution. It is sometimes referred to as "the mystery" of life or "abiogenesis."
Traditionally, the belief that life can emerge from nonliving things is called spontaneous generation, or "spontaneous evolution." This was a common belief before Louis Pasteur's experiments showed that it was impossible for the creation of life to occur by the natural process.
Many scientists believe that it is possible to go from nonliving substances to living. However, the conditions needed are extremely difficult to reproduce in the laboratory. 에볼루션사이트 interested in the origins and evolution of life are also eager to know the physical properties of the early Earth as well as other planets.
Furthermore, the growth of life depends on a sequence of very complex chemical reactions that can't be predicted based on basic physical laws alone. These include the reading and the replication of complex molecules, such as DNA or RNA, in order to make proteins that perform a specific function. These chemical reactions can be compared with the chicken-and-egg problem which is the development and emergence of DNA/RNA, a protein-based cell machinery, is essential for the onset life. Although, without life, the chemistry required to enable it appears to be working.
Research in the area of abiogenesis requires collaboration between scientists from various disciplines. This includes prebiotic chemists the astrobiologists, the planet scientists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The term "evolution" today is used to describe the general changes in genetic traits over time. These changes could be the result of the adaptation to environmental pressures as described in Darwinism.
This is a process that increases the frequency of genes that confer a survival advantage over others and causes a gradual change in the appearance of a group. These changes in evolutionary patterns are caused by mutations, reshuffling of genes in the process of sexual reproduction, and also by the flow of genes.
While mutation and reshuffling of genes occur in all living organisms and the process by which beneficial mutations become more common is called natural selection. 에볼루션 무료 바카라 is because, as noted above those who have the beneficial trait tend to have a higher fertility rate than those who do not have it. Over the course of many generations, this variation in the numbers of offspring produced can result in a gradual shift in the average amount of desirable traits in a population.
One good example is the growing the size of the beaks on different species of finches found on the Galapagos Islands, which have evolved different shaped beaks that allow them to easily access food in their new environment. These changes in the form and shape of living organisms may also be a catalyst for the creation of new species.
Most of the changes that occur are caused by a single mutation, but occasionally several will happen at the same time. Most of these changes are not harmful or even detrimental to the organism, but a small percentage can have a positive 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 process that could result in the accumulation of changes over time that lead to a new species.
Many people confuse the concept of evolution with the notion that inherited characteristics can be changed through conscious choice or use and abuse, a notion known as soft inheritance. This 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 independent process, that is influenced by the forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo sapiens) evolved from primates - a group of mammals that also includes chimpanzees and gorillas and bonobos. The earliest human fossils prove that our ancestors were bipeds - walkers on two legs. Biological and genetic similarities indicate that we have a close relationship with chimpanzees. In actual fact our closest relatives are the 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 developed a range of characteristics over time, including bipedalism, the use of fire and advanced tools. But it's only in the last 100,000 years or so that the majority of the essential characteristics that differentiate us from other species have emerged. They include a huge, complex brain human ability to create and use tools, and cultural variety.
The process of evolution occurs when genetic changes allow members of a population to better adapt to their surroundings. This adaptation is driven by natural selection, which is a process by which certain traits are favored over other traits. People with better adaptations are more likely to pass on their genes to the next generation. This is the way all species evolve, and the foundation for the theory of evolution.
Scientists call this the "law of natural selection." The law says that species that have a common ancestor, tend to develop similar characteristics over time. This is because these characteristics make it easier for them to survive and reproduce in their natural environment.
Every organism has a DNA molecule, which is the source of information that helps guide their growth and development. The DNA molecule consists of base pairs that are spirally arranged around phosphate molecules and sugar molecules. The sequence of bases within each strand determines the phenotype or the individual's unique appearance and behavior. Variations in a population can be caused by mutations and reshufflings of genetic material (known collectively as alleles).
Fossils of the earliest human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. These fossils, despite a few differences in their appearance all support the theory of modern humans' origins in Africa. The evidence from fossils and genetics suggests that early humans left Africa and moved to Asia and Europe.