The Berkeley Evolution Site
Students and teachers who explore the Berkeley site will find a wealth of resources to assist them in understanding and teaching evolution. The materials are organized into optional learning paths such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains how creatures who are better able to adapt biologically to changing environment survive over time and those who do not disappear. Science is concerned with the process of biological evolutionary change.
What is Evolution?
The word evolution can be used to refer to a variety of nonscientific meanings. For instance it could mean "progress" and "descent with modifications." Scientifically it is a term used to describe a changes in the traits of organisms (or species) over time. This change is based in biological terms on natural selection and drift.
Evolution is one of the fundamental tenets of modern biology. It is a theory that has been verified through thousands of scientific tests. Evolution doesn't deal with spiritual beliefs or God's presence in the same way as other scientific theories such as the Copernican or germ theory of diseases.
Early evolutionists such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to evolve in a gradual 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 claims that different species of organisms have an ancestry that can be proven through fossils and other evidence. This is the modern view of evolution that is supported by numerous research lines in science, including molecular genetics.
While scientists do not know the exact mechanism by which organisms evolved however they are sure that the evolution of life on earth is a result of natural selection and genetic drift. 에볼루션게이밍 with advantages are more likely to survive and reproduce. These individuals transmit their genes to the next generation. Over time the gene pool gradually changes and evolves into new species.
Some scientists employ the term evolution in reference to large-scale changes, like the evolution of an animal from an ancestral one. Other scientists, such as population geneticists, define evolution more broadly by referring to a net change in allele frequencies over generations. Both definitions are valid and acceptable, however certain scientists argue that allele frequency definitions miss important aspects of the evolution.
Origins of Life
The emergence of life is a key stage in evolution. This occurs when living systems begin to evolve at a micro-level - within individual cells, for example.
The origins of life is a topic in many disciplines that include biology, chemistry and geology. The nature of life is an area that is of immense interest to scientists, as it challenges the theory of evolution. It is sometimes referred to "the mystery" of life or "abiogenesis."
The notion that life could arise from non-living things was called "spontaneous generation" or "spontaneous evolutionary". This was a common belief prior to Louis Pasteur's tests proved that the creation of living organisms was not possible by a natural process.
Many scientists still believe it is possible to go from nonliving substances to life. The conditions required to create life are difficult to replicate in a laboratory. This is why scientists studying the nature of life are also keen to understand the physical properties of early Earth and other planets.
The growth of life is dependent on a variety of complex chemical reactions, which cannot be predicted by simple physical laws. These include the reading and the replication of complex molecules, like DNA or RNA, to produce proteins that serve a specific function. These chemical reactions are often compared with the chicken-and-egg dilemma of how life first appeared with the appearance of DNA/RNA and protein-based cell machinery is essential for the onset of life, however, without the appearance of life, the chemistry that makes it possible is not working.
Research in the area of abiogenesis requires collaboration between scientists from a variety of fields. This includes prebiotic scientists, astrobiologists and planetary scientists.
Evolutionary Changes
The term "evolution" is used to describe the general changes in genetic traits over time. These changes may be the result of adapting to environmental pressures, as described in Darwinism.
This latter mechanism increases the number of genes that confer an advantage for survival in the species, leading to an overall change in the appearance of the group. These evolutionary changes are caused by mutations, reshuffling of genes during sexual reproduction, and gene flow.
Natural selection is the process that makes beneficial mutations more common. All organisms undergo mutations and reshuffles of genes. This occurs because, as we've mentioned earlier, those individuals with the beneficial trait tend to have a higher reproduction rate than those without it. Over the course of many generations, this variation in the number of offspring produced can result in gradual changes in the amount of desirable traits in a population.
An excellent example is the growth of beak size on different species of finches in the Galapagos Islands, which have evolved different shaped beaks to enable them to more easily access food in their new environment. These changes in form and shape can aid in the creation of new organisms.
Most of the changes that take place are the result of one mutation, but occasionally, multiple mutations occur at once. The majority of these changes are neither harmful nor even harmful to the organism however a small portion of them could have an advantageous impact on survival and reproduction, thus increasing their frequency in the population over time. Natural selection is a mechanism that could result in the accumulation of change over time that eventually leads to a new species.
Many people think that evolution is a form of soft inheritance that is the belief that inherited traits can be changed through conscious choice or abuse. This is a misinterpretation of the biological processes that lead up to the process of evolution. It is more accurate to say that the process of evolution is a two-step, independent process, which involves the forces of natural selection and mutation.
Origins of Humans
Humans today (Homo sapiens) evolved from primates - a species of mammals that includes gorillas, chimpanzees, and bonobos. Our predecessors walked on two legs, as demonstrated by the earliest fossils. Genetic and biological similarities suggest that we have an intimate relationship with Chimpanzees. In actual fact, our closest relatives are the chimpanzees belonging to the Pan genus. This includes pygmy, as well as bonobos. The last common ancestor of modern humans and chimpanzees dated 8 to 6 million years old.
Humans have evolved a wide range of traits over time including bipedalism, the use of fire, and the development of advanced tools. It is only within the last 100,000 years that we've developed the majority of our key traits. These include language, a large brain, the ability to create and utilize complex tools, and the ability to adapt to cultural differences.
The process of evolution occurs when genetic changes allow members of a population to better adapt to their environment. Natural selection is the process that drives this change. Certain characteristics are more desirable than others. People with better adaptations are more likely to pass their genes to the next generation. This is the process that evolves all species, and it is the basis of the theory of evolution.
Scientists refer to it as the "law of natural selection." The law says that species that have a common ancestor, tend to develop similar traits over time. This is because the characteristics make it easier for them to live and reproduce in their natural environment.
Every living thing has a DNA molecule, which contains the information needed to control their growth and development. The DNA structure is composed of base pair arranged in a spiral around phosphate and sugar molecules. The sequence of bases within each strand determines phenotype which is the person's distinctive appearance and behavior. Variations in a population can be caused by reshufflings and mutations of genetic material (known collectively as alleles).
Fossils from the early human species Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia and Europe. Although there are some differences they all support the hypothesis that modern humans first appeared in Africa. The fossil and genetic evidence suggests that early humans left Africa and moved to Asia and Europe.