The Berkeley Evolution Site
Teachers and students who browse the Berkeley site will find resources to aid in understanding and teaching evolution. The resources are organized into a variety of learning paths, such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection describes how species who are better able to adapt biologically to changing environments survive longer and those who do not become extinct. This process of evolution in biology is what science is all about.
What is Evolution?
The term "evolution" can have a variety of meanings that are not scientific. For instance it could mean "progress" and "descent with modifications." Scientifically it refers to a change in the characteristics of living organisms (or species) over time. The reason for this change is biological terms on natural selection and drift.
Evolution is a key concept in modern biology. It is a concept that has been tested and verified by thousands 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 religious belief or God's existence.
Early evolutionists like 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 scala naturae. 에볼루션코리아 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 asserts that all species of organisms share an ancestry that can be traced through fossils and other evidence. This is the modern view of evolution, and is supported by many research lines in science that include molecular genetics.
Scientists don't know how organisms have evolved however they are certain that natural selection and genetic drift is the primary reason for the development of life. Individuals with advantageous traits are more likely to survive and reproduce, and these individuals pass their genes on to the next generation. As time passes, the gene pool gradually changes and evolves into new species.
Certain scientists use the term evolution in reference to large-scale changes, such the evolution of one species from an ancestral one. Some scientists, like population geneticists define evolution in a broad sense, talking about the net change in the frequency of alleles across generations. Both definitions are acceptable and accurate however, some scientists claim that the definition of allele frequency is lacking essential aspects of the evolution process.
Origins of Life
The most important step in evolution is the emergence of life. This occurs when living systems begin to develop at the micro level, within individual cells, for instance.
The origins of life is one of the major topics in various disciplines, including biology, chemistry and geology. The question of how living organisms began is a major topic in science due to it being an important challenge to the theory of evolution. It is sometimes referred to as "the mystery" of life or "abiogenesis."
The idea that life could be born from non-living objects was referred to as "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 an organic process.
Many scientists believe it is possible to transition from living to nonliving substances. The conditions necessary for the creation of life are difficult to replicate in a laboratory. Researchers who are 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.
The growth of life is dependent on a variety of complex chemical reactions that are not predicted by the basic physical laws. These include the transformation of long information-rich molecules (DNA or RNA) into proteins that carry out functions, and the replication of these complex molecules to create new DNA or RNA sequences. These chemical reactions can be compared to the chicken-and-egg problem which is the development and emergence of DNA/RNA, a protein-based cell machinery, is required for the beginning of life. However, without life, the chemistry that is required to make it possible is working.
Abiogenesis research requires collaboration among scientists from various fields. This includes prebiotic chemists, astrobiologists, planetary scientists, geologists and geophysicists.
Evolutionary Changes
The term "evolution" today is used to describe general changes in genetic traits over time. These changes could result from the response to environmental pressures as described in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This is a process that increases the frequency of genes in a species that offer an advantage in survival over others which results in a gradual change in the appearance of a population. The specific mechanisms responsible for these evolutionary changes are mutation or reshuffling genes during sexual reproduction, and also gene flow between populations.
Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo changes and reshuffles of their genes. This happens because, as we've mentioned earlier those who have the beneficial trait tend to have a higher fertility rate than those without it. This difference in the number of offspring born over many generations can result in a gradual change in the number of advantageous traits within the group.
This can be seen in the evolution of various beak designs on finches that are found in the Galapagos Islands. They have developed these beaks so that they can eat more quickly in their new home. These changes in the shape and appearance of living organisms may also be a catalyst for the creation of new species.
The majority of the changes that take place are the result of one mutation, but occasionally several will happen at the same time. Most of these changes are neutral or even harmful to the organism however, a small proportion of them can have an advantageous impact on survival and reproduction, thus increasing the frequency of these changes in the population over time. 에볼루션 바카라사이트 is a mechanism that could result in the accumulation of changes over time that lead to a new species.
Some people confuse the idea of evolution with the notion that the traits inherited from parents can be changed through conscious choice, or through use and abuse, which is known as soft inheritance. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that trigger it. It is more accurate to say that the process of evolution is a two-step, independent process that involves the forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a species of mammal species that includes gorillas and chimpanzees. Our ancestors walked on two legs, as evidenced by the earliest fossils. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In reality, our closest relatives are the chimpanzees from the Pan genus. This includes pygmy as well as bonobos. The last common ancestor shared between modern humans and chimpanzees was 8 to 6 million years old.
Humans have evolved a wide range of characteristics over time such as bipedalism, use of fire, and the development of advanced tools. But it's only in the last 100,000 years or so that the majority of the characteristics that differentiate us from other species have emerged. These include language, a large brain, the ability to construct and use complex tools, as well as the diversity of our culture.
Evolution happens when genetic changes allow individuals of a population to better adapt to their environment. This adaptation is driven by natural selection, which is a process by which certain traits are favored over other traits. The more adaptable are more likely to pass their genes on to the next generation. This is how all species evolve, and it is the foundation of the theory of evolution.
Scientists refer to this as the "law of natural selection." The law says that species that share a common ancestor tend to develop similar traits over time. This is because these characteristics make it easier for them to live and reproduce in their environment.
Every living thing has an molecule called DNA that holds the information needed to control their growth. The structure of DNA is composed of base pair that are arranged in a spiral around sugar and phosphate molecules. The sequence of bases found in each strand determines the phenotype, the distinctive appearance and behavior of a person. The variations in a population are caused by reshufflings and mutations of genetic material (known collectively as alleles).
Fossils from the earliest human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. These fossils, despite differences in their appearance, all support the hypothesis of the origins of modern humans in Africa. The fossil and genetic evidence suggests that the first humans left Africa and moved to Asia and Europe.