The Berkeley Evolution Site
The Berkeley site has resources that can assist students and teachers to understand and teach about evolution. The materials are arranged in various learning paths that can be used in a variety of ways for example "What does T. rex look like?"
Charles Darwin's theory of natural selection explains that over time, animals that are more adaptable to changing environments do better than those that don't become extinct. Science is concerned with the process of biological evolutionary change.
What is Evolution?
The term "evolution" could have many nonscientific meanings. For instance it could refer to "progress" and "descent with modifications." Scientifically it refers to a change in the characteristics of organisms (or species) over time. In biological terms, this change is due to natural selection and genetic drift.
Evolution is a key concept in modern biology. It is an established theory that has stood up to the test of time and thousands of scientific tests. Evolution does not deal with God's presence or spiritual beliefs in the same way as other theories in science, like the Copernican or germ theory of disease.
Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical traits were predetermined to change in a step-wise manner, over time. They referred to this as the "Ladder of Nature" or scala naturae. Charles Lyell used the term to describe this idea in his Principles of Geology, first published in 1833.
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 have an ancestry that can be traced by fossils and other evidence. This is the current view on evolution, and is supported by a variety of areas of science, including molecular biology.
Scientists don't know how organisms evolved however they are certain that natural selection and genetic drift is the primary reason for the development of life. Individuals with advantageous characteristics are more likely to survive and reproduce. These individuals then pass their genes on to the next generation. In time this leads to a gradual accumulation of changes to the gene pool that gradually result in new species and forms.
Some scientists also employ the term"evolution" to describe large-scale evolutionary changes such as the creation of a new species from an ancestral species. Other scientists, such as population geneticists, define the term "evolution" more broadly by referring to a net change in the frequency of alleles across generations. Both definitions are valid and reliable however some scientists believe that the allele-frequency definition omits crucial aspects of the evolutionary process.
Origins of Life
A key step in evolution is the development of life. This happens when living systems begin to develop at a micro-level - within cells, for instance.
The origins of life are an important topic in a variety of areas such as biology and chemistry. The nature of life is a subject of great interest in science because it challenges the theory of evolution. It is sometimes referred to "the mystery" of life or "abiogenesis."
The notion that life could be born from non-living objects was referred to as "spontaneous generation" or "spontaneous evolutionary". It was a popular belief prior to Louis Pasteur's experiments proved that the emergence of living organisms was not possible through the natural process.
Many scientists believe that it is possible to go from nonliving substances to life. However, the conditions needed are extremely difficult to replicate in labs. Researchers who are interested in the origins and development of life are also eager to learn about the physical characteristics 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 simple physical laws. These include the reading and replication of complex molecules, like DNA or RNA, to produce proteins that serve a specific function. These chemical reactions are often compared to the chicken-and-egg issue of how life came into existence: The development of DNA/RNA as well as protein-based cell machinery is crucial to the birth of life, however, without the appearance of life the chemical reaction that is the basis for it does not appear to work.
Abiogenesis research requires collaboration between researchers from different disciplines. This includes prebiotic chemists, the astrobiologists, the planet scientists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The term "evolution" is commonly used today to describe the cumulative changes in the genetic characteristics of a population 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 mechanism also increases the number of genes that provide the advantage of survival for an animal, resulting in an overall change in the appearance of a group. These changes in evolutionary patterns 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 changes and reshuffles of their genes. As mentioned above, those with the beneficial trait have a higher reproductive rate than those who do not. Over the course of several generations, this difference in the numbers of offspring born could result in an inclination towards a shift in the average number of beneficial characteristics in a particular population.
One good example is the growing beak size on different species of finches found on the Galapagos Islands, which have evolved different shaped beaks to allow them to more easily access food in their new home. These changes in shape and form could also help create new organisms.
The majority of changes are caused by one mutation, although sometimes multiple occur at the same time. Most of these changes can be negative or even harmful however, a small percentage can have a beneficial impact on survival and reproduction with increasing frequency as time passes. Natural selection is a mechanism that could result in the accumulation of change over time that leads to the creation of a new species.
Some people confuse the idea of evolution with the notion that traits inherited can be altered by conscious choice, or through use and abuse, a concept known as soft inheritance. This is a misinterpretation of the biological processes that lead up to evolution. It is more accurate to say that evolution is a two-step, independent process, which involves the forces of natural selection as well as mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, which is a group of mammal species which includes chimpanzees as well as gorillas. 에볼루션 블랙잭 prove that our ancestors were bipeds, walkers on two legs. Genetic and biological similarities suggest that we are closely related to Chimpanzees. In actual fact we are the most closely related to the chimpanzees within the Pan Genus which includes pygmy chimpanzees and bonobos. The last common ancestor shared between humans and chimpanzees was between 8 and 6 million years old.
Humans have evolved a wide range of traits throughout time, including bipedalism, the use of fire, and the development of advanced tools. It's only in the last 100,000 years that we have developed the majority of our important characteristics. They include language, a large brain, the ability to create and utilize complex tools, as well as cultural diversity.
The process of evolution is when genetic changes allow members of a group to better adapt to the environment. This adaptation is triggered by natural selection, a process that determines certain traits are more desirable than other traits. The ones with the best adaptations are more likely to pass on their genes to the next generation. This is the way that all species evolve, and it is the basis of the theory of evolution.
Scientists call it the "law of natural selection." The law says that species that have a common ancestor are more likely to develop similar characteristics over time. This is because these traits allow them to survive and reproduce in their natural environment.
All organisms possess the DNA molecule, which contains the information necessary to direct their growth. The DNA molecule consists of base pairs that are spirally arranged around sugar molecules and phosphate molecules. The sequence of bases within each strand determines phenotype or the individual's unique appearance and behavior. Variations in a population can be caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils of the first human species, Homo erectus and Homo neanderthalensis were discovered in Africa, Asia, and Europe. These fossils, despite a few differences in their appearance, all support the hypothesis of modern humans' origins in Africa. The evidence from fossils and genetics suggests that early humans left Africa and moved to Asia and Europe.