10 Evolution Site Tricks Experts Recommend
The Berkeley Evolution Site
The Berkeley site contains resources that can help students and educators understand and teach evolution. The materials are arranged in optional learning paths, such as "What does T. rex look like?"
Charles Darwin's theory of natural selection states that over time, animals that are more able to adapt to changing environments do better than those that do not become extinct. This process of evolution in biology is the basis of science.
What is Evolution?
The term "evolution" could have many nonscientific meanings. For instance it could refer to "progress" and "descent with modifications." It is an academic term that refers to the process of changing traits over time in organisms or species. This change is based in biological terms on natural drift and selection.
Evolution is a central tenet of modern biology. It is an established theory that has withstood the test of time and a multitude of scientific tests. Unlike many other scientific theories like the Copernican theory or the germ theory of disease, the evolution theory is not a discussion of religious belief or God's existence.
Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical traits were predetermined to change in a step-like manner, over time. This was called 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 states that all species of organisms share an ancestry that can be traced using fossils and other evidence. This is the modern view of evolution, which is supported by a variety of scientific fields, including molecular biology.
While scientists don't know exactly how organisms evolved, they are confident that the evolution of life on earth is the result of natural selection and genetic drift. Individuals with advantageous characteristics are more likely to survive and reproduce. They pass on their genes on to the next generation. As time passes, the gene pool gradually changes and develops into new species.
Some scientists employ the term evolution in reference to large-scale changes, like the evolution of a species from an ancestral one. Others, like population geneticists, define evolution more broadly by referring to an overall change in the frequency of alleles across generations. Both definitions are acceptable and accurate however some scientists believe that the definition of allele frequency is lacking essential aspects of the evolution process.
Origins of Life
The development of life is an essential step in evolution. The emergence of life occurs when living systems start to evolve at a micro level, such as within individual cells.
The origin of life is an issue in a variety of disciplines such as geology, chemistry, biology and chemistry. The question of how living things got their start is of particular importance in science since it poses an enormous challenge to the theory of evolution. It is often described as "the mystery of life," or "abiogenesis."
The notion that life could emerge from non-living things was called "spontaneous generation" or "spontaneous evolutionary". It was a popular belief prior to Louis Pasteur's tests showed that the development of living organisms was not possible by a natural process.
Many scientists believe it is possible to move from living to nonliving substances. However, the conditions needed are extremely difficult to replicate in a laboratory. Researchers interested in the origins and development of life are also eager to understand 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 basic physical laws. These include the reading and re-reading of complex molecules, such as DNA or RNA, to produce proteins that perform a specific function. These chemical reactions can be compared with a chicken-and egg problem: the emergence and development of DNA/RNA, protein-based cell machinery, is required for the onset life. Although, without life, the chemistry needed to create it appears to be working.
Research in the area of abiogenesis requires collaboration between scientists from various disciplines. This includes prebiotic chemists astrobiologists, planetary scientists geophysicists, geologists, and geophysicists.
Evolutionary Changes
The term "evolution" is commonly used to describe the accumulated changes in the genetic characteristics of a population over time. These changes could result from adaptation to environmental pressures, as explained in the article 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 those genes in a species which confer an advantage in survival over others which results in gradual changes in the overall appearance of a particular population. These evolutionary changes are triggered by mutations, reshuffling of genes during sexual reproduction, and the flow of genes.
While reshuffling and mutation of genes are common in all living organisms, the process by which beneficial mutations are more prevalent is called natural selection. As mentioned above, those with the beneficial characteristic have a higher reproduction rate than those who don't. Over the course of many generations, this difference in the numbers of offspring produced can result in an inclination towards a shift in the number of advantageous traits within a group of.
A good example of this is the growth of beak size on various species of finches on the Galapagos Islands, which have evolved different shaped beaks to allow them to more easily access food in their new environment. These changes in the shape and appearance of organisms could 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 sometimes, several changes occur at the same time. Most 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 survival of the organism and its reproduction, thereby 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.
Some people confuse the notion of evolution with the notion that traits inherited can be altered through conscious choice or by use and abuse, a notion known as soft inheritance. This is a misunderstanding of the nature of evolution and of the actual biological processes that cause it. A more accurate description is that evolution is a two-step process involving the independent and often antagonistic forces of natural selection and mutation.
Origins of Humans
Humans of today (Homo sapiens) evolved from primates - a group of mammals that includes chimpanzees, gorillas, and bonobos. The earliest human fossils show that our ancestors were bipeds, walkers with two legs. Genetic and biological similarities show that we share an intimate relationship with Chimpanzees. In fact we are the most closely related to the chimpanzees within the Pan genus that includes pygmy and pygmy chimpanzees and bonobos. The last common ancestor of modern humans and chimpanzees dated 8 to 6 million years old.
Humans have evolved a variety of characteristics over time including bipedalism, the use of fire, and the development of advanced tools. However, Going In this article is only in the last 100,000 years or so that the majority of the essential characteristics that differentiate us from other species have developed. These include a large, complex brain and the capacity of humans to construct and use tools, as well as cultural diversity.
Evolution occurs when genetic changes enable members of a group to better adapt to their environment. Natural selection is the mechanism that triggers this adaptation. Certain characteristics are more desirable than others. The ones with the best adaptations are more likely to pass on their genes to the next generation. This is the process that evolves all species, and it is the foundation of the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states that species that have a common ancestor are likely to develop similar traits over time. This is because these traits help them to survive and reproduce within their environment.
Every living thing has the DNA molecule, which contains the information needed to guide their growth. The DNA molecule is made up of base pairs arranged spirally around sugar molecules and phosphate molecules. The sequence of bases within each strand determines the phenotype which is the person's distinctive appearance and behavior. A variety of mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction can cause variations in a population.
Fossils of the first human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. Despite some differences they all support the notion that modern humans first appeared in Africa. The fossil evidence and genetic evidence suggest that early humans migrated out of Africa into Asia and then Europe.