The Berkeley Evolution Site
The Berkeley site offers resources that can help students and teachers learn about and teach evolution. The resources are organized into a variety of learning paths like "What did T. rex taste like?"
Charles Darwin's theory of natural selection states that over time creatures that are better able to adapt biologically to changing environments do better than those that don't become extinct. This process of biological evolution is the main focus of science.
What is Evolution?
The term "evolution" can have many nonscientific meanings, including "progress" or "descent with modification." It is scientifically based and is used to describe the process of change of characteristics over time in organisms or species. This change is based in biological terms on natural selection and drift.
Evolution is a key principle in modern biology. It is an established theory that has withstood the tests of time and thousands of scientific experiments. Contrary to other theories of science such as the Copernican theory or the germ theory of disease, evolution is not a discussion of religion or God's existence.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to change in a gradual manner over time. They called this the "Ladder of Nature" or scala naturae. Charles Lyell used the term to describe this concept 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 share an ancestry that can be traced by fossils and other evidence. This is the current view of evolution, and is supported by many lines of scientific research that include molecular genetics.
Scientists do not know how organisms have evolved but they are sure that natural selection and genetic drift is responsible for the evolution of life. People with advantages are more likely than others to survive and reproduce. These individuals then pass their genes on to the next generation. As time passes, the gene pool gradually changes and evolves into new species.
Some scientists also use the term evolution to refer to large-scale changes in evolutionary processes like the creation of an entirely new species from an ancestral species. Others, like population geneticists, define it more broadly by referring the net change in the frequency of alleles across generations. Both definitions are correct and palatable, but some scientists argue that allele-frequency definitions do not include important aspects of evolution.
Origins of Life
A key step in evolution is the development of life. 에볼루션 바카라사이트 of life takes place when living systems begin to evolve at a micro level, like within individual cells.
The origins of life are one of the major topics in various disciplines that include biology, chemistry and geology. The question of how living organisms began has a special place in science due to it being an enormous challenge to the theory of evolution. It is often described as "the mystery of life," or "abiogenesis."
Traditionally, the idea that life can emerge from nonliving things is known as spontaneous generation, or "spontaneous evolution." This was a popular view before Louis Pasteur's experiments proved that it was impossible for the development of life to be a result of the natural process.
Many scientists believe that it is possible to make the transition from nonliving materials to living. The conditions needed for the creation of life are difficult to replicate in a laboratory. This is why researchers investigating the beginnings of life are also interested in determining the physical properties of the early Earth and other planets.
The growth of life is dependent on a number of complex chemical reactions which are not predicted by simple physical laws. These include the reading and the replication of complex molecules, like DNA or RNA, to create proteins that perform a particular function. These chemical reactions can be compared to the chicken-and-egg problem: the emergence and development of DNA/RNA, the protein-based cell machinery, is essential for the beginning of life. However, without life, the chemistry required to create it does appear to work.
Abiogenesis research requires collaboration among scientists from various fields. This includes prebiotic scientists, astrobiologists, and planetary scientists.
Evolutionary Changes
The term "evolution" is used to describe cumulative changes in genetic characteristics over time. These changes may be the result of the adaptation to environmental pressures as described in Darwinism.
The latter is a mechanism that increases the frequency of genes that confer an advantage in survival over other species which results in gradual changes in the overall appearance of a group. The specific mechanisms behind these evolutionary changes are mutation and reshuffling of genes in sexual reproduction, as well as 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 is because, as mentioned above those who have the beneficial trait tend to have a higher reproduction rate than those with it. This difference in the number of offspring produced over a number of generations could cause a gradual change in the average number of beneficial traits in the group.
One good example is the growth of beak size on different species of finches found on the Galapagos Islands, which have developed different beak shapes to allow them to more easily access food in their new environment. These changes in form and shape can also aid in the creation of new species.
The majority of the changes that take place are caused by one mutation, but sometimes, several changes occur at the same time. Most of these changes may be neutral or even harmful however, a small percentage could have a positive impact on survival and reproduce and increase their frequency as time passes. Natural selection is a process that can produce the accumulating changes over time that lead to the creation of a new species.
Many people confuse the concept of evolution with the notion that the traits inherited from parents can be altered by conscious choice or use and abuse, a concept called soft inheritance. This is a misunderstanding of the biological processes that lead up to the process of evolution. A more accurate description of evolution is that it is a two-step process involving the independent and often conflicting forces of mutation and natural selection.
Origins of Humans
Humans of today (Homo Sapiens) evolved from primates, a species of mammal species that includes chimpanzees as well as gorillas. Our ancestral ancestors were walking on two legs, as shown by the oldest fossils. Genetic and biological similarities suggest that we are closely related to chimpanzees. In actual fact, our closest relatives are chimpanzees from the Pan genus. This includes pygmy as well as bonobos. The last common human ancestor as well as chimpanzees lived between 8 and 6 million years ago.
Humans have evolved a wide range of characteristics over time, including bipedalism, the use of fire and advanced tools. It's only in the last 100,000 years that we have developed the majority of our key traits. These include language, a large brain, the capacity to build 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 surroundings. This adaptation is triggered by natural selection, a process whereby certain traits are more desirable than others. Those with the better adaptations are more likely to pass their genes to the next generation. This is the way all species evolve, and the basis of the theory of evolution.
Scientists call it the "law of natural selection." The law states that species that have a common ancestor, tend to develop similar traits over time. This is because those characteristics make it easier for them to survive and reproduce in their natural environment.
Every organism has DNA molecules, which provides the information necessary to control their growth and development. The DNA structure is composed of base pair which are arranged in a spiral, around sugar and phosphate molecules. The sequence of bases in each strand determines the phenotype, the appearance and behavior of an individual. 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 were discovered in Africa, Asia, and Europe. These fossils, despite some differences in their appearance all support the theory of modern humans' origins in Africa. Genetic and fossil evidence also suggest that early humans moved out of Africa into Asia and then Europe.