The Berkeley Evolution Site
Students and teachers who explore the Berkeley site will find resources to help them understand and teach evolution. The resources are organized into optional learning paths, such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains that over time creatures that are more able to adapt to changing environments survive and those that are not extinct. This process of biological evolution is the basis of science.
What is Evolution?
The term "evolution" could be used to refer to a variety of nonscientific meanings. For example, it can mean "progress" and "descent with modifications." It is an academic term that refers to the process of changing characteristics over time in organisms or species. This change is based in biological terms on natural selection and drift.
Evolution is a key concept in the field of biology today. It is a concept that has been verified by thousands of scientific tests. Unlike many other scientific theories like the Copernican theory or the germ theory of disease, the evolution theory does not address issues of spiritual belief or God's existence.
Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical characteristics were predetermined to change, in a step-wise manner, as time passes. mouse click the up coming post referred to this as the "Ladder of Nature" or the scala naturae. Charles Lyell used the term to describe this concept in his Principles of Geology, first published in 1833.
Darwin presented his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It states that all species of organisms share the same ancestry, which can be traced through fossils and other evidence. This is the current understanding of evolution, and is supported by many lines of scientific research that include molecular genetics.
While scientists do not know exactly how organisms evolved but they are certain that the evolution of life on earth is a result of natural selection and genetic drift. People with traits that are advantageous are more likely to survive and reproduce, and these individuals pass their genes on to the next generation. Over time the gene pool gradually changes and develops into new species.
Some scientists also use the term evolution to describe large-scale evolutionary changes, such as the formation of the new species from an ancestral species. Certain scientists, including population geneticists, define evolution in a broad sense, talking about the net variation in the frequency of alleles over generations. Both definitions are valid and reliable however, some scientists claim that the definition of allele frequency is lacking essential aspects of the evolution process.
Origins of Life
The birth of life is a crucial step in evolution. The beginning of life takes place when living systems start to develop at a microscopic level, like within cells.
The origins of life are an important issue in a variety of fields such as biology and chemistry. The nature of life is a subject of great interest in science, as it challenges the theory of evolution. It is often called "the mystery of life" or "abiogenesis."
Traditionally, the idea that life could emerge from nonliving things is called spontaneous generation or "spontaneous evolution." This was a popular view before Louis Pasteur's experiments showed that it was impossible for the emergence of life to occur by a purely natural process.
Many scientists believe it is possible to transition from nonliving substances to living ones. However, the conditions that are required are extremely difficult to reproduce in a laboratory. This is why researchers investigating the nature of life are also interested in determining the physical properties of early Earth and other planets.
Additionally, the evolution of life is dependent on the sequence of extremely complex chemical reactions that can't be predicted from basic physical laws alone. These include the reading and the replication of complex molecules, such as DNA or RNA, to create proteins that serve a specific function. These chemical reactions can be compared with the chicken-and-egg problem which is the development and emergence of DNA/RNA, protein-based cell machinery, is required for the beginning of life. Although, without life, the chemistry required to create it is working.
Abiogenesis research requires collaboration among scientists from different disciplines. This includes prebiotic scientists, astrobiologists and planet scientists.
Evolutionary Changes
The term "evolution" today is used to describe general changes in genetic traits over time. These changes can 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 process increases the number of genes that offer a survival advantage in a species, resulting in an overall change in the appearance of an entire group. These changes in evolutionary patterns are caused by mutations, reshuffling genes during sexual reproduction, and gene flow.
Natural selection is the process that makes beneficial mutations more frequent. All organisms undergo changes and reshuffles of their genes. As previously mentioned, those who have the advantageous trait have a higher reproduction rate than those that do not. Over the course of several generations, this variation in the numbers of offspring born can result in a gradual shift in the number of beneficial characteristics in a particular population.
This is evident in the evolution of different beak shapes for finches from the Galapagos Islands. They have created these beaks to ensure that they can eat more easily in their new habitat. These changes in form and shape can also aid in the creation of new species.
Most of the changes that take place are caused by one mutation, but sometimes, several changes occur at the same time. Most of these changes can be negative or even harmful, but a small number can have a beneficial impact on survival and reproduction with increasing frequency as time passes. This is the process of natural selection, and it can eventually result in the cumulative changes that eventually result in the creation of a new species.
Many people think that evolution is a form of soft inheritance, which is the idea that inherited traits can be altered by conscious choice or abuse. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that cause it. It is more precise to say that evolution is a two-step, separate process that 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 gorillas and chimpanzees. The earliest human fossils show that our ancestors were bipeds. They were walkers with two legs. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In fact we are the most closely related to the chimpanzees within the Pan genus which includes bonobos and pygmy chimpanzees. The last common ancestor between modern humans and chimpanzees was 8 to 6 million years old.
Humans have evolved a wide range of traits throughout time including bipedalism, the use of fire and advanced tools. It's only within the last 100,000 years that we've developed the majority of our important traits. They include a huge brain that is sophisticated, the ability of humans to construct and use tools, as well as cultural variety.
Evolution occurs when genetic changes allow individuals of a population to better adapt to their surroundings. This adaptation is triggered by natural selection, which is a process by which certain traits are favored over other traits. The ones with the best adaptations are more likely to pass their genes to the next generation. This is how all species evolve and the basis of the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states that species that have an ancestor in common will tend to develop similar characteristics as time passes. This is because these characteristics make it easier for them to survive and reproduce in their environment.
All organisms possess an molecule called DNA that holds the information necessary to direct their growth. The DNA structure is composed of base pair that are arranged in a spiral around sugar and phosphate molecules. The sequence of bases in each strand determines the phenotype - the characteristic appearance and behavior of a person. Variations in mutations and reshuffling of the genetic material (known as alleles) during reproduction causes variation in a population.
Fossils from the early human species Homo erectus, as well as Homo neanderthalensis have been discovered in Africa, Asia and Europe. Despite some differences, these fossils all support the idea that modern humans first came into existence in Africa. Genetic and fossil evidence also suggest that early humans migrated out of Africa into Asia and then Europe.