Teachers and students who browse the Berkeley site will find resources to help them understand and teach evolution. The resources are arranged into different learning paths, such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection explains that in time, creatures more adaptable to changing environments do better than those that do not become extinct. This process of evolution is the main focus of science.
What is Evolution?
The word evolution has many nonscientific meanings, such as "progress" or "descent with modification." It is scientifically based and refers to the process of change of characteristics over time in organisms or species. This change is based in biological terms on natural drift and selection.
Evolution is one of the fundamental tenets of modern biology. It is a theory that has been confirmed by thousands of scientific tests. Contrary to other theories of science such as the Copernican theory or the germ theory of disease, evolution does not address issues of spiritual belief or the existence of God.
Early evolutionists, such as Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical traits were predetermined to change in a step-like fashion 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 asserts that all species of organisms have an ancestry that can be traced by fossils and other evidence. This is the modern view of evolution, which is supported by numerous research lines in science which includes molecular genetics.
Although scientists aren't able to determine exactly how organisms evolved but they are certain that the evolution of life on earth is a result of natural selection and genetic drift. Individuals with advantageous traits are more likely to live and reproduce, and they 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" to refer to large-scale changes, like the evolution of an animal from an ancestral one. Other scientists, like population geneticists, define evolution more broadly by referring the net variation in the frequency of alleles over generations. Both definitions are correct and palatable, but some scientists argue that allele-frequency definitions omit important features of evolutionary process.
Origins of Life
The development of life is a crucial step in evolution Kr. The emergence of life happens when living systems start to evolve at a micro level, like within cells.
The origins of life are an important issue in many areas such as biology and the field of chemistry. The nature of life is a topic that is of immense interest to scientists, as it challenges the theory of evolution. It is often referred to as "the mystery of life" or "abiogenesis."
Traditionally, the notion that life could emerge from nonliving things is called spontaneous generation, or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's research showed that it was impossible for the emergence of life to be a result of an entirely natural process.
Many scientists still believe that it is possible to transition from nonliving substances to life. However, the conditions that are required are extremely difficult to reproduce in the laboratory. Researchers who are interested in the origins and development of life are also keen to learn about the physical characteristics of the early Earth as well as other planets.
Furthermore, the growth of life is an intricate sequence of chemical reactions that cannot be predicted from the fundamental physical laws alone. These include the transformation of long, information-rich molecules (DNA or RNA) into proteins that perform functions as well as the replication of these complex molecules to produce new DNA or RNA sequences. These chemical reactions can be compared with the chicken-and-egg issue which is the development and emergence of DNA/RNA, the protein-based cell machinery, is required to begin the process of becoming a living organism. Although, without life, the chemistry needed to make it possible appears to be working.
Abiogenesis research requires collaboration between researchers from different disciplines. This includes prebiotic scientists, astrobiologists and planet scientists.
Evolutionary Changes
The term "evolution" is typically used to describe the accumulated changes in genetic characteristics of populations over time. These changes may be the result of adapting to environmental pressures, as described in Darwinism.
This mechanism also increases the number of genes that provide a survival advantage in a species, resulting in an overall change in the appearance of an entire group. These evolutionary changes are triggered by mutations, reshuffling genes in the process of sexual reproduction, and also by gene flow.
Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo changes and reshuffles in their genes. This happens because, as mentioned above those who have the beneficial trait tend to have a higher fertility rate than those without it. Over the course of many generations, this difference in the numbers of offspring born could 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 different species of finches on the Galapagos Islands, which have evolved different shaped beaks to enable them to more easily access food in their new environment. 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 occur are the result of one mutation, but occasionally several will happen at the same time. Most of these changes are not harmful or even harmful to the organism, however, a small proportion of them can have an advantageous impact on survival and reproduction, thus increasing their frequency in the population over time. This is the mechanism of natural selection, and it can eventually result in the accumulating changes that ultimately lead to an entirely new species.
Many people confuse evolution with the idea of soft inheritance which is the notion that traits inherited from parents can be changed through conscious choice or abuse. This is a misinterpretation of the nature of evolution, and of the actual biological processes that trigger it. A more accurate description is that evolution is a two-step process that involves the distinct and often antagonistic forces of mutation and natural selection.
Origins of Humans
Humans of today (Homo Sapiens) evolved from primates, a group of mammal species that includes chimpanzees and gorillas. The earliest human fossils prove that our ancestors were bipeds - walkers with two legs. Genetic and biological similarities suggest that we are closely related to chimpanzees. In fact we are the closest with chimpanzees in the Pan Genus that includes pygmy and pygmy chimpanzees and bonobos. The last common human ancestor and chimpanzees was born between 8 and 6 million years ago.
Humans have evolved a wide range of traits throughout time such as bipedalism, use of fire, and the development of advanced tools. But it's only in the past 100,000 years or so that most of the essential traits that distinguish us from other species have developed. These include language, a large brain, the capacity to build and use sophisticated tools, and a cultural diversity.
The process of evolution occurs when genetic changes allow individuals of a population to better adapt to their environment. This adaptation is driven by natural selection, a process that determines certain traits are preferred over others. The better adapted are more likely to pass on their genes to the next generation. This is the process that evolves all species and forms the basis 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 more likely to develop similar traits over time. This is because these traits make it easier to survive and reproduce within their environment.
Every organism has the DNA molecule, which contains the information needed to control their growth. The DNA molecule is made up of base pairs that are arranged in a spiral around sugar molecules and phosphate molecules. The sequence of bases within each strand determines the phenotype, or the individual's characteristic appearance and behavior. A variety of mutations and reshufflings of the genetic material (known as alleles) during sexual reproduction can cause variation in a group.
Fossils from the first human species, Homo erectus, as well as Homo neanderthalensis have been discovered in Africa, Asia and Europe. While there are some differences between them they all support the idea that modern humans first came into existence in Africa. The fossil evidence and genetic evidence suggest that early humans migrated from Africa into Asia and then Europe.
