The Berkeley Evolution Site

Students and teachers who explore the Berkeley site will find a wealth of resources to help them understand and teach evolution. The resources are arranged into different learning paths like "What did T. rex taste like?"

Charles Darwin's theory on natural selection explains how creatures who are better able to adapt biologically to a changing environments over time, and those that don't end up becoming extinct. Science is concerned with this process of biological evolution.

What is Evolution?

The term "evolution" can have many nonscientific meanings, such as "progress" or "descent with modification." It is a scientific term that is used to describe the process of change of characteristics over time in organisms or species. In biological terms, this change is caused by natural selection and genetic drift.

Evolution is a key principle in the field of biology today. It is a theory that has been verified by thousands of scientific tests. Unlike many other scientific theories, such as the Copernican theory or the germ theory of disease, the evolution theory does not address issues of religious belief or God's existence.

Early evolutionists, like Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical characteristics were predetermined to change, in a step-like way, over time. They called this the "Ladder of Nature" or the 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 a common ancestry which can be traced through fossils and other evidence. This is the current perspective on evolution, and is supported in a wide range of disciplines that include molecular biology.

Although scientists aren't able to determine exactly how organisms developed, they are confident that the evolution of life on earth is a result of natural selection and genetic drift. People with desirable traits are more likely to live and reproduce, and these individuals pass their genes on to the next generation. In time this leads to an accumulation of changes in the gene pool which gradually create new species and forms.

Some scientists also employ the term"evolution" to refer to large-scale evolutionary changes such as the creation of an entirely new species from an ancestral species. Others, like population geneticists, define it more broadly by referring to a net variation in the frequency of alleles over generations. Both definitions are valid and acceptable, but some scientists believe that allele-frequency definitions miss important aspects of the evolutionary process.

Origins of Life

The birth of life is a key stage in evolution. The emergence of life happens when living systems start to evolve at a micro level, such as within cells.

The origin of life is an important subject in many areas that include biology and the field of chemistry. The nature of life is a topic of great interest in science, as it challenges the theory of evolution. It is sometimes referred to "the mystery" of life or "abiogenesis."

The idea that life could emerge from non-living matter was known as "spontaneous generation" or "spontaneous evolutionary". This was a popular belief prior to Louis Pasteur's tests showed that the creation of living organisms was not achievable through an organic process.

Many scientists believe it is possible to move from living to nonliving substances. The conditions needed for the creation of life are difficult to reproduce in a lab. Researchers investigating the beginnings of life are also interested in understanding the physical properties of early Earth and other planets.

Furthermore, the growth of life depends on a sequence of very complex chemical reactions that cannot be predicted based on basic physical laws on their own. This includes the conversion of long information-rich molecules (DNA or RNA) into proteins that carry out functions as well as the replication of these complex molecules to generate new DNA or sequences of RNA. These chemical reactions are often compared with the chicken-and-egg dilemma of how life began: The development of DNA/RNA as well as protein-based cell machinery is crucial to the birth of life, but without the appearance of life, the chemical process that allows it does not appear to work.

Abiogenesis research requires collaboration with researchers from different fields. This includes prebiotic scientists, astrobiologists, and planetary scientists.

Evolutionary Changes

The word evolution is usually used today to describe the cumulative changes in the genetic characteristics of a population over time. These changes can result from adaptation to environmental pressures, as discussed in the entry on Darwinism (see the entry on Charles Darwin for background) or natural selection.

This latter mechanism increases the number of genes that confer a survival advantage in a species, resulting in an overall change in the appearance of a group. These evolutionary changes are triggered by mutations, reshuffling of genes in the process of sexual reproduction, and also by the flow of genes.

While reshuffling and mutations of genes happen in all living organisms and the process by which beneficial mutations become more common is called natural selection. As noted above, individuals who possess the desirable characteristic have a higher reproduction rate than those that do not. Over many generations, this variation in the numbers of offspring born could result in a gradual shift in the number of advantageous traits in a population.

A good example of this is the growing beak size on different species of finches in the Galapagos Islands, which have developed different beak shapes to allow them to more easily access food in their new home. These changes in form and shape can also aid in the creation of new species.

The majority of changes are caused by a single mutation, although sometimes multiple occur at once. The majority of these changes could be neutral or even harmful, but a small number may have a positive effect on survival and reproduction and increase their frequency over time. Natural selection is a mechanism that could result in the accumulation of change over time that leads to a new species.

Some people mistakenly associate evolution with the concept of soft inheritance which is the notion that inherited traits can be changed by deliberate choice or misuse. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that trigger it. A more accurate description of evolution is that it is a two-step procedure that involves the distinct and often antagonistic forces of mutation and natural selection.

Origins of Humans

Humans today (Homo sapiens) evolved from primates - a group of mammals that includes gorillas, chimpanzees, and bonobos. Our predecessors walked on two legs, as shown by the first fossils. Genetic and biological similarities suggest that we are closely related to the chimpanzees. In actual fact we are the closest connected to chimpanzees belonging to the Pan genus which includes bonobos and pygmy chimpanzees. The last common ancestor of humans and chimpanzees was between 8 and 6 million years old.

As time has passed, humans have developed a variety of characteristics, including bipedalism and the use fire. They also invented advanced tools. It's only within the last 100,000 years that we've developed the majority of our essential traits. They include language, a large brain, the ability to create and utilize complex tools, as well as the ability to adapt to cultural differences.


The process of evolution occurs when genetic changes allow members of a group to better adapt to the 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 their genes to the next generation. This is the way that all species evolve, and it is the foundation 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 traits over time. It is because these traits help them to reproduce and survive within their environment.

Every organism has a DNA molecule, which provides the information necessary to guide their growth and development. The DNA molecule is composed of base pairs arranged spirally around phosphate molecules and sugar molecules. simply click the following site of bases found in each strand determines the phenotype - the appearance and behavior of an individual. Different changes and reshuffling of genetic material (known as alleles) during reproduction causes variation in a population.

Fossils from the earliest human species, Homo erectus and Homo neanderthalensis, have been found 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. Evidence from fossils and genetics suggest that early humans came out of Africa into Asia and then Europe.