The Berkeley Evolution Site

Teachers and students who visit the Berkeley site will find resources to aid in understanding and teaching evolution. The materials are organized into optional learning paths like "What did T. rex taste like?"

Charles Darwin's theory on natural selection describes how species who are better able to adapt biologically to a changing environment survive over time and those that don't end up becoming extinct. This process of evolution is the basis of science.

What is Evolution?


The term "evolution" has a variety of nonscientific meanings, such as "progress" or "descent with modification." Scientifically it refers to a changing the characteristics of living things (or species) over time. In biological terms this change is caused by natural selection and genetic drift.

Evolution is a key concept in modern biology. It is a concept that has been tested and proven by thousands of scientific tests. Evolution doesn't deal with the existence of God or religious beliefs like other scientific theories such as the Copernican or germ theory of diseases.

Early evolutionists like 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 referred to as the "Ladder of Nature" or scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology.

Darwin presented his theory of evolution in his book On the Origin of Species published in the early 1800s. It states that all species of organisms share an ancestry that can be traced through fossils and other lines of evidence. This is the current view of evolution, which is supported in many scientific fields, including molecular biology.

Scientists do not know how organisms evolved, but they are confident that natural selection and genetic drift are the primary reason for the development of life. 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, this results in a gradual accumulation of changes in the gene pool that gradually result in new species and types.

Certain scientists also use the term evolution to refer to large-scale changes in evolutionary processes, such as the formation of a new species from an ancestral species. 에볼루션 바카라 무료 Evolution , like population geneticists, define evolution more broadly by referring to an overall change in allele frequencies over generations. Both definitions are acceptable and precise however some scientists believe that the definition of allele frequency is lacking important features of the evolutionary process.

Origins of Life

The most important step in evolution is the emergence of life. The beginning of life takes place when living systems begin to evolve at a micro level, like within cells.

The origins of life is a topic in many disciplines, including geology, chemistry, biology and chemistry. The origin of life is a topic of interest in science, as it is a challenge to the theory of evolution. It is often referred to "the mystery" of life or "abiogenesis."

Traditionally, the notion that life could emerge from nonliving objects is known as spontaneous generation, or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's experiments proved that it was impossible for the emergence of life to occur by a purely natural process.

Many scientists believe it is possible to move from living to nonliving substances. However, the conditions required are extremely difficult to replicate in labs. Researchers who are interested in the origins and development of life are also eager to learn about the physical characteristics of the early Earth as well as other planets.

The life-cycle of a living organism is dependent on a variety of complex chemical reactions that are not predicted by simple physical laws. These include the reading and replication of complex molecules, like DNA or RNA, in order to make proteins that perform a particular function. These chemical reactions can be compared to a chicken-and egg problem that is the emergence and growth of DNA/RNA, a protein-based cell machinery, is required to begin the process of becoming a living organism. Although, without life, the chemistry needed to enable it appears to be working.

Research in the field of abiogenesis requires collaboration between scientists from various disciplines. This includes prebiotic scientists, astrobiologists, and planet scientists.

Evolutionary Changes

Today, the word evolution is used to describe gradual changes in genetic traits over time. These changes may result from adaptation to environmental pressures as described in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.

The latter is a mechanism that increases the frequency of genes that offer an advantage in survival over other species and causes an ongoing change in the overall appearance of a group. These evolutionary changes are triggered by mutations, reshuffling of genes during sexual reproduction and gene flow.

While mutation and reshuffling of genes happen in all living things The process through which beneficial mutations are more prevalent is known as natural selection. This occurs because, as noted above, those individuals with the beneficial trait tend to have a higher reproductive rate than those who do not have it. Over the course of several generations, this difference in the number of offspring produced can result in an inclination towards a shift in the number of beneficial traits in a population.

This can be seen in the evolution of different beak shapes on finches from the Galapagos Islands. They have developed these beaks so that they can access food more easily in their new environment. These changes in shape and form can aid in the creation of new organisms.

The majority of changes are caused by a single mutation, although sometimes multiple occur simultaneously. The majority of these changes are neither harmful nor even harmful to the organism however, a small proportion of them can be beneficial to survival and reproduction, thus increasing their frequency in the population over time. Natural selection is a mechanism that can produce the accumulating change over time that leads to a new species.

Many people confuse the concept of evolution with the idea that inherited characteristics can be changed through conscious choice or by use and abuse, a concept called soft inheritance. This is a misunderstood understanding of the nature of evolution and of the actual biological processes that lead to it. A more precise description is that evolution involves a two-step process, which involves the separate and often conflicting forces of mutation and natural selection.

Origins of Humans

Humans today (Homo sapiens) evolved from primates - a group of mammals that also includes chimpanzees, gorillas, and bonobos. Our ancestral ancestors were walking on two legs, as demonstrated by the earliest fossils. Genetic and biological similarities show that we share the same ancestry with chimpanzees. In actual fact, our closest relatives are the chimpanzees of the Pan genus. This includes pygmy, as well as bonobos. The last common ancestor between humans and chimpanzees was 8 to 6 million years old.

Humans have evolved a variety of characteristics over time including bipedalism, the use of fire and advanced tools. It is only in the last 100,000 years or so that the majority of the traits that distinguish us from other species have been developed. These include language, large brain, the capacity to construct and use complex tools, and the diversity of our culture.

The process of evolution occurs when genetic changes enable members of the group to better adapt to their environment. Natural selection is the process that triggers this adaptation. Certain characteristics 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 for the theory of evolution.

Scientists refer to it as the "law of Natural Selection." The law states that species that have a common ancestor are more likely to develop similar characteristics over time. This is because these traits help them to survive and reproduce within their environment.

Every living thing has an molecule called DNA that holds the information needed to control their growth. The structure of DNA is composed of base pair arranged in a spiral around phosphate and sugar molecules. The sequence of bases within each strand determines the phenotype or the individual's unique appearance and behavior. Variations in mutations and reshuffling of the genetic material (known as alleles) during reproduction causes variations in a population.

Fossils of the earliest human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. Although there are some differences, these fossils all support the notion that modern humans first came into existence in Africa. Evidence from fossils and genetics suggest that early humans migrated from Africa into Asia and then Europe.