The Berkeley Evolution Site
The Berkeley site has resources that can help students and educators understand and teach evolution. The resources are organized into various learning paths that can be used in a variety of ways for example "What does T. rex look like?"
Charles Darwin's theory on natural selection explains how animals who are better able to adapt biologically to a changing environment survive over time and those who do not disappear. This process of biological evolution is the basis of science.
What is Evolution?
The term "evolution" can have many nonscientific meanings. For instance, it can mean "progress" and "descent with modifications." Scientifically, it refers to a changes in the traits of living organisms (or species) over time. The reason for this change is biological terms on natural drift and selection.
Evolution is an important principle in modern biology. It is a theory that has been tested and confirmed by a myriad of scientific tests. It does not address God's presence or spiritual beliefs like other theories of science, such as the Copernican or germ theory of disease.
Early evolutionists, including Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather), believed that certain physical traits were predetermined to change in a step-like manner, as time passes. click through the next site 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 different species of organisms have an ancestry that can be determined through fossils and other evidence. This is the current understanding of evolution, which is supported by numerous research lines in science that include molecular genetics.
While scientists don't know exactly how organisms developed however they are sure 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 transmit their genes to the next generation. In time this leads to a gradual accumulation of changes in the gene pool which gradually result in new species and forms.
Some scientists also employ the term evolution to refer to large-scale evolutionary changes, such as the formation of a new species from an ancestral species. Others, like population geneticists, define evolution more broadly by referring to an overall change in the frequency of alleles across generations. Both definitions are acceptable and accurate, although some scientists argue that the definition of allele frequency is lacking crucial aspects 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 start to evolve at a micro level, such as within individual 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 because it is a challenge to the theory of evolution. It is often called "the mystery of life" or "abiogenesis."
Traditionally, the belief 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 an entirely 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 replicate in a laboratory. Researchers studying the origins of life are also interested in understanding the physical properties of the early Earth and other planets.
The development of life is dependent on a variety of complex chemical reactions that are not predicted by simple physical laws. This includes the conversion of long information-rich molecules (DNA or RNA) into proteins that perform a function and the replication of these complex molecules to produce new DNA or RNA sequences. These chemical reactions are often compared with the chicken-and-egg problem of how life began with the appearance of DNA/RNA and proteins-based cell machinery is vital for the beginning of life, but without the development of life the chemistry that makes it possible does not appear to work.
Research in the field of abiogenesis requires cooperation among scientists from many different fields. This includes prebiotic chemists, astrobiologists, planetary scientists geophysicists, geologists, and geophysicists.
Evolutionary Changes
Today, the word evolution is used to describe the cumulative changes in genetic characteristics over time. These changes could be the result of the adaptation to environmental pressures as discussed in Darwinism.
This process increases the number of genes that offer an advantage for survival in the species, leading to an overall change in the appearance of a group. These changes in evolutionary patterns are caused by mutations, reshuffling of genes in the process of sexual reproduction, and also by the flow of genes.
Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo mutations and reshuffles of their genes. As noted above, individuals with the beneficial characteristic have a higher reproduction rate than those who don't. This differential in the number of offspring born over a number of generations could cause a gradual change in the average number advantageous characteristics in the group.
A good example of this is the growing beak size on various species of finches in the Galapagos Islands, which have developed different beak shapes that allow them to easily access food in their new home. These changes in shape and form could aid in the creation of new organisms.
The majority of changes are caused by one mutation, however sometimes multiple occur simultaneously. Most of these changes may be neutral or even harmful however, a small percentage may have a positive effect on survival and reproduction with increasing frequency over time. This is the process of natural selection and it is able to be a time-consuming process that produces the cumulative changes that eventually result in a new species.
Some people confuse the notion of evolution with the notion that inherited characteristics can be altered by conscious choice or by use and abuse, a concept called soft inheritance. This is a misinterpretation of the nature of evolution, and of the actual biological processes that trigger it. A more precise description is that evolution is a two-step process involving the independent and often antagonistic forces of natural selection and mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a group of mammal species which includes chimpanzees and gorillas. Our ancestors walked on two legs, as evidenced by the oldest fossils. Biological and genetic similarities indicate that we have an intimate relationship with Chimpanzees. In fact our closest relatives are chimpanzees belonging to the Pan genus. This includes pygmy, as well as bonobos. The last common human ancestor and chimpanzees was born between 8 and 6 million years ago.
Humans have evolved a wide range of characteristics over time such as bipedalism, use of fire, and the development of advanced tools. It's only within the last 100,000 years that we have developed the majority of our essential characteristics. They include a huge, complex brain and the capacity of humans to create and use tools, and cultural diversity.
The process of evolution occurs when genetic changes allow members of the group to better adapt to the environment. This adaptation is triggered by natural selection, a process whereby certain traits are favored over other traits. The more adapted are more likely to pass on their genes to the next generation. This is how all species evolve and is the basis for the theory of evolution.
Scientists refer to it as the "law of Natural Selection." The law states that species which have a common ancestor, tend to develop similar characteristics over time. This is because those traits allow them to survive and reproduce in their environments.
All organisms possess a DNA molecule that contains the information needed to guide their growth. The DNA molecule is made up of base pairs that are spirally arranged around sugar molecules and phosphate molecules. The sequence of bases within each strand determines 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 earliest human species, Homo erectus and Homo neanderthalensis were discovered in Africa, Asia, and Europe. While there are some differences between them, 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 from Africa into Asia and then Europe.