Why All The Fuss Over Evolution Site?
The Berkeley Evolution Site
The Berkeley site offers resources that can help students and educators learn about and teach evolution. The materials are arranged into different 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 adaptable to changing environments survive and those that do not become extinct. Science is all about the process of biological evolution.
What is Evolution?
The term "evolution" can be used to refer to a variety of nonscientific meanings. For instance, it can mean "progress" and "descent with modifications." Scientifically, it is a term used to describe a changes in the traits of living things (or species) over time. In biological terms the change is due to natural selection and genetic drift.
Evolution is a fundamental tenet in the field of biology today. It is a theory that has been proven through thousands of scientific tests. Contrary to other theories of science such as the Copernican theory or the germ theory of disease, the evolution theory does not address issues of religion or the existence of God.
Early evolutionists like Erasmus Darwin (Charles’s grandfather) and Jean-Baptiste Lamarck believed that certain physical characteristics were predetermined to evolve in a stepped-like manner over time. They called this 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 published his theory of evolution in his book On the Origin of Species published in the early 1800s. It states that all species of organisms have an ancestry that can be traced using fossils and other evidence. This is the modern view of evolution, which is supported by a variety of research lines in science that include molecular genetics.
While scientists do not know exactly how organisms developed but they are certain 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. These individuals pass on their genes to the next generation. Over time this leads to a gradual accumulation of changes in the gene pool, which eventually create new species and types.
Certain scientists use the term"evolution" in reference to large-scale changes, such the development of an animal from an ancestral one. Certain scientists, including population geneticists, define the term "evolution" in a broader sense by referring to the net change in the frequency of alleles across generations. Both definitions are valid and reliable, although some scientists argue that the definition of allele frequency is lacking crucial aspects of the evolutionary process.
Origins of Life
One of the most crucial steps in evolution is the appearance of life. This happens when living systems begin to evolve at a micro-level - within individual cells, for example.
The origin of life is an important issue in a variety of disciplines such as biology and chemistry. The nature of life is a topic of interest in science because it challenges the theory of evolution. It is often referred to as "the mystery of life," or "abiogenesis."
Traditionally, the belief that life could emerge from nonliving things is known as spontaneous generation or "spontaneous evolution." This was a common belief before Louis Pasteur's experiments showed that it was impossible for the development of life to occur by a purely natural process.
Many scientists still think it is possible to go from living to nonliving substances. The conditions needed for the creation of life are difficult to replicate in a laboratory. Researchers who are interested in the origins and development of life are also eager to know the physical properties of the early Earth as well as other planets.
Furthermore, the growth of life is the sequence of extremely complex chemical reactions that can't be predicted from the fundamental physical laws alone. These include the reading and replication of complex molecules, such as DNA or RNA, in order to make proteins that perform a particular function. These chemical reactions are often compared with the chicken-and-egg problem of how life began with the emergence of DNA/RNA and protein-based cell machinery is essential for the onset of life, but without the development of life the chemistry that makes it possible isn't working.
Research in the area of abiogenesis requires collaboration among scientists from various fields. This includes prebiotic chemists, the astrobiologists, the planet scientists, geologists and geophysicists.
Evolutionary Changes
The term "evolution" is commonly used to describe the accumulated changes in genetic characteristics of a population over time. These changes could result from adaptation to environmental pressures, as described 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 the advantage of survival for a species, resulting in an overall change in the appearance of an entire group. The specific mechanisms behind these evolutionary changes are mutation or reshuffling genes during sexual reproduction, and gene flow between populations.
While reshuffling and mutation of genes occur in all living things, the process by which beneficial mutations are more prevalent is known as natural selection. This is because, as mentioned above those with the advantageous trait are likely to have a higher reproductive rate than those who do not have it. This differential in the number of offspring produced over a number of generations could result in a gradual change in the number of advantageous characteristics in the group.
An excellent example is the growing beak size on different species of finches on the Galapagos Islands, which have developed different beak shapes to enable them to more easily access food in their new home. These changes in shape and form could also help create new organisms.
The majority of changes are caused by one mutation, although sometimes multiple occur at once. 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. Natural selection is a process that could result in the accumulation of changes over time that lead to a new species.
Some people confuse the idea of evolution with the notion that traits inherited can be altered by conscious choice, or through use and abuse, a notion known as soft inheritance. This is a misunderstanding of the biological processes that lead up to the process of evolution. It is more precise to say that evolution is a two-step independent process, that is influenced by the forces of natural selection and mutation.
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 show that our ancestors were bipeds, walking on two legs. 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 and bonobos. The last common ancestor of modern humans and chimpanzees was born between 8 and 6 million years ago.
Humans have developed a range of traits over 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 create and use tools, as well as cultural diversity.
Evolution is when genetic changes allow members of a group to better adapt to their environment. This adaptation is triggered by natural selection, which is a process by which certain traits are more desirable than others. The more adapted are more likely to pass their genes on to the next generation. This is the process that evolves all species and is the basis of the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states that species that share a common ancestor tend to develop similar characteristics over time. This is because the characteristics make it easier for them to survive and reproduce in their environments.
All organisms possess an molecule called DNA that holds the information needed to control their growth. The DNA molecule is made up of base pairs that are spirally arranged around phosphate molecules and sugar molecules. The sequence of bases within each strand determines the phenotype which is the person's distinctive appearance and behavior. Variations in a population can be caused by reshufflings and mutations of genetic material (known collectively as alleles).
Fossils from the first human species, Homo erectus, and Homo neanderthalensis have been discovered in Africa, Asia and Europe. These fossils, despite differences in their appearance all support the hypothesis that modern humans' ancestors originated in Africa. Genetic and fossil evidence also suggest that early humans migrated out of Africa into Asia and then Europe.