The Berkeley Evolution Site
Teachers and students who browse the Berkeley site will find a wealth of resources to help them understand and teach evolution. The resources are organized into optional learning paths, such as "What does T. rex look like?"
Charles Darwin's theory on natural selection explains how creatures who are better equipped to adapt biologically to a changing environments over time, and those that don't disappear. This process of evolution in biology is what science is all about.
What is Evolution?
The term "evolution" could be used to refer to a variety of nonscientific meanings. For instance it could mean "progress" and "descent with modifications." It is a scientific term that is used to describe the process of changing characteristics in a species or species. This change is based in biological terms on natural selection and drift.
Evolution is one of the fundamental tenets of modern biology. It is an accepted theory that has stood up to the test of time and a multitude of scientific tests. Unlike many other scientific theories like the Copernican theory or the germ theory of disease, the evolution theory is not a discussion 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 gradual manner, as time passes. They referred to this as 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.
Darwin presented his theory of evolution in his book On the Origin of Species which was written in the early 1800s. It states that all species of organisms share an ancestry that can be traced through fossils and other evidence. This is the current view of evolution, which is supported by a variety of lines of scientific research that include molecular genetics.
Scientists do not know how organisms evolved however they are certain that natural selection and genetic drift are responsible for the development of life. People with desirable traits are more likely than others to live and reproduce. They pass on their genes on to the next generation. Over time, this results in a gradual accumulation of changes in the gene pool which gradually result in new species and types.
Some scientists also use the term"evolution" to describe large-scale evolutionary changes, such as the formation of a new species from an ancestral species. Other scientists, like population geneticists, define it more broadly, referring to the net change in the frequency of alleles across generations. Both definitions are correct and acceptable, but certain scientists argue that allele frequency definitions omit important features of evolutionary process.
Origins of Life
The most important step in evolution is the development of life. This happens when living systems begin to evolve at the micro level - within cells, for example.
The origins of life are an issue in a variety of disciplines that include geology, chemistry, biology and chemistry. The origin of life is an area of great interest in science because it is a challenge to the theory of evolution. It is often referred to "the mystery" of life or "abiogenesis."
Traditionally, the belief that life could emerge from nonliving things is called spontaneous generation, or "spontaneous evolution." This was a common belief before Louis Pasteur's experiments proved that it was impossible for the emergence of life to happen through an entirely natural process.
Many scientists still believe it is possible to go from nonliving substances to life. The conditions required to make life are not easy to reproduce in a lab. Researchers interested in the origins and evolution of life are also keen to understand the physical properties of the early Earth as well as other planets.
Furthermore, the growth of life is dependent on an intricate sequence of chemical reactions that cannot be predicted from basic physical laws alone. These include the reading and re-reading of complex molecules, such as DNA or RNA, in order to make proteins that serve a specific function. These chemical reactions are often compared with the chicken-and-egg dilemma of how life began in the first place. The appearance of DNA/RNA and protein-based cell machinery is crucial to the birth of life, but without the emergence of life the chemistry that makes it possible isn't working.
Research in the area of abiogenesis requires collaboration between scientists from a variety of fields. This includes prebiotic scientists, astrobiologists, and planet scientists.
Evolutionary Changes
The term "evolution" is used to describe general changes in genetic traits over time. These changes may be the result of the adaptation to environmental pressures as explained in Darwinism.
The latter is a mechanism that increases the frequency of those genes in a species that offer an advantage in survival over other species, resulting in a gradual change in the overall appearance of a particular population. The specific mechanisms responsible for these changes in evolutionary process include mutation, reshuffling of genes during sexual reproduction, and gene flow between populations.
Natural selection is the process that makes beneficial mutations more common. All organisms undergo mutations and reshuffles of their genes. As noted above, individuals who possess the desirable characteristic have a higher reproduction rate than those who do not. Over many generations, this difference in the numbers of offspring produced can result in an inclination towards a shift in the average number of beneficial characteristics in a particular population.
This can be seen in the evolution of different beak shapes on finches from the Galapagos Islands. They have created these beaks to ensure that they can eat more easily in their new environment. visit this link in shape and form could aid in the creation of new organisms.
The majority of changes are caused by a single mutation, however sometimes multiple occur simultaneously. The majority of these changes are neutral or even harmful to the organism however, a small proportion of them can be beneficial to the longevity and reproduction of the species, thus increasing their frequency in the population over time. This is the mechanism of natural selection, and it is able to eventually result in the gradual changes that eventually lead to a new species.
Some people confuse the notion of evolution with the idea that traits inherited can be altered through conscious choice, or through use and abuse, a notion known as 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 is a two-step process which involves the separate, and often competing, forces of natural selection and mutation.
Origins of Humans
Humans today (Homo sapiens) evolved from primates, a group of mammals that includes chimpanzees and gorillas and bonobos. Our ancestral ancestors were walking on two legs, as evidenced by the first fossils. Genetic and biological similarities suggest that we are closely related to chimpanzees. In actual fact our closest relatives are chimpanzees belonging to the Pan genus. This includes pygmy, as well as bonobos. The last common human ancestor as well as chimpanzees was born between 8 and 6 million years ago.
Humans have evolved a wide range of traits over time including bipedalism, the use of fire and advanced tools. However, 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. They include a huge brain that is sophisticated and the capacity of humans to build and use tools, as well as cultural diversity.
Evolution occurs when genetic changes allow members of a population to better adapt to their environment. This adaptation is driven by natural selection, a process whereby certain traits are more desirable than others. The ones with the best adaptations are more likely to pass on their genes to the next generation. This is the way that all species evolve and forms the foundation of the theory of evolution.
Scientists refer to it as the "law of natural selection." The law says that species that share a common ancestor tend to develop similar characteristics over time. It is because these traits make it easier to reproduce and survive within their environment.
Every organism has an molecule called DNA that holds the information needed to control their growth. The DNA molecule consists 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 reshuffling of the genetic material (known as alleles) during sexual reproduction cause variation in a population.
Fossils from the early human species Homo erectus, and Homo neanderthalensis have been found in Africa, Asia and Europe. While there are some differences between them, these fossils all support the notion that modern humans first came into existence in Africa. The genetic and fossil evidence suggests that early humans left Africa and migrated to Asia and Europe.