The Berkeley Evolution Site
Teachers and students who visit the Berkeley site will find resources to assist them in understanding and teaching evolution. The materials are organized into a variety of learning paths such as "What did T. rex taste like?"
Charles Darwin's theory of natural selection states that over time, animals that are better able to adapt biologically to changing environments thrive, and those that do not become extinct. look at this site is all about this process of biological evolutionary change.
What is Evolution?
The term "evolution" could have many nonscientific meanings. For example it could mean "progress" and "descent with modifications." It is scientifically based and is used to describe the process of changing characteristics over time in organisms or species. In Read the Full Article of biology, this change is based on natural selection and genetic drift.
Evolution is an important concept in modern biology. It is an accepted theory that has stood the test of time and a multitude of scientific tests. It does not address God's presence or spiritual beliefs in the same way as other theories in science, like the Copernican or germ theory of diseases.
Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical characteristics were predetermined to change in a gradual way, over time. This was known as the "Ladder of Nature" or 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 different species of organisms have the same ancestry, which can be proven through fossils and other lines of evidence. This is the current view on evolution, and is supported by a variety of scientific fields that include molecular biology.
Scientists do not know the evolution of organisms but they are sure that natural selection and genetic drift is the reason for the development of life. People with advantages are more likely to live and reproduce. They then pass their genes to the next generation. Over time, the gene pool gradually changes and evolves into new species.
Some scientists also use the term"evolution" to refer to large-scale changes in evolutionary processes like the creation of the new species from an ancestral species. Other scientists, like population geneticists, define it more broadly by referring the net variation in the frequency of alleles over 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
A key step in evolution is the emergence of life. The emergence of life occurs when living systems begin to develop at a micro level, like within individual cells.
The origins of life is an issue in a variety of disciplines that include biology, chemistry, and geology. The nature of life is a subject that is of immense interest to scientists because it challenges the theory of evolution. It is often referred to as "the mystery of life" or "abiogenesis."
The notion that life could arise from non-living things was called "spontaneous generation" or "spontaneous evolutionary". It was a popular belief prior to Louis Pasteur's tests showed that the creation of living organisms was not possible through an organic process.
Many scientists still think it is possible to transition from living to nonliving substances. The conditions needed for the creation of life are difficult to replicate in a laboratory. This is why scientists studying the beginnings of life are also interested in understanding the physical properties of the early Earth and other planets.
The growth of life is dependent on a variety of complex chemical reactions that are not predicted by basic physical laws. These include the reading and re-reading of complex molecules, like DNA or RNA, in order to make proteins that perform a particular function. These chemical reactions are often compared to the chicken-and-egg problem of how life began in the first place. The development of DNA/RNA as well as protein-based cell machinery is essential for the beginning of life, however, without the emergence of life the chemical process that allows it isn't working.
Abiogenesis research requires collaboration among researchers from different disciplines. This includes prebiotic chemists, astrobiologists, planetary scientists, geologists and geophysicists.
Evolutionary Changes
The term "evolution" is commonly used to refer to the accumulated changes in the genetic traits of an entire population over time. These changes could result from adaptation to environmental pressures as discussed in the entry on Darwinism (see the entry on Charles Darwin for background) or may result from natural selection.
This mechanism also increases the frequency of genes that provide a survival advantage in an animal, resulting in an overall change in the appearance of the group. These changes in evolutionary patterns are caused by mutations, reshuffling of genes during sexual reproduction and gene flow.
Natural selection is the process that makes beneficial mutations more common. All organisms undergo mutations and reshuffles of genes. As noted above, individuals who possess the desirable trait have a higher reproduction rate than those who don't. Over the course of several generations, this difference in the numbers of offspring born can result in an inclination towards a shift in the number of advantageous traits within a group of.
One good example is the growth of beak size on various species of finches found on the Galapagos Islands, which have developed beaks with different shapes to enable them to more easily access food in their new habitat. These changes in the shape and form of organisms can also be a catalyst for the creation of new species.
The majority of changes are caused by a single mutation, but sometimes several occur at the same time. The majority of these changes could be harmful or neutral however, a small percentage can have a beneficial impact on the survival of the species and reproduce with increasing frequency as time passes. Natural selection is a process that causes the accumulating change over time that leads to a new species.
Many people mistakenly associate evolution with the concept of soft inheritance, which is the idea that inherited traits can be altered by conscious choice or abuse. This is a misinterpretation of the nature of evolution, and of the actual biological processes that trigger it. It is more accurate to say that the process of evolution is a two-step, independent process that involves the forces of natural selection as well as mutation.
Origins of Humans
Modern humans (Homo Sapiens) evolved from primates, a species of mammal species which includes chimpanzees as well as gorillas. The earliest human fossils indicate that our ancestors were bipeds. They were walkers on two legs. Genetic and biological similarities show that we have the same ancestry with Chimpanzees. In reality our closest relatives are the chimpanzees from the Pan genus. This includes pygmy as well as bonobos. The last common ancestor of modern humans and chimpanzees was born between 8 and 6 million years ago.
Over time humans have developed a range of traits, including bipedalism as well as the use of fire. They also invented advanced tools. It is only within the last 100,000 years that we've developed the majority of our key traits. They include language, a large brain, the capacity to construct and use complex tools, and the diversity of our culture.
Evolution occurs when genetic changes enable members of a 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 on their genes to the next generation. This is the process that evolves all species and forms the basis of the theory of evolution.
Scientists refer to this as the "law of natural selection." The law states that species that have a common ancestor are likely to acquire similar traits as time passes. This is because those characteristics make it easier for them to live and reproduce in their environment.
Every organism has an molecule called DNA that holds the information necessary to direct their growth. The structure of DNA is made of base pairs which are arranged in a spiral, around phosphate and sugar molecules. The sequence of bases in each string determines the phenotype or the appearance and behavior of an individual. The variations in a population are caused by mutations and reshufflings in genetic material (known collectively as alleles).
Fossils from the early human species Homo erectus and Homo neanderthalensis have been found in Africa, Asia and Europe. These fossils, despite a few differences in their appearance all support the idea that modern humans' ancestors originated in Africa. The fossil evidence and genetic evidence suggest that early humans migrated from Africa into Asia and then Europe.