The Academy's Evolution Site
Biological evolution is one of the most central concepts in biology. The Academies have long been involved in helping those interested in science understand the concept of evolution and how it influences all areas of scientific exploration.
This site provides a wide range of tools for teachers, students as well as general readers about evolution. It includes key video clip from NOVA and WGBH produced science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol of the interconnectedness of life. It is a symbol of love and harmony in a variety of cultures. It also has many practical applications, like providing a framework for understanding the history of species and how they respond to changing environmental conditions.
Early attempts to describe the biological world were built on categorizing organisms based on their physical and metabolic characteristics. These methods depend on the collection of various parts of organisms or short DNA fragments have greatly increased the diversity of a Tree of Life2. However the trees are mostly comprised of eukaryotes, and bacterial diversity remains vastly underrepresented3,4.
Genetic techniques have significantly expanded our ability to visualize the Tree of Life by circumventing the requirement for direct observation and experimentation. Particularly, molecular methods enable us to create trees using sequenced markers such as the small subunit ribosomal gene.
Despite the massive expansion of the Tree of Life through genome sequencing, a large amount of biodiversity is waiting to be discovered. This is especially the case for microorganisms which are difficult to cultivate and which are usually only present in a single sample5. A recent analysis of all genomes that are known has created a rough draft of the Tree of Life, including many bacteria and archaea that are not isolated and whose diversity is poorly understood6.
The expanded Tree of Life can be used to assess the biodiversity of a specific area and determine if specific habitats require special protection. This information can be utilized in a range of ways, from identifying the most effective treatments to fight disease to enhancing crops. click through the next site is also extremely beneficial in conservation efforts. 에볼루션 슬롯게임 helps biologists discover areas that are most likely to have cryptic species, which could perform important metabolic functions and are susceptible to human-induced change. While funds to protect biodiversity are essential, ultimately the best way to protect the world's biodiversity is for more people living in developing countries to be empowered with the necessary knowledge to act locally in order to promote conservation from within.
Phylogeny
A phylogeny (also known as an evolutionary tree) shows the relationships between species. Using molecular data similarities and differences in morphology, or ontogeny (the process of the development of an organism) scientists can create a phylogenetic tree that illustrates the evolutionary relationships between taxonomic categories. The role of phylogeny is crucial in understanding the relationship between genetics, biodiversity and evolution.
A basic phylogenetic Tree (see Figure PageIndex 10 Identifies the relationships between organisms that have similar characteristics and have evolved from an ancestor with common traits. These shared traits can be either homologous or analogous. Homologous characteristics are identical in their evolutionary journey. Analogous traits might appear similar however they do not share the same origins. Scientists combine similar traits into a grouping referred to as a clade. For instance, all the organisms that make up a clade share the characteristic of having amniotic eggs and evolved from a common ancestor who had eggs. A phylogenetic tree is constructed by connecting the clades to determine the organisms which are the closest to one another.
For a more precise and accurate phylogenetic tree scientists use molecular data from DNA or RNA to determine the relationships between organisms. This information is more precise and provides evidence of the evolution of an organism. Researchers can utilize Molecular Data to determine the evolutionary age of organisms and determine how many species share a common ancestor.
The phylogenetic relationships between organisms are influenced by many factors including phenotypic plasticity, a kind of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more similar to one species than another, obscuring the phylogenetic signals. please click for source can be mitigated by using cladistics, which incorporates the combination of homologous and analogous traits in the tree.
In addition, phylogenetics can help predict the duration and rate of speciation. This information can help conservation biologists make decisions about the species they should safeguard from extinction. In the end, it's the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The fundamental concept in evolution is that organisms alter over time because of their interactions with their environment. Many theories of evolution have been developed by a wide variety of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop slowly in accordance with its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who designed the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits cause changes that can be passed onto offspring.
In the 1930s and 1940s, ideas from different areas, including natural selection, genetics & particulate inheritance, merged to form a modern evolutionary theory. This defines how evolution is triggered by the variation in genes within the population and how these variations change with time due to natural selection. This model, which encompasses genetic drift, mutations in gene flow, and sexual selection is mathematically described mathematically.
Recent developments in the field of evolutionary developmental biology have shown that genetic variation can be introduced into a species by mutation, genetic drift, and reshuffling genes during sexual reproduction, as well as through migration between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of an individual's genotype over time) can lead to evolution that is defined as change in the genome of the species over time and also by changes in phenotype over time (the expression of the genotype within the individual).
Incorporating evolutionary thinking into all areas of biology education can increase student understanding of the concepts of phylogeny and evolution. In a study by Grunspan and colleagues., it was shown that teaching students about the evidence for evolution increased their understanding of evolution in the course of a college biology. For more information about how to teach evolution, see The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily: a Framework for Integrating Evolution into Life Sciences Education.
Evolution in Action
Traditionally scientists have studied evolution by looking back--analyzing fossils, comparing species, and observing living organisms. Evolution is not a distant moment; it is an ongoing process. Bacteria mutate and resist antibiotics, viruses evolve and escape new drugs, and animals adapt their behavior in response to the changing environment. The results are usually evident.
It wasn't until the late 1980s that biologists began realize that natural selection was in action. The main reason is that different traits can confer a different rate of survival and reproduction, and they can be passed down from generation to generation.
In the past when one particular allele - the genetic sequence that controls coloration - was present in a group of interbreeding species, it could quickly become more prevalent than the other alleles. As time passes, that could mean that the number of black moths in the population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
The ability to observe evolutionary change is easier when a species has a rapid generation turnover, as with bacteria. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain. samples from each population are taken regularly and over 50,000 generations have now been observed.
Lenski's work has shown that mutations can alter the rate at which change occurs and the efficiency at which a population reproduces. It also shows that evolution takes time, which is difficult for some to accept.
Another example of microevolution is the way mosquito genes that are resistant to pesticides are more prevalent in areas where insecticides are used. That's because the use of pesticides creates a selective pressure that favors people who have resistant genotypes.
The rapidity of evolution has led to a growing awareness of its significance particularly in a world that is largely shaped by human activity. This includes the effects of climate change, pollution and habitat loss, which prevents many species from adapting. Understanding evolution can assist you in making better choices regarding the future of the planet and its inhabitants.