20 Resources To Make You Better At Evolution Site
The Academy's Evolution Site
Biology is a key concept in biology. The Academies are committed to helping those who are interested in the sciences understand evolution theory and how it is incorporated across all areas of scientific research.
This site provides teachers, students and general readers with a wide range of learning resources on evolution. It includes the most important video clips from NOVA and WGBH's science programs on DVD.
Tree of Life
The Tree of Life is an ancient symbol that symbolizes the interconnectedness of life. It is seen in a variety of cultures and spiritual beliefs as a symbol of unity and love. It has numerous practical applications in addition to providing a framework to understand the history of species, and how they react to changes in environmental conditions.
Early approaches to depicting the world of biology focused on separating organisms into distinct categories that had been identified by their physical and metabolic characteristics1. These methods, based on sampling of different parts of living organisms or sequences of small fragments of their DNA, significantly expanded the diversity that could be represented in a tree of life2. These trees are largely composed by eukaryotes, and bacterial diversity is vastly underrepresented3,4.
Genetic techniques have greatly expanded our ability to represent the Tree of Life by circumventing the need for direct observation and experimentation. Particularly, molecular techniques allow us to build trees using sequenced markers such as the small subunit of ribosomal RNA gene.
Despite the rapid growth of the Tree of Life through genome sequencing, a large amount of biodiversity remains to be discovered. This is particularly true for microorganisms, which are difficult to cultivate and are typically only found in a single specimen5. A recent analysis of all genomes that are known has produced a rough draft of the Tree of Life, including numerous archaea and bacteria that are not isolated and their diversity is not fully understood6.
The expanded Tree of Life can be used to evaluate the biodiversity of a specific region and determine if specific habitats need special protection. This information can be utilized in a variety of ways, including finding new drugs, fighting diseases and improving crops. This information is also extremely valuable to conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with potentially significant metabolic functions that could be at risk of anthropogenic changes. While conservation funds are important, the most effective way to conserve the world's biodiversity is to empower more people in developing countries with the knowledge they need to act locally and support conservation.
Phylogeny
A phylogeny, also called an evolutionary tree, illustrates the relationships between various groups of organisms. By using molecular information 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. Phylogeny is essential in understanding biodiversity, evolution and genetics.
A basic phylogenetic Tree (see Figure PageIndex 10 Determines the relationship between organisms with similar characteristics and have evolved from an ancestor that shared traits. These shared traits could be homologous, or analogous. Homologous traits share their evolutionary origins and analogous traits appear similar but do not have the same ancestors. Scientists arrange similar traits into a grouping called a Clade. For example, all of the organisms that make up a clade share the characteristic of having amniotic egg and evolved from a common ancestor who had these eggs. The clades are then linked to form a phylogenetic branch to determine which organisms have the closest connection to each other.
For a more precise and precise phylogenetic tree scientists make use of molecular data from DNA or RNA to establish the relationships among organisms. This information is more precise and provides evidence of the evolutionary history of an organism. Researchers can use Molecular Data to estimate the evolutionary age of organisms and determine the number of organisms that share the same ancestor.
The phylogenetic relationship can be affected by a variety of factors that include the phenomenon of phenotypicplasticity. This is a type of behavior that changes as a result of specific environmental conditions. This can cause a characteristic to appear more resembling to one species than another and obscure the phylogenetic signals. However, this issue can be cured by the use of techniques such as cladistics which incorporate a combination of homologous and analogous features into the tree.
Additionally, phylogenetics aids determine the duration and rate of speciation. This information can assist conservation biologists in making choices about which species to protect from extinction. It is ultimately the preservation of phylogenetic diversity which will create an ecosystem that is complete and balanced.
Evolutionary Theory
The central theme in evolution is that organisms change over time as a result of their interactions with their environment. Many theories of evolution have been developed by a wide range of scientists, including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who envisioned an organism developing slowly according to its requirements, the Swedish botanist Carolus Linnaeus (1707-1778) who designed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or non-use of traits can cause changes that can be passed on to the offspring.
In the 1930s and 1940s, theories from various fields, including genetics, natural selection, and particulate inheritance--came together to form the current evolutionary theory synthesis, which defines how evolution is triggered by the variation of genes within a population and how those variations change over time due to natural selection. This model, which is known as genetic drift or mutation, gene flow, and sexual selection, is a cornerstone of modern evolutionary biology and can be mathematically explained.
Recent developments in the field of evolutionary developmental biology have shown that variations can be introduced into a species by mutation, genetic drift and reshuffling of genes during sexual reproduction, and also through the movement of populations. These processes, in conjunction with other ones like directional selection and gene erosion (changes in frequency of genotypes over time) can lead to evolution. Evolution is defined by changes in the genome over time as well as changes in the phenotype (the expression of genotypes in individuals).
Students can gain a better understanding of phylogeny by incorporating evolutionary thinking throughout all aspects of biology. In a recent study conducted by Grunspan et al. It was found that teaching students about the evidence for evolution increased their understanding of evolution in a college-level course in biology. For more details on how to teach about evolution read The Evolutionary Power of Biology in all Areas of Biology or Thinking Evolutionarily A Framework for Infusing Evolution into Life Sciences Education.
Evolution in Action
Scientists have studied evolution by looking in the past, analyzing fossils and comparing species. They also study living organisms. However, evolution isn't something that occurred in the past, it's an ongoing process that is that is taking place today. Viruses evolve to stay away from new drugs and bacteria evolve to resist antibiotics. Animals alter their behavior in the wake of a changing world. The results are often visible.
에볼루션 바카라 무료체험 wasn't until the late 1980s that biologists began realize that natural selection was at work. The key is that various traits confer different rates of survival and reproduction (differential fitness) and can be passed from one generation to the next.
In the past, if an allele - the genetic sequence that determines colour - was present in a population of organisms that interbred, it could become more common than any other allele. Over time, that would mean the number of black moths within the population could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
It is easier to track evolution when an organism, like bacteria, has a rapid generation turnover. Since 1988, Richard Lenski, a biologist, has been tracking twelve populations of E.coli that descend from a single strain. Samples from each population have been collected regularly, and more than 500.000 generations of E.coli have passed.
Lenski's work has demonstrated that a mutation can profoundly alter the rate at the rate at which a population reproduces, and consequently the rate at which it alters. It also demonstrates that evolution is slow-moving, a fact that some are unable to accept.
Microevolution is also evident in the fact that mosquito genes for resistance to pesticides are more common in populations that have used insecticides. This is due to pesticides causing an enticement that favors those with resistant genotypes.
The rapid pace at which evolution can take place has led to a growing awareness of its significance in a world shaped by human activity, including climate change, pollution and the loss of habitats which prevent many species from adjusting. Understanding the evolution process can help us make better decisions regarding the future of our planet and the life of its inhabitants.