So , You've Purchased Evolution Site ... Now What?
The Academy's Evolution Site
Biology is one of the most important concepts in biology. The Academies have been for a long time involved in helping those interested in science understand the theory of evolution and how it affects all areas of scientific research.
This site provides students, teachers and general readers with a range of learning resources on evolution. It also includes important video clips from NOVA and WGBH produced science programs on DVD.
Tree of Life
The Tree of Life, an ancient symbol, represents the interconnectedness of all life. It is an emblem of love and unity across many cultures. It also has practical uses, like providing a framework to understand the history of species and how they respond to changes in environmental conditions.
The earliest attempts to depict the biological world focused on the classification of organisms into distinct categories that had been distinguished by physical and metabolic characteristics1. These methods, which relied on sampling of different parts of living organisms or small fragments of their DNA significantly expanded the diversity that could be included in the tree of life2. These trees are mostly populated by eukaryotes and the diversity of bacterial species is greatly underrepresented3,4.
Genetic techniques have greatly expanded our ability to visualize the Tree of Life by circumventing the need for direct observation and experimentation. We can create trees using molecular techniques like the small-subunit ribosomal gene.
Despite the rapid expansion of the Tree of Life through genome sequencing, much biodiversity still remains 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 has produced an initial draft of a Tree of Life. This includes a variety of archaea, bacteria, and other organisms that haven't yet been isolated, or their diversity is not thoroughly understood6.
The expanded Tree of Life is particularly beneficial in assessing the biodiversity of an area, helping to determine whether specific habitats require special protection. The information can be used in a range of ways, from identifying the most effective remedies to fight diseases to enhancing the quality of crops. The information is also incredibly beneficial in conservation efforts. It can help biologists identify areas that are most likely to be home to species that are cryptic, which could have important metabolic functions, and could be susceptible to changes caused by humans. Although funds to protect biodiversity are essential, ultimately the best way to ensure the preservation of biodiversity around the world is for more people living in developing countries to be empowered with the necessary knowledge to act locally to promote conservation from within.
Phylogeny
A phylogeny (also known as an evolutionary tree) shows the relationships between species. By using molecular information as well as morphological similarities and distinctions or ontogeny (the process of the development of an organism) scientists can create an phylogenetic tree that demonstrates the evolutionary relationships between taxonomic categories. The role of phylogeny is crucial in understanding biodiversity, genetics and evolution.
A basic phylogenetic Tree (see Figure PageIndex 10 ) identifies the relationships between organisms that share similar traits that evolved from common ancestors. These shared traits may be analogous or homologous. Homologous traits are identical in their evolutionary roots and analogous traits appear similar, but do not share the same ancestors. Scientists put similar traits into a grouping called a clade. All members of a clade share a characteristic, like amniotic egg production. They all evolved from an ancestor with these eggs. The clades are then connected to form a phylogenetic branch to identify organisms that have the closest connection to each other.
For a more precise and accurate phylogenetic tree, scientists use molecular data from DNA or RNA to identify the relationships among organisms. This information is more precise and provides evidence of the evolutionary history of an organism. Researchers can utilize Molecular Data to calculate the evolutionary age of living organisms and discover how many species share the same ancestor.
The phylogenetic relationships of organisms are influenced by many factors, including phenotypic flexibility, a kind of behavior that alters in response to unique environmental conditions. This can cause a trait to appear more resembling to one species than another and obscure the phylogenetic signals. This problem can be addressed by using cladistics. This is a method that incorporates a combination of homologous and analogous traits in the tree.
Additionally, phylogenetics can aid in predicting the duration and rate of speciation. This information will assist conservation biologists in making choices about which species to save from extinction. In the end, it's the preservation of phylogenetic diversity that will lead to an ecosystem that is complete and balanced.
Evolutionary Theory
The central theme of evolution is that organisms acquire various characteristics over time as a result of their interactions with their environments. Several theories of evolutionary change 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 gradually according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits causes changes that could be passed on to offspring.
In the 1930s and 1940s, theories from various fields, including genetics, natural selection and particulate inheritance--came together to create the modern evolutionary theory synthesis, which defines how evolution happens through the variation of genes within a population, and how these variants change in time due to natural selection. This model, which encompasses genetic drift, mutations, gene flow and sexual selection is mathematically described mathematically.
Recent discoveries in the field of evolutionary developmental biology have revealed that variation can be introduced into a species by genetic drift, mutation, and reshuffling of genes in sexual reproduction, as well as through the movement of populations. These processes, in conjunction with others such as 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 phenotype (the expression of genotypes in an individual).
Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking in all areas of biology. In a recent study conducted by Grunspan and co., it was shown that teaching students about the evidence for evolution boosted their understanding of evolution during the course of a college biology. For more information on how to teach about evolution, please look up The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: A Framework for Infusing the Concept of Evolution into Life Sciences Education.
Evolution in Action
Traditionally, scientists have studied evolution by looking back, studying fossils, comparing species, and observing living organisms. Evolution is not a distant event, but an ongoing process. Bacteria mutate and resist antibiotics, viruses evolve and escape new drugs and animals change their behavior in response to a changing planet. 에볼루션 카지노 사이트 that result are often evident.
It wasn't until the 1980s that biologists began realize that natural selection was also at work. The key is the fact that different traits can confer a different rate of survival as well as reproduction, and may be passed down from one generation to the next.
In the past, if a certain allele - the genetic sequence that determines color - was found in a group of organisms that interbred, it might become more common than other allele. As time passes, this could mean that the number of moths that have black pigmentation could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.
It is easier to see evolutionary change when a species, such as bacteria, has a high 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 were taken frequently and more than 50,000 generations of E.coli have passed.
Lenski's research has shown that a mutation can dramatically alter the efficiency with the rate at which a population reproduces, and consequently, the rate at which it evolves. It also demonstrates that evolution takes time, a fact that some people find difficult to accept.
Microevolution is also evident in the fact that mosquito genes that confer resistance to pesticides are more prevalent in populations that have used insecticides. Pesticides create a selective pressure which favors those who have resistant genotypes.
The rapidity of evolution has led to a greater recognition of its importance particularly in a world which is largely shaped by human activities. This includes climate change, pollution, and habitat loss that hinders many species from adapting. Understanding the evolution process will help you make better decisions regarding the future of the planet and its inhabitants.