Why We Why We Evolution Site And You Should Too

The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those interested in science to learn about the theory of evolution and how it can be applied throughout all fields of scientific research.

This site provides teachers, students and general readers with a variety of learning resources on evolution. It includes key video clips from NOVA and the WGBH-produced science programs on DVD.

Tree of Life

The Tree of Life is an ancient symbol that represents the interconnectedness of all life. It appears in many religions and cultures as symbolizing unity and love. It also has important practical applications, such as providing a framework to understand the evolution of species and how they respond to changing environmental conditions.

The first attempts at depicting the world of biology focused on the classification of organisms into distinct categories that had been identified by their physical and metabolic characteristics1. These methods are based on the sampling of different parts of organisms, or DNA fragments, have significantly increased the diversity of a Tree of Life2. However the trees are mostly made up of eukaryotes. Bacterial diversity is not represented in a large way3,4.

By avoiding the need for direct experimentation and observation, genetic techniques have allowed us to represent the Tree of Life in a more precise way. We can construct trees using molecular methods like the small-subunit ribosomal gene.

The Tree of Life has been greatly expanded thanks to genome sequencing. However, there is still much diversity to be discovered. This is especially relevant to microorganisms that are difficult to cultivate and are typically present in a single sample5. A recent study of all genomes known to date has produced a rough draft of the Tree of Life, including a large number of bacteria and archaea that have not been isolated, and which are not well understood.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, which can help to determine if certain habitats require special protection. This information can be used in a range of ways, from identifying new remedies to fight diseases to enhancing the quality of crops. The information is also incredibly beneficial to conservation efforts. It helps biologists discover areas most likely to be home to cryptic species, which may have important metabolic functions and be vulnerable to human-induced change. Although funds to protect biodiversity are essential however, the most effective method to protect the world's biodiversity is for more people in developing countries to be empowered with the knowledge to act locally to promote conservation from within.

Phylogeny

A phylogeny (also called an evolutionary tree) depicts the relationships between species. Using molecular data, morphological similarities and differences, or ontogeny (the course of development of an organism) scientists can create an phylogenetic tree that demonstrates the evolutionary relationships between taxonomic categories. Phylogeny is essential in understanding evolution, biodiversity and genetics.

A basic phylogenetic tree (see Figure PageIndex 10 ) determines the relationship between organisms that share similar traits that have evolved from common ancestral. These shared traits can be either analogous or homologous. Homologous traits are identical in their evolutionary origins, while analogous traits look like they do, but don't have the same ancestors. Scientists combine similar traits into a grouping called a clade. For instance, all of the species in a clade have the characteristic of having amniotic eggs and evolved from a common ancestor who had these eggs. A phylogenetic tree can be constructed by connecting clades to identify the species which are the closest to each other.

To create a more thorough and precise phylogenetic tree scientists use molecular data from DNA or RNA to establish the relationships between organisms. This information is more precise and provides evidence of the evolutionary history of an organism. Researchers can use Molecular Data to determine the age of evolution of organisms and determine how many organisms share an ancestor common to all.

The phylogenetic relationships between species can be affected by a variety of factors including phenotypic plasticity, an aspect of behavior that changes in response to specific environmental conditions. This can cause a trait to appear more resembling to one species than another, obscuring the phylogenetic signals. However, this problem can be solved through the use of techniques such as cladistics which incorporate a combination of similar and homologous traits into the tree.

Additionally, phylogenetics can help predict the duration and rate at which speciation takes place. This information can help conservation biologists make decisions about the species they should safeguard from the threat of extinction. It is ultimately the preservation of phylogenetic diversity which will lead to an ecologically balanced and complete ecosystem.

Evolutionary Theory

The main idea behind evolution is that organisms change over time due to their interactions with their environment. Several theories of evolutionary change have been developed by a variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who proposed that a living organism develop gradually according to its requirements and needs, the Swedish botanist Carolus Linnaeus (1707-1778) who conceived the modern hierarchical taxonomy, as well as Jean-Baptiste Lamarck (1744-1829) who suggested that use or disuse of traits cause changes that can be passed on to the offspring.

In the 1930s & 1940s, theories from various fields, such as genetics, natural selection, and particulate inheritance, came together to create a modern evolutionary theory. This defines how evolution is triggered by the variation of genes in a population and how these variants alter over time due to natural selection. This model, which is known as genetic drift mutation, gene flow, and sexual selection, is a key element of modern evolutionary biology and can be mathematically described.

Recent developments in evolutionary developmental biology have demonstrated how variation can be introduced to a species via genetic drift, mutations, reshuffling genes during sexual reproduction and migration between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of a genotype over time) can result in evolution, which is defined by changes in the genome of the species over time, and also the change in phenotype over time (the expression of the genotype within the individual).

Students can gain a better understanding of the concept of phylogeny through incorporating evolutionary thinking throughout all areas of biology. A recent study conducted by Grunspan and colleagues, for example, showed that teaching about the evidence that supports evolution increased students' understanding of evolution in a college biology course. For more information on how to teach about evolution, look up The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily A Framework for Infusing Evolution in Life Sciences Education.

Evolution in Action

Scientists have studied evolution by looking in the past--analyzing fossils and comparing species. They also observe living organisms. Evolution is not a past event, but an ongoing process. The virus reinvents itself to avoid new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior 에볼루션 룰렛 무료 에볼루션 바카라 에볼루션, our website, because of the changing environment. The resulting changes are often evident.

But it wasn't until the late 1980s that biologists understood that natural selection could be observed in action as well. The main reason is that different traits result in the ability to survive at different rates and reproduction, and can be passed on from one generation to another.

In the past, if a certain allele - the genetic sequence that determines color - was present in a population of organisms that interbred, it might become more prevalent than any other allele. As time passes, this could mean that the number of moths sporting black pigmentation may 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 the species, like bacteria, has a rapid generation turnover. Since 1988 the biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples of each are taken every day and over fifty thousand generations have passed.

Lenski's research has shown that mutations can drastically alter the speed at the rate at which a population reproduces, and consequently the rate at which it evolves. It also demonstrates that evolution takes time, which is difficult for some to accept.

Microevolution can be observed in the fact that mosquito genes for resistance to pesticides are more common in populations that have used insecticides. Pesticides create a selective pressure which favors individuals who have resistant genotypes.

The rapidity of evolution has led to an increasing recognition of its importance particularly in a world shaped largely by human activity. This includes pollution, climate change, 에볼루션바카라사이트 and habitat loss that hinders many species from adapting. Understanding evolution will aid you in making better decisions regarding the future of the planet and its inhabitants.