The Academy's Evolution Site

The concept of biological evolution is a fundamental concept in biology. The Academies are committed to helping those who are interested in the sciences comprehend the evolution theory and how it is incorporated in all areas of scientific research.

This site provides a wide range of resources for students, 에볼루션게이밍 teachers and general readers of 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 important practical uses, like providing a framework to understand the history of species and how they react to changing environmental conditions.

The earliest attempts to depict the biological world focused on categorizing species into distinct categories that were identified by their physical and metabolic characteristics1. These methods rely on the sampling of different parts of organisms or short DNA fragments, have greatly 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.

In avoiding the necessity of direct experimentation and observation, genetic techniques have made it possible to represent the Tree of Life in a more precise way. 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, much biodiversity still remains to be discovered. This is particularly relevant to microorganisms that are difficult to cultivate, and are typically found in one sample5. A recent study 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 their diversity is not fully understood6.

The expanded Tree of Life can be used to determine the diversity of a particular area and determine if specific habitats need special protection. The information is useful in a variety of ways, such as finding new drugs, 에볼루션 바카라사이트 battling diseases and improving the quality of crops. The information is also valuable for conservation efforts. It can help biologists identify areas that are likely to be home to cryptic species, which may have vital metabolic functions and are susceptible to human-induced change. Although funding to safeguard biodiversity are vital however, the most effective method 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 in order to promote conservation from within.

Phylogeny

A phylogeny (also known as an evolutionary tree) shows the relationships between organisms. Using molecular data as well as morphological similarities and distinctions or ontogeny (the course of development of an organism) scientists can create a phylogenetic tree which illustrates the evolutionary relationship between taxonomic categories. The phylogeny of a tree plays an important role in understanding the relationship between genetics, biodiversity and evolution.

A basic phylogenetic Tree (see Figure PageIndex 10 ) determines the relationship between organisms with similar traits that evolved from common ancestral. These shared traits can be either homologous or analogous. Homologous traits are similar in their evolutionary journey. Analogous traits may look like they are however they do not have the same ancestry. Scientists put similar traits into a grouping referred to as a the clade. For instance, all the organisms that make up a clade share the trait of having amniotic egg and evolved from a common ancestor 에볼루션사이트 that had eggs. A phylogenetic tree can be constructed by connecting the clades to identify the species which are the closest to each other.

Scientists make use of DNA or RNA molecular information to build a phylogenetic chart that is more precise and precise. This information is more precise than morphological data and provides evidence of the evolutionary background of an organism or group. Researchers can utilize Molecular Data to determine the age of evolution of organisms and identify how many species share an ancestor common to all.

The phylogenetic relationships between organisms can be affected by a variety of factors, including phenotypic flexibility, an aspect of behavior that alters in response to unique environmental conditions. This can cause a characteristic to appear more similar to one species than another, clouding the phylogenetic signal. However, this issue can be reduced by the use of techniques such as cladistics which include a mix of homologous and analogous features into the tree.

Additionally, phylogenetics can aid in predicting the duration and rate of speciation. This information can help conservation biologists decide which species they should protect from the threat of extinction. In the end, it's the preservation of phylogenetic diversity which will lead to an ecologically balanced and complete ecosystem.

Evolutionary Theory

The fundamental concept of evolution is that organisms acquire distinct characteristics over time based on their interactions with their environment. Several theories of evolutionary change have been developed by a wide variety of scientists including the Islamic naturalist Nasir al-Din al-Tusi (1201-1274) who believed that an organism would evolve gradually according to its needs as well as the Swedish botanist Carolus Linnaeus (1707-1778) who designed modern hierarchical taxonomy, and Jean-Baptiste Lamarck (1744-1829) who suggested that the use or misuse of traits can cause changes that can be passed onto offspring.

In the 1930s and 1940s, concepts from various fields, including genetics, natural selection and particulate inheritance -- came together to form the modern evolutionary theory synthesis, which defines how evolution is triggered by the variations of genes within a population and how these variants change over time as a result of natural selection. This model, 에볼루션 사이트 called genetic drift mutation, gene flow, and sexual selection, is the foundation of modern evolutionary biology and can be mathematically explained.

Recent developments in the field of evolutionary developmental biology have revealed that variation can be introduced into a species through genetic drift, mutation, and reshuffling of genes in sexual reproduction, and also through migration between populations. These processes, along with others like directional selection and genetic erosion (changes in the frequency of the genotype over time) can result in evolution that is defined as changes in the genome of the species over time and also by changes in phenotype over time (the expression of that genotype within the individual).

Students can gain a better understanding of the concept of phylogeny by using evolutionary thinking in all areas of biology. In a recent study conducted by Grunspan et al., it was shown that teaching students about the evidence for evolution boosted their understanding of evolution during an undergraduate biology course. To learn more about how to teach about evolution, please look up The Evolutionary Potential in All Areas of Biology and Thinking Evolutionarily: 에볼루션사이트 A Framework for 에볼루션사이트 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 observe living organisms. But evolution isn't just something that occurred in the past. It's an ongoing process happening today. The virus reinvents itself to avoid new medications and bacteria mutate to resist antibiotics. Animals adapt their behavior because of the changing environment. The changes that occur are often evident.

It wasn't until the late 1980s that biologists began to realize that natural selection was in play. The key is that various traits have different rates of survival and reproduction (differential fitness) and are passed from one generation to the next.

In the past, if an allele - the genetic sequence that determines colour - was found in a group of organisms that interbred, it could be more prevalent than any other allele. Over time, this would mean that the number of moths sporting black pigmentation in a group could increase. The same is true for many other characteristics--including morphology and behavior--that vary among populations of organisms.

Monitoring evolutionary changes in action is easier when a species has a rapid turnover of its generation like bacteria. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. Coli that descended from a single strain. samples of each population are taken every day and more than 50,000 generations have now been observed.

Lenski's research has revealed that a mutation can profoundly alter the efficiency with which a population reproduces and, consequently the rate at which it alters. It also shows that evolution takes time, which is difficult for some to accept.

Microevolution can also be seen in the fact that mosquito genes that confer resistance to pesticides are more common in populations that have used insecticides. This is due to pesticides causing a selective pressure which favors those with resistant genotypes.

The speed at which evolution can take place has led to an increasing awareness of its significance in a world shaped by human activities, including climate changes, pollution and the loss of habitats that prevent many species from adjusting. Understanding the evolution process can help us make better decisions regarding the future of our planet, and the lives of its inhabitants.