The Academy's Evolution Site

Biological evolution is one of the most fundamental concepts in biology. The Academies are involved in helping those who are interested in the sciences comprehend the evolution theory and how it is permeated across all areas of scientific research.

This site provides a range of resources for teachers, students and general readers of evolution. It 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 appears in many cultures and spiritual beliefs as an emblem of unity and love. It has many practical applications in addition to providing a framework for understanding the history of species, and how they respond to changes in environmental conditions.

The first attempts at depicting the world of biology focused on categorizing species into distinct categories that were identified by their physical and metabolic characteristics1. These methods, based on sampling of different parts of living organisms or on small fragments of their DNA, significantly increased the variety that could be included in a tree of life2. However these trees are mainly composed of eukaryotes; bacterial diversity is not represented in a large way3,4.

In avoiding the necessity of direct experimentation and observation genetic techniques have enabled us to depict the Tree of Life in a more precise manner. Particularly, molecular techniques allow us to construct trees using sequenced markers like the small subunit of ribosomal RNA gene.

The Tree of Life has been significantly expanded by genome sequencing. However there is still a lot of diversity to be discovered. This is particularly true for microorganisms that are difficult to cultivate, and which are usually only found in a single specimen5. Recent analysis of all genomes has produced a rough draft of the Tree of Life. This includes a wide range of archaea, bacteria and other organisms that haven't yet been isolated or their diversity is not well understood6.

The expanded Tree of Life is particularly useful for assessing the biodiversity of an area, assisting to determine if specific habitats require special protection. This information can be utilized in a variety of ways, from identifying the most effective treatments to fight disease to enhancing crops. The information is also useful for conservation efforts. It can aid biologists in identifying the areas most likely to contain cryptic species with important metabolic functions that could be vulnerable to anthropogenic change. While conservation funds are important, the best method to protect the biodiversity of the world is to equip more people in developing countries with the information they require to take action locally and encourage conservation.

Phylogeny

A phylogeny (also called an evolutionary tree) shows the relationships between different organisms. Utilizing molecular data similarities and differences in morphology or ontogeny (the process of the development of an organism), scientists can build a phylogenetic tree which illustrates the evolutionse/redirect.aspx?url=https://theflatearth.win/wiki/Post:10_Graphics_Inspirational_About_Evolution_Gaming">에볼루션게이밍 rate at which speciation takes place. This information can help conservation biologists make decisions about the species they should safeguard from extinction. In the end, it is the conservation of phylogenetic diversity which will create an ecosystem that is balanced and complete.

Evolutionary Theory

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

In the 1930s & 1940s, 에볼루션바카라에볼루션 바카라 사이트 - mouse click the next webpage - concepts from various fields, such as genetics, natural selection, and particulate inheritance, were brought together to create a modern synthesis of evolution theory. This explains how evolution is triggered by the variation of genes in the population and how these variations change over time as a result of natural selection. This model, known as genetic drift mutation, gene flow, and sexual selection, is the foundation of modern evolutionary biology and is mathematically described.

Recent discoveries in the field of evolutionary developmental biology have revealed how variation can be introduced to a species through mutations, genetic drift, 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 an individual's genotype over time), can lead to evolution, [Redirect Only] which is defined by 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 aspects of biology education could increase student understanding of the concepts of phylogeny and evolution. A recent study by Grunspan and colleagues, for instance, showed that teaching about the evidence supporting evolution increased students' understanding of evolution in a college-level biology class. For more information about how to teach evolution look up The Evolutionary Potency 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 through looking back, studying fossils, comparing species and studying living organisms. However, evolution isn't something that occurred in the past, it's an ongoing process, happening right now. Viruses reinvent themselves to avoid new antibiotics and bacteria transform to resist antibiotics. Animals adapt their behavior as a result of the changing environment. The changes that result are often apparent.

But it wasn't until the late 1980s that biologists realized that natural selection can be seen in action, as well. The key is that various traits have different rates of survival and reproduction (differential fitness) and are transferred from one generation to the next.

In the past, if one allele - the genetic sequence that determines color - was found in a group of organisms that interbred, it might become more common than any other allele. Over time, this would mean that the number of moths with 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 observe evolution when the species, like bacteria, has a rapid generation turnover. Since 1988, biologist Richard Lenski has been tracking twelve populations of E. coli that descended from a single strain; samples from each population are taken on a regular basis and over fifty thousand generations have been observed.

Lenski's research has revealed that mutations can alter the rate at which change occurs and the effectiveness at which a population reproduces. It also shows that evolution takes time, a fact that is hard for some to accept.

Microevolution can be observed in the fact that mosquito genes for pesticide resistance are more prevalent in areas where insecticides have been used. This is because pesticides cause an enticement that favors those with resistant genotypes.

The rapid pace at which evolution can take place has led to an increasing appreciation of its importance in a world that is shaped by human activity--including climate change, pollution and the loss of habitats which prevent many species from adjusting. Understanding the evolution process will help us make better decisions regarding the future of our planet, as well as the lives of its inhabitants.