Where results make sense
About us   |   Why use us?   |   Reviews   |   PR   |   Contact us  

Topic: Evolutionary tree

Related Topics

In the News (Thu 18 Apr 19)

  Evolution - Wikipedia, the free encyclopedia
Evolutionary biology is a subfield of biology concerned with the origin and descent of species, as well as their change over time.
Evolutionary biology as an academic discipline in its own right emerged as a result of the modern evolutionary synthesis in the 1930s and 1940s.
Evolutionary developmental biology is an emergent subfield of evolutionary biology that looks at genes of related and unrelated organisms.
en.wikipedia.org /wiki/Evolution   (3641 words)

 Population Thinking and Tree Thinking in Systematics
Tree thinking recognizes that species are not independent replicates within a class (as earlier group thinkers had tended to see them), but are instead interconnected parts of an evolutionary tree.
Evolutionary histories of the developmental type don’t narrate a tree—a branching history—they select one important endpoint (usually us) and then trace up from the root through the tree to that endpoint, employing a variety of narrative and nomenclatural devices that minimize the branching aspect of evolution.
Tree thinking, in contrast to this sort of developmental thinking, emphasizes the divergent character of evolutionary history and the complexity and irregularity of the evolutionary tree.
rjohara.net /cv/1997Scripta.html   (3698 words)

 Evolutionary tree - Encyclopedia.WorldSearch   (Site not responding. Last check: 2007-10-20)
Most of the tree was based on ideas from cladistics; where more than two groups are shown in a single branch, there is disagreement about how they diverged.
The description as a "tree" results from earlier ideas of life as a progression from lower to higher forms.
Evolutionary relationships of casque-headed tree frogs with co-ossified skulls (family Hylidae) (University of Kansas publications, Museum of Natural History, v.
encyclopedia.worldsearch.com /evolutionary_tree.htm   (222 words)

 Mapping individual gene data on an evolutionary tree
Given an evolutionary species tree and a set of trees built on the same extant species according to similarity between individual gene families, find a mapping of the individual gene trees onto the species tree exhibiting gene duplications and losses to account for the differences.
Given an evolutionary species tree and a patterns of presence/absence of a number of genes in the extant species, find hypothetical evolutionary scenarios explaining the patterns by phenomena of gene emergence, horizontal transfer, and gene loss at various extant and ancestor tree nodes.
In this project, the database and herpesvirus evolutionary tree previously made with 19 genomes is extended to include 31 sequenced complete herpesvirus genomes and 357 homologous protein families (HPF) presented in two or more of the genomes.
www.dcs.bbk.ac.uk /~mirkin/Mapp2.html   (705 words)

 PHYLOGENETIC ANALYSIS   (Site not responding. Last check: 2007-10-20)
In the distance-based methods the input to the problem consists of evolutionary distance (such as edit distances from sequences, strength of antibody cross reactions etc.) and the goal is to reconstruct a weighted tree whose pair wise distances "agree" with a given evolutionary distances.
The goal is to build a tree with the input taxa at the leaves and inferred taxa in the internal nodes, that minimizes the cost of mutations implied by the evolutionary history.
Ultrametric trees or approximation of them can be used to deduce both the branching patterns of evolutionary history and some measure of the time that has passed along each branch.
www.msci.memphis.edu /~giri/compbio/f99/hari/hari.html   (1070 words)

 Bioinformatics and Genomics - Week 14
The root is that branch that connects to remander of the Tree; that is, it is the branch that connects to the enclosing clade.
An unrooted tree shows only the evolutionary relationships between the organisms in the tree, and does not actually infer the placement of a common ancestor in the structure or the evolutionary path used to obtain the current relationships.
For a large number of organisms, the number of generated trees becomes so large that the task cannot be accomplished, and so heuristics (methods which produce an answer in a computable length of time, but for which the answer may not be optimal) are used to select a subset of trees to create.
www.library.csi.cuny.edu /~davis/Bio_326/lectures/lect14/lect_14.html   (4517 words)

 human evolution: The Evolutionary Tree
, and tree shrews, and are classified as lower primates or prosimians.
Optimization theory in plant evolution: an overview of long-term evolutionary prospects in the angiosperms.
The ecology and evolution of Hawaiian spider communities: the diversification of Hawaiian spiders illustrates universal principles behind community assembly on evolutionary and ecological scales.
www.infoplease.com /ce6/society/A0858697.html   (322 words)

 Tree Contractions and Evolutionary Trees
An evolutionary tree is a rooted tree where each internal vertex has at least two children and where the leaves are labeled with distinct symbols representing species.
Evolutionary trees are useful for modeling the evolutionary history of species.
An agreement subtree of two evolutionary trees is an evolutionary tree which is also a topological subtree of the two given trees.
epubs.siam.org /sam-bin/dbq/article/28350   (171 words)

 Problems of Building a Consistent Evolutionary Tree -- Evolution or Creation? -- Faith Facts
Every student has been shown the "evolutionary tree," with a nice sequence of life from ooze to zoo to you.
He insists that, "There is not a trace at the molecular level of the traditional evolutionary series: cyclostome [invertebrate] to fish to amphibian to reptile to mammal." In fact, he says that studies of the dispersion of molecular characteristics is so great, that "Each class is isolated and unique.
Even famous paleontologist Mary Leakey admitted this in a 1984 book when she stated, "...in the present state of our knowledge, I do not believe it is possible to fit the known hominid fossils into a reliable pattern." (9, pg.
faithfacts.gospelcom.net /ev_origins_b.html   (2492 words)

 "Evidence of Evolutionary Transitions" by Michael J. Benton, Ph.D.
Dinosaurs with feathers and whales with legs are pretty startling discoveries, but biologists were convinced they existed from the predictions of their evolutionary trees.
Evolutionary transitions are demonstrated by so-called 'missing links', fossils like Archaeopteryx, and the whole array of intermediates between dinosaurs and modern birds that lie on either side of it.
But, the evidence for evolutionary transitions can be seen also in geographic distributions: close relatives are often found close to each other at the base of the evolutionary branch.
www.actionbioscience.org /evolution/benton2.html   (2127 words)

 Phylogeny   (Site not responding. Last check: 2007-10-20)
The final goal of such an analysis is to prepare an evolutionary tree describing the relationship of the various taxa with respect to each other.
There exist various methods for the preparation of evolutionary trees: These are "Distance Methods" based on a matrix containing pair wise distance values between all sequences in the alignment, and "Character-Based Methods" that carry out calculations on each of the individual residues of the sequences.
Corrections of the observed distance values, according to an evolutionary model, may be introduced to obtain trees with true evolutionary distances (PAM values, Kimura's formula), or corrections are carried out with reference to an outgroup (Farris, 1971; Klotz et al, 1979).
www.icp.ucl.ac.be /~opperd/private/phylogeny.html   (1346 words)

 Squirrels' evolutionary 'family tree' reveals major influence of climate, geology
And their DNA evidence shows the first branchings in the lineages of modern African ground and tree squirrels date to shortly after that.
And the authors' evidence suggests that both tree and flying squirrel lineages crossed between the two continents there at a time when the land bridge was open and the environment properly leafy.
The exception among South American tree squirrels is a pygmy variety that the researchers' evidence suggests diverged from other squirrels as long as 35 million years ago, when South America was still presumably isolated.
www.eurekalert.org /pub_releases/2003-02/du-se021903.php   (1093 words)

 UCI biologist proposes pruning human evolutionary tree 06/26/03
Ayala, who received the 2002 National Medal of Science for advances in evolutionary genetics, believes that paring down the Hominid family tree to four well-defined branches, plus one tentative branch, and redefining the species groups will better illustrate the course of human evolution.
Ayala and Cela-Conde propose trimming the human evolutionary tree by eliminating as branches Paranthropus, Orrorin and Kenyanthropus.
In the new tree, Orrorin loses its status as a branch and becomes a subgenus of Praeanthropus.
www.irvineworldnews.com /Astories/june26/ucievolve.html   (609 words)

 The New Evolutionary Tree: Five Kingdoms of Life   (Site not responding. Last check: 2007-10-20)
Instead of the image of a ladder or tree with many branches, with ever-increasing diversity and complexity, the evolution of species is now more accurately portrayed as a bush or a multi-trunk tree.
Such a model equalizes the evolutionary status of all five major life kingdoms, each of which still continues with its particular adaptation to this day.
An example is the mycorrhizal association between many species of fungi and the roots of trees and shrubs, which are fundamental to the ecological viability of forests.
www.svn.net /rmetzner/geo_kingdoms.html   (1237 words)

 Telling the Tree: Narrative Representation and the Study of Evolutionary History
The tree in this figure is branching, but the branching is far less important as a conveyor of information than is the sequence of taxa reading from lower left to upper right, all of which (with the exception of the hypothetical ancestor at the bottom) are living today.
If evolutionary biologists are concerned that not only students but also their colleagues in other disciplines learn these principles correctly—and I believe they should be so concerned—then they need to give attention to the processes by which their research results are simplified.
Conclusions about evolutionary processes that are based on the structure of trees that have been, by selective simplification, brought into alignment with preexisting nomenclature probably say less about evolution than they do about the narrative character of the preexisting nomenclature.
rjohara.net /cv/1992BP.html   (8443 words)

 Fossils cited as missing branch of evolutionary tree - 3/15/00   (Site not responding. Last check: 2007-10-20)
LONDON - Scientists have discovered 45-million-year-old foot bones in China from an extinct primate that fills in a missing branch of the evolutionary tree.
On the evolutionary tree, the creatures are somewhere between prosimians, such as lemurs and tarsiers which leaped and clung to trees, and anthropoids such as monkeys, apes and humans which walk on four or two limbs.
The lack of physical evidence led to doubts about whether Eosimias was a primate and if it was where it fitted into the family tree.
www.detnews.com /2000/religion/0003/15/03160010.htm   (376 words)

 Creation Moments - Radio   (Site not responding. Last check: 2007-10-20)
We are all familiar with the evolutionary tree of life.
More often than not, DNA information disagrees with a creature's supposed lineage as it is presented on the evolutionary tree of life.
The facts are killing the evolutionary tree of life.
www.creationmoments.com /radio/transcript.asp?track_id=786   (294 words)

 Science News Online (2/6/99): DNA's Evolutionary Dilemma
Such reconstructions of an evolutionary tree branching from a single ancestor have hinged on evidence that sub-Saharan Africans have accumulated more variations in their genetic makeup than any other geographic group.
The resulting jumbling of DNA traits and patterns has diminished the reliability of reconstructed evolutionary trees and estimates of their ages, in Relethford's view.
Advocates of evolutionary branching, such as Mark Stoneking of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, say that feverish bursts of genetic change crop up only at certain mitochondrial "hot spots" that are not crucial to their findings.
www.sciencenews.org /sn_arc99/2_6_99/bob1.htm   (2227 words)

 Evolutionary Trees and Multiple Alignment
A tree that is a good hypothesis forms the basis of a short message describing the strings.
The probability of a tree and the strings (R2) is the product of the prior probability of the tree and the sum of the probabilities of all such multiple-alignments given the tree.
The forest of 2 singleton trees corresponds to the null-theory.
www.csse.monash.edu.au /~lloyd/tildeStrings/Multiple/92.HICSS_25   (6485 words)

 Bioinformatics Research at the University of Waterloo
It is now routine for biologists to conduct evolutionary analyses of large DNA and protein sequence datasets.
A computational bottleneck in these analyses is the recovery of the topology of the evolutionary tree for a set of sequences.
A tree-building algorithm then attempts to identify edges in the subset that are compatible with each other and hereby produces an evolutionary tree.
monod.uwaterloo.ca /papers/expanded.php?paper=2000002   (264 words)

 Discovering Biodiversity   (Site not responding. Last check: 2007-10-20)
It's the metaphorical Tree of Life, the branching evolutionary tree of genetic descent by which the Earth's millions of species have diversified from one another.
Ecologists and evolutionary biologists are of course within our intended audience, but the course is also of relevance to students throughout the life sciences, because the genetic structure of life's history has broad-reaching implications and applications throughout biology.
A travelogue through highlights in the Tree of Life, from archaeans and bacteria through the eukaryotes (protists, plants, fungi, and animals), with portraits of interesting organisms and their evolutionary stories.
salticidae.org /2005Bio448G   (695 words)

 HHMI News: Molecular Biologists Prune Branches from the Animal Family Tree
These kinds of relationships have been drawn over the years by zoologists who painstakingly constructed evolutionary trees using animal morphology, or comparisons of form and structure.
Their work substantiates earlier genetic investigations suggesting that the vast majority of animals, from oysters to humans, belong to one of three primary evolutionary lines, rather than the multiple branches suggested by morphological studies.
On the new, gene-based tree, animals with backbones are on the same branch as starfish and their relatives-a longstanding classification based on similarities in development.
www.hhmi.org /news/carroll.html   (774 words)

 Tree of Life Web Project Home
The Tree of Life Web Project (ToL) is a collaborative effort of biologists from around the world.
ToL pages are linked one to another hierarchically, in the form of the evolutionary tree of life.
Starting with the root of all Life on Earth and moving out along diverging branches to individual species, the structure of the ToL project thus illustrates the genetic connections between all living things.
tolweb.org /tree/phylogeny.html   (229 words)

 Tree of Life Help
The Tree of Life is a collection of WWW pages illustrating the phylogenetic (or evolutionary) tree of organisms, and presenting information about the characteristics of thousands of different groups of organisms.
The tree or taxon list is also one of the principal means of navigation along the branches of the Tree of Life: it has links to deeper parts of the tree (toward the root) and to finer parts of the tree (toward the tips).
Below the tree may be various topics, including an introduction to the group, characteristics of members of the group, internet and literature references, etc.
tolweb.org /tree/home.pages/treehelp.html   (257 words)

 Biological Complexity - Evolutionary Tree of Life
Genetic change is the basis of biological evolution –; an ever-developing pattern of species in interacting ecosystems distributed across the globe.
The historical record of the genetic changes that have taken place during the last four billion years is rather like a web, especially because of occasional "horizontal gene transfer" between species, but it is often presented as a tree or star diagram.
The story of terrestrial evolution is about continual variation in the genetic make-up of species and the ecological effects of those variations.
www.phy.auckland.ac.nz /staff/prw/biocomplexity/evolutionary_tree.htm   (382 words)

 Man’s Social Evolutionary Tree
This subspecies was the evolutionary by product of a frightful era when men want about in armored contraptions that seemed like motorized dinosaurs, and crashed into and pulverized each other for God and country.
Now women, by virtue of their growing power and influence, took charge of the evolutionary tree, and selected men who were sensitive, considerate, had tiny little testicles, and who looked like either Alan Alda or Phil Donahue.
However, the most intelligent women were too busy creating their own little castles to find time to mate, and pretty soon the world was filled with the offspring of sensitive men and stupid women.
www.homestead.com /flowstate/files/zevoltree.htm   (971 words)

Try your search on: Qwika (all wikis)

  About us   |   Why use us?   |   Reviews   |   Press   |   Contact us  
Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.