Outgroup: An outgroup is used in
phylogenetic analyses to figure out where the root of the tree should be placed
(and sometimes which character state is ancestral on the tree). An outgroup is a lineage that falls outside the clade being studied but is closely related to that clade.
Why do we need an outgroup?
The outgroup is used as a point of comparison for the ingroup and specifically
allows for the phylogeny to be rooted
. Because the polarity (direction) of character change can be determined only on a rooted phylogeny, the choice of outgroup is essential for understanding the evolution of traits along a phylogeny.
What does it mean for an organism to be an outgroup?
Outgroup (out-group) is an
evolutionary term used to denote a taxa or lineage that is outside a group of taxa being studied
. Outgroups are used to root a phylogeny as well as to infer which in-group is likely to had a particular evolutionary change. For example, a scientist is studying organism A and organism B.
How would you describe an outgroup?
An outgroup is
any group that you don’t belong to
, while an ingroup is a group that you associate yourself with. One basis for stereotypes is the tendency to see members of an outgroup as similar (called outgroup homogeneity) and members of your ingroup as different from each other (called ingroup heterogeneity).
What does it mean if two species are very far apart on a tree?
If two species have a small distance between them (as measured by the number of differences in their character sequences), then they have a recent common ancestor; but if they are far apart, then
their common ancestor is in the remote past
.
Is basal taxon and outgroup the same?
No, they are not the same
. When we construct a phylogenetic tree, we branch the organisms on the basis of their evolutionary history.
What is a good outgroup?
In general, an outgroup should be
as close as possible to the ingroup
. If there is a risk that it is really part of the ingroup, then other outgroups are needed in addition, to help resolve those relationships. Multiple outgroups give a more reliable picture.
What is an outgroup example?
An out-group, conversely, is a group someone doesn’t belong to; often we may feel disdain or competition in relationship to an out-group.
Sports teams, unions
, and sororities are examples of in-groups and out-groups; people may belong to, or be an outsider to, any of these.
What is another word for outgroup?
In this page you can discover 6 synonyms, antonyms, idiomatic expressions, and related words for out-group, like:
the-ingroup
, in-group, ingroup, unconstituted, extroverted and outgroup.
Where does the outgroup go on a cladogram?
An outgroup may be included on
a cladogram to compare the other groups to
. In the example cladogram, the outgroup is Species E. It is related to the root organism but it is not as closely related to the other terminal nodes or species as those terminal nodes are to each other.
What is ingroup and outgroup examples?
Sports teams, unions, and sororities
are examples of in-groups and out-groups; people may belong to, or be an outsider to, any of these.
What is the difference between ingroup and outgroup?
Within such categorization people find comfort and meaning in the groups they place themselves in. An Ingroup is a group to which a person identifies as being a member. An Outgroup is
a social group with which an individual does not identify
.
Why are Ingroups and Outgroups important?
Concepts intro- duced subsequently, such as ingroups and outgroups, intergroup boundaries, and group vitalities, are
important to the study of intergroup communication and can assist when analyzing interactions with those from another culture
(be it national, organizational, gen- erational, etc.).
What does the length of a phylogenetic tree indicate?
Branch lengths indicate
genetic change
i.e. the longer the branch, the more genetic change (or divergence) has occurred. Typically we measure the extent of genetic change by estimating the average number of nucleotide or protein substitutions per site.
Humans,
chimpanzees
, gorillas, orangutans and their extinct ancestors form a family of organisms known as the Hominidae. Researchers generally agree that among the living animals in this group, humans are most closely related to chimpanzees, judging from comparisons of anatomy and genetics.
Two species are more related
if they have a more recent common ancestor
, and less related if they have a less recent common ancestor.
