Question

how do evolutionary relationship is linked to classification explain with an example

Answer 1

How Do We Study Evolutionary
Relationships?
Systematics is the part of science that deals
with grouping organisms and determining how
they are related. It can be divided into two
main branches:
Taxonomy focuses on classifying, naming,
and grouping organisms. A group, or taxon ,
can be a population, a species, a genus, or
a higher-level grouping, such as family,
order, class, phylum, kingdom, or domain.
The plural of taxon is taxa .
Phylogenetics is the study of determining
evolutionary relationships, or patterns of
descent of organisms.
All of the species of organisms that are alive
today have descended from ancestral species.
This is due to evolution , or simply change
over time. The evolutionary relationships of
ancestral species and their descendants can
be diagrammed using branching evolutionary
trees. Just like your family tree, an
evolutionary tree indicates which ancestors
gave rise to which descendants.
How to Read an Evolutionary
Tree
An evolutionary tree can also be called a
phylogenetic tree , or a just a phylogeny. There
are many different ways to draw phylogenies,
but they do all have certain parts that you
must understand before you try to interpret
them.
The root of a phylogeny represents the
common ancestor of all the descendants in
the tree. The descendant taxa are labeled at
the tips of the tree. A node splits into two
branches and indicates a divergence or
speciation event. The node itself represents
the common ancestor of any descendants that
branch off of it. The two taxa that branch off
at a node are called sister taxa . They share
an immediate common ancestor. In this
phylogeny, taxa B and C are sister taxa. They
are both equally related to taxon A.
The branches of a phylogeny can be rotated
around a node without changing evolutionary
relationships. If you want to determine how
two or more taxa are related, it is important to
look at the nodes and branches in a tree and
not just the ordering of descendant taxa.
Sometimes the evolutionary relationships
between taxa cannot be determined. This
results in a phylogeny with a polytomy , or a
node from which more than two groups split.
A clade is a group that includes an ancestor
and all of its descendants. Clades, also called
monophyletic groups , can be nested in larger
clades. For example, mammals are a
monophyletic group because they all
descended from a common ancestor. Within
the mammals, there are also many smaller
clades, such as primates or bats.
Not all groupings of organisms qualify as
monophyletic. A paraphyletic group consists of
an ancestor and only some of its descendants.
Reptiles are animals like crocodiles, lizards,
and snakes. This is actually a paraphyletic
grouping because the ancestor that gave rise
to all reptiles also gave rise to birds. If birds
are added to the definition of reptiles, then it
could be considered a monophyletic group.
A polyphyletic group is made up of various
descendants with no recent common ancestor.
Marine mammals are polyphyletic. Whales and
seals are both marine mammals, but they are
not closely related at all. Seals are more
closely related to bears than they are to
whales. Whales share a more recent common
ancestor with deer than they do to seals.

Answer 2

the more closely two species are related the more characteristics they will have in common.
eg. a brother and a sister are closely related and they have a common ancestor in the first generation before them.
a girl and her first cousin are closely related but less related than her brother. the cousins have common ancestor i.e. their grandparents in the second generation.
thus evolutionary relationships are traced in the second generation