Evolution
The history and science of origin and evolution comprise two events, the beginning of life and expansion of life. Our earth originated about 4.5 billion years ago. The term evolution is derived from two Latin words and means the act of unfolding or unrolling. English philosopher Herbert Spencer first used it. Evolution is defined as the change in heritable traits of biological populations over successive generations. These traits are the manifestations of genes that are passed down from parent to offspring during reproduction.
Cladistics
Cladistics is a technique in the classification of organisms, where they are grouped into different clades. The proof for the relationships that are hypothesized is based on the shared derived characteristics known as synapomorphies. These characteristics do not exist in many of the distant ancestors and groups. The common ancestor along with its descendants is considered to be a part of the clade. The rate of closeness is directly proportional to the cladistic grouping and is useful in analyzing the evolutionary mechanism.
Outgroups
Outgroups are significant in studying cladistics or phylogenetics (that describe the evolutionary relationship between different organisms). Further, it is also important to understand the differences and similarities between different organisms.
Taxonomy
It is the branch of biology that works with the identification of organisms at first, then naming, and classification of them into phenetic or phylogenetic groups (a classification system). In other words, it is the scientific study of biological diversity and a part of systematic biology.
Phylogenetics
Phylogenetics is the scientific study of how various groups of organisms are related at the evolutionary level. It finds the relationship between various organisms based on their evolutionary similarities and differences. It is a part of the taxonomy. Although the taxonomic study is not only concerned about phylogeny but taxonomic studies are also concerned about the classification and nomenclature of the different individuals from different taxon.
Answer:
PATTERN OF EVOLUTION:
THERE ARE TWO TYPES OF PATTERN : CONVERGENT AND DIVERGENT
CONVERGENT EVOLUTION: when two unrelated animals converging on the same form or structure, because that form is very adaptive in their common environment. it describes the acquisition of same biological trait in unrelated species.
DIVERGENT EVOLUTION: In this process in which two or more related species become more and more dissimilar. in this case, similarity is due to the common origin .
SPECIATION: Speciation is refers to the splitting of a single ancestral species in to two or more descendant species. It is a process not an event . According to charles darwin, the prigin of a species is not a sudden instant in the history of life but one that results from a steady accumulation of diiferences. Those differences are the product of natural selection of variation present in populations.
Speciation is defined as the evolution of "isolating mechanism" traits that reduce gene flow between populations. Due to reduced gene flow , genetic differences can accumulate due to genetic drift or because selection favours different alleles in different populations. At some time populations may become so different from each other that they no longer would or could interbreed. Thry have become reproductively isolated from each other.
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