Bio 112 Chapter 20

Phylogeny

The evolutionary history and relationship of an organism or group of organisms. Which organisms it might have evolved, closely related species, shared ancestry but not necessarily on similarities and differences

Systematics

the field that scientists use to organize and classify organisms based on evolutionary relationships (fossil records, DNA analysis)

limitation 1 of phylogenetic trees

organisms may be related but evolved under significantly caried surroundings

limitation 2 of phylogenetic trees

branches do not account for the length of time

limitation 3 of phylogenetic trees

groups that are not closely related but evolved under similar conditions, may appear more phenotypically similar

Taxonomy

is the science of classifying organisms to construct internationally shared classification system with each organism placed into more and more inclusive groupings

Homologous structures

when the features overlap morphologically and genetically

Analogy or homoplasy

When the features overlap morphologically and genetically

Homologous

similar embryonic origin

Analogous

similar function

Molecular systematics

describes the use of information on the molecular level including DNA analysis

Cladistics

sorts organisms into clades : groups of of organisms that descended from a single ancestor

Monophyletic group

a single clade and must include all descendants from a branch

Shared ancestral character

if a characteristic is found in the ancestor of a group

Maximum parsimony

events that occurred in the simplest, most obvious way. Scientists look for the most obvious and simple order of evolutionary events leading to the occurrence of traits

Horizontal gene transfer

the introduction of genetic material from one species to another species by mechanisms other than the vertical transmission from parent(s) to offspring

HGT in prokaryotes, Transformation

naked DNA is taken up by bacteria

HGT in prokaryotes, transduction

genes are transferred using a virus

HGT in prokaryotes, conjugation

the use a hollow tube called a pilus to transfer genes between organisms

Gene transfer agents

small virus-like particles that transfer random genomic segments from one species of prokaryote to another

What is used to determine phylogeny

evolutionary history

What do scientists in the field of systematics accomplish

organize and classify organisms

Which statement about taxonomic classification system is correct

subspecies are the most specific category of classification

on a phylogenetic tree, which term refers to lineages that diverged from the same place

sister taxa

Which statement about analogies is correct

They are derived by similar environmental constraints

What do scientists use to apply cladistics

homologous traits

What is true about organisms that are a part of the same clade

They evolved from a shared ancestor

Why do scientists apply the concept of maximum parsimony

to decipher accurate phylogenies

The transfer of genes by a mechanisms not involving reproduction is called

Horizontal gene transfer

particles that transfer genetic material from one species to another, especially in marine prokaryotes

gene transfer agents

What does the trunk of the classic phylogenetic tree represent

single common ancestor

Which phylogenetic model proposes that all three domains of life evolved from a pool of primitive prokaryotes

ring of life