Understanding Diversity: Systematics

Question 1

Systematics

Answer 1

It is the scientific study of the diversity of organisms and their evolutionary relationships.

Question 2

Taxonomy

Answer 2

It is the branch of systematics devoted to naming, describing and clasifying organisms.

Question 3

Classification

Answer 3

It is the process of arranging organisms into groups based on similarities that reflect evolutionary relationships.

Question 4

Hierarchical system of classification includes

Answer 4

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species.
Each formal grouping at any given level is a taxon.

Question 5

Three-domain classification

Answer 5

Archaea, Bacteria and Eukarya. Eukarya includes the fungi, plants, animals and protists.
It is based on molecular data.

Question 6

Interpret a cladogram

Answer 6

Each branch represents a clade or a group of organisms with a common ancestor. Each node, or branching point, represents the splitting of two or more new groups from a common ancestor. The node represents the most recent common ancestor of the clade represented by the branches. The root represents the most recent common ancestor of all the clades shown in the tree.

Question 7

Vertical gene transfer

Answer 7

Genes are transmitted from parent to offspring within the same species.

Question 8

Horizontal gene transfer

Answer 8

Genes are exchanged between one genome and another within one taxon or between genomes in different taxons. Genes move from one indivual to another or from one species to another species in the same generation.

Question 9

Homology

Answer 9

The presence in two or more species of a trait derived from a common ancestor. It impies evolution from a common ancestor.

Question 10

Convergent evolution

Answer 10

Independent evolution of similar structures in distantly related organisms.

Question 11

Homoplasy

Answer 11

It refers to superficially similar characters that are not homologous.

Question 12

Shared ancestral characters

Answer 12

They suggest a distant common ancestor.

Question 13

Shared derived characters (Synapomorphies)

Answer 13

They indicate a more recent common ancestor and can be used as evidence for constructing cladograms.

Question 14

Molecular systematics

Answer 14

Comparisons of nucleotide sequences in DNA and RNA, and of amino acid sequences in proteins, provide important information about how closely organisms are related.

Question 15

Monophyletic group

Answer 15

It includes all the descendants of the most recent common ancestor.

Question 16

Paraphyletic group

Answer 16

It consists of a common ancestor and some of, but not all, its descendants.

Question 17

Poluphyletic group

Answer 17

It consists of organisms that evolved from different recent ancestors.

Question 18

Outgroup analysis

Answer 18

An outgroup is a taxon that diverged earlier than any of the other taxa being investigated. They are used to determine which characters in a given group of taxa are ancestral and which are derived.

Question 19

Parsimony

Answer 19

The simplest explanation to interpret the data.