SYSTEMATICS: UNIT 1 PRINCIPLES AND METHODS OF SYSTEMATICS

The naming of organisms and their categorization

Taxonomy

The arrangement of organisms into groups based on ex. Trait similarity (justifying the groups)

Classification

The clustering of groups or organisms based on a unifying set of principles (evolutionary)

Systematics

The study of relationships among organisms and the classification and naming of those organisms

Systematics

Systematics is a science that includes and encompasses traditional?

Traditional taxonomy

Systematics primary goal is the reconstruction of?

Phylogeny ( evolutionary history of life)

Systematics is founded on the principles of?

Evolution

Means “change”

• viewed as the cumulative changes occurring since the origin of the universe

Evolution

Define by Charles Darwin as “descent with modification”

Biological evolution (evolution of life)

The transfer of genetic material from parents to offspring through time

Descent

Descent may occur by?

May occur by asexual reproduction or sexual reproduction

• from the time life originated 3.8 billion years ago, all life has been derived from pre-existing life

Descent through time results in the formation of a?

Lineage

Lineage is a set of organisms interconnected through time and?

A set of organisms interconnected through time and space by the transfer of genetic material from parents to offspring

Refers to a change in the genetic material that is transferred from parents to offspring

• such that the genetic material of the offspring is different from that of the parent(s)

Modification

Modification may occur by:?

• mutation (direct alteration of DNA)

• Genetic recombination (meiotic crossing over; independent assortment)

In modification, systematics in concerned with the?

Is concerned with the identification of the unique modifications of evolution

• typical land animals; with long skulls and large carnivorous teeth

• Their skulls (particularly in the ear region) strongly resemble those of living whales and are unlike those of any other mammal

Pakicetus

Lived a more aquatic lifestyle. Its legs are shorter, and its hands and feet are enlarged like paddles. Its tail is longer and more muscular

Ambulocetus

Evolution is observed through?

• population

• Species

A group of interbreeding individuals of the same species that is geographically delimited

Population

A group of populations that are related to one another by certain characteristics and distinct from other groups of individuals

Species

What are the drivers of evolution?

• genetic drift

• Natural selection

Fluctuations in allele frequencies from one generation to the next because of the populations finite size

Genetic drift

A few individuals from a population start a new population with a different allele frequency than the original population

Founder drift

• example of genetic drift

Occurs when a large population is suddenly reduced to just a few survivors because of events like natural disasters or disease

• this small group carries only a small part of the original populations genetic variety

Bottleneck effect

• example of genetic drift

The process whereby one genotype leaves more offspring than another genotype because of superior life attributes

Natural selection

What is the advantage of natural selection

• survival advantage is conferred to individuals harboring a particular mutation that tends to favour a changing environmental condition

• These individuals reproduce and pass on the “ new” genes, altering the gene pool

The formation of new species from pre-existing species

Specification

Specification follows?

It follows lineage divergence

• the splitting of one lineage into two separate lineages

• Two divergent lineage may change independently of one another, and may be designated as separate species

Taxonomy is a major part of systematics that includes four components:

• description

• Identification

• Nomenclature

• Classification

In taxonomy this is the general subject of study

• is a group of one (or more) populations of organism(s), which a taxonomist adjudges to be a unit

Taxon (plural:taxa)

Usually a taxon is given a?

A name or rank

The assignment of features or attributes to a taxonomy

Description

In description, features/attributes are called?

Characters

In description, two or more form of characters are called?

Character states

Ex: character: petal color

Character states: yellow; blue

What is the purpose of description?

Used as communication tool for concisely categorizing the attributes of a taxon, organisms or some part of the organism

The process of associating an unknown taxon with a known one

• the recognition that the unknown in new to science and warrants formal description and naming

Identification

How to identify?

By describing its characteristics and comparing it to those of other taxa to see if they conform to

Ex: use of dichotomous keys

Is a list of paired statements

Dichotomous key

Each item in a dichotomous key is called a?

Lead

• are contrasting descriptions of certain characteristics

• Paired leads

(couplet)