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 effect

• 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)

• the user makes a choice about a particular characteristic of an organisms described in the key

• Eventually the user will be led to the name of the organism that they are trying to identify

The formal naming of taxa according to some standardized system

Nomenclature

Formal names are known as?

Scientific names

Scientific names are conventionally translated into?

Latin language

Scientific names follows the?

Binomial nomenclature (Carole’s Linnaeus; mid 18th. Century)

Scientific names consists of two parts which is?

Genus: capitalized (Cocos)

Specific: epithet (nucifera)

What is the fundamental principle of nomenclature?

All taxa may bear only one scientific name

The arrangement of taxa into some type of order

Classification

What is the purpose of classification

To provide a system of cataloguing and expressing relationship between taxa

Methods of classifying organisms utilize categories called?

Ranks

• ranks are arranged in hierarchical manner

The primary taxonomic rank?

Domain: Eukarya

Kingdom: Animalia

Phylum/Division: Chordata

Class: Mammalia

Order: Carnivora

Family: Felidae

Genus: Panthers

Species: P. tigris

Importance of systematics: important in providing?

important in providing information on the diversity of life

• it provides the basis for acquiring p, cataloguing and retrieving information about life’s diversity

• It provides documentation through collection and storage of reference specimens

  • e.g In reference herbaria

Estimated total number of species on earth?

8.7 million

• 6.5 million species on land

• 2.2 million in oceans

Systematist make and?

Make and maintain collections

• have the training to collect, process, and identify specimens

• To curate and mange depositories of earth’s biodiversity

Myriad “new” species await discovery in collections

Value of collection

What kind of data are specimens?

• locality data

• Historic occurrences, global climate change

Value of collection: specimens have specimens

• symbionts, pollen and fungal spores

Value of collection: archive of molecules

• DNA data

Value of collection: teaching

• biodiversity

• University, public etc

Value of collection: critical role in identification

• ecology, monitoring, pests, aliens etc

• Majority of described species have yet to be revised, keyed, etc

• On-line database construction

Value of collection: voucher specimen deposition

• allowing identification to be checked

Importance of systematics

• develop a system of names

• Provide classification of organisms

Taxonomy (alpha taxonomy)

• ideal: stable and universal language

• Names are primary anchors for information storage and retrieval

Taxonomist provide identification, identification are?

• hypotheses that the unknown is conspecific with the type of the species

Identification can be provided as?

• keys

• Monographs

• Field guides

• Digital: websites; CD’s

Why does species identification matter?

• basic research on evolution, ecology

• Endangered/protected species

• Agricultural pests/beneficial species

• Disease vectors/pathogens

• Invasive species

• Environmental quality indicators

• Managing for sustainable harvesting

• Consumer protection, ensuring food quality

• Fidelity of seed banks, culture collection

Many disciplines depend on identifications provided by taxonomy examples are?

• ecologist

• Agriculturist (plants & pests)

• Public health officials, doctors, conservation biologist

Importance of systematics: it is an integrative and?

It is an integrative and unifying science

• it uses data from all fields of biology:

  • morphology, anatomy, embryology, chemistry, ecology, genetics, etc

• Systematist understands all aspect of the organisms biological specialties with the goal of understanding evolutionary history and relationships of the group

Importance of systematics: knowing the phylogeny of life can?

Knowing the phylogeny of life can give insight into other fields and have significant practical value

Discovered to posses steroid compounds (birth control pills)

Dioscorea (Wild yam)

Importance of systematics: it provides the scientific basis for?

It provides the scientific basis for defining or delimiting species ( subspecies or varieties), establishing distinction from other closely related and similar taxa

“The study of biodiversity” is the major tool in documenting biodiversity and can be a major tool for helping to save it

Systematics

• ex: moral issue of species loss accelerated by rampant destruction of habitat such as deforestation

• Conservation biology:

  • identify “hot spots” of diversity

  • Identify species at greater risk

• folk taxonomy

• Names of edible as well as poisonous plants

• Important in order to communicate acquired experiences to other members of the family and the tribe

Pre- Linnaean taxonomy, Earliest taxonomy

History of taxonomy: Begun in the eastern world

Ancient taxonomy

• father of Chinese medicine

• Educated his people in agriculture and medicine by documenting plants good for cultivation and with medicinal value

Shen Nung, Emperor of China (circa 3000 BC)

? BC Egyptian wall paintings of medicinal plants

• providing knowledge about medicinal plants and their names examples are?

celery of the hill country and celery of the delta

• Greek philosopher

• The first to classify all living things (some still used today)

• Divided the animals with blood (vertebrates) into live-bearing (viviparous) and egg-bearing (oviparous)

• Formed groups within the animals that we recognize today as insects, crustacea and testacea (molluscs)

The Greeks and Romans, Aristotle

• a student of Aristotle

• Wrote a morphology-based classifications of all known plants in De Historia Plantarum, which contained 480 species

• Described plants in terms of differences in ovary position; fused or unfused petals/ sepals

Theophrastus

• Greek physician

• Wrote De Materia Medica

• Contained around 600 species of medicinal plants

• Plant classification is based on the medicinal properties of the species

Dioscorides (40-90 AD)

• Roman soldier and later a politician

• Wrote Naturalis Historia

  • described several plants and gave them Latin names

  • Eg. Populus alba and Populus infra

  • He was known as the father of botanical Latin

Plinius (23-79 AD)

• “herbals” or books about medicinal applications of plants

• Book printing made possible publications of large numbers of books

The herbalists

Popular herbalists include?

Brunfels, Bock, Fuchs, Mattioli, Turner, L’Obel

• development of microscope made possible the detailed study of different species

• Taxonomic works became original enough to replace the Ancient Greek works

• Collection of specimen became part of the growing sciences

• Emphasis turned from medical aspects to taxonomic aspects

1.4 Early taxonomists, end of the 16th century

• Italian taxonomist recognized as “ the first taxonomist”

Caesalpino (1519-1603)

In 1583, Caesalpino wrote the?

He wrote De Plantis documenting 1500 species

• classification based on growth habit together with fruit and seed form

Caesalpino recognized the plant families?

Brassicaceae and Astraceae

a Swiss physician and anatomist

Gaspard Bauhin ( 1560-1624)

Gaspard Bauhin wrote the?

Wrote Pinax Theatri Botanici in 1623

• a listing of 6000 species

• Included synonyms which was a great necessity of the time

  • by this time, species were known with many different names in different books

Gaspard Baulin recognized?

Recognized genera and species as major taxonomic levels

English naturalist

• most important contribution: the establishment of species as the ultimate unit of taxonomy

John ray (1627-1705)

John ray published the book?

Published the book Methodus Plantarum Nova, which contained around 18000 plant species

• classification was based on many combined characters, as opposed to earlier taxonomists

Constructed a botanical classification before Carolus Linnaeus

Joseph Pitton de Tournefort (1656-1708)

Joseph Pitton de Tournefort published?

Published Institutiones Rei Herbariae, in which around 9000 species were listed in 698 genera

• plant classification was exclusively based on floral characters with emphasis on the classification of genera

Staring point of modern taxonomy?

Linnaean era

Wrote 2 books that marked the starting points of modern botanical and zoological taxonomy

Carolus Linnaeus (1707-1778)

• Species Plantarum (1753)

• Systema Naturae (1758)

The books introduced the binary form of species names for both plants and animals

• epithet names

Descriptions of the species that distinguished it from other known species in the genus

Epithet names

• Founded modern taxonomy

• Swedish botanist

Carolus Linnaeus (1707-1778)

Today every plant or animal name published before 1753 or 1758 respectively is called?

Prelinnaean, thus not valid

Linnaeus establish many of the rules taxonomist use today, example is?

Critica botanica (1735)

• include rules for the formulation of genetic names

• Terms like Corolla, stamen, filament and anther were created as well as well-known taxon names like mammalia

• 1950’s evolutionary synthesis

• Integration of systematics with other fields

• Objective is a broad understanding of plants evolution

Taxonomy and systematics modern times

Taxonomy and systematics modern times incorporates?

• physiology

• Genetics

• Morphology

• Adaptation

• Ecology

• Biogeography