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Evolution and Biodiversity 5.3- Classification and Biodiversity

Essential idea:

• Species are named and classified using an

internationally agreed system.

Nature of science:

• Cooperation and collaboration between groups

of scientists − scientists use the binomial system to identify a species

rather than the many different local names. (4.3)

Puma

Mountain Lion

Cougar Florida Panther

All are Felis concolor

International-mindedness: • There are international codes of nomenclature

and agreements as to the principles to be

followed in the classification of living organisms.

Theory of knowledge: • The adoption of a system of binomial nomenclature is

largely due to Swedish botanist and physician Carolus

Linnaeus (1707–1778).

– Published Systema Natura in 1758.

– Gave binomials for all species known at that time.

– Based on physical characteristics (morphology).

Theory of knowledge: • Linnaeus also defined four groups of humans, and the divisions

were based on both physical and social traits.

– "Europæus albus" (white European), "Americanus rubescens" (red

American), "Asiaticus fuscus" (brown Asian) and "Africanus Niger" (black

African).

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Theory of knowledge: • By 21st-century standards, his descriptions can be regarded as

racist.

• How does the social context of scientific work affect the

methods and findings of research?

• Is it necessary to consider the social context when evaluating

ethical aspects of knowledge claims?

Understandings

• The binomial system of names for species is universal among

biologists and has been agreed and developed at a series of

congresses.

– The IBC of Vienna in 1905 voted to accept his naming convention.

– Since then both the IBC and ICZ have been the bodies that oversee the

international efforts to maintain consistent naming conventions and use

of taxon.

– Periodically the congresses meet to discuss issues affecting

classification.

Understandings

• When species are discovered they are given scientific

names using the binomial system.

– Scientific name is written in italics or underlined.

– Genus is always capitalized, species is always lowercase. (Ex: Homo sapiens or Homo sapiens)

Understandings

• When species are discovered they are given scientific

names using the binomial system.

– ex: Canis = dog lupus = wolf

latrans = to bark

lupus = wolf familiaris = familiar

Understandings

• Taxonomists classify species using a hierarchy of taxa.

– Is a Koala bear a bear?

– Is a Jellyfish a fish?

The Species Concept • Morphological Species Concept

– Used by Linnaeus

– Uses anatomical features

– Physically different

– Problem- individual variation

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The Species Concept • Biological Species Concept

– Proposed by Ernst Mayr (1942)

– Interbreeding natural populations that are reproductively isolated

– Produce viable, fertile offspring

– Problems

o Asexual organisms

o Geographically isolated populations

o Extinct species?

The Species Concept • Alternative Concepts of Species

– Ecological-defined by its niche (role)

– Pluralistic-defined by the most important factors that

distinguish the species

– Geneological- defined by the genetic history

Understandings • All organisms are classified into three domains.

– Domain Bacteria (Eubacteria)

– Domain Archaea (Archaebacteria)

– Domain Eukarya (Eukaryotes)

Six Kingdom System • Archaebacteria

• Eubacteria

• Protista

• Fungi

• Plantae

• Animalia

Understandings • The principal taxa for classifying eukaryotes are kingdom,

phylum, class, order, family, genus and species. • The principal taxa for classifying eukaryotes are kingdom,

phylum, class, order, family, genus and species. – Taxon : group with similar traits

o Kingdom

Phylum

Class

Order

Family

Genus

Species

Kids Play Chess On Freeways Get Smashed

Understandings

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Understandings • In a natural classification, the genus and accompanying higher taxa consist

of all the species that have evolved from one common ancestral species.

Understandings • Taxonomists sometimes reclassify groups of species when new

evidence shows that a previous taxon contains species that

have evolved from different ancestral species.

– Previously used a five kingdom classification.

– Previously placed archaebacteria as precursor to bacteria

– Today archaebacteria more closely related to eukaryotes

Understandings • Natural classifications help in identification of species and allow

the prediction of characteristics shared by species within a

group. – Mountain Lion: Animalia-Chordata-Mammalia-Carnivoras-Felidae-Felis-concolor

– Wolf: Animalia-Chordata-Mammalia-Carnivoras-Canidae-Canis-lupus

– Dog: Animalia-Chordata-Mammalia-Carnivoras-Canidae-Canis-lupus-familiaris

Applications • Application: Classification of one plant and one animal species

from domain to species level.

– Human:

o Eukaryote

o Animalia

o Chordata

o Mammalia

o Primate

o Hominidae

o Homo

o sapiens

Applications • Application: Classification of one plant and one animal

species from domain to species level.

– Homework: Classify a plant of your choice and describe why it is

in each taxa. (use chart as example)

Taxa Level (List Specimen) Describe

charateristics at

this level

Domain

Kingdom

Phyla

Class

Order

Family

Genus

Species

Applications • Application: Recognition features of bryophyta, filicinophyta,

coniferophyta and angiospermophyta.

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Applications • Application: Recognition features of porifera, cnidaria, platylhelmintha,

annelida, mollusca, arthropoda and chordata.

Applications

• Application: Recognition of features of birds, mammals, amphibians, reptiles

and fish.

Skill • Skill: Construction of dichotomous keys for use in identifying

specimens

– Help organize organisms by characteristics

– Used to name organisms

Skill

• Skill: Construction of dichotomous keys for use in identifying

specimens

– Dichotomous Keys

o Help organize organisms by characteristics

o Used to name organisms