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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
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