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Essential idea: Species are named and classified using an internationally agreed system.
By Chris Paine
https://bioknowledgy.weebly.com/http://www.tokresource.org/tok_classes/biobiobio/biomenu/classification/index.htm
The Swedish botanist Carolus Linnaeus originally invented the binomial system to help him consistently name plants he identified. The system was eventually adopted by other scientists and remains to the accepted naming system for species. Though species may have many common names to avoid confusion scientists always use the scientific/binomial name.
5.3 Classification of biodiversity
Understandings
Statement Guidance
5.3.U1 The binomial system of names for species is universal
among biologists and has been agreed and developed
at a series of congresses.
5.3.U2 When species are discovered they are given scientific
names using the binomial system.
5.3.U3 Taxonomists classify species using a hierarchy of taxa.
5.3.U4 All organisms are classified into three domains. Archaea, eubacteria and eukaryote should be
used for the three domains. Members of these
domains should be referred to as archaeans,
bacteria and eukaryotes. Viruses are not
classified as living organisms.
5.3.U5 The principal taxa for classifying eukaryotes are
kingdom, phylum, class, order, family, genus and
species.
5.3.U6 In a natural classification, the genus and
accompanying higher taxa consist of all the species
that have evolved from one common ancestral species.
5.3.U7 Taxonomists sometimes reclassify groups of species
when new evidence shows that a previous taxon
contains species that have evolved from different
ancestral species.
5.3.U8 Natural classifications help in identification of species
and allow the prediction of characteristics shared by
species within a group.
Applications and Skills
Statement Guidance
5.3.A1 Classification of one plant and one animal species
from domain to species level.
5.3.A2 Recognition features of bryophyta, filicinophyta,
coniferophyta and angiospermophyta.
Students should know which plant phyla have
vascular tissue, but other internal details are
not required.
5.3.A3 Recognition features of porifera, cnidaria,
platylhelmintha, annelida, mollusca, arthropoda and
chordata.
Recognition features expected for the selected
animal phyla are those that are most useful in
distinguishing the groups from each other and
full descriptions of the characteristics of each
phylum are not needed.
5.3.A4 Recognition of features of birds, mammals,
amphibians, reptiles and fish.
5.3.S1 Construction of dichotomous keys for use in
identifying specimens.
5.3.U2 When species are discovered they are given scientific names using the binomial system.
5.3.U2 When species are discovered they are given scientific names using the binomial system.
5.3.U1 The binomial system of names for species is universal among biologists and has been
agreed and developed at a series of congresses.
The 21st International Congress of Zoology (ICZ)
http://iszscon2012.haifa.ac.il/
http://www.ibc2017.cn/index.html
• Carl Linnaeus orginally published Systema Natura in 1758 in which he gave binomials for all species known at that time.
• 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.
http://www.tokresource.org/tok_classes/biobiobio/biomenu/classification/index.htm
5.3.U2 When species are discovered they are given scientific names using the binomial system.
5.3.U2 When species are discovered they are given scientific names using the binomial system.
5.3.U2 When species are discovered they are given scientific names using the binomial system.
5.3.U2 When species are discovered they are given scientific names using the binomial system.
5.3.U2 When species are discovered they are given scientific names using the binomial system.
5.3.U2 When species are discovered they are given scientific names using the binomial system.
5.3.U7 Taxonomists sometimes reclassify groups of species when new evidence shows that a
previous taxon contains species that have evolved from different ancestral species.
Historically classification systems have been revised repeatedly based on emerging evidence.
Recent evidence from genetic studies of ribosomal RNA has shown that "prokaryotes" are far more diverse than anyone had suspected.
Previously in the second half of the 20th century all living organisms were classified into five kingdoms. This included prokaryotes being placed in one kingdom and eukaryotes were split-up into the remaining four kingdoms.
ribosomal RNA is found in all organisms and evolves slowly so is a good way to track evolution over long time periods.Recent work
http://academic.pgcc.edu/~kroberts/Lecture/Chapter%204/04-23_WhittakerTax_L.jpg
5.3.U4 All organisms are classified into three domains.
http://www.ucmp.berkeley.edu/alllife/threedomains.html
The Prokaryotae are now divided into two domains, the Bacteria and the Archaea
No one of these groups is ancestral to the others, and each shares certain features with the others as well as having unique characteristics of its own.
Bacteria and the Archaea are as different from each other as either is from the Eukaryota, the third domain.
Revision of the classification system lead to a new level of taxon called domains.
5.3.U4 All organisms are classified into three domains.
Archaea Bacteria (Eubacteria) Eukaryota
Examples are often, but always, extremophiles:• Sulfolobus sp. grow in volcanic
springs with optimal growth occurring at pH 2-3 and temperatures of 75-80 °C
• Halobacterium sp. (lives in water with high salt concentrations)
• Staphylococcus aureus (above)can cause skin infections and respiratory disease
• Cyanobacteria sp. Arephotosynthetic
• Rhizobium sp. live symbiotically with plants and fix nitrogen
Includes several kingdoms including fungi, animals and plants. Examples range from algae to Humans.
• No nuclear membrane• RNA and biochemistry distinct
from bacteria
• No nuclear membrane • Nuclear membrane
Features and examples of each domain:
http://en.wikipedia.org/wiki/Three-domain_system
n.b. viruses are not classified as living organisms in the same way that eukaryotes, archaeans, and bacteria are. They are however of considerable biological importance.
5.3.U3 Taxonomists classify species using a hierarchy of taxa.
5.3.U5 The principal taxa for classifying eukaryotes are kingdom, phylum, class, order, family,
genus and species.
Not all domains use the same taxa – the example above is for Eukaryotes
5.3.U5 The principal taxa for classifying eukaryotes are kingdom, phylum, class, order, family,
genus and species.
5.3.U5 The principal taxa for classifying eukaryotes are kingdom, phylum, class, order, family,
genus and species.
5.3.A1 Classification of one plant and one animal species from domain to species level.
Learn a mnemonic, one animal example and one plant example:
Domain Does Eukaryota Eukaryota
Kingdom Kennard Animalia Plantae
Phylum Play Chordata Spermatophyta
Class Classical Mammalia Eudicotyledons
Order Or Primates Magnoliidae
Family Folk Hominidae Ranunculales
Genus Guitar Homo Ranunculus
Species Songs? Sapiens Acris
http://commons.wikimedia.org/wiki/File:Masai_Woman.jpg http://commons.wikimedia.org/wiki/File:Ranunculus_macro.jpg
5.3.A2 Recognition features of bryophyta, filicinophyta, coniferophyta and angiospermophyta.
e.g.e.g.
e.g.e.g.
5.3.A2 Recognition features of bryophyta, filicinophyta, coniferophyta and angiospermophyta.
Leaves, roots and stems Vascular tissue
Reproductive structures
Bryophytes(mosses, hornworts and liverworts)
•No roots, but structures similar to root hairs called rhizoids•Mosses have simple leaves and
stems• Liverworts have a flattened thallus
None Spores produced in capsules, which develop at the end of a stalk
Filicinophytes(ferns)
•Roots present• Short non-woody stems.• Leaves usually divided into pairs of
leaflets
Yes Spores produced in sporangia on the underside of the leaves
Coniferophytes(conifer shrubs and trees)
•Roots, present•Woody stems• Leaves usually narrow with a thick
waxy cuticle
Yes Seeds develop from ovules in female cones. Male cones produce pollen.
Angiospermophytes(flowering plants)
• Leaves and roots variable in structure• Stems maybe woody (shrubs and
trees)
Yes Seeds develop from ovules in ovaries, insideflowers. Seeds are dispersed by fruits which develop from the ovaries.
5.3.A4 Recognition of features of birds, mammals, amphibians, reptiles and fish.
The most familiar animal from the chordata phyla belong the to subphylum vertebrata. Can you match the different classes with the images?
Fish (Agnatha,Chondrichthyes, Osteichthyes)
Birds
(aves)
Mammals
(mammalia)
Amphibians
(amphibia)
Reptiles
(reptilia)
http://commons.wikimedia.org/
n.b. Fish is not a true class it is actually a grouping of three similar classes.
5.3.A4 Recognition of features of birds, mammals, amphibians, reptiles and fish.
The most familiar animal from the chordata phyla belong the to subphylum vertebrata. Can you match the different classes with the images?
http://commons.wikimedia.org/
Fish (Agnatha,Chondrichthyes, Osteichthyes)
Birds
(aves)
Mammals
(mammalia)
Amphibians
(amphibia)
Reptiles
(reptilia)
n.b. Fish is not a true class it is actually a grouping of three similar classes.
5.3.A4 Recognition of features of birds, mammals, amphibians, reptiles and fish.
Limbs Gas Exchange Reproduction Other features
Mammals 4 Pentadactyllimbs
Lungs with alveoli
• Internal fertilization• Give birth to live young• Mammary glands secrete
milk
• Hairs growing from the skin• Teeth including living tissue
birds 4 Pentadactyllimbs, 2 limbs modified as wings
Lungs with parabronchialtubes
• Internal fertilization• Hard shells around the
eggs
• Feathers growing from skin• Beak but no teeth
reptiles 4 Pentadactyllimbs
Lungs with extensive folding
• Internal fertilization• Soft shells around eggs
• Dry scaly impermeable skin• Simple teeth – no living
tissue
amphibians 4 Pentadactyllimbs
Simple lungs with small internal folds and moist surfaces
• External fertilization in water
• Protective jelly around eggs
• Larval stage lives in water
• Soft moist permeable skin
fish Fins Gills • External fertilization inmost species
• Scales grow from the skin • with a single gill slit • Swim bladder for buoyancy
A summary of key features that can be used to distinguish between the vertebrate classes
5.3.A3 Recognition features of porifera, cnidaria, platylhelmintha, annelida, mollusca, arthropoda
and chordata.
chordata
porifera
cnidaria platylhelmintha
annelida mollusca
arthropoda
http://commons.wikimedia.org/
What about other phyla? Can you match the names with the images?
5.3.A3 Recognition features of porifera, cnidaria, platylhelmintha, annelida, mollusca, arthropoda
and chordata.
Chordata (animals with a backbone) should be easy. Try using the key to help identify the rest of the phyla.
5.3.A3 Recognition features of porifera, cnidaria, platylhelmintha, annelida, mollusca, arthropoda
and chordata.
http://commons.wikimedia.org/
Can you match the phyla with the images?
chordata porifera
cnidaria
platylhelmintha
annelida
mollusca
arthropoda
5.3.A3 Recognition features of porifera, cnidaria, platylhelmintha, annelida, mollusca, arthropoda
and chordata.
Symmetry Segmentation Digestive tract Other features
porifera(sponges)
None None No mouth or anus • Porous• attached to rocks• Filter feeder
cnidaria(corals, jellyfish)
Radial None Mouth but no anus • Stinging cells• Tentacles
platylhelmintha(flatworms)
Bilateral None Mouth but no anus • Flattened body
annelida
(earthworms,
leeches)
Bilateral Very segmented
Mouth and anus • bristles often present
Mollusca
(oyster, snails,
octopus)
Bilateral Non-visible segmentation
Mouth and anus • Most have shell made of CaCO3
Arthropoda
(ant, scorpion,
crab)
Bilateral Segmented Mouth and anus • Exoskeleton• jointed appendages
Chordata
(fish, birds,
mammals)
Bilateral Segmented Mouth and anus • notochord• hollow dorsal nerve cord• (some have ) pharyngeal slits
A summary of key features that can be used to distinguish between animal phyla
5.3.S1 Construction of dichotomous keys for use in identifying specimens.
5.3.S1 Construction of dichotomous keys for use in identifying specimens.
5.3.S1 Construction of dichotomous keys for use in identifying specimens.
5.3.U6 In a natural classification, the genus and accompanying higher taxa consist of all the
species that have evolved from one common ancestral species.
Natural classification groups together species that share a common ancestor from
which they evolved. This is called the Darwinian principle of common descent
.
Grouping together birds, bats and bees because they fly would be an artificial classification as they do not share a common ancestor and evolved the ability to fly independently.
It is expected that members of a group share important attributes or 'homologous’ traits that are inherited from common ancestors. For example Lions share more traits with Jaguars than with Clouded Leopards.
Natural classification is not straightforward as convergent evolution can make distantly related organisms appear similar and adaptive radiation can make similar organisms appear very different from each other.
Plants and fungi were once classified together because they both possessed shared characteristics such as cell walls. It is now known that this is an artificial grouping as their cell walls have a different molecular biology and they evolved separately.
5.3.U8 Natural classifications help in identification of species and allow the prediction of
characteristics shared by species within a group.
If a new species of Ant is discovered then scientists would predict that the species should possess amongst other characteristics six jointed legs, a head, thorax, abdomen, elbowed antennae, ‘antibiotic’ secretory glands. If the species does not match the expected set of characteristics this brings into question either the classification of the species or of Ants as a family.
Natural classification is very helpful when dealing with new species:
“New species of legless amphibian discovered in remote Cambodian rainforest”
http://www.abc.net.au/news/2015-01-17/new-species-of-legless-amphibian-found-in-cambodia/6022048
Dichotomous keys can be used to help identify the species. The keys can place a specimen with the most closely related species, genus, family or phyla using natural classification. To what level of classification a specimen can be placed depends on how unique it is.
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