Unit 2 – Diversity of LifeUnit 2 – Diversity of Life- Millions of species (2-4.5 million) exist on planet Millions of species (2-4.5 million) exist on planet

earth (huge amount of biodiversity).earth (huge amount of biodiversity).- Classifying all these species helps make sense of Classifying all these species helps make sense of

all the biodiversity.all the biodiversity.- Many species have become extinct in the past.Many species have become extinct in the past.- Many existing species are becoming extinct Many existing species are becoming extinct

before we even know they exist! Some of these before we even know they exist! Some of these species could be important for our species in species could be important for our species in terms of medical or ecological significance.terms of medical or ecological significance.

- TaxonomyTaxonomy – the science of naming and – the science of naming and classifying organismsclassifying organisms

- TaxonTaxon – a group of organisms in a classification – a group of organisms in a classification systemsystem

Binomial NomenclatureBinomial NomenclatureTwo-word standard naming system for all known Two-word standard naming system for all known organismsorganisms

Based on the dead language latin – dead because it Based on the dead language latin – dead because it is not spoken any more and thus doesn’t change is not spoken any more and thus doesn’t change over timeover time

Two part name – genus + species: ex. Two part name – genus + species: ex. Homo Homo sapiens, Canis lupissapiens, Canis lupis

Universal over Universal over allall languages so species identification languages so species identification cannot be mistaken from language to language.cannot be mistaken from language to language.

a scientific (biological) name can help distinguish a scientific (biological) name can help distinguish common name confusion.common name confusion.

What is a Gopher?What is a Gopher?In Saskatchewan, In Saskatchewan, a gopher is this:a gopher is this:

In Florida, a In Florida, a gopher is this:gopher is this:

Species name: Urocitellus richardsonii

Species name: Species name: Gopherus Gopherus polyphemuspolyphemus

LinnaeusLinnaeusCarl von Linne (Carolus Linnaeus – he “Latinized” his Carl von Linne (Carolus Linnaeus – he “Latinized” his name) – Swedish botanist: developed the Linnaean name) – Swedish botanist: developed the Linnaean system of classification (binomial nomenclature)system of classification (binomial nomenclature)

His system of naming organisms is still used todayHis system of naming organisms is still used today

3 rules used:3 rules used:

Genus – always capitalized, ex: Genus – always capitalized, ex: CanisCanis

Species – always not capitalized ex: Species – always not capitalized ex: lupislupis

Entire species name (genus and species) is Entire species name (genus and species) is underlined (if handwritten) or italicized (if typed)underlined (if handwritten) or italicized (if typed)

Underlined (or italicized) so that the scientific name Underlined (or italicized) so that the scientific name stand out from rest of the text presentstand out from rest of the text present

7 Levels of Classification (Taxons)7 Levels of Classification (Taxons)Kingdom – ex: AnimalsKingdom – ex: Animals

Phylum (animals) / Division (plants) - ex: Phylum (animals) / Division (plants) - ex: ChordataChordata

Class – ex: MammaliaClass – ex: Mammalia

Order – ex: PrimatesOrder – ex: Primates

Family – ex: HominidaeFamily – ex: Hominidae

Genus – ex: Genus – ex: HomoHomo

Species – ex: Species – ex: sapienssapiens

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Questions 1-3, page 521Questions 1-3, page 5211.1. What is binomial nomenclature?What is binomial nomenclature?

- It is a system that gives every species a unique two-part - It is a system that gives every species a unique two-part name that identifies it. The first part is the genus, and name that identifies it. The first part is the genus, and the second part is the species descriptor.the second part is the species descriptor.

2.2. Name each taxon in the Linnaean system of Name each taxon in the Linnaean system of classification, from most general to most specific.classification, from most general to most specific.

- kingdom, phylum, class, order, family, genus, species- kingdom, phylum, class, order, family, genus, species

3.3. What are some limitations of the Linnaean classification What are some limitations of the Linnaean classification system?system?

- It only accounts for physical and structural similarities - It only accounts for physical and structural similarities between organisms, which can be the result of between organisms, which can be the result of convergent evolution and therefore not indicative of convergent evolution and therefore not indicative of relatedness.relatedness.

Questions 4-5, p521Questions 4-5, p5214.4. How is a scientific name similar to an address that How is a scientific name similar to an address that

includes city and state?includes city and state?- A state (or province) has many cities as a genus has - A state (or province) has many cities as a genus has

many species. Like species descriptors, city names many species. Like species descriptors, city names cannot be used alone because the same city names can cannot be used alone because the same city names can occur in different states (or provinces), as with Portland occur in different states (or provinces), as with Portland (Maine and Oregon).(Maine and Oregon).

5.5. Which two species are more closely related: Which two species are more closely related: Ursus Ursus maritimusmaritimus, , Ursus americanusUrsus americanus, or , or Bufo americanusBufo americanus??

- - Ursus maritimus Ursus maritimus (polar bears) and (polar bears) and Ursus americanusUrsus americanus (black bear) are most closely related; they belong to the (black bear) are most closely related; they belong to the same genus.same genus.

Question 6, p521Question 6, p5216.6. During his voyage, Charles Darwin collected During his voyage, Charles Darwin collected

thousands to organisms, which he classified thousands to organisms, which he classified using the Linnaean classification system. using the Linnaean classification system. How did this system help him share his How did this system help him share his findings with other naturalists?findings with other naturalists?

- Others could understand the relationships - Others could understand the relationships between organisms, such as Darwin’s between organisms, such as Darwin’s finches, and there was uniformity in temrs of finches, and there was uniformity in temrs of language. Had he used common names language. Had he used common names alone, they would have required translation alone, they would have required translation into many languages.into many languages.

Dichotomous KeysDichotomous KeysDichotomous keys are used to identify Dichotomous keys are used to identify objects or organisms that have already objects or organisms that have already been described by another scientist.been described by another scientist.

As its name implies (di- means "two"), a As its name implies (di- means "two"), a dichotomous key is made up of paired dichotomous key is made up of paired statements.statements.

Each pair of statements divides the Each pair of statements divides the objects to be classified into two categories.objects to be classified into two categories.

This means that each object must fit into This means that each object must fit into one category or the other, but not both.one category or the other, but not both.

Sample Dichotomous Key:Sample Dichotomous Key:

# of Kingdoms?# of Kingdoms?- 1753: Two kingdoms1753: Two kingdoms – Animalia & Plantae – Animalia & Plantae

- 1866: Three kingdoms1866: Three kingdoms – Animalia, Plantae & – Animalia, Plantae & ProtistaProtista

- 1938: Four kingdoms1938: Four kingdoms - Animalia, Plantae, - Animalia, Plantae, Protista, & MoneraProtista, & Monera

- 1959: Five kingdoms1959: Five kingdoms - Animalia, Plantae, - Animalia, Plantae, Protista, Monera & FungiProtista, Monera & Fungi

- 1977: Six Kingdoms1977: Six Kingdoms - Animalia, Plantae, - Animalia, Plantae, Protista, Bacteria, Fungi, & ArchaeaProtista, Bacteria, Fungi, & Archaea

History of the Kingdom SystemHistory of the Kingdom System

3 Domains Tree of Life3 Domains Tree of Life

3 Domains of Life3 Domains of Life1.1. Domain – BacteriaDomain – Bacteria

- - One kingdom: Bacteria- One kingdom: Bacteria- Single celled prokaryotes (lack a nucleus and Single celled prokaryotes (lack a nucleus and

organelles)organelles)- One of the largest group of organisms on earthOne of the largest group of organisms on earth

2.2. Domain – ArchaeaDomain – Archaea- One Kingdom: ArchaeaOne Kingdom: Archaea- Single celled prokaryotes (lack a nucleus and Single celled prokaryotes (lack a nucleus and

organelles)organelles)- Live in extreme environments: deep sea vents, hot Live in extreme environments: deep sea vents, hot

geysers, Antarctic waters, salty lakes, acidic geysers, Antarctic waters, salty lakes, acidic environmentsenvironments

3.3. Domain – EukaryaDomain – Eukarya- Four kingdoms:Four kingdoms:

- PlantaePlantae- ProtistaProtista- FungiFungi- AnimaliaAnimalia

- Single-celled (protista) or multicellular (fungi, Single-celled (protista) or multicellular (fungi, plantae & animalia)plantae & animalia)

- Eukaryotic: cells possess a nucleus and organellesEukaryotic: cells possess a nucleus and organelles

Questions 1-2, page 535Questions 1-2, page 5351.1. Why is classification of life considered a Why is classification of life considered a

work in progress?work in progress?- Scientists are always finding more information - Scientists are always finding more information

about organisms that forces a re-about organisms that forces a re-examination of classification schemes.examination of classification schemes.

2.2. What kingdoms are included in each of What kingdoms are included in each of the three domains in the modern tree of the three domains in the modern tree of life?life?

- Bacteria: bacteriaBacteria: bacteria- Archaea: archaeaArchaea: archaea- Eukarya: protista, fungi, plantae, animaliaEukarya: protista, fungi, plantae, animalia

Questions 3-4, page 535Questions 3-4, page 5353.3. If you come cross across an unusual single-celled organism, If you come cross across an unusual single-celled organism,

what parts of the cell would you study to classify it into one of the what parts of the cell would you study to classify it into one of the three domains?three domains?

- Nucleus (or lack thereof) and cell wall- Nucleus (or lack thereof) and cell wall

4.4. Explain, using the traditional definition of species, why it is Explain, using the traditional definition of species, why it is difficult to classify some bacteria and archaea at the species difficult to classify some bacteria and archaea at the species level.level.

- A species can be defined as an interbreeding group of A species can be defined as an interbreeding group of organisms that produce fertile offspring. But bacteria and organisms that produce fertile offspring. But bacteria and archaea do not breed to produce offspring; they reproduce by archaea do not breed to produce offspring; they reproduce by binary fission. In reproduction, as it is generally defined, binary fission. In reproduction, as it is generally defined, parents also pass genetic material to their offspring. parents also pass genetic material to their offspring. However, many bacteria and archaea can take up genetic However, many bacteria and archaea can take up genetic material from their environment – a transfer of genes outside material from their environment – a transfer of genes outside of typical reproduction that does not occur in eukaryotes.of typical reproduction that does not occur in eukaryotes.

Question 5, p535Question 5, p535

5.5. History of Life – The Archaea lineage History of Life – The Archaea lineage may include the first life on Earth, which may include the first life on Earth, which began under much different began under much different environmental conditions from those environmental conditions from those present today. What characteristics of present today. What characteristics of archaea help support this statement?archaea help support this statement?

- Archaea exist in extreme environments that - Archaea exist in extreme environments that are similar to those of early Earth.are similar to those of early Earth.