Chapter 14 Chapter 14 Lesson 2Lesson 2

ClassifyingClassifying SpeciesSpecies

ClassificationClassification

• grouping objects grouping objects or organisms or organisms based on based on similaritiessimilarities

1. 1. TaxonomyTaxonomy – the science of – the science of classifying organismclassifying organism ss- - similaritiessimilarities among organisms indicates among organisms indicates

that they are somehow relatedthat they are somehow related

2.2.    What categories are used to classify What categories are used to classify organismsorganisms??a.a.    HomologiesHomologies – similar structures or – similar structures or

similar biochemistry that results from a similar biochemistry that results from a common ancestorcommon ancestor

b.b. Embryonic developmentEmbryonic development – development – development of fetusof fetus

c.c.    Genetics Genetics – DNA and gene similarities– DNA and gene similaritiesd.d.    Evolutionary historyEvolutionary history

History of Classification History of Classification SystemsSystems

1.1.    Aristotle - ~350 BCAristotle - ~350 BC

a.a.    Developed the 1Developed the 1stst widely widely accepted classification systemaccepted classification system

b.b.  Divided organisms into plants or Divided organisms into plants or animalsanimals

c.c. Plants were further divided by Plants were further divided by size and structure (trees, shrubs, size and structure (trees, shrubs, herbs)herbs)

d. d. Animals were classified by where Animals were classified by where they lived (land, sea, or air)they lived (land, sea, or air)

Early ClassificationEarly Classification

• Previous classification system – 2 kingdom: Previous classification system – 2 kingdom: Plantae and Animalia Plantae and Animalia

• Declared inadequateDeclared inadequate

• Next system: addedNext system: added– Protista - microorganisms and bacteria – Protista - microorganisms and bacteria – – Fungi – mushrooms, molds, and yeastsFungi – mushrooms, molds, and yeasts

Carolus LinneausCarolus Linneausa.a. Classification system based on Classification system based on

physical and structural physical and structural similarities of organismssimilarities of organisms

b.b.    System called – System called – Binomial Binomial nomenclaturenomenclature – two word names – two word names

                            i.i.      11stst part – Genus part – Genus                            ii.ii. 22ndnd part – Species part – Species

c.c. LatinLatin

d.d.    Ex. Humans – Ex. Humans – Homo sapiensHomo sapiense.e.  Scientific names must be in Scientific names must be in italicsitalics

or or underlined underlined f.f. Genus name is capitalized, species Genus name is capitalized, species

name is lower casename is lower case

Scientific NamesScientific Namesi.i.    common names can be common names can be

misleading because they vary misleading because they vary (language or location)(language or location)

ii.ii.    scientific names are scientific names are recognized worldwiderecognized worldwide

iii.iii.  scientific names indicate scientific names indicate relationships – relationships – 1.1.     Maple Trees – Genus – AcerMaple Trees – Genus – Acer

2.2. Acer rubrumAcer rubrum – red maple – red maple

3.3.     Acer saccharumAcer saccharum – sugar maple – sugar maple

Classification GroupsClassification Groups • TaxonTaxon – a group of organism (plural – – a group of organism (plural –

taxa)taxa)• Seven Classification Taxa Seven Classification Taxa ––

1.1.      KingdomKingdom – largest taxa, includes – largest taxa, includes many types of organism with some many types of organism with some similaritiessimilarities

2.2.        PhylumPhylum3.3.        ClassClass4.4.        OrderOrder5.5.        FamilyFamily6.6.        GenusGenus7.7.      SpeciesSpecies – smallest category, only – smallest category, only

includes one type of organismincludes one type of organism

• Similar species grouped in one GenusSimilar species grouped in one Genus

• Similar Genus are grouped in one family & so onSimilar Genus are grouped in one family & so on

• Categories – always based on similarities Categories – always based on similarities among organismsamong organisms

• Ex.Ex. – – Phylum Chordata –Phylum Chordata – backbones backbones

• Class MammalClass Mammal – warm-blooded, hair or fur, – warm-blooded, hair or fur, produce milk for youngproduce milk for young

• Order Carnivore - Order Carnivore - sharp teeth, claws, hunt and sharp teeth, claws, hunt and eat meateat meat

• As we learn more, the classification of an As we learn more, the classification of an organism can changeorganism can change

• SpeciesSpecies – a group of organisms that can mate – a group of organisms that can mate and produce fertile youngand produce fertile young

Six KingdomsSix KingdomsDiffer in cell structureDiffer in cell structure

oo    Unicellular Unicellular vs. vs. multicellularmulticellular

oo    PProkaryotic vs. rokaryotic vs. EukaryoticEukaryotic

- Differ in means of Differ in means of obtaining energyobtaining energy

• autotrophic vs.autotrophic vs. heterotrophicheterotrophic

3. 3. ProtistaProtista – (protists) – (protists)

a.a.    EukaryoticEukaryoticb.b.      Single celled (but some, like algae, are Single celled (but some, like algae, are

multicellular)multicellular)c.c.      Most are microscopicMost are microscopicd.d.      Do not have complex organ systemsDo not have complex organ systemse.e.      2 main divisions – 2 main divisions –

1.1.        AlgaeAlgae – autotrophic – autotrophica.a.          Plant-like, but do not have leaves or stemsPlant-like, but do not have leaves or stemsb.b.        Important base of many food chainsImportant base of many food chains

2.2.        ProtozoaProtozoa– heterotrophic– heterotrophica.a.        Animal-likeAnimal-likeb.b.          Amoeba, parameciumAmoeba, paramecium

4.4. FungiFungi

a.a. EukaryotesEukaryotes

b.b. Unicellular (yeasts) and multicellular Unicellular (yeasts) and multicellular (mushrooms and molds)(mushrooms and molds)

c.c.    Heterotrophic – mainly decomposersHeterotrophic – mainly decomposers

d.d.    Cell walls contain – Cell walls contain – chitinchitin – a long-chain – a long-chain polymer of of beta-glucose that forms a hard, that forms a hard, semitransparent materialsemitransparent material

e.e.     Absorb food through cell wallsAbsorb food through cell walls

f.f.      Develop from spores, do not moveDevelop from spores, do not move

5.5. Plantea: (Plants)Plantea: (Plants)a.a. EukaryoticEukaryotic

b.b. MulticellularMulticellular

c.c.    Autotrophic (photosynthetic)Autotrophic (photosynthetic)

d.d.    Cell walls contain Cell walls contain cellulosecellulose

e.e.    Tissues, organs, organs systemsTissues, organs, organs systems

f.f. Do not move aroundDo not move around

g.g. Trees, moss, ferns, grassTrees, moss, ferns, grass

6.6. Animalia (animals)Animalia (animals)

a.a. EukaryoticEukaryotic

b.b.    MulticellularMulticellular

c.c.    HeterotrophicHeterotrophic

d.d.    Able to move at some time in lifeAble to move at some time in life

e.e.    No cell wallsNo cell walls

f.f.      Tissues, organs, organ systems Ex. Tissues, organs, organ systems Ex. Nervous, circulatory, muscle systemsNervous, circulatory, muscle systems

g.g.      Ex. Hydra, sponges, coral, fish, insects, Ex. Hydra, sponges, coral, fish, insects, birds, frogs, mammalsbirds, frogs, mammals

Biological KeysBiological Keys• also called dichotomous (2 branched) keyalso called dichotomous (2 branched) key

• series of paired (2) statements that compare series of paired (2) statements that compare or describe characteristics of organisms in or describe characteristics of organisms in order to identify themorder to identify them

• To use a key you always start with the first To use a key you always start with the first set of sentences, read the description, set of sentences, read the description, compare it to your organism, then follow the compare it to your organism, then follow the instructions to continue the keyinstructions to continue the key

• YYou will work to find the name through ou will work to find the name through descriptions until the name of your organism descriptions until the name of your organism is givenis given

How to make a dichotomous How to make a dichotomous keykey

• divide your samples into 2 groups using divide your samples into 2 groups using one characteristicone characteristic

• write a set of 2 sentences describing the write a set of 2 sentences describing the characteristics you have used to divide characteristics you have used to divide your object/organismsyour object/organisms

• Characteristics must be objective (ex. 5 Characteristics must be objective (ex. 5 cm) not subjective (ex. Short/long)cm) not subjective (ex. Short/long)

ExampleExample1.Has straight sides………………………go to 21.Has straight sides………………………go to 2

Does not have straight sides……….go to 4Does not have straight sides……….go to 4

2. Has 3 sides ………………………………………2. Has 3 sides ………………………………………triangletriangleHas more than three sides………………go to 3Has more than three sides………………go to 3

3. Has 4 sides 3. Has 4 sides ……………………………………………..Square……………………………………………..SquareHas more than 4 sides …………………..starHas more than 4 sides …………………..star

4.Diameter is same all over………….circle4.Diameter is same all over………….circleDiameter varies…………………………….ovalDiameter varies…………………………….oval