Classification of Living Things

Tacitus bellus

Populus tremuloidesQuaking Aspen

Finding Order in Diversity

• *To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner. All Scientist will be using the same name

• Taxonomy is the branch of biology that groups and names organisms based on studies of their different characteristics.

• Biologists who study taxonomy are called taxonomists.

• Classification systems change with expanding knowledge.

Carolus von Linnaeus(1707-1778)

Carolus Linnaeus• Swedish botanist

• Developed Binomial Nomenclature

• ***All Scientist will be using the same scientific name.

• Two-word naming system– Genus

» Noun, Capitalized, Underlined or Italicized

– Species

» Descriptive, Lower Case, Underlined or Italicized

– Each species is assigned a two-partscientific name

» Ex. Ursus arctos

System of Classification

• Linnaeus’s hierarchical system of classification includes eight levels (from largest to smallest)

• Grizzly Bear (common name)

– Domain Eukarya

– Kingdom Animalia

– Phylum Chordata

– Class Mammalia

– Order Carnivora

– Family Ursidae

– Genus Ursus

– Species arctos

Each of the levels is called a TAXON

Ursus arctos(scientific name)

System of Classification

• Taxonomic categories, an acronym:– Domain Dear

– Kingdom King

– Phylum Phillip

– Class Came

– Order Over

– Family For

– Genus Good

– Species Soup

KPCOFGS

Use the table to complete the worksheetWorksheet

• Phylogeny – evolutionary relationships among organisms

• Evolutionary classification –strategy of grouping organisms together based on their evolutionary history– Fossil record

– Comparative homologies

– Comparative sequencing of DNA/RNA among organisms

– Molecular clocks

Evolutionary Classification

Molecular Clock

Allows scientist to compare DNA sequences from two species to estimate how long it has been since they diverged from a common ancestor

Taxonomic Diagrams

Phylogenetic Tree: Represent hypothesized evolutionary relationships

Mammals Turtles Lizards and Snakes Crocodiles Birds

Looks like a

Branch on a

tree

Attempt to trace the

process of evolution by

focusing on shared features

CladogramTaxonomic Diagrams

Which

organism is

the

outgroup

Mammals

Which 2

organism

are more

closely

related

Crocodiles

and birds

Refer to page 496 to 497

Group

practice

Individual practice

The more

specific

you get,

the more

options

you have.

(3)

(6)

(32)

(90)

(493)

(5,404)

(94,240)

(953,434)

Dichotomous Keys Identify Organisms

• Dichotomous keys contain pairs of contrasting descriptions.

• After each description, the key directs the user to another pair of descriptions or identifies the organism.

Example: 1. a) Is the leaf simple? Go to 2

b) Is the leaf compound? Go to 3

2. a) Are margins of the leaf jagged? Go to 4b) Are margins of the leaf smooth? Go to 5

Worksheet

Classification of Living Things

Domains (Notice the domains on the chart)

• Most inclusive category

• Larger than a kingdom

• There are 3

– Eukarya – includes the kingdoms

» Protists, Fungi, Plants & Animals

– Bacteria – corresponds to the kingdom Eubacteria

– Archaea – corresponds to the kingdom Archaebacteria

Slides 17-23

• Is more specific with the classification

Kingdoms

• (Eubacteria and Archaebacteria) Prokaryotes, with or without peptidoglycan in cell walls

• Protista – Eukaryotes, diverse, not fungi, plants, or animals

• Fungi – Eukaryotes, multicellular (except yeasts), heterotrophic, chitin in cell walls

• Plantae – Eukaryotes, multicellular, autotrophic, cell wall containing cellulose

• Animalia – Eukaryotes, multicellular, heterotrophic, no cell wall

Kingdom -Eubacteria

• Common name: Bacteria

• Unicellular prokaryotes

• Peptidogylcan in cell wall

• Ecologically diverse

• Basic shapes are cocci, bacilli, spirilla

• Reproduce both sexually and asexually

Bacillus anthracis(spores can live in soil

for years)

Streptococcus mutans(can cause endocarditis

and dental caries)

Kingdom -Archaebacteria

• Cell wall does not contain peptidogylcan

• Cell membrane contains unusual lipids not found in other organisms

• Live in extreme environments (devoid of oxygen):

– volcanic hot springs

– brine pools

– black organic mud

Archaea

first detected in extreme

environments, such as volcanic hot

springs.

Kingdom Protista

• A classification problem – consists of organisms that cannot be classified as animals, plants, or fungi

• Most unicellular, some colonial and some multicellular

• Autotrophic and heterotrophic

• Some move with flagella, pseudopods or cilia

• Animal-like, plant-like and fungus-like groups

• Reproduce by mitosis and meiosis

Entamoeba histolytica

Kingdom Fungi

• Most feed on dead, decaying organic matter by secreting digestive enzymes into their food source then absorbing it into their bodies

• Cell walls of CHITIN

• Most multicellular; some unicellular

• Heterotrophic

Boletus zelleri(Edible, but often infected with fly

larvae)

Epidermophyton floccosum

(one of the causes of athlete's foot)

Kingdom Plantae

• Multicellular

• Nonmotile – cannot move from place to place

• Cell wall with cellulose

• Mostly photosynthetic autotrophs

Sunflowers in Fargo, North Dakota

Ginkgo bilobaGinkgos are often very

long-lived. Some specimens are thought to be more than 3,500

years old.

Kingdom Animalia

• Multicellular

• Heterotrophic

• No cell walls or chloroplasts

• Incredibly diversity

Hymenoptera Dialictus zephrum

Txodes scapularisDeer tick

Hierarchical Systemof Classification

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

• From general

to more

specific

How Many Kingdoms?6Kingdoms

• Activity: What am I?

Ecotherms vs Endotherms

• Ectotherm, Any so-called cold-blooded animal; that is, any animal whose regulation of body temperature depends on external sources, such as sunlight or a heated rock surface. The ectothermsinclude the fishes, amphibians, reptiles, and invertebrates.

• Endotherm, so-called warm-blooded animals; that is, those that maintain a constant body temperature independent of the environment. The endotherms primarily include the birds and mammals.