Chapter 18 Why Classify Classification is used to name organisms and group them in a logical manner Biologists have classified and named over 15 million species Estimate that 2 million 100 million have yet to be discovered ID: 332231
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Slide1
Classification of Living Things
Chapter 18Slide2
Why Classify
Classification is used to name organisms and group them in a logical manner Biologists have classified and named over 1.5 million species
Estimate that 2 million- 100 million have yet to be discoveredSlide3
Taxonomy
A branch of biology where scientists classify organisms and assign each a universally accepted nameSlide4
Taxonomy
A good classification system puts organisms in groups with other organisms that are similar
Originally based on
physical characteristics
Physical traits are shared amongst unrelated organisms
Convergent evolutionShark vs. dolphin
Bird vs. batSlide5
Common Names
Organism were originally referred to by common namesNames that are unique to a small group of
people
With
out discussion; draw what comes to mind when you hear the word: catSlide6
Use of common names
Common names can be
misleading
Given based on physical characteristics and what the organism reminds us
of
j
ellyFISH
seaHORSE
Sea CUCUMBERSlide7
Use of common names
Common names vary among languages and even regions in the same country Mountain lion
Puma
Cougar
PantherSlide8
Use of common names
Different species sometimes share a common nameWhat is a buzzard???
United States-
Vulture
United Kingdom (England)-
HawkSlide9
Removing Confusion
First Naming system
scientists used detailed physical descriptions
Names were long and
hard to remember
Carolus
Linnaeus (mid 18
th
century)
Developed a two word naming
system called Binomial
nomenclature
shows
ancestral
relationSlide10
Binomial Nomenclature
scientific names are used to avoid confusionUniversally accepted
Cathartes
aura
Buteo
jamaicensis
Slide11
Taxonomic Nomenclature
Kingdom
Phylum
Class
Order
Family
Genus
Species
Kids
Prefer
Candy
Over
Fried
Green
Spinach
Hierarchical system (consists of levels)
Each level is a taxon Slide12
Kingdom- Animalia
Phylum- Chordata Class- MammaliaOrder- Carnivora
Family- Felidae
Genus-
Panthera
Species- leoSlide13
Binomial Nomenclature
Rules
to follow
Always written in
italics
(or underlined)
First word is
capitalized (genus name)
Second word is
lowercased (species name)Slide14
Binomial Nomenclature
Genus a group of closely related species
UrsusSlide15
Binomial Nomenclature
Species
a group of similar organisms that can breed and produce fertile offspring
Ursus
Ursus
Ursus
a
rctos
maritimus
americanisSlide16Slide17
Modern Evolutionary Classification
18.2Slide18
Modern Evolutionary classification
Taxonomic groups are invented by scientist to group organisms with similar characteristicsSlide19
Which Similarities are most important
Taxonomists try to group organisms according to biologically important characteristics
Linnaeus grouped species based on visible similarities (Dolphin example: Fish vs. Mammal)
Barnacle
crab
limpetSlide20
Evolutionary Classification
Limpet and barnacle larvae are very different.
Barnacles have jointed limbs, Limpets DON’T !
Barnacles have a segmented body, Limpets DON’T !
Barnacles have an exoskeleton that molts, Limpets DON’T !Slide21
Crab and barnacle larvae are very similar
Barnacles have jointed limbs, So do CRABS !
Barnacles have a segmented body, So do CRABS !
Barnacles have an exoskeleton that molts, So do CRABS !
Evolutionary ClassificationSlide22
Evolutionary Classification
Organisms are grouped together based on evolutionary decent
not just physical traits
(WHY??)
The higher the level of the taxon, the further back in time is the common ancestor Slide23
Lion
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Felidae
Genus: Panthera
Species: leo
Tiger
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Felidae
Genus: Panthera
Species: tigrisSlide24
Lion
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Felidae
Genus: Panthera
Species: leo
Grey Wolf
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Canis
Species: C. lupusSlide25
Cladistic analysis
Cladogram
: a diagram used to show evolutionary relationships
A way of classifying organisms
using only new evolutionary characteristics
Derived characteristics-
These characteristics appear in later organisms but not earlier onesSlide26
Molecular Clock
Used to compare DNA of organismsThe more similar the DNA the more recently the organisms branched off from one another
Neutral Mutations- are not affected by natural selection
Accumulate in the DNA over time (at the same rate in all species)Slide27
Cladogram
Help us to understand how one lineage branched from another in the course of evolution.
(family tree)Slide28
1. ______ Wings
2. ______ 6 Legs
3. ______ Segmented Body
4. ______ Double set of wings
5. ______ Jumping Legs
6. ______ Crushing mouthparts
7. ______ Legs
8. ______ Curly AntennaeSlide29
Answer
1. ___F___ Wings2. ___C___ 6 Legs3. ___A___ Segmented Body
4. ___G___ Double set of wings
5. ___E___ Jumping Legs
6. ___D___ Crushing mouthparts
7. ___B___ Legs8. ___H___ Curly AntennaeSlide30
Kingdoms and Domains
The tree of Live “Evolves”Slide31
Changes in the classification system
New biological understanding lead to a more accurate classification systemGenes show important similarities at the molecular level
Linnaeu’s
didn’t know about DNA
DNA from organisms can be sequenced and compared to show evolutionary relationships
. Slide32
Molecular Clocks
DNA comparisons can be used to estimate how long 2 species have been evolving independently. Mutations in the genes accumulate at different rates
The more similar mutations 2 species have the closer related they areSlide33
Effect on Classification
Scientist used to believe there were just 2 groups of living things: plants and animals
2 kingdom system doesn’t adequately represent diversity of life
6 kingdom system:
Eubacteria
ArchaebacteriaProtista
Fungi
Plantae
Animalia Slide34
Eubacteria
ProkaryoteUnicellular
Autotroph or Heterotroph
Cell wall with peptidoglycan (extra outer layer)
Ecologically diverse (Common Bacteria)
Free-living soil organismsParasitesPhotosyntheticAnaerobic
aerobicSlide35
Archaebacteria
ProkaryoteUnicellularAutotroph or Heterotroph
Cell wall
without
peptidoglycan layer
Live in the most extreme environments (first living organisms)Volcanic hot springsBrine poolsBlack organic mud (NO oxygen)Slide36
Protista
EukaryoteMost are unicellularAutotroph or Heterotroph
Cell walls of cellulose
Some have chloroplasts
Made up of organisms that
cannot be classified elsewhere Slide37
Fungi
EukaryoteMost are Multicellular (some unicellular)Heterotrophs
Feed on dead or decaying matter
Secrete digestive enzymes to break down food
Cell wall of chitinSlide38
Plantae
EukaryoteMulticellularAutotrophCarry out photosynthesis
Chloroplasts
Cell wall of cellulose
Non-motile (cannot move from place to place)Slide39
Animalia
EukaryoteMulticellularHeterotroph
No cell wall
Most can move (at least at some point in there life cycle)
Very diverse group
Species that exist in almost every part of the planet Slide40
3 Domain System
Molecular clock analysis allows scientists to group organisms according to how long they have been evolving independently The
domain
is a more inclusive category than any other
3 Domains: Bacteria, Archaea, and EukaryaSlide41
Domain/ Kingdom Relationship