why do scientistslhsblogs.typepad.com/files/classification-intro-ppt.pdf · taxonomy – branch of...
TRANSCRIPT
TAXONOMY – branch of biology that
names organisms according to their
characteristics
Why classify? › How many known species are there?
› What are the defining characteristics?
› What are the relationships between these species?
Not all organisms fit into Aristotle’s
2 groups (plants or animals)
Common names can be misleading
Common names vary from place to
place
Same organisms have different names in
different countries
Not all organisms fit into Aristotle’s 2
groups (plants or animals)
Common names can be
misleading
Common names vary from place to
place
Same organisms have different names in
different countries
A jellyfish isn’t a fish but a seahorse is a fish, a sea cucumber sounds like a plant but its an animal
Not all organisms fit into Aristotle’s 2
groups (plants or animals)
Common names can be misleading
Common names vary from place
to place
Same organisms have different names in
different countries
Not all organisms fit into Aristotle’s 2
groups (plants or animals)
Common names can be misleading
Common names vary from place to
place
Same organisms have different
names in different countries
Description using Latin names
Red Oak – Quercus foliis obtuse-sinuatis
setaceo-mucronatis
Which means – oak with leaves with
deep blunt lobes bearing hairlike
bristles… so what’s the problem?
The name is TOO LONG!
The name doesn’t show evolutionary
relationships.
Devised a new system based on
morphology (organisms form & structure)
Linnaeus’s Classification System
› Organisms grouped in a hierarchy of seven
different levels
› Each organism has a 2 part name (binomial
nomenclature)
WH
ITE P
INE
AFR
ICA
N L
ION
Kingdom -
Phylum -
Class -
Order -
Family -
Genus -
Species -
Kingdom –
Phylum –
Class –
Order –
Family –
Genus –
Species –
Binomial nomenclature – a two-name
naming system
› ALWAYS italicized or underlined
1st Name: Genus
› First letter CAPITALIZED
2nd Name: Species Identifier
› lower case
EXAMPLE: Homo sapiens (humans)
Scientists classify organisms according to…
1. Fossil Record
2. Morphology
3. Embryology
4. Chromosomes
5. Macromolecules (DNA & Proteins)
Shape & Function
Homologous Characteristics
› Same embryological origin, similar structure
and function
› Ex: bat wing & human arm
Analogous Characteristics
› Different embryological origin, similar
structure and function
› Ex: bird wing & butterfly wing