Group Activity
-get yourselves into groups of 4
-Brainstorm and list 20 domesticated animals
-your job is to group your list of animals into different categories
-you MUST:
-use more than three categories
-be prepared to describe the criteria you used for your groupings
“Systematic grouping of organisms into categories on the basis of defined criteria”
Taxonomy
“the science of classifying ALL organisms”
-Very general
- millions of species?
- how to start classifying?
• behaviour
• where they live/habitat
• appearance and characteristics
(MORPHOLOGY)
Mosquitoes –50 species
Seed plants – 260 000 species
Challenges to Classification?
- Yesterday?
• Variation:
o over space and time
o among individualsEvolution
DNA
The biggest classification problem has always been consistency
• Ancient Greece
(Coles notes)
Aristotle
(384 – 322 BC)
-First to introduce classification and binomial definition
- classify ALL LIVING things (Historia Animalium)
- blood/no blood, water/land
-Hierarchical; each organism fixed position
• Humans
• Animals
• Plants
Great Chain of
Being
Issues?
-complex plants below simple animals
-little genetic relationship
-Evolution?
-Virtually no innovation to Aristotle’s work till the 16th century
-virtually 2000 years!!!
-shamans/Aboriginal healers/Andrea Cesalpino
• Irregularity amongst names
-needed agreed upon set of naming guidelines
-Scientific naming
- the father of taxonomy
- 2 key contributions to classification:
1. Consistent way of grouping species according to morphological similarities
2. Naming system
- 2 parts
1. Genus species; capitalized, italicized
2. species specific species; italicized
Systema Nature (1735)
Gerbera hybrida
-standard naming system for all organisms
-simple
-convenient
-flawed
Ursus americanus
Ursus maritimus
Phascolarctus cinereus
Share many characteristics
Share few characteristics
kingdom
phylum
class
order
family
genus
species
Ranks based on shared
characteristics
-each level = taxon
General/fewer similarities
Specific/moreSpecific/more
Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
sapiens
- refined into subcategories
“structure in which a large set of items is broken down into smaller subset, ultimately leading to the smallest available classification unit.”
- series of branching two-part statements used to identify organisms
- large set broken down to smallest classification unit
- larger number of species, the more specific questions become
Dichotomous Key practicePage 18
Textbook
Difficulties?
• number of species
• distinguishing characteristics are internal
• agreeing on criteria
Activity
Get into groups of 4-6
Within your group you will be creating your own dichotomous key
The subject of your key will be classifying each member of your group
Remember dichotomous keys “are a series of branching two-part statements used to identify organisms.”
Therefore your keys need to contain multiple steps and be specific
When, finished, you must demonstrate the viability of your key to Mr. Faulhafer for assessment
Complete questions 5 and 8 on page 20 of textbook
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