1. ACTIVATING STRATEGY

2. Brainstorm some other objects that we classify on a daily basis…

3. classificaton How do we make sense of the world around us? Standard:
Students will derive the relationship between single-celled and multi-celled organisms
and the increasing complexity of systems.
Element:
c. Examine the evolutionary basis of modern classification systems.

4. Biologists find it easier to communicate and retain information about organisms when the organisms are organized into groups
One of the principal tools used to accomplish this is biological classification

5. Taxonomic Classification
How do biologists define “species”?
Members of the same species can…
A) Interbreed
AND
• B) produce fertile offspring
Guided notes III. E.

6. Classification defined…
grouping of organisms or objects based on a set of criteria that helps organize, communicate and retain information OR
Systematic grouping of organisms based on common characteristics

7. Early Systems of Classification
Aristotle was first to create a classification system ( BCE)
All organisms were unchanging and fixed on the “ladder of life”
System was differentiated between plants and animals;
plants grouped by size;
animals grouped by type of blood, habitat, and morphology

8. Carolus Linnaeus ( )
Expanded Aristotle’s plan into a formal, scientific system
Based on morphology and behavior– what is morphology?
First formal system of taxonomic organization
What is taxonomy?

9. Linnaeus’s system Names have 2 parts: Genus species
Genus –first letter is always capitalized
Species –written in lower case letter
Italicized when typed;
Underlined when written
Method of naming organisms (aka binomial nomenclature)
System is still valid today
Names are mainly Latin or rooted in Greek

10. EXAMPLES OF BINOMIAL NOMENCLATURE
The scientific name for dog is:
Canis familiaris
Modern humans:
Homo sapiens

11. Quercus Rubra musca domestica Pisum sativum felia Domestica Answers:
Now it is your turn to try! Listed below are four scientific names…indicate on your review sheet which are right or wrong and correct the names that are written incorrectly…
Quercus Rubra
musca domestica
Pisum sativum
felia Domestica
Answers:
1) Quercus rubra
2) Musca domestica
3) Pisum sativum
4) Felia domestica
(Don’t forget…yours should be underlined!)

12. Modern classification systems
Linnaeus’s system was modified in the 1800’s to reflect new found knowledge of evolutionary history
Modern systems are based on taxonomic categories
Taxon = a group of named organisms

13. Taxa range from very broad to specific
DOMAIN
The broader the characteristics, the more species the taxon contains
(like nesting boxes)
Can you think of another non-biology example?
Beginning of guided notes

14. Taxonomic Classification
DOMAIN
KINGDOM
PHYLUM
CLASS
Guided notes III. C.
ORDER
FAMILY
GENUS
SPECIES

15. How can we possibly remember this?
[Dear]
King
Phillip
Came
Over
For
Good
Spaghetti
Guided notes III. D.

16. example
The named taxonomic unit at any level of the hierarchy is called a taxon

17. Modern classification includes phylogeny
Phylogeny-- the evolutionary history of a species
(it shows how related each one is to the others)
This is shown on a phylogenetic tree

18. Closer look at the phylogenetic species concept
Phylogeny → the evolutionary history of a species
Species defined as…a cluster of organisms that is distinct from other clusters
shows evidence of a pattern of ancestry and descent

19. Cladistics
Modern classification systems use cladistics– a method that classifies organisms according to the order that they diverged from a common ancestor
Shared, derived characters are used to make a cladogram

20. Species Concepts… Species Concept Classification determined by:
Benefits
Limitations
Typological
Compares physical traits
Descriptions provide detailed records of physical characteristics
Alleles produce wide variation within a species
Biological
Similar characteristics; ability to breed together and produce fertile offspring
Still used frequently because it applies in most cases
Does not account for extinct species or different species that interbreed
Phylogenetic
Evolutionary history
Accounts for extinct species; considers molecular data
Evolutionary histories are not known for all species

21. Definitions to add to guided notes
prokaryote v. eukaryote
peptidoglycan: a type of polymer in Eubacteria cell walls
cellulose: a structural polysaccharide of plant cell walls
chitin: a structural polysaccharide found in many fungal cell walls and in the exoskeleton of all arthropods (insects, spiders, millipedes, crabs)
Definitions to add to guided notes

22. Definitions (continued)
autotroph: an organism that uses energy from the sun (or from inorganic substances) to make organic molecules for food
heterotroph: an organism that obtains organic food molecules by eating other organisms
Definitions (continued)