Classification

Purpose: To organize and identify Earth’s diversity of life
🡪scientists use a classification system

Taxonomy
- the science of classifying organisms based on:

Physical similarities → (anatomy)
Chemical make up → (DNA and proteins)
Evolutionary relationship → (common ancestry - fossils)
Developmental similarities → (embryology)

First taxonomist was ARISTOTLE

people

Carolus Linnaeus (1700’s)

Practical classification
Hierarchical system with 7 levels
Kingdom largest group
Phylum
Class
Order
Family
Genus
smallest group species

7 taxa (levels)
Largest taxa: Kingdom

# of Kingdoms: 2

- Plantae
- Animalia

Stayed this way until 1960s!

THOMANS WHITTAKER

Increased # of Kingdoms to 5: -Animal - Plant - Fungi
- Protist - Monera

Why?

Separated out those without nucleus from those with nucleus
Separated out one celled organisms from many celled
Divided those with nucleus by how they obtained energy

CARL WOESE

created taxa (level) above kingdom
🡪 called DOMAIN (in 1980)

Archaebacteria – live in extreme conditions
Eubacteria - live in normal conditions

NOW 8 TAXA

Domain largest group
Kingdom

Phylum
Class
Order
Family
Genus
species smallest group

each taxon has a group of related taxa below it

Delightful

Kids

Prefer

Candy

Over

Fresh

Green

Salad

breeds are different but can interbreed. i.e; dogs

hybrids aren’t fertile, are made from crossing above species

Binomial Nomenclature - Scientific Naming

Example- Canis familiaris - dog

CLASSIFICATION IS BASED ON

HOMOLOGY- Organisms with homologous structures are grouped together.

Molecular Biology – Organisms with similar DNA are grouped together.

\n Dichotomous Key- a bunch of yes or no questions to determine species based on traits

Cladogram Diagram --// showing evolutionary relationships among organisms

GROUPS

Domain

organized by cell type; prokaryotic vs eukaryotic

Archae and bacteria are prokaryotic and eukarya are eukaryotic

Kingdom

within the domains

Archaebacteria
Kingdom

Eubacteria

Kingdom

and for eukaryotic

animal, plant, fungi and protist kingdoms

PROTISTA MOVEMENT-

flagella; tail moves through water for protista movement

Cilia; short hair like projections for protista movement

Amoeboid; crawling movement with pseudopods

pulsing; no good way to explain like just kind of pulses and moves?