Transcript Classification of Organisms - Science 4 Warriors

Classification of Organisms
Chapter 17
Biodiversity
The variety of organisms considered at all
levels of populations to ecosystems.
 Biologists have classified almost 2 million species
 More remain unidentified
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Taxonomy
 The science of describing,
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naming, and classifying
organisms
 A particular group within
a taxonomic system is
called a taxon
Taxonomy continued
Aristotle classified organisms into
2 groups – plants or animals.
This was inadequate because more
and more organisms are found and
described.
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The Linnaean System
The system of grouping organisms into
hierarchical categories according to their
form and structure.
Each category represents a level or
grouping from larger, more general
categories to smaller, more specific
categories.
Levels of Classification
 Modern version of Linnaeus’s system uses 8
levels: (see page 338)
1. Domain
2. Kingdom
3. Phylum
4. Class
5. Order
6. Family
7. Genus
8. Species
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Binomial Nomenclature
System of two-part names. The genus
name followed by the species identifier.
 The species name is written in Italics with the genus
name capitalized
 Species names generally come from Latin roots
 Subspecies – variations of a species that live in
different geographic areas
Binomial Nomenclature
(examples)
Homo sapiens
Chaos chaos
The species name or scientific name is
written in italics with the genus name
capitalized
Systematics
Modern biologists use this to classify
organisms not only by visible similarities,
but also similarities in embryos,
chromosomes, proteins, and DNA. The
goal is to classify organisms in terms of
their natural relationships
Phylogenetics
The analysis of the evolutionary or ancestral
relationships among taxa.
Systematists usually use several types of
evidence to hypothesize about polygenetics.
Use phylogenetic diagram
Cladistics
A system of phylogenetic analysis that used
shared and derived characters as the only
criteria for grouping taxa
Three Domains of Life
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Three Domains of Life
Domain Bacteria
Domain Archaea
Domain Eukarya
Small, single-celled
prokaryotic
organisms
Prokaryotes, live in
harsh places, has
distinctive cell
membranes
Eukaryotic
organisms, large
cells with true
nucleus and
complex organelles
Ex. Cyanobacteria
& Hetrotrophic
bacteria
Ex. Halophiles and
Thermophiles
Ex. Everything else:
plants, animals, etc.
Six Kingdoms
Eubacteria
Arachaebacteria
Protista
Fungi
Plantae
Animalia
See page 349