Download Classification of Organisms

Classification of
Organisms
What’s in a name?
Outline
I.
II.
III.
VI.
V.
Species
Origins of taxonomy
Modern criteria for classification
The changing classification system
Biodiversity and total species
Species
Species - A group of organisms that
share common characteristics and
can interbreed.
Origins of taxonomy
A. Aristotle (384-322 B.C.)-simple
classification using structural complexity,
behavior and degree of development at
birth.
B. Carolus Linnaeus (1707-1778) Classification
based on resemblance to other life forms
C. Charles Darwin (1809-1882)-categories
reflect evolutionary relationship
In the Linnean System of Classification, each
specific type of organism has a unique name.
Known as the binomial name,
name, it is unique for
each recognized species.
This binomial name consists of a genus name,
usually derived from a group of related
organisms...
and a species name which is unique to a
specific group of similar organisms
found within the larger genus grouping.
Texas Bluebonnet
Lupinus texensis / Lupinus texensis
Evolution and Natural Selection
Evolution
Darwin
Change occurring in a line of descent over time
Natural Selection
Some traits are favored over others
Individuals vary in a population
Some heritable traits are more adaptive than
others
The outcome of differences in survival and
reproduction of individuals
Adaptive traits become more common in a
particular environment
should reflect the
Evolutionary relationship:
Classification
Today, the process of classification focuses on
reconstructing phylogeny, or evolutionary history
All species that have ever lived are related
Fossil and geologic records give evidence of
evolution
A sycamore leaf
dropped 50 mya
Tree fern dated 250 mya
Categories of Classification
Species
Genus
Family
Order
Class
Phylum
Kingdom
Domain
III.
Modern criteria for classification
Anatomy-homologous structures and
analogous structures
Developmental stages-embryology
Biochemical comparisons also provide
evidence of evolution
Fossil dating
Evidence of
Morphological Divergence
Homologous structures vs Analogous
structures
Evidence From
Comparative Embryology
Ontogeny Recapitulates Phylogeny
Evidence from
Comparative Biochemistry
Molecular clocks
Mutations
Nucleic Acid comparisons
Protein comparisons
Protein comparisons
Primary structure of three versions of cytochrome
C, a major protein component of electron
transport systems in cells: yeast (top row), wheat
(middle row) & primate (bottom row).
RACCOON RED PANDA
DIVERGENCE
approximately
40 million years ago
GIANT PANDA
DIVERGENCE
15-20 million years ago
SPECTACLED
BEAR
SLOTH SUN
BEAR BEAR
BLACK
BEAR
POLAR BROWN
BEAR
BEAR
GREEN PYTHON
NILE CROCODILE
SEA TURTLE
CHAMELEON
DINOSAURS
Fig. 20.13, p. 322-23
OWL
VI.
The changing classification system
1 Prior to 1970: two-kingdom system
Plants and animals
2 1969: Roger Whittaker-five-kingdom system
Monera, Protista, Fungi, Plantae, Animalia
3 Recent proposal: Carl Woese-three-domain
system
Bacteria, Archaea, Eukarya
How Many Kingdoms?
Whittaker’s Five-Kingdom Scheme
Monera
Protista
Fungi
Plantae
Animalia
Six Kingdom Scheme
Carl Woese
Includes the Archaebacteria
eukaryotic organisms that are not animals, plants,
or fungi put into Protist
V.
Biodiversity and total species
How many species exist?
1. 1.5 million species categorized
2. Up to 30 million species may exist
7000 to 10,000 new species identified
annually
Many classified species are becoming extinct
as their habitats are destroyed