Transcript Chapter-14-Notes-2011

Classification of Organisms
Chapter 14 Notes
14-1 Categories of Biological
Classification
A. Taxonomy – The science of classifying
living organisms, based on shared
characteristics
B. Binomial Nomenclature – two-word
system for naming organisms
C. Scientific Names –
1. Each organism is assigned a unique twoword scientific name. Consists of Genus,
species, ex. Homo sapiens
*helps scientists classify newly discovered species
Scientific Names (con’t)
2. These enable scientists to
communicate in the same scientific
language with each other about
organisms, regardless of their own
native language
3. There could be confusion when
different cultures, societies, or
nations, refer to the same organism
by different common names.
What Makes Up a Scientific
Name?
•
•
Two different types of organisms
cannot have the same scientific name,
so every species has its own unique
scientific name.
Ex: All red oaks have the same
scientific name (Quercus rubra)
because they are all the same species,
but willow oaks (Quercus phellos)
have a different species than red
oaks.
Table 1
Classifying Organisms
1. There are 8 levels to the
classification hierarchy:
a. Domain, kingdom, phylum, class,
order, family, genus, species (in
order from least specific to most
specific)
b. Phrase to help memorize: Did King
Phillip Come Over For Grape Soda?
Classification of Ursus arctos
Grizzly bear
Black bear
Giant
panda
Red fox
Abert
squirrel
KINGDOM Animalia
PHYLUM Chordata
CLASS Mammalia
ORDER Carnivora
FAMILY Ursidae
GENUS Ursus
SPECIES Ursus arctos
Coral
snake Sea star
Example
14-2 How Biologists Classify
Organisms
A. Biological species – a group of
natural populations that are
interbreeding or that could
interbreed, and that are
reproductively isolated from other
groups
Biological Species
1. Hybrids – offspring that result
from interbreeding by individuals
of different species
a. Example: Wolves and dogs
b. Not all species interbreeding
produce fertile offspring (like a
horse and a donkey producing a
mule)
Evolutionary History
1. Phylogeny – an organism’s
evolutionary history
2. Convergent evolution –
organisms evolve similar
structures independently, usually
because they live in similar
habitats
a. Example: shark and dolphin
Convergent Evolution/Analogous
Structures
Evolutionary History (con’t)
3. Analogous structures – similar
features that evolved through
convergent evolution.
a. Homologous structures are similar
because of common ancestry, but
analogous structures are similar
because of similar natural selection
acting on two different species in
similar environments.
Evolutionary History (con’t)
4. Cladistics – using shared
characteristics to infer
relationships between organisms
a. Cladograms – branching diagrams
which show the evolutionary
relationships among groups of
organisms
Cladogram
Cladistics (con’t)
b. Ancestral character – a characteristic
that evolved in a common ancestor of
both groups
c. Derived character - a characteristic
that evolved in an ancestor of one
group but not of the other; they are
the characteristics listed on the
bottom of a cladogram that separate
the two groups above it.
Traditional Classification Versus Cladogram
Appendages
Crab
Conical Shells
Barnacle
Limpet
Crustaceans
Crab
Gastropod
Barnacle
Limpet
Molted
exoskeleton
Segmentation
Tiny free-swimming
larva
CLASSIFICATION
BASED ON VISIBLE
SIMILARITIES
CLADOGRAM
Evolutionary History (con’t)
5. Phylogenetic tree – another type
of branching diagram that shows
evolutionary relationships, it
separates organisms also on the
basis of how important a
character is (like feathers on
birds)
Phylogenetic Tree vs. Cladogram