Transcript Classification - Sonoma Valley High School

Classification
The organization of living things
DOMAIN
ARCHAEA
DOMAIN
EUKARYA
Kingdoms
DOMAIN
BACTERIA
Eubacteria
Archaebacteria
Protista
Plantae
Fungi
Animalia
Taxonomy
• Taxonomy is the system scientist use to name
organisms & put living things into groups
• Organisms are grouped by how closely related they
are.
Binomial nomenclature
• Each organism is given a unique
scientific name
• The name has 2 parts: genus
species
• The genus is always capitalized and
the species is not, both are either
underlined or in italics
– E.g.: Usrus arctor – the grizzly bear
why do you think this naming
system was developed?
Hierarchical system of classification
• There are 8 levels
of organization
• The largest level,
Domain is the
most inclusive
– Domain, kingdom,
phylum/division,
class, order,
family, genus,
species
Classification of Ursus arctos
Grizzly bear Black bear
Giant
panda
Red fox
Coral Sea star
Abert
squirrel snake
KINGDOM Animalia
PHYLUM Chordata
CLASS Mammalia
ORDER Carnivora
FAMILY Ursidae
What criteria do you think
was used to narrow down
each category?
GENUS Ursus
SPECIES Ursus arctos
Phylogeny
• Living things are
groups by their line of
Crab
Limpet
Barnacle
evolutionary
descent.
• A picture called a
cladogram is used to
show how organisms
are related and what
characteristics
CLASSIFICATION
separate different
BASED ON VISIBLE
groups
SIMILARITIES
Appendages
Conical Shells
Crustaceans
Crab
Gastropod
Barnacle
Limpet
Read this
cladogram
from the
bottom up.
The traits
shown apply
to everything
above it.
Each branch
represents a
different
linage. The
lowest line
represents a
common
ancestor.
Molted
exoskeleton
Segmentation
Tiny free-swimming larva
CLADOGRAM
Macromolecules & classification
• In the past biologist
could only look at
physical & behavioral
characteristics to
classify organisms
• Now we can use: RNA,
DNA (nuclear &
mitochondrial) and
proteins
• The more genes
organisms have in
common the more
closely related they are
Which sets of mammals are the
most closely related?
Those the top two
animals look alike they
are not closely related.
Molecular Clock
• By comparing differences in amino acid sequences in
the same protein found in different species scientist
can figure out how long ago they diverged from a
common ancestor (DNA & RNA can also be used)
To paraphrase
As you know radiometric dating is very helpful in determining the age of
fossils. We can also use the rate of genetic mutations to construct a
molecular clock that can give us information about how long ago two
linages diverged. As you saw with the amino acid lab, species that are
more closely related have more similarities in their DNA.
Summary Review
1. What is the classification of living things called?
2. What is it called when biologist group things by
evolutionary lines?
3. What is a drawing of the evolutionary tree?
Examine this chart and cladogram. You
should be able to construct your own
cladogram using a similar type of chart.