Classification

1
Classification

• The organization of living things

DOMAIN ARCHAEA
DOMAIN EUKARYA
Kingdoms
Eubacteria Archaebacteria Protista Plantae Fungi A
nimalia
DOMAIN BACTERIA
2
Taxonomy

• Taxonomy is the system scientist use to name
  organisms put living things into groups
• Organisms are grouped by how closely related they
  are.

3
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?
4
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

5
Classification of Ursus arctos
What criteria do you think was used to narrow
down each category?
6
Phylogeny
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.

• Living things are groups by their line of
  evolutionary descent.
• A picture called a cladogram is used to show how
  organisms are related and what characteristics
  separate different groups

Appendages
Conical Shells
Crustaceans
Gastropod
Crab
Crab
Limpet
Limpet
Barnacle
Barnacle
Molted exoskeleton
Segmentation
Tiny free-swimming larva
CLASSIFICATION BASED ON VISIBLE SIMILARITIES
CLADOGRAM
7
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.
8
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)

9
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.

10
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.