Transcript The Major Lineages of Life

The Major Lineages of Life
Molecular data
challenges 5 Kingdoms
Monera was too diverse
2 distinct lineages of
prokaryotes
Protists are still too diverse
not yet sorted out
Chapter 26
Phylogeny and the Tree of Life
• Phylogeny is the evolutionary history of a
species or group of related species
• The discipline of systematics classifies
organisms and determines their evolutionary
relationships
• Systematists use fossil, molecular, and genetic
data to infer evolutionary relationships
• Taxonomy is the ordered division and naming
of organisms
3 Domain system
• Domains = “Super” Kingdoms
– Bacteria
– Archaea
• extremophiles = live in extreme environments
– methanogens
– halogens
– thermophiles
– Eukarya
• eukaryotes
–
–
–
–
protists
fungi
plants
animals
Classification
Eukaryote
• Old 5 Kingdom system
Prokaryote
• Monera, Protists, Plants, Fungi,
Animals
• New 3 Domain system
– reflects a greater understanding
of evolution & molecular
evidence
• Prokaryote: Bacteria
• Prokaryote: Archaebacteria
• Eukaryotes
– Protists
– Plants
– Fungi
– Animals
Archaebacteria
&
Bacteria
Kingdom
Bacteria
Kingdom
Archaebacteria
Kingdom
Protista
Kingdom
Fungi
Kingdom
Plantae
Kingdom
Animalia
Fungi
Kingdoms
absorptive
nutrition
Animalia
ingestive
nutrition
Plantae
autotrophs
Protista
uni- to
multicellular
Eubacteria
multicellular
Archaebacteria
prokaryotes
Single-celled ancestor
eukaryotes
heterotrophs
Finding commonality in variety
• Organisms classified
from most general
group, domain, down
to most specific,
species
– domain, kingdom,
phylum, class, order,
family, genus, species
use the mnemonic!
The Evolutionary Perspective
Phylogenies are inferred from
morphological and molecular data
• To infer phylogenies, systematists gather
information about morphologies, genes, and
biochemistry of living organisms
• Organisms with similar morphologies or DNA
sequences are likely to be more closely related
than organisms with different structures or
sequences
Cladistics
• Cladistics groups organisms by common descent
• A clade is a group of species that includes an
ancestral species and all its descendants
• Clades can be nested in larger clades, but not all
groupings of organisms qualify as clades