Transcript Unit 6: Classification and Diversity

Unit 6: Classification and Diversity
KEY CONCEPT
Organisms can be classified based on physical
similarities.
Unit 6: Classification and Diversity
Linnaeus developed the scientific naming system still used today.
• Taxonomy is the science of naming and classifying
organisms.
White oak:
Quercus alba
• We always write names in the Genus and species.
Unit 6: Classification and Diversity
• Binomial nomenclature is a two-part scientific naming
system.
– uses Latin words
– scientific names always written in italics
– two parts are the genus name and species descriptor
Unit 6: Classification and Diversity
• A genus includes one or more physically similar species.
– Species in the same genus are thought to be closely
related.
– Genus name is always capitalized.
• A species descriptor is the second part of a scientific name.
– always lowercase
– always follows genus
name; never written alone
Tyto alba
Unit 6: Classification and Diversity
• Scientific names help scientists to communicate.
– Some species have very similar common names.
– Some species have many common names.
Unit 6: Classification and Diversity
Linnaeus’ classification system has seven levels.
• Each level is
included in the
level above it.
• Levels get
increasingly
specific from
kingdom to
species.
Unit 6: Classification and Diversity
The Linnaean classification system has limitations.
• Linnaeus taxonomy doesn’t account for molecular
evidence.
• The technology didn’t exist during Linneaus’ time.
• Linnaean system based only on physical similarities.
Unit 6: Classification and Diversity
• Physical similarities are
not always the result of
close relationships.
• Genetic similarities more
accurately show
evolutionary relationships.
Unit 6: Classification and Diversity
Racoon
Kingdom:
Phylum:
Class:
Order:
Family:
Genus:
Species:
Red Panda
Animalia
Chordata
Mammalia
Carnivora
Procyonidae
Procyon
P. lotor
Kingdom:
Phylum:
Class:
Order:
Family:
Genus:
Species:
Animalia
Chordata
Mammalia
Carnivora
Ailuridae
Ailurus
A. fulgens
Unit 6: Classification and Diversity
KEY CONCEPT
Modern classification is based on evolutionary
relationships.
DNA!!!
De-oxy Ribo Nucleic Acid
Unit 6: Classification and Diversity
Cladistics is classification based on common ancestry.
• Phylogeny is the evolutionary history for a group of
species.
• evidence from living species, fossil record, and molecular data
• shown with branching tree diagrams
Unit 6: Classification and Diversity
• Evolutionary trees.
– classification based on common ancestry
– species placed in order that they descended from
common ancestor
Unit 6: Classification and Diversity
Classification is always a work in progress.
• The tree of life shows our most current understanding.
• New discoveries can lead to changes in classification.
• Until 1866: only two kingdoms,
Animalia and Plantae
Animalia
Plantae
Unit 6: Classification and Diversity
Classification is always a work in progress.
• The tree of life shows our most current understanding.
• New discoveries can lead to changes in classification.
• Until 1866: only two kingdoms,
Animalia and Plantae
Animalia
– 1866: all single-celled
organisms moved to
kingdom Protista
Plantae
Protista
Unit 6: Classification and Diversity
Classification is always a work in progress.
• The tree of life shows our most current understanding.
• New discoveries can lead to changes in classification.
• Until 1866: only two kingdoms,
Animalia and Plantae
Animalia
– 1866: all single-celled
organisms moved to
kingdom Protista
Plantae
Protista
– 1938: prokaryotes moved
to kingdom Monera
Monera
Unit 6: Classification and Diversity
Classification is always a work in progress.
• The tree of life shows our most current understanding.
• New discoveries can lead to changes in classification.
• Until 1866: only two kingdoms,
Animalia and Plantae
Animalia
– 1866: all single-celled
organisms moved to
kingdom Protista
Plantae
Protista
– 1938: prokaryotes moved
to kingdom Monera
– 1959: fungi moved to
own kingdom
Monera
Fungi
Unit 6: Classification and Diversity
Classification is always a work in progress.
• The tree of life shows our most current understanding.
• New discoveries can lead to changes in classification.
• Until 1866: only two kingdoms,
Animalia and Plantae
Animalia
– 1866: all single-celled
organisms moved to
kingdom Protista
Plantae
Protista
– 1938: prokaryotes moved
to kingdom Monera
– 1959: fungi moved to
own kingdom
Archea
Fungi
Bacteria
– 1977: kingdom Monera
split into kingdoms Bacteria and Archaea
Unit 6: Classification and Diversity
• Kingdom eubacteria.
– one of largest groups
on Earth
– classified by shape,
need for oxygen, and
diseases caused
Unit 6: Classification and Diversity
• Kingdom Archaebacteria .
– cell walls chemically
different from bacteria
– differences discovered by
studying RNA
– known for living in extreme
environments
Unit 6: Classification and Diversity
– Kingdom Protista
Unit 6: Classification and Diversity
Kingdom Plantae
Unit 6: Classification and Diversity
Kingdom Fungi
Unit 6: Classification and Diversity
Kingdom Animalia
Unit 6: Classification and Diversity
• Bacteria and archaea can be difficult to classify.
– transfer genes among themselves outside of
reproduction
bridge to transfer DNA
– blurs the line
between “species”
– more research
needed to
understand
prokaryotes