Transcript Organizing the Diversity

TAXONOMY:
Organizing Life’s Diversity
“Random” Facts
• It is estimated that there are between 3 and
30 million species on this planet.
• We have named about 1 million animal
species, and a half million species of
microorganisms and plants.
• We are further along with some species than
others.
So how do you organize the
diversity of life?
• Use your classification skills…
• Taxonomy: branch of biology that is
concerned with the identifying, naming
and classification of organisms
NOT TAXIDERMY!
John Ray, 1600’s:
• “When men do not know the name and
properties of natural objects – they cannot
see and record accurately.”
The Cat of Many Names…
Puma concolor
1700’s
• Carl von Linne =
Linnaeus
• Father of Taxonomy
• Systema Naturae
Binomial Naming System
• Genus: generic,
descriptive of similar
species, thought to
be the same type of
organism
• Specific
Name/epithet: in
combo with genus,
identifies one
specific organism
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Bufo americanus
Mustella vison
Escherichia coli
Canus lupus
Turdus migratorius
• Linnaean scheme
based on perceived
similarities or
differences in
morphological
traits
Species…
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Biological species concept
Ecological species concept
Morphological species concept
Genealogical species concept
Olinguito: first mammalian carnivore species
newly identified in the Americas in 35 years.
Why does it matter?
Linnaeus: Father of Taxonomy
• Binomial system = core organizing unit
for classification scheme
Back in the ancient days...
• Lumped all livings
into two groups:
plants and animals
• 14 groups –
mammals, bird, fish,
etc
• Subdivided those by
size of organisms
1500’s – 1700’s
• Age of European
global exploration
• Identification and
description
• Invention of the light
microscope (1600’s)
Rethinking Classification
• 2 Kingdom System
• Plants and Animals
• Persisted for quite
awhile
• Fungi and bacteria =
plants
• 1800’s, added third
= protists
The hierarchy today…(an enhanced
version of Linnaeus’ scheme)
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Kingdom (most inclusive)
Phylum
Class
Order
Family
Genus
Species (most exclusive)
Patterns of Relationships
• Higher taxa
• Reflect relationships
among species
LIONS, TIGERS, AND HOUSE
CATS…
Most general grouping?
Most specific grouping?
Whittaker’s System (circa 1969)
• 5 Kingdoms
• Today, we say that
there are 6
kingdoms
• Domains
Let’s practice…group the following objects
into two categories:
Then keep breaking them into
smaller groups…
Where would this fit in?
Successful for 20+ years…
• Recognized two
fundamentally different
types of cells (pro vs
euk)
• Levels of organization
(uni vs multi)
• Recognized three
kingdoms of
multicellular eukaryotes
based on modes of
nutrition
But…
• There appeared to be two distinct lines
of bacteria (prokaryotes)
• There were the nagging protists…
• AND…new genetic innovations help
complicate things 
• And it led to…
Domains: Superkingdoms
Lumpers vs Splitters
• You can continue to subdivide categories…
• Ex: superorder, order, suborder, and
infraorder
• and ultimately end up with 30+ different
categories that can be used to classify
Take Home Message(s)
• Classification today is based on evolutionary
relationships
• Increased complexity makes more variations
possible
• More confident in groupings of families down
than about relationships among the major
groups
• This is the “best fit” hypothesis based on the
data.
• Continually tweaked!
Domain Eukarya
• Contain a
membrane-bound
nucleus and
membrane-bound
organelles
• Uni and multicellular
• Sexual repro
common
• Huge diversity…
• Intro to plant lab…
Most Prokaryotes
• Ubiquitous
• Mostly unicellular
• Cocci, bacilli,
helices
• 1-5 micrometers
• Cell wall =
peptidoglycan
• Capsule
• Pili
Most Prokaryotes cont.
• No nucleus –
chromosome =
circular
• Reproduce
asexually
• Metabolic diversity
• Of significant
importance to
humans
Domain Bacteria
• Most diverse and
widespread
• Most of the known
prokaryotes
• Every major mode
of nutrition and
metabolism is
represented
Domain Archaebacteria
• Thought to originate
from earliest cells
• Extremophiles
• Methanogens
• Extreme halophiles
• Extreme
thermophiles
Domain Eukarya: Protista
• Unicellular eukaryotes +
“simple” multicellular
relatives
• 20+ kingdoms?
• Mostly aquatic
• Nutritionally diverse
• Mostly aerobic
• Protozoa, Algae,
absorptive
Domain Eukarya: Fungi
• Multicellular
eukaryotes
• Saprobes,
exoenzymes
• Cell wall = chitin
• Some are symbiotic
• Critical ecosystem
value
• Commercial value
Domain Eukarya: Plantae
• Multicellular
eukaryotes that
carry out
photosynthesis
• Grouped by
adaptations to
terrestrial living
• Cell wall = cellulose
Domain Eukarya: Plantae
• Bryophytes:
liverworts,
hornworts, mosses
• Embryos remain
attached
• Nonvascular
Domain Eukarya: Plantae
• Seedless Vascular
plants: lycophytes,
ferns, horsetails,
whisk ferns
• No seed stage
• Require water for
reproduction
Domain Eukarya: Plantae
• Gymnosperm:
Ginkgo, cycads,
gnetae, conifers
• vascular, naked
seeds
Domain Eukarya: Plantae
• Angiosperm: bear
seeds within protective
chambers
• FLOWERING
PLANTS
Domain Eukarya: Animalia
• What is an animal?
Domain Eukarya: Animalia
• Multicellular
eukaryotes that
INGEST other
organisms
• Held together by
structural proteins
• Have nervous and
muscle tissue
Domain Eukarya: Animalia
• MOST reproduce
sexually
• Go through stages
of embryonic
development
• Have Hox genes
Domain Eukarya: Animalia
• Aerobic
• Broken into two
major groups based
on the presence of a
backbone
• Radial or bilateral
symmetry
• MOST have
Cephalization
Pause for activity…
• Purpose:
– To practice/hone
your classification
skills…
– Experience the real
challenges of
classification