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Chapter 3
The Diversity of Life
Part Two: Classification and
Diversity
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Taxonomic Groups
• Six kingdoms
– Prokaryotes
1. Archaeobacteria
2. Eubacteria
– Eukaryotes
3. Plantae
– producer
4. Fungi
– consumer
5. Animalia
http://www.ucmp.berkeley.edu/
– consumer
6. Protista
http://tolweb.org/tree/phylogeny.html
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Systematics
Understanding the history of life
Systematics is based on our
understanding the life diversified
from a single origin. Diversity is a
product of descent with modification.
• Taxonomy
– Naming and classification of life
– System of organizing the
relationships between organisms
• Taxonomic groups
– The six kingdoms and their
subordinate groups
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Taxonomic Groups
• Taxa range from broad
(phylum) to narrow (species)
Kingdom
Phylum
Class
Order
Family
Genus
Species
Animalia
Chordata
Mammalia
Primates
Hominidae
Homo
Homo sapiens
– Species
• Group of individuals that can
interbreed
• Name includes genus
• Italicized
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Taxonomic Groups
• Primitive traits
– Appear early in
evolutionary history
– Hagfish group traits
• Derived traits
– Evolved later
– Present only in some
subgroups
– Jaws, lungs, claws or nails,
feather, fur, and mammary
glands
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Prokaryotes- Eubacteria
Prokaryotes: Unicellular (mostly) organisms without a nucleus
Bacteria may be aerobic or anaerobic
Classified as
1. heterotrophs
fermentation and respiration
2. autotrophs
photoautotrophic or chemoautotrophs
• Critical to Earth System as a mechanism for recycling nutrients
like carbon, nitrogen and sulfur
• Carbon is removed from the atmosphere by plants. Bacteria
oxidize this carbon after plants death, which recycles it back to
the atmosphere as CO2. No CO2= No plants= No life
• Oldest known fossils are 3.5 billion years old: bacteria like
organisms
• Most common in rock record are stromatolites: Layered mats of
cyanobacteria
Photo: http://www.sharkbay.org/terrestial_enviroment/page_15.htm
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Prokaryotes- Archaeans
•
•
Discovered in the 1970’s
Inhabit extreme environments
– Temperatures >100 degrees Centigrade
• Hot springs
– Low or no oxygen
– Alkaline or Acidic conditions
•
•
They are methanogens: they produce
methane
Have probably not changed much through
time: recognized as far back as 3.8 bya
http://www.ucmp.berkeley.edu/archaea/archae
asy.html
- No driving mechanism for evolution. No
competition.
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Eukaryotes: Protista
• Eukaryotes: organisms with
complex cells with nuclei.
• Protozoans (single celled,
nuclei)
– Animal-like protists divided on
the basis of locomotion and
morphology
• Amoebas
– Change shape
• Flagelleates
– Flagellum for locomotion
• Ciliate
– Cilia for locomotion
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Protista
• Unicellular algae
– Plant-like protists
• Dinoflagellates
• Diatoms: chert
• Calcareous nannoplankton:
chalk
• Originated in the Mesozoic
Era
– Important marine producers
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Protista
Protozoans with skeletons
• Foraminifera
Chambered skeleton of
calcium carbonate
Very abundant
Useful for dating rocks and
sediments
Why?
They are good index fossils.
Planktonic, over 250,000
species, distinct ranges
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Protista
• Protozoa with
skeletons
• Radiolarians
– Skeleton made out of
opal (SiO2): chert
– Related to foraminifera
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Eukaryotes: Fungi
• Decomposers
– Obtain nutrients from
dead organisms using
digestive enzymes
(heterotrophs)
– Spore producers
• Diverse
– Yeast
– Mushroom
• Poor fossil record
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Plants
• First land plants in the
Ordovician (490-443my)
• Vascular versus Nonvascular
– Vessels for transport of
water, dissolved nutrients,
food
– Transportation of materials
by diffusion
• Example: Mosses
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Spore Plants
• Ferns
– Devonian (417-354my)
– Adapted to life on land with
roots and leaves
– Spores
• One set of chromosomes
• Fertilized by sperm
• Sperm migration requires
moisture
– Vast Late Paleozoic swamps
led to coal formation
– Origin of name
“Pennsylvanian Period” after
coal mines in Pennsylvania
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Seed Plants
• Seeds enabled plants to exploit drier,
non coastal habitats
• Gymnosperms
– Greek word meaning “Naked seed” plants
– Conifers
• Cone-bearing plants
• Eggs are fertilized in cone by pollen
– Pollen bears sperm; carried by wind
• Dominant in the Mesozoic
• Angiosperms
– Flowering plants
• Pollen carried by pollenators (animals)
• Dominant in the Cenozoic
http://en.wikipedia.org/wiki/Angiosperm
http://www.ucmp.berkeley.edu/seedplants/seedplants.html
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Animalia
• Two groups
– Vertebrates
• Possess a backbone
– Invertebrates
• Coelomates
– Body cavity housing
internal organs
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Animals- Sponges
– Simple invertebrates
– Suspension feeds
• Strain particles from
water
• Mostly eat bacteria
• Flagella pump water
through internal canals
– Calcium carbonate or
silica spicules support
structure
• Cambrian - modern
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Cnidarians
• Jellyfish and corals
• Polyp and Medusae
stage
• Radial symmetry and
more complex body
plan including mouth,
tentacles and digestive
cavity
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Arthropods
•
•
Insects, crabs, spiders, lobsters,
trilobites
Trilobite
– Three-lobed body
• Central, left-and right- lobed
–
–
–
–
•
•
External skeleton
Gill-like structure for respiration
Legs
Primitive eyes
Common in Cambrian (560-490
mya)
Illustrates that complex life formed
early in Earth History and
challenges traditional view of
evolution as a move from primitive
to advanced forms of life.
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Mollusks
• Bivalves (Clams)
• Gastropods (snails)
• Cephalopods (octopuses)
•Shell of aragonite, calcite, or both
•All share a common body plan, though
they evolved to fit different ecological
niches: crawlers, filter feeders,
swimmers
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Mollusks
• Cephalopods
– Squids, octopuses, chambered nautilusses
– Swim in the sea
• Jet propulsion
• Eyes
– Carnivores
• Catch with tentacles
• Eat with strong beak
• Chambered nautilus
– Bouyancy due to gas in shell
– Pressure accomodated by increased surface area
• Common in Phanerozoic
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Lophophores
• Brachiopods
– Shell divided into two
valves
– Lampshells
– Lophophores
• Pump water
• Strain food
– Inarticular brachiopods
• Lack hinge teeth
• Lingula
– Articulate brachiopods
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Bryozoans
• Moss animals
• Ressemble corals, but
more closely related to
brachiopods
– Lophophore extended
from skeleton to feed
– Calcified skeleton
• Colonial
• Ordovician
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Echinoderms
• Spiny-skinned form
• Five-fold symmetry
– Starfishes
• Predators
• Lower Paleozoic
– Sea urchins
• Regular sea urchins
– Radially symmetrical
bodies
• Irregular sea urchins
– Bilaterally symmetric
– Burrowers
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Echinoderms
• Crinoids
– Sea lillies
– Sieve food using arms
• Pass food to mouth with
tube feet
– May swim
– May be attached by
flexible stalk
– Disk-shaped plates
from stalk
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Chordates
Notochord, Gills and Tail
Notochord
– Flexible, rodlike structure that supports body for
some part of life cycle
– Spinal cord
• Runs next to notochord
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Vertebrates
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Vertebrates
• Fishes
– Devonian 417 to 354 mya: Age of
Fishes
– Jawless Fishes “Class Agnatha”
– Placoderms: Earliest jawed fishes.
Armored plates but no teeth- sharp
jaws instead. Devonian
– Ray-finned fishes
• Fins supported by thin bones radiating
from body
– Lobe-finned fishes (sharks)
• Tetrapods: Amphibians
An Ichthyosaur
– Amphi meaning both, Bios meaning
life
– 3000 living species
– Devonian: Ichthyostega climbs28to
shore in Greenland
Vertebrates: Tetrapods
• Tetrapods: Reptiles
– Eggs with protective shells
– Ectothermic
• Environment controls internal body
temperature
• Question: What might be an advantage of this
quality?
– Dinosaurs
• Primitive reptiles 225 to 65 mya
– Birds
• Endothermic
• Evolved from Dinosaurs
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Vertebrates: Tetrapods
• Mammals
– Endothermic; Hair
– Bear live young
– Monotremes
• Mammals that lay eggs
– Marsupial
• Offspring develop in
pouch
– Placental
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Answers to your questions…
• How often do geologists find
new species?
• What kind of fossils are in N.
Idaho?
• What is the most common type
of fossil found today?
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Fungal Spores from the Rhynie Chert, Scotland
Devonian age (417-354my)
Total named species on Earth: 1.5
million.
Actual number may= 100 million
(mostly insects), but probably around
13-14 million. (Society for
Conservation Biology)
Grad student here in department found
new species of brachiopod, got to name
it.
Stephen J. Gould estimated that 99% of
all plant and animal species are exinct.
Hagerman Fossils (S. Idaho): Pliocene
age (3.7-3.1my). 140 species including
horses, saber tooth cats, ground
sloths…
Miocene (20my) Plant Fossils
Cambrian Trilobites at Lake Pend
Oreille (545-495my)
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