Chapter 3
The Diversity of Life
1
Guiding Questions
• What are fossils?
• How do scientists arrange organisms in
natural groups?
• What is the most fundamental taxonomic
division of life?
• What kinds of organisms constitute the
Protista and Fungi?
2
Fossils
• Tangible remains or
signs of ancient
organisms
• Found mostly in
sedimentary rocks
(why?) or sediments,
especially marine
sediments
• Thousands to millions
of years old
Nautilus
3
Fossils
• Most fossils are hard
parts of organism
–
–
–
–
Teeth, skeleton
Earthworm setae
Insect mandibles
Crinoid (left)- ‘sea lily’
that is actually an
animal with a CaCO3
skeleton.
4
Fossils
• Hard parts may be
completely replaced
by minerals
• This crinoid’s CaCO3
skeleton has been
completely replaced
by pyrite (fool’s gold).
5
Fossils
• Fossilization of soft
parts is rare
– Requires oxygen-poor
environment
– Burial in fine-grained
sediment
• Permineralization
– Infilling of woody tissue
by inorganic materials
– Petrified wood
6
Petrified Wood
7
Fossils
• Fossil need not be skeletal
• Mold
– 3-D negative imprint
Brachiopod fossils (left):
S = shell
M = mold
8
Fossils
• Impressions
– 2-D preservation of
outlines and surface
features
• Carbonization (left)
– Concentrated residue
of remaining carbon
9
Fossils
• Trace fossils
– Tracks/trackways
– Trails
– Burrows
• Provides behavioral
information about
extinct animals (how?)
10
Fossils
• Fossils provide biased view of biota
– Not all organisms are preserved (over-/underrepresented)
• Rare organisms
• Lacking hard parts
– Not all skeletal material is preserved
• Scavengers
• Transport and abrasion
• Post-burial alteration of rock
– Not all fossils are exposed at the surface
– Some are destroyed by plate tectonics, metamorphism,
etc.
11
Putative Jellyfish fossils
12
The Current Hotspot
American/Mongolian team excavating an ankylosaur fossil in the Gobi Desert in Mongolia.
13
Buy Fossils Now!
• eBay http://www.ebay.com
• http://www.arizonaskiesmeteorites.com/Din
osaur_Fossils_For_Sale/
14
Taxonomy
15
Human Genealogy
(Who else is hanging
around in your
family tree?)
16
Taxonomic Scheme
•
•
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Kingdom
Phylum
Class
Order
Family
Genus
Species
17
Taxonomic Scheme
•
•
•
•
•
•
•
Karl
Plays
Cards
Only
For
Green
Stamps
18
Taxonomic Scheme
•
•
•
•
•
•
•
Kids
Prefer
Candy
Over
Fat
Gooey
Snails
19
Taxonomic Scheme
•
•
•
•
•
•
•
•
Kingdom
Phyum
Sub-phylum
Class
Order
Family
Genus
Species
- Animal
- Chordate
- Vertebrate
- Mammal
- Primate
- Hominid
- Homo
- Homo sapiens
20
More Mnemonics
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•
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•
•
Animalia
Chordata
Vertebrata
Mammalia
Primata
Hominid
Homo
Homo sapiens
•
•
•
•
•
•
•
•
Ana
Caught
Vince
Making
Piping
Hot
Ham
Sandwiches
21
•
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Animalia
Chordata
Vertebrata
Mammalia
Primata
Hominid
Homo
Homo sapiens
•
•
•
•
•
•
•
•
A
chocolate
valentine
may
produce
hot and
heavy
sweethearts
22
•
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Animalia
Chordata
Vertebrata
Mammalia
Primata
Hominid
Homo
Homo sapiens
•
•
•
•
•
•
•
•
A
crystal
vase
might
possibly
hold
hybrid
sunflowers
23
•
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Animalia
Chordata
Vertebrata
Mammalia
Primata
Hominid
Homo
Homo sapiens
•
•
•
•
•
•
•
•
Amy
cutout
valentines for
Ma,
Pa,
her
husband and
sister
24
Chordates
25
Fish
Amphibian
26
Reptile
Mammal
27
Birds
28
Primates
Baboon
Prosimian
29
The Pinnacle of Evolution?
30
Other Hominids?
Bigfoot
Sasquatch
Jersey Devil
Abominable Snowman
31
Other Hominids?
Neanderthal
Homo habilis
Homo erectus
32
Taxonomic Groups
• Six kingdoms
– Prokaryotes
• Archaeobacteria
• Eubacteria
– Eukaryotes
•
•
•
•
Plantae-producers
Fungi-consumers
Animalia-consumers
Protista
33
Taxonomic Groups
• Taxonomy
– Study of composition and relationship of the
taxonomic groups
• Taxonomic groups
– The six kingdoms and their subordinate groups
– Taxon/taxa
34
Taxonomic Groups
• Linnaean taxa range from
broad (phylum) to narrow
(species)
– Phylum-one of the major
categories of organisms
– Species
• Group of individuals that
can interbreed
• Name includes genus
• Italicized or underlines
• Class Mammalia
– Order primates
35
Taxonomic Groups
• Phylogeny
– “tree of life”
– structure formed by
branches of species
• Cluster into groups
with similar traits,
equivalent to taxa
– Genus (genera)
• small clusters
36
Taxonomic Groups
• Clade
– Cluster of species that share a
common ancestry and have
homologous structures
– All species within each clade
must be traceable to a common
ancestor; must be
monophyletic
• Cladistics
• Homologous-structures
derived from the same
“blueprint” of common
ancestry.
37
Taxonomic Groups
• Primitive traits
– appear early in evolutionary
history; relatively
unchanged
– hagfish group traits
• Derived traits
– evolved later; often much
changed from ancestral
forms
– present only in some
subgroups
– jaws, lungs, claws or nails,
feather, fur, and mammary
glands
38
Taxonomic Groups
• Horse ancestry
– Detailed phylogeny due to
abundant fossil record
• Three clades
– Subfamilies
• All members of the
modern horse family
belong to Equus and
originated in North
America
39
Prokaryotes
• Bacteria (bacterium), as
a group, gain nutrition in
a variety of ways
– photosynthetic
– chemosynthetic
– consumers
• As a group, at least 3
billion years old
40
Prokaryotes
• Archaeobacteria
– Can tolerate extreme
conditions-extremophiles
• very high temperatures
– hot springs
• low or no oxygen
• acidic conditions
41
Prokaryotes
• Eubacteria
– divided by structure of cell
walls
– Cyanobacteria
• photosynthetic
– spherical or filamentous
• can form mats or scum
42
Protista
• Many single celled
organisms
• Some simple
multicellular
organisms
• Includes Algae
– “seaweeds”
Amoeba
43
Protista
• Protozoans
– Animal-like protists
• Amoebas
– change shape; no rigid form
• Flagellates
– flagellum for locomotion
• Ciliates
– cilia for locomotion
44
Protista
• Unicellular algae
– plant-like protists
• Dinoflagellates
• Diatoms
• Calcareous nannoplankton
• Originated in the
Mesozoic Era
– among the most important
marine producers
45
Protista
• Dinoflagellates
– two flagella for locomotion
• drift
– dormancy
• armor in a cyst
• often fossilized as cysts
46
Protista
• Diatoms
– Two-part skeleton of
opal (SiO2)
• Halves fit together
– Freshwater and marine
• Most planktonic
• Some benthic
– Accumulations can
produce diatomaceous
earth and chert
47
Protista
• Calcareous
Nannoplankton
– Small spherical cells
– Armored
• overlapping plates of
calcium carbonate
– Mostly marine plankton
• Accumulations can
produce chalk
48
Protista
• Multi-cellular algae
– Much drifts
– Some attaches to
seafloor
• Some red and green
algae secrete calcium
carbonate skeletons
– limestone
49
Protista
• Protozoans with
skeletons
– Foraminifera
• Chambered skeleton of
calcium carbonate
• Very abundant
• Useful for dating rocks
and sediments
50
Protista
• Protozoa with
skeletons
• Radiolarians
– Skeleton made out of
opal (SiO2)
– Related to foraminifera
51
Fungi
• Decomposers
– Obtain nutrients from dead organisms
• Diverse
– Yeast
– Mushroom
• Poor fossil record
52
Plants
• Differ from multicellular
green algae
– Internal fertilization of egg
– Tissue
• Vascular
– Vessels for transport of
water, dissolved nutrients,
food
• Non-vascular
– Transportation of materials
by diffusion
• moss
53
Plants
• Seedless Vascular
Plants
– Evolved first
– Psilotum
• Simplest vascular plant
• No leaves or roots
• Similar to earliest fossil
forms
54
Plants
• Ferns
– Roots and leaves
– Alternation of generations
• Spore-producing then spermproducing generation
– Spores
• One set of chromosomes
• Fertilized by sperm
• Requires moisture
– Vast Late Paleozoic swamps
led to coal formation
55
Plants
• Gymnosperms
– “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 pollinators (animals)
56
Animals
• Two groups
– Vertebrates
• Possess a backbone
– Invertebrates
• Coelom
– Body cavity housing
internal organs
• Protostomes
– First opening becomes the
mouth
• Deuterostomes
– First opening becomes the
anus
57
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
58
Cnidarians
• Jellyfish and corals
• Radial symmetry
• Inner and outer body layer
– Jelly-like layer in between
• Use tentacles to catch prey
– Stinging cells
• Sexual and asexual
reproduction
59
Protostome Invertebrate
• Segmented worms
– Fluid-filled coelom
• Primitive skeleton
– Each segment has own
coelomic cavity
• Expand, contract for
movement
60
Arthropods
• Insects, crabs, spiders,
lobsters, trilobites
• Trilobite
– Three-lobed body
• Central, left-and rightlobed
– External skeleton
– Gill-like structure for
respiration
– Legs
– Primitive eyes
• Common in Cambrian
61
Arthropods
• Crustaceans
– Head of five fused segments
– Thorax and abdomen
– Weakly calcified exoskeleton
• Insects
–
–
–
–
Head, thorax, abdomen
Two pairs of wings
Poor fossil record
Precede angiosperms
62
Arthropods
• Onychophorans
– Intermediate between
segmented worms and
arthropods
– Early forms
• Marine
• Nearly to base of Paleozoic
– Modern forms
• terrestrial
63
Mollusks
• Clams, snails, octopuses
– Shell of aragonite, calcite,
or both
– Mantle
• Fleshy, sheetlike organ
• Secretes shell
– Radula
• File-like structure for food
– Base of Cambrian
• Monoplacophorans
– Primitive mollusks
64
Mollusks
• Gastropods
– Snails
– Marine and freshwater
– Terrestrial
• Lung
– Most grazers
• Some suspension
feeders
– Beginning of
Paleozoic
65
Mollusks
• Cephalopods
– Squids, octopuses,
chambered nautiluses
– Swim in the sea
• Jet propulsion
• Eyes
– Carnivores
• Catch with tentacles
• Eat with strong beak
• Chambered nautilus
– Buoyancy due to gas in
shell
• Common in Phanerozoic
66
Mollusks
• Clams, mussels, oysters, scallops
–
–
–
–
Shell divided into two valves
No head or radula
Muscles pull shell together
Suspension feeders mostly
67
Lophophores
• Brachiopods
– Shell divided into two
valves
– Lampshells
– Lophophores
• Pump water
• Strain food
– Inarticular brachiopods
• Lack hinge teeth
• Lingula
– Articulate brachiopods
68
Bryozoans
• Moss animals
• Colonial
• Closely related to
brachiopods
– Lophophore extended
from skeleton to feed
– Calcified skeleton
• Ordovician
69
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
70
Echinoderms
• Crinoids
– Sea lilies
– Sieve food using arms
• Pass food to mouth with
tube feet
– May swim
– May be attached by
flexible stalk
– Disk-shaped plates
from stalk
71
Chordates
• Notochord
– Flexible, rodlike structure
• Runs length of body
• Supports body
– For some part of
lifecycle
– Spinal cord
• Runs next to notochord
• Primitive Chordate
– Lancet
• Notochord is skeleton
• Can swim
• Usually rests
72
Vertebrates
• Notochord develops
into vertebral column
– Usually bony
– Cartilage in sharks
73
Conodonts
• “Cone-teeth”
– Originally thought to
be teeth of a marine
animal
• Later determined to be
eel-like fish and a
vertebrate
74
Vertebrates
• Fishes
– Ray-finned fishes
• Fins supported by thin
bones radiating from body
– Lobe-finned fishes
• Evolved into amphibians
• Coelacanth
– Discovered in 1939
• Amphibians
– First to live on land as
adults
– Metamorphosis
75
Vertebrates
• Reptiles
– Eggs with protective
shells
– Ectothermic
• Environment controls
internal body
temperature
• Dinosaurs
• Birds
– Endothermic
76
Vertebrates
• Mammals
– Endothermic; Hair
– Bear live young
– Montreme
• Lay eggs
– Marsupial
• Offspring develop in
pouch
– Placental
• Therapsids
– Ancestral mammals
– Arose in Mesozoic
77
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