Exam 1 (Lectures 1-9) Flashcards
What is it important for all geoscientists to study the elements of the fossil record?
a) deciphering the dynamic history of life on Earth
b) dating rock units & geologic events
c) correlating stratigraphic horizons
d) interpreting ancient environments
ETC.
Paleontology:
The study of the history of life, as preserved by fossils.
Fossil:
Any tangible evidence of ancient life.
Body Fossil:
Representation of the actual morphology of an ancient animal or plant.
Trace Fossil:
Preserved evidence of organism activity (tracts, trails, burrows, etc.)
Chemical Fossil:
Chemical evidence of ancient life (coal, oil, natural gas, etc.)
Major Milestones in the History of Life on Planet Earth:
1) Age of the Earth
2) Oldest Minerals on Earth
3) Oldest Fossils on Earth
4) Oldest fossils in the State of Utah
5) Oldest Multicellular animal fossils
6) Oldest shelled animal fossils
7) Oldest vertebrate animal fossils
8) Oldest terrestrial plants
9) Oldest terrestrial vertebrate:
10) Oldest human
1) Age of Earth
(based on radiometric dates of meteorites) = 4.5 billion years
2) Oldest minerals on Earth
(dated radiometrically) = Earliest Precambrian (Hadean), 4.4 billion years old; individual zircon crystals from Australia
3) Oldest fossils on Earth
(stromatolites and microscopic cyanobacteria) = Early Precambrian (Archaean); Isua, 3.7 billion years old, Greenland; Apex Chert, 3.5 billion years old, Australia; Warrawoona Group, 3.4 billion years old, Australia; Swaziland Supergroup, 3.4 billion years old, southern Africa
4) Oldest fossils in the State of Utah
(several species of microscopic cyanobacteria) = Mid-Late Precambrian (Proterozoic), Uinta Mountain Group, northeastern Utah, 1.6-0.7 billion years old.
5) Oldest multicellular animal fossils
(soft-bodied “Ediacaran Fauna”) = Late Precambrian (Proterozoic), 580-545 million years old; southern Australia, eastern & northern Canada, southern Africa, Great Britain.
6) Oldest shelled animal fossils
(small shelly “Tommotian Fauna”) = Latest Precambrian/Earliest Cambrian, 540 million years old; Russia, Scandinavia, California.
7) Oldest vertebrate animal fossils
(jawless “fish”) = Early Cambrian, 530 million years old; China.
8) Oldest terrestrial plants
(“psilophytes”) = Early Devonian, 400 million years old; Rhynie Chert, Scotland
9) Oldest terrestrial vertebrate
(Ichthyostega) = Late Devonian, 370 million years old; Greenland.
10) Oldest human
(Homo sapiens) = Pleistocene, 130,000 years old; Kibish, Ethiopia.
“System of Nature” (Systema Naturae):
Attempt by Karl von Linne’ (and others) in the 18th Century to classify all life forms in a hierarchical framework for scientific communication.
“Tree of Life”:
Metaphor suggested by Charles Darwin (and others) in the 19th century to convey the connectedness of all the living world in an evolutionary context.
Extinct:
Group of organisms that lived in the past but have no living individuals today.
Extant:
Group of organisms with living individuals.
Ontogeny:
Growth stages from birth to death of an individual organism.
Phylogeny:
Evolutionary history of a taxonomic group of organisms.
Analogy:
Morphologic convergence of features with separate evolutionary origins.
Homology:
Morphologic divergence of features with the same evolutionary origin.
Vertebrate:
Animals with an internal bony skeleton (fish, amphibian, reptile, bird, mammal)
Invertebrate:
All other animals that aren’t vertebrates (e.g. sponge, coral, mollusk, arthropod, echinoderm, etc.)
Two Alternative Views of Life History:
Uniformitarianism & Catastrophism
Uniformitarianism:
View that the Earth and its inhabitants have changed gradually and incrementally through time by natural processes that can be seen occurring around us today.
Catastrophism:
View that the Earth and its inhabitants have changed abruptly and spasmodically through time by numerous major, sudden, unpredictable “catastrophes”.
Organic Evolution:
Uniformitarian view that life has had a dynamic history through time.
Creationism:
Catastrophist view that all living things appeared suddenly and simultaneously and that life subsequently has had a static (unchanging) history through geologic time.
Intelligent Design:
Non-scientific view that there are no adequate scientific explanations for the complexities of life, so only a supernatural explanation will suffice.
What good is it to study (and memorize) taxonomy of living & fossil organisms?
a) we need an objective means of organizing an enormous amount of data for analyzing & interpreting significant relationships among the various kinds of animals & plants
b) we need short, simple names for ease of international communication among scientists who may not all speak the same language
c) we need clear, concise definitions of categories to avoid confusion & misinterpretations
d) we need a hierarchical system of classification to convey information about the evolutionary closeness of different kinds of organisms
e) we need a meaningful way to depict & appreciate the diversity of life on Earth.
Taxonomy:
The systematic biological classification of living and fossil organisms.
Phenetics:
Classification based on overall morphologic similarity of individual specimens.
Cladistics:
Classification based on evolutionarily significant characteristics. (homologous features…assuming evolutionary progression)
Karl von Linne’ (a.k.a. Carolus Linnaeus)
18th century Swedish Biologist, developed Systema Naturae
Systema Naturae:
Systematic way of naming organisms
Taxon:
Kingdom, Phylum, Class, Order, Family, Genus, Species
The Five Kingdoms:
Monera Protista Fungi Plantae Animalia
Monera:
unicellular; prokaryote cells
Protista:
unicellular; eukaryote cells
Fungi:
multicellular; eukaryote cells; non-motile; non-photosynthetic
Plantae:
multicellular; eukaryote cells; non-motile; photosynthetic
Animalia:
multicellular; eukaryote cells; motile; non-photosynthetic
Species concept:
fundamental unit of taxonomy
Recognition, identification, diagnosis & description of new species
The paleo definition of species has to be based on morphology, not reproduction
I.C.Z.N.:
International Code of Zoological Nomenclature
I.C.B.N.:
International Code of Botanical Nomenclature
Homonyms:
Same name for different taxa
Synonyms:
Different names for the same taxon
Types of Types:
Holotype Paratype(s) Syntypes Neotype Topotype(s)
Holotype:
Single type specimen representing a taxon
Paratype(s):
Additional specimen(s) to reinforce the holotype
Syntypes:
Multiple type specimens (as opposed to a single holotype)
Neotype:
New type specimen to replace lost or destroyed holotype
Topotype(s):
Specimens collected from the same locality as the holotype or syntypes
Taxonomy:
The formal classification of biological entities, generally is based upon physical morphology (observed) and evolutionary relationships (inferred).
What are the two common approaches to taxonomy? What is different about them?
Phenetics & Cladistics
Vary in both philosophy and procedures
Phenetics:
(i.e. classification based on overall morphologic similarity) embodies the traditional approach of the Linnaean taxonomic hierarchy
Cladistics:
(i.e., classification based on certain key homologous features) is a more modern approach that seeks to identify evolutionarily linked “clades” of taxa
What is the rationale behind a Phenetics approach?
The greater number of physical characteristics hat two organisms share, the more closely related they must be.
What is the rationale behind a Cladistics approach?
Certain evolutionarily derived characteristics have key importance in understanding how two organisms may be related, regardless of the total number of characteristics they share.
Generally more subjective
minimizes the chance that you will confuse analogous characteristics with homologous characteristics.
Clade:
An evolutionarily linked group of organism taxa with a common ancestor.
Cladogram:
A branching type of graph that depicts the evolutionary relationships of clades on the basis of important homologous characters.
Outgroup:
A single taxon that represents the most primitive condition for all your taxa.
Ingroup:
All the other taxa of interest in your study - i.e. everything except for the outgroup
Crown Group:
The most derived (most advanced) clade in your study.
Branches:
Lines on a cladogram that represent particular taxa.
Nodes:
Branch points on a cladogram that represent the pertinent shared derived characters by the clades; a node represents the point of evolutionary divergence between taxa.
Monophyly:
Group of taxa that includes the common ancestor and all descendants; a true clade must by monophyletic in order to indicate a true evolutionary relationship among all the members.
Paraphyly:
Group of taxa that includes the common ancestor, but not all descendents are included; note that Linnaean taxa can be paraphyletic, but true clades cannot be paraphyletic.
Polyphyly:
Group of taxa that does not include the common ancestor (or even all the descendants of that common ancestor) of al the taxa in the group, and thus it is not an evolutionarily meaningful group of taxa; note that this it be avoided in any serious classification (based on either phenetics or cladistics) because it may be based in part on analogous (rather than homologous) characters.
The underlying rationale of both phenetics and cladistics approaches to classifying modern and fossil taxa is to reflect the ____________ relationships among those taxa.
evolutionary
Neither a phenetics nor cladistics approach necessitates that ____ be a factor in the analysis, so the temporal trends in the evolution of any particular lineage are inferred on the basis of a progression of ___________________ characters rather than ______________ occurrences in the stratigraphic record
time
“primitive to advanced”
“early to recent”
The traditional ___________________ is fully compatible with a phenetics approach, but it cannot be applied directly using a cladistic approach, which seeks to define clades rather than the traditional Linnean taxonomic categories.
Linnaean taxonomy
Monerans “Domains”:
Bacteria & Archaea
Four types of Protists:
Foraminifera, Radiolarians, Diatoms, Coccoliths
What good are microscopic fossils?
1) They’re very important in interpretations of biostratigraphy, paleoecology, paleoclimatology & paleogeography;
2) Countless specimens to study can be recovered from very small samples, including subsurface drill cores from oil wells.
Prokaryote Cells:
Cells in which the genetic material (genes) floats freely in the cytoplasm. “unicellular”
Eukaryote Cells:
Cells in which the genetic material is confined inside a nucleus “multicellular”
Autotrophs:
Organisms that produce their own sustenance (food) by themselves via photosynthesis (i.e., some monerans, some protists & all plants) or via chemosyntheis (i.e., sulfur reducing archaeobacteri in hot springs & deep sea thermal vents)
Heterotrophs:
Organisms that must sustain themselves by eating food (i.e. fungi & animals)
Benthos (Benthic):
Living on or within the se floor or lake bottom
Plankton (Planktic):
Living up off the sea floor in the water column
Kingdom Monera:
Single-celled organisms with prokaryote cells, including sulfur-reducing Archaeobacteria & photosynthetic Cyanobacteria (“Blue-green algae”)
The most primitive life forms (appearing in very early Precambrian & extending up to the present)
Kingdom Monera Geologic Range:
Very Early Precambrian - Present
What is the only kingdom that is prokaryote?
Monera
Stromatolites:
Layered mats, mounds & columns created by multiple sheets of cyanobacteria.
Oncolites:
Concentrically layered “algal balls” created by multiple sheets of cyanobacteria.
Kingdom Protista:
Single-celled organism with eukaryote cells, including several hard-shelled groups with an excellent fossil record (e.g., Foraminifera, Radiolaria, Diatoms, & Coccolithophores)
What are the four groups in kingdom protista with a great fossil record?
Foraminifera, Radiolaria, Diatoms, and Coccolithophores
Phylum Sarcodina:
Microscopic, unicellular, heterotropic “protozoans” (inappropriately called “one-celled animals”) that are characterized by lobe-like or finger-like extensions of the outer cell membrane (“pseudopods”), which are used for locomotion & capturing food particles; live exclusively in water (except for some moebas that live parasitically in intestinal tracts of animals)
Class Rhizopoda:
amoebas (no shell; no fossils) & foraminifera (microscopic calcite shells)
Order Foraminiferida (“Forams”):
Protists in a multi-chambered, calcite shell perforated by many tiny holes; all are marine; includes both benthic & planktic forms; CAMBRIAN TO RECENT
Order Foraminiferida (“Forams”) Geologic Range:
CAMBRIAN TO RECENT
Class Radiolaria (“Rads”):
Protists in a spherical or conical shell that is constructed as an open latticework of opal silica; all are marine; only planktic forms; CAMBRIAN TO RECENT
Class Radiolaria (“Rads”) Geologic Range:
CAMBRIAN TO RECENT
Phylum Chrysophyta:
Microscopic, unicellular, photosynthetic autotrophs (inappropriately called “one-celled plants”); live exclusively in water.
Class Bacillariophycae (“Diatoms”):
Protists in a radially symmetrical, discoidal or ovoidal shell composed of opal silica; both marine & fresh water; both benthic & planktic forms; JURASSIC TO RECENT
Class Bacillariophycae (“Diatoms”): Geologic Range:
JURASSIC TO RECENT
Class Coccolithophycae (Coccolithophores):
Protists in a spherical shell that is covered by disc-like or star-shaped calcite plates (“coccoliths”); all are marine; only planktic forms; TRIASSIC TO RECENT
Class Coccolithophycae (Coccolithophores) Geologic Range:
TRIASSIC TO RECENT
What will you see in calcerous ooze?
Planktic Forminifera
What will you see in siliceous ooze?
Radiolaria (planktic)
What are some common protists in the fossil record?
Planktic Foraminifera Benthic Foraminifera Planktic Radiolaria Planktic Centric Diatoms Benthic Pennate Diatoms Planktic Coccoliths Discoasters
Why should we care about fossil sponges (and other sponge-like animals)?
a) Sponges represent the simplest multicellular animals with a fossil record spanning more than half a billion years
b) some sponges & sponge-like organisms have been important reef-formers in the past (archaeocyathids in Cambriand, stromatoporoids in Silurian-Devonian, and calcisponges in Permian-Triassic)
c) Some sponges are major contributors of carbonate sediment
d) Some sponges produce sliceous spicules that provide a source of silica for diagenetic chert formation.
What are the Multicellular grades of organization of animal development?
a) Cellular Grade
b) Tissue Grade
c) Organ Grade
Cellular Grade:
Organism composed of many differentiated cells, which function semi-independently and are not joined together as tissues (e.g., Phylum Porifera and Archaeocyatha)
Tissue Grade:
Simple organism with various types of tissues (e.g., Phylum Porifera & Archaeocyatha)
Organ Grade:
Complex organism containing many highly developed organs, such as a heart, stomach, intestine, etc. (e.g., the true metazoans)
Phylum Porifera:
(“pore-bearing organisms): Sponges with a porous body containing spicules and/or spongin; simple, aquatic, filter-feeding animals
Class Hexactinellida:
(“Glass Sponges”): Relatively rigid sponges composed of calcite spicules; no spongin; exclusively marine, mostly in shallow water; CAMBRIAN TO HOLOCENE
Class Hexactinellida Geologic Range:
CAMBRIAN TO HOLOCENE
Class Calcarea:
(“Calcisponges”): Relatively rigid sponges composed of calcite spicules; no spongin; exclusively marine, mostly in shallow water; CAMBRIAN TO HOLOCENE
Class Calcarea Geologic Range:
CAMBRIAN TO HOLOCENE
Class Demospongea:
(“Demosponges”): Flexible sponges composed of soft spongin; with or without siliceous spicules; inhabit marine and fresh water; CAMBRIAN TO HOLOCENE
Class Demospongea Geologic Range:
CAMBRIAN TO HOLOCENE
Class Stromatoporoidea:
(“Stromatoporoids”): Hard, solid, sponge-like organisms composed of densely laminated skeleton of calcite and containing radiating “pillars” of calcite within the “laminae”; no evidence of spongin; exclusively marine, occuring mostly as reef-builders in shallow tropical waters; ORDOVICIAN TO CRETACEOUS
Class Stromatoporoidea Geologic Range:
ORDOVICIAN TO CRETACEOUS
Class Sclerospongia:
Hard, solid sponge composed of a densely laminated skeleton of aragonite or calcite plus soft spongin containing siliceous spicules; exclusively marine, occurring mostly in cryptic habitats in shallow tropical waters; ORDOVICIAN TO RECENT (not very important as fossils)
Class Sclerospongia Geologic Range:
ORDOVICIAN TO RECENT
Ostium:
Small pore in the sponge wall, through which water enters the body.
Canal:
Tubular channel starting at an ostium and extending through the sponge wall.
Spongocoel:
Large cavity in the interior of the sponge body
Osculum:
Large opening, through which water is expelled from the spongocoel.
Spongin:
The soft, flexible, organic material that makes many sponges “spongy”
Spicules:
Tiny, hard, needle-like structures of either silica or calcite (not all sponges have these)
Draw and label a diagram of typical sponge
See 4a
Problematical Relatives? of Sponges:
Stromatoporoids
Archaeocyathids
Stromatoporoids:
laminated organisms that are usually classified in Phylum Porifera
Laminae:
Individual, thin, calcite layers that make up the stromatoporoid skeleton
Latilaminae:
Discrete units of multiple calcite laminae.
Pillars:
Long calcite rods within the latilaminae; oriented perpendicular to the laminae.
Mamelons:
Rounded bumps on the surface of a stromatoporoid skeleton
Astrorhizae:
Star-like arrangement of radiating, branching grooves on the mamelons.
Draw and label a diagram of a stromatoporoid:
See 4b
Archaeocyathids:
cup-like organisms that are usually classified in a separate phylum
Phylum Archaeocyatha:
(“ancient cup-like” organisms): Sponge-like organisms with a rigid calcite skeleton of two concentric, porous walls; simple, aquatic, filter-feeding animals.
Class Regulares:
Archaeocyathids in which the skeleton lacks dissepiments; LOWER CAMBRIAN
Class Regulares Geologic Range:
LOWER CAMBRIAN
Class Irregulares:
Archaeocyathids in which the basal part of the skeleton has tiny, irregularly arranged, subhorizontal partitions, called dissepiments; LOWER CAMBRIAN
Class Irregulares Geologic Range:
LOWER CAMBRIAN
Outer wall:
Outermost of the two concentric walls of an archaeocyathid.
Inner Wall:
Innermost of the two concentric walls of an archaeocyathid.
Septa (parietal walls):
Rigid, radiating partitions that separate the outer and inner walls. (archaeocyathid)
Intervallum:
Open space between the outer and inner walls. (archaeocyathid)
Central cavity:
Open space inside the inner wall (archaeocyathid)
Tip:
Pointed bottom end of the archaeocyathid skeleton.
Holdfast:
Calcareous projections of the skeleton near its tip, which serve to anchor the arcaeocyathid skeleton in place in the sediment
