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
Draw and label a diagram of a typical archaeocyathid:
See 4b
Cnidarians:
Corals and their Relatives
Why should be study fossil corals?
a) Corals are very simple organisms that are voracious predators
b) corals are excellent indicators of warm, shallow, marine paleoenvironments
c) some coral taxa were major reef-builders
d) coral reefs are (and were) among the diverse ecosystems on Earth
e) some coral taxa are important biostratigraphic index fossils, especially rugose & tabulate corals in the Paleozoic
Phylum Cnidaria Three classes:
Class Scyphozoa
Class Hydrozoa
Class Anthozoa
Class Anthozoa Subclasses:
Subclass Ceriantipatheria Subclass Octocorallia Subclass Zoantharia
Subclass Zoantharia Three Orders:
Order Tabulata
Order Rugosa
Order Scleractinia
Class Scyphozoa:
true jellyfish; very poor fossil record
Class Hydrozoa:
“fire corals” and their kin; sparse fossil record
Class Anthozoa:
true corals and sea anemones; rich fossil record
Subclass Zoantharia:
6 orders of hard corals + 3 orders of soft sea anemones
Order Tabulata:
(tabulate corals), Early Ordovician to Permian
Order Tabulata Geologic Range:
Early Ordovician to Permian
Order Rugosa:
(horn corals), Middle Ordovician to Permian
Order Rugosa Geologic Range:
Middle Ordovician to Permian
Order Scleractinia:
(modern corals), Middle Triassic to Present
Order Scleractinia Geologic Range:
Middle Triassic to Present
Medusa:
Pelagic, sac-like body form or growth stage (Cnidarians)
Polyp:
Benthic, barrel-like body form or growth stage (Cnidarians)
Radial symmetry:
Multiple vertical symmetry planes radiating outward from the center (Cnidarians)
Basal Disc:
Flattened top portion of the polyp, on which the mouth occurs (Cnidarians).
Oral Disc:
Flattened top portion of the polyp, on which the mouth occurs. (Cnidarians)
Mouth:
The single opening to the central cavity (enteron) (Cnidarians)
Pharynx:
Throat-like tube leading from mouth into the central cavity (enteron). (Cnidarians)
Tentacles:
Arm-like, cnidoblast-bearing structures surrounding the mouth. (Cnidarians)
Enteron:
Central body cavity, which contains mesentery and digestive tissues. (cndarians)
Mesenteries:
Radiating vertical sheets of tissue (Cnidarians)
Cnidoblasts:
“stinging cells”, which contain the poisonous nematocysts (Cnidarians)
Nematocysts:
Toxin-bearing sacs within the cnidoblasts (Cnidarians)
Corallum:
Skeleton of the entire coral colony
Corallite:
Skeleton of a single coral polyp.
Theca:
Outer wall of corallite
Calice:
Bowl-shaped top surface of corallite.
Fossula:
Deep, slot-like indentation in calice.
Columella:
Pillar (axis) in center of corallite.
Septa:
Radiating, vertical, blade-like partitions inside corallite.
Tabulae:
Stacked, horizontal, platform-like partitions inside corallite.
Dissepiments:
Multiple domed plates connecting the septa inside corallite.
Reef:
Biologically produced prominence on the sea floor
Tabulate Corals:
(order tabulata), Early Ordovician to Permian (Syringopora & Favosites are colonial)
Tabulate Corals Geologic Range:
Early Ordovician to Permian
Horn Corals:
Order Rugosa, MIDDLE ORDOVICIAN TO PERMIAN, Heliophyllum & Cystiphyllum are solitary; Pachyphyllum & Hexagonaria are colonial
Horn Corals Geologic Range:
Middle Ordovician to Permian
Modern Corals:
Order Scleractinia, Middle Triassic to Present:(Montastraea & Septastrea are colonial)
Modern Corals Geologic Range:
Middle Triassic to Present
Coral ecology and paleoecology:
Corals are sessile, benthic carnivores that capture, poison, kill and devour tiny worms, crustaceans, etc. They typically are fully marine animals (no fresh water forms).
Hermatypic:
(=reef-building) corals live in warm, shallow, clear, agitated, normal marine water. They house symbiotic algae (zooxanthellae) in their tissues, so they requrei sunlight.
Ahermatypic:
(=non-reef-bulding) corals may live in cold, deep, marine water. They do not have zooxanthellae, so they do not require sunlight in their habitat.
Geologic importance of Tabulate corals:
important reef-builders in Middle Ord. to Dev.
Geologic importance of Rugose corals:
important facies and age indicators through their range.
Geologic importance of Scleractinian corals:
Important reef-builders through their entire range.
Reef formation: DRAW DIAGRAM A-D
Successive stages in the development of modern (scleractinian) coral reefs on subsiding volcanic islands (seamounts), as proposed by Charles Darwin from his observations made while sailing through the South Pacific on the voyage of the H.M.S. Beagle in the 1830’s. A,B, Volcanic island skirted by a fringing reef. C, Volcanic island with a lagoon and barrier reef encircling it. D, Coral atoll with a central lagoon and no vestige of an emergent island above sea level.
How do we know for sure that life has evolved?
a) The worldwide successions of geologic strata contain successions of abundant fossils that offer clear evidence of the different kinds of living things that lived on Earth at different times from the distant past to the present day
b) there is no interval of geologic time with fossils of all types contained in the same or contemporaneous strata.
The fact of evolution:
The fossil record provides tangible evidence that life has changed markedly through time and that life has become progressively more complex, more advanced & more diverse through time.
The theory of evolution:
The mechanism of evolutionary change (i.e. natural selection)
Natural Selection:
Species evolved by differential reproduction, in which those individuals that are best fit within the physical and biological environment will produce the most offspring and over many generations will concentrate their advantageous characteristics in the population; thus, less advantageous characteristics eventually will be lost from the population over time. “Survival of the fittest” (Charles Darwin, Origin of Species, 1859)
Heredity
Inheritance of acquired characteristics
Who?
Jean Baptisete Lamarck, French, late 18th century
Heredity
Blending inheritance
Who?
Charles Darwin, English, middle 19th century
Heredity
Genetic Inheritance
Who?
Gregor Mendel, Austrian, late 19th century
Genes:
independent, inheritable units that dictate the physical traits of the offspring.
Chromosomes:
Paired strings of genes, occurring in the nucleus of eukaryote cells
Two Ultimate sources of new variation in an evolving species:
Gene mutation & chromosome mutation
Gene mutation:
Imperfect replication of the DNA molecules that compose the genes
Chromosome mutation:
Imperfect duplication of chromosomes during cell division.
Five characteristics of biological evolution:
Opportunistic, Competitive, Adaptive, Universal, Irreversible
Opportunistic:
The course of evolution is not pre-determined
Competitive:
Those that can out-compete their peers will survive to reproduce
Adaptive:
Species gradually become better fit to survive in their environment
Universal:
All living things are subject to the pressures of evolutionary change
Irreversible:
Once a species is extinct, it cannot reappear
Patterns of biological evolution:
Divergent Evolution, Convergent Evolution, Parallelism
Divergent Evolution:
(“Adaptive Radiation”): Divergence of homologous characteristics
Convergent Evolution:
Convergence of analogous features
Parallelism:
Evolution of different lineages along parallel pathways.
Phyletic Gradualism:
View that evolution results from small, incremental changes proceeding at slow, uniform rates.
Punctuated Equilibria:
View that evolution is stepwise, resulting from short bursts of major change that punctuate long intervals of equilibrium with little or no change.
Karl von Linne’
Early 1700’s
Swedish
Diversity of life; taxonomic principles based on anatomical similarities of groups of organisms; the “species” concept
Comte de Buffon
Mid 1700’s
French
Species change from generation to generation by “degeneration” from their original perfect form.
Jean-Baptiste Lamarck
Late 1700’s
French
Species change from generation to generation by “adaptation”; inheritance of acquired characteristics.
William Smith
Early 1800’s
English
Biostratigraphy based on “faunal succession”; geologic map based on relative ages of rock units.
Charles Darwin
Mid 1800’s
English
Species change via “natural selection”
Gregor Mendel
Late 1800’s
Austrian
Heredity baseed on inheritance of “genes”
Hermann Muller
Early 1900’s
German
Gene “mutations” caused by external agents (e.g., x-rays) as a mechanism for introducing new genetic diversity into the breeding population.
James Watson & Francis Crick
Mid 1900’s
American & English
Chemical structure of genes; DNA as the chemical basis of heredity
Niles Eldredge & Stephen Jay Gould
American
Late 1900’s
Evolution proceeds by “punctuated equilibria”; non-uniform, spasmodic rates of evolutionary change
Allopatric Speciation:
The speciation model by which two or more new species appear as a result of evolution occurring in different populations of the same ancestral species that were geographically separated (i.e, reproductively isolated) over an extended length of time.
Punctuated Equilibria:
Interval of very rapid evolutionary change within a taxon
Stasis:
Interval during which little or no evolutionary change occurs within a taxon
“Hopeful Monster”:
Concept of a radical new mutation appearing in an offspring, which may or may not impart a significant adaptive advantage
“Red Queen”:
Concept of the ongoing evolution of a taxon proceeding just enough to keep that taxon from going extinct.
Why are bryozoans given a name that literally means “moss animals”?
Because of their numerous tiny feeding tentacles, the fuzzy surface of a bryozoan colony often resembles that of moss, and some forms even are green, but they are not moss-they are animals!
Zoarium:
Skeleton of the entire bryozoan colony; may assume various growth forms, such as encrusting, massive, branching (bush-like or stick-like), etc.
Zoecium:
Body wall or skeleton iof individual bryozoan animal
Aperture:
Main opening in zoecium through which the animal brings in water & food
Operculum:
Hinged lid covering the aperture of some bryozoans (Cheilostomes)
Zooid:
Individual bryozoan animal; typically <1mm in diameter
Ancestrula:
Initial (sexually produced) zooid of the colony. (Bryozoan)
Kenozooids:
Individuals specialized for asexual budding of other zooids in the colony. (Bryozoan)
Gonozooids:
Individuals specialized for producing gametes (sex cells)
Autozooids:
Normal feeding individuals within the colony.
Draw a digram of the Bryozoan zoarium
7a
Life Habits and Paleoecology of Bryozoans:
- Sessile, epifaunal, benthic filter feeders (using a lophophore).
- Stenolaemates and Gymnolaemates live mainly in clear, shallow, normal marine water.
- Often associated with articulate brachiopods & rugose corals in the Paleozoic.
- Often associated with gastropods & pelecypods in the Mesozoic & Cenozoic.
Phylum Bryozoa:
Exclusively colonial invertebrates that live in a small colony (zoarium) of individuals (zooids), each of which lives in a tiny chamber (zoecium) and feeds by means of a lophophore; detailed taxonomy is based upon the microscopic shape of the zoecia and the zoecial apertures, as well as the macroscopic growth form of the zoarium.
Subphylum Ectoprocta:
Anus located outside the lophophre; mostly marine; the only bryozoan subphylum with a fossil record; Ordovician to Recent
Subphylum Ectoprocta Geologic Range:
Ordovician to Recent
Class Stenolaemata:
(“narrow throat”): Characterized by long, tubular, narrow, highly calcified zoecia, which continue to grow longer and longer throughout the life of the colony; Ordovician to Recent
Class Stenolaemata Geologic Range:
Ordovician to Recent
Order Cryptostomata:
(“Hidden mouth”): Exemplified by the finger-like Rhombopora; Ordovician to Permian
Order Cryptostomata Geologic Range:
Ordovician to Permian
Order Trepostomata:
(“change mouth”): Exemplified by the button-like Prasopora, the twig-like Dekayella, and also the common Batostoma, Eridotrypa, Hallopora, and Heterotrypa; Ordovician to Triassic
Order Trepostomata Geologic Range:
Ordovician to Triassic
Order Fenestrata:
(“windows”): Exemplified by the lace-like Fenestella, Fenestrellina and Archimedes; Ordovician to Triassic
Order Fenestrata Geologic Range:
Ordovician to Triassic
Order Cyclostomata:
(“round mouth”): Exemplified by the organpipe-like Idmonea; Ordovician to Recent
Order Cyclostomata Geologic Range:
Ordovician to Recent
Class Gymnolaemata:
(“naked throat”): Characterized by box-like or cylinder-like enclosures around the zoecia, which remain a fixed size throughout the life of the colony; Ordovician to Recent
Class Gymnolaemata Geologic Range:
Ordovician to Recent
Order Cheilostomata:
(“lip mouth”): Exemplified by the bush-like Bugula and sheet-like Membranipora; Jurassic to Recent
Order Cheilostomata Geologic Range:
Jurassic to Recent
Graptolites: (what about them)
Extinct, but can be used for very precise age dating, used to define stratigraphic boundaries
Why are graptolites thought to be related to vertebrate animals?
Their morphology, as seen in some exquisitely preserved chertified fossil specimens, seems to closely resemble that of modern pterobranchs, which are marine creatures that possess a small tube resembling a notocord. Since vertebrate animals possess a notocord in an early embryonic stage, it is infered that vertebrates and pterobranchs are distant cousins, although their common ancestor probably occurred way back in the Precambrian. Thus by extension, graptolites are commonly fit on an offshoot of a branch of the family tree that contains the true vertebrates. However, the arguments linking graptolites to vertebrates are so tenuous that their correct taxonomic affinities remain uncertain.
Phylum Hemichordata similar/different than Bryozoans?
Different phylum than Bryozoans, similar structures
Class Enteropneusta:
modern “acorn worms” - only fossil record is trace fossils
Class Pterobranchia:
modern pterobranchs - no fossil record at all
Class Graptolithina:
Paleozoic graptolites - good fossil record, mainly in black shales
Order Dendroidea Geologic Range:
Middle cambrian to Lower Pennsylvanian
Order Graptoloidea Geologic Range:
Lower Ordovician to Lower Devonian
Classes of Hemichordata:
Enteropneusta, Pterobranchia, Graptolithina
Orders of Graptolithina
Dendroidea, Graptoloidea
Rhabdosome:
Entire graptolite colony
Zooid:
Individual graptolite animal
Theca:
Chitinous shell of an individual zooid
Sicula:
The single, conical theca of the first zooid in the colony; attached at top end to the nema
Nema:
Hollow thread-like structure extending from the top of the sicula
Stipe:
Single branch of a colony, containing a string of thecae.
Dissepiments:
Connections between the stipes of some types of rhabdosomes
Draw and label a graptolite
7c
Life Habits and Paleoecology of Graptolites:
- Colonial (probably had alternation of generations)
- Filter feeders (feeding habit using a lophophore, as inferred by analogy with modern pterobranchs)
- Benthic (dendroid graptolites) or planktic (graptoloid graptolites)
- Marine (generally open ocean and/or deep water)
- Excellent index fossils in Ordovician & Silurian deep-water deposits.
Colonia:
Alternation of sexual/asexual generation to generation
Why are fossils important in stratigraphic studies of the geologic record?
Fossils of continually evolving life forms directly reflect the passage of geologic time, and therefore they provide direct evidence of relative time throughout the stratigraphic record as well as a very useful means for age-dating rocks and correlating regionally extensive rock units. Virtually all boundaries in the geologic time scale are determined using fossils.
Stratigraphy:
The science of dating and correlating geologic units of various types
Biostratigraphy:
Stratigraphy based on body fossils
Ichnostratigraphy:
Stratigraphy based on trace fossils.
Lithostratigraphy:
Stratigraphy based on rock types and lithologic characteristics.
Magnetostratigraphy:
Startiraphy based on paleomagnetic signatures in the rocks.
Chronostratigraphy:
Worldwide geologic time scale, based on all types of stratigraphy
Time Units vs. Rock Units Example
Time Units (Early Cambrian) Rock Units (Lower Cambrian)
Biostratigraphic Zones:
The various kinds of units employed for biostratigraphic correlation.
Biozone:
Total geologic range of a given species (the basic unit of biostratigraphy)
Range Zone:
Time between the fist and last occurrences of a species in the study area.
Difference between biozone and range zone?
Biozone is more theoretic, range zone is actual data
Concurrent Range Zones:
Overlapping ranges of different species.
Assemblage Zone:
Zone based on several different species that usually occur together.
Peak Zone:
Acme, Abundance zone, Zone based on peak abundance of a species.
Interval Zone:
Consecutive range zone: Unit between two biostratigraphic time planes which itself may not have any fossils in it (Barren)
First Appearance Datum (FAD):
Earliest (lowest) appearance of an index fossil (F.O.)
Last Appearance Datum (LAD):
Latest (highest) occurrence of an index fossil (L.O.)
Facies:
Group of beds with recurrent characteristics that reflect the depositional environment
Lithofacies:
Facies based on common sediment characteristics
Biofacies:
Facies based on recurring taxa of body fossils
Ichnofacies:
Facies based on recurring taxa of trace fossils
Index Fossil:
Guide Fossil: A stratigraphically useful taxon with a narrow age range
Facies Fossil:
A taxon with a broad age range but restricted paleoenvironmental signficance
Stratigraphic Leaking:
Younger fossils residing in older rocks
Stratigraphic Reworking:
Older fossils residing in younger rocks.
Lazarus Taxa:
Re-appearance of supposedly extinct taxa at a higher stratigraphic level.
Elvis Taxa:
Convergent evolution produces “impersonators” of extinct taxa.
Zombie Taxa:
Stratigraphic reworking allows extinct taxa to occur in younger sediments.
Stratigraphic Resolution:
Finness (or coarseness) of the time increments that re discerned.
Stratigraphic Precision:
Margin of error in determining the stratigraphic position of data points.
Signor-Lipps Effect:
Owing to sparse distribution and incomplete preservation of fossil assemblages, it is difficult to differentiate between sudden or gradual extinction patterns.
Nicolaus Steno (Niels Stensen):
Mid 1700’s
Danish
Foundations of physical stratigraphy based on detailed geologic field observations; established the principle of “superposition of strata.”
James Hutton:
Late 1700’s
Scottish
Concept of uniformitarianism “The present is the key to the past”, and “No vestige of a beginning - no prospect of an end”)
Georges Cuvier:
Early 1800’s
French
Concept of “comparative anatomy” to demonstrate relationships between various kinds of animals based on their physical characteristics; first geologic map of a major region (Paris Basin) based on fossil occurrences, published in 1811.
William Smith:
Early 1800’s
English
Concept of “faunal succession” in stratigraphy; first geologic map of an entire country (Great Britain) based on relative ages of rock units, published in 1815.
Charles Lyell:
Early 1800’s
English
Major voice in the establishment of uniformitarianism as the foundation of historical geology; wrote the first widely selling geology textbook (“Principles of Geology”, 1830-1833) and founded one of the first major geology journals (Geological Magazine).
Adam Sedgwick:
Early 1800’s
English
Established the Cambrian System of rocks & Cambrian Period of the geologic time scale based on physical & biostratigraphy in southern Britain
Roderick Murchison:
Early 1800’s
English
Established the Silurian System of rocks & Silurian Period of the geologic time scale based on physical & biostratgipahy in soutern Britain
James Hall:
Mid 1800’s
American
First state geologist in America (New York); directed the first biostratigraphic surveys & earlist geologic maps in eastern Norh America.
“Brachiopoda” literally means “arm-foot” why?
Originally, the bi-valved brachiopods were thought to be related to the bi-valved mollusks, which have a muscular organ called a “foot”. The brachiopod lophophore, which is used in filter-feeding, has two arm-like branches, which early biologist erroneously confused with the “foot” of mollusks. Because brachiopods share the “lophophore” (feeding structure with tentacles) with bryozoans, the braciopods in fact are much more closely related to the tiny, colonial bryozoans than they are to mollusks!
Phylum Brachiopoda:
bivalved animals with a lophophore & a pedicle
What are the two classes of Brachiopoda?
Class Inarticulata and Class Articulata
Class Inarticulata:
(brachiopods without a hinge; Lower Cambrian to Recent) - Four Orders
Class Inarticulata Geologic Range:
Lower Cambrian to Recent
Class Articulata:
brachiopods with a hinge; Lower Cambrian to Recent - Six Orders
Class Articulata Geologic Range:
Lower Cambrian to Recent
Lophophore:
Distinctive feeding structure inside the brachiopod shell, consisting of two arm-like “brachia” that bear cilia, which beat back and forth in the water to create microcurrents and strain suspended food particles from the water; attached to inside of brachial valve.
Brachia:
Two arm-like branches of the lophophore; attached to brachial valve.
Pedicle:
Tough, fleshy stalk attached to pedicle valve and extending from the beak of the shell. (Brachiopod)
Mantle:
Thin sheet of tissue that lines the inside of the brachiopod shell
Periostracum:
Brown, scaley, organic “skin” coating the outside of some brachiopod shells.
Adductor muscles:
Muscles that close the two valves of the shell.
Diductor muscles:
Muscles that open the two valves of the shell (only found in Articulates).
Pedicle adjustor muscles:
Muscles that move the main body mass around at the end of the pedicle (only found in Articulates).
Oblique muscles:
Muscles that rotate and/or slide the two valves with respect to one another (only found in Inarticulates).
Valves:
The two main parts of the brachiopod shell
Brachial valve:
“Dorsal” valve, to which the lophopore is attached
Pedicle valve;
“Ventral” valve, to which the pedicle is attached.
Commissure:
Broad “anterior” margin of the shell opposite the pedicle and hinge.
Beak:
Pointed “posterior” end of the shell, from which the pedicle protrudes.
Hinge:
Structure at the beak that holds the two valves together and allows them to open and close in an articulated fashion (only found in Articulates).
Tooth & socket structure:
Small projections & corresponding pits on inside of the beak.
Interarea:
Outside pt of the shell located between the two pointed parts of the beak.
Pedicle Opening:
Hole or notch in the beak to allow the pedicle to protrude from the shell.
Foramen:
Round hole on the pedicle valve.
Delthyrium:
“V”-shaped notch on pedicle valve.
Notothyrium:
“V”-shaped notch on brachial valve.
Brachidium:
Calcareous lophophore support on insde of bracial valve (only in Articulates)
Crura:
Simple, forked brachidium in Rhynchonellids
Spiralium:
Ornate, coiled brachidium in Spiriferids
Loop:
Curved, lasso-like brachidium in Terebratulids
Fold:
Broad central ridge (usually on brachial valve) extending from beak to commissure.
Sulcus:
Deep central groove (usually on pedicle valve) corresponding to the fold.
Class Inarticulata:
brachiopods without a hinge; shell may be composed of calcite, calcium phosphate, or layered or unlayered chitinophosphate
Orders of Class Inarticulata:
Paterinida, Obolellida, Lingulida, Acrotretida
Order Paterinida:
Cambrian to Ordovician, Tiny (<5mm) brachiopods with a biconvex, phosphatic shell that has both a delthyrium and notothyrium; not very important
Order Obolellida:
Cambrian Only, Small (usually <1cm) brachiopods with a biconvex, calcite shell that has a tiny, slit-like pedicle foramen; not very important
Order Lingulida:
Cambrian to Recent: Circular or elongate brachiopods (up to 5 cm long) with a biconvex, chitinophosphatic shell; moderately important as fossils
Order Acrotretida:
Cambrian to Recent: Tiny (usually <2mm) brachiopods with a flattened, circular, calcite or phosphatic shell; no pedicle; some forms are attached by cementing one valve to a rock or another shell; somewhat important as fossils.
Class Articulata:
Brachiopods with a hinge; shell always composed of layered calcite
Order Orthida:
Cambrian to Permian, Inequivalved shell, which may be biconvex, concavoconvex, plano-convex or convexo-concave, commonly with fine to coarse radiating ribs “costae”, pedicle protrudes through notothyrium and delthyrium; no brachidium; usually impunctate, but some forms are punctate; important as fossils.
Order Pentamerida:
Cambrian to Devonian, Biconvex shell, usually with a smooth surface; characterized by a trough-shaped or spoon-like structure (“spondylium”) inside the pedicle valve, to which the pedicle is attached; simple rod-like or blade-like lophophore supports on brachial valve; always impunctate; not very important.
Order Strophomenida:
Ordovician to Triassic, Grossly inequivalved shell, usually panlo-convex or concavo-convex, commonly with radiating ribs and/or concentric growth lines; characterized by a very wide hingeline and inflated pedicle valve; sometimes a pedicle foramen, or else no pedicle opening at all; sometimes there are long spines on pedicle valve; wide variety of spiralled lophophore supports; always pseudopunctate; this is the most diverse brachiopd order, so it is very important.
Order Rhynchonellida:
Ordovician to Recent; Biconvex shell with a short hingeline and prominent beak; characterized by a strongly corrugated (“plicate”) shell with a very priminent fold and sulcus; pedicle protrudes throug a delthyrium; simple, forked brachidium (“crura”); usually impunctate, but some forms are punctate; important as fossils.
Order Spiriferida:
Ordovician to Jurassic: Very wide, biconvex shell with a long hingeline and short beak-to-commissure distance; characterized by its “wing-like appearance; promient fold and sulcus; pedicle protrudes through a delthyrium or pedicle foramen; thightly spiralled brachidium (“spiralium”); may be impunctate or punctate; important as fossils.
Order Terebratulida:
Devonian to Recent, Biconvex shell with a very short hingleine characterized by its “Aladdin’s Lam;” appearance; shell surface smooth or finely ribbed; pedicle usually protrudes through a pedicle foramen; loop-shaped brachidium; always punctate; important as fossils.
