Biol 3P03 Midterm #1 Flashcards
week 1-4
between today and how many mya have all the major milestones in the evolution of life happened
~542 mya (phanerozoic era)
when did the greatest faunal turnover happen
paleozoic-mesozoic (=permian-triassic) boundary
what happened during the greatest faunal turnover
95% of marine animal life became extinct
how long have the earliest signs of prokaryotic life postdates the oldest rocks
a few hundred million years
what is the universal tree of life divided into
bacteria, archaea, and major subdivisions of eucarya
what do tommotian-type/ small shelly fauna (SSF) represent
the first appearance of diverse skeletal material (primarily phosphatic)
what was the first evidence of biomineralization
cloudina (earliest known calcareous fossil)
what percent range of species have no fossil record
~85-97%
what is the biological species concept
a species is an array of populations which are actually or potentially interbreeding, and which are reproductively isolated from other such arrays under natural conditions
what is the morphological species concept
a species is a diagnosable cluster of individuals within which there is a paternity of ancestry and descent, and beyond which there is not
what is the evolutionary species concept
“a lineage evolving separately from others and with its own unitary evolutionary role and tendencies”
what is taphonomy
the study of the processes (biological, chemical, and physical) that occur between the death of an organism and its final state in the rock
what are the 4 types of processes of fossilization in body fossils
dissolution (and replacement), permineralization, carbonization, and unaltered
how do mold and casts work
- shell buried in sediment
- shell dissolved leaving cavity (mold)
- cavity fills with sediment to form a cast
- a shell (body fossil) partially incomplete revealing underlying internal mold and cast
what are the 5 favourable conditions for preservation
- anoxic conditions
- rapid burial
- suitable sediment (fine-grained)
- absence of diagenesis or metamorphism
- presence of hard parts
what are the three types of fossils
body, trace, and chemical
what is a body fossil
bodily remains of the organisms preserved in the rocks
what is a trace fossil
features in the rocks left by organisms as they lived their lives
what is a chemical fossil
a distinctive organic chemical derived from an organism and preserved in the rocks
what is fossil content used to interpret
the age of rocks (biostratigraphy) and paleoenvironmental conditions at the time when the sediments were deposited
what is a Global Stratotype section & Points (GSSP)
an internationally agreed upon stratigraphic section which serves as the reference section for a particular boundary on the geologic time scale
what are common fossils
abundant organisms with high fossilization potential
what makes excellent index fossils
common fossils with a short geologic range and wide geographic distributions
what is acme
peak abundance and diversity
what are trilobites useful for
subdividing the Cambrian period
what are graptolites used for
extensive subdivision of the Ordovician and Silurian Periods
what is the unconformity type that separates the Muav and Redwall Limestone Foundations
a disconformity between the horizontal beds of sedimentary rock, but with substantial missing time
how do fossils/ specimens change when stress is added
the fossils get smaller
what do high familial diversities of skeletal benthos coincide with
times of greatest continental fragmentation and sea level rise
what does ecological biogeography explain
the distribution of plants and animals in terms of present-day climatic and ecological conditions
what is the basis of paleoenvironmental reconstruction
ecological biogeography
what can shorten range zones
limiting synchroneity, non-preservation, metamorphism, erosion, barriers
what is the zombie effect
the apparent range extension of a taxon due to reworking of its fossils into younger strata by sedimentary processes
what is the Elvis taxon
a taxon which has been misidentified as having re-emerged in the fossil record after a period of extinction
what does the Elvis taxon represent
evolutionary convergence in an unrelated clade
phylogeny of common metazoans in the fossil record derive from what
a common ancestral flagellate protozoan
what are components in the diploblastic body plan
2 layers of tissues separated by inert, gelatinous mesoglea; tissue-grade organization, not differentiated into organs; and radial symmetry
why phylum has a diploblastic body plan
phylum cnidaria - jellyfish, hydra, sea fans, sea anemones, and corals
what are the components of a parazoan body plan
groups of cells organized into 2 layers (endoderm and ectoderm) separated by jelly-like material, punctuated by amoebocytes (wandering cells); and cell grade of organization, not differentiated into tissues and organs
what are parazoans the link between
protozoans and true multicellular animals (eumetazoa)
what are choanoflagellates
the probable ancestors of sponges
what is the anatomy of phylum Porifera
choanocytes line the walls of the ostia and draw water toward the spongocoel and waste is eliminated through the large osculum. Archeocytes digest food, transport nutrients, and develop into sex cells, and spongocytes and sclerocytes secrete spicules
what are the 3 extant classes of sponges
demospongiae, hexctinellida, calcarea
what are common in paleozoic reef rocks and molecular evidence of fossilized sternes in deposits from the Cryogenian (“snowball earth”) period
demospongiae, hexctinellida, calcarea, stromatoporoids
what is the anatomy of phylum Archeocyatha
skeletons were simple double-walled conical structures (with perforated walls separated by vertical setpa) with a broad, rooted base and a wide circular opening
when did burrowing become pervasive and why
during the Ordovician because there was an abundance of infaunal coelomates
what is the anatomy of phylum Cnidaria
the simplest of the Eumetozoans: have a diploblastic body plan (true tissues, nervous muscular, reproductive systems, but no respiratory, circulatory, or excretory systems)
what do polyps and medusae represent
the alternation of generations that is typical of phylum Cnidaria
what is the anatomy of class Anthozoa
possess hollow tentacles and an enteron divided longitudinally by vertical mesenteries; both colonial and solitary forms occur
what is included in class Anthozoa
corals, sea anemones, and sea pens
what are the 2 subclasses of class Anthozoa and what do they include
subclass octocorallia: sea pens & sea fans
subclass Zoantharia: corals sea anemones
what are the three orders of subclass zoantharia
order scleractinian
order rugosa
order tubulata
what are the two pieces of evidenced that supports scleractinian corals evolving from a non-skeletal zoantharian
- a hiatus between the first scleractinian and the disappearance of both rugosa and tabulate in terminal paleozoic mass extinction
- different skeletal composition (aragonite in scleractinian, calcite in rugose and tabulate)
what is the anatomy of order tabulata
exclusively colonial, consists of aggregates of polygonal, circular or elliptical tube-like corallites with horizontal tabulae; verticle septa are usually absent, but very short septa may be present
what is the anatomy of order rugosa
both solitary and colonial with calcite skeletons, polyp resided in calyx (depression), vertical septa inserted radially and hen in quadrants to produce bilateral symmetry
what is the shape of solitary corallites in order rugosa
like curved horns
how is the corallum produced in colonial taxa of order rugosa
asexual budding of initial corallite
anatomy of order Scleractinia
both solitary and colonial, aragonite skeletons, verticle septa inserted radially to produce radial symmetry, and no tabulae
what do stromatolites form and when did they form it
formed reef-like structures and were very common in the Mesoproterozoic (middle Proterozoic)
what is the skeletal structure of phylum Archeocyatha
simple double-walled conical structures, with perforated walls separated by verticle septa, with broad, rooted bade and a wide circular opening
what did the mass extinctions during the Devonian result in
worldwide near-total collapse of the massive reef communities
what taxa disappeared or almost completely disappeared during the Devonian mass extinction
few rugose coral species survived, stromatoporoid and tabulate corals almost completely disappeared
what geological groups were the least and most impacted by the Devonian mass extinction
tropical groups were the most affected and polar groups were only affected a little.
what does the polar groups surviving the Devonian mass extinction suggest
an episode of global cooling was largely responsible for the extinctions near the end
what is the inarticulate lingula
an extant brachiopod species that is a generalist “living fossil”
what is an articulate terebratulid
a relict that lives in cryptic or deep-water marine habitats
what does articulate mean in reference to brachiopods
valves joined along articulated “ball and socket” hinge
what are characteristics of brachiopod Class Calciata (Articulate)
- 2 calcareous valves secreted by a mantle
- plane of symmetry through valves
- valves not identical
- are filter feeders
valves are articulated (“ball and socket”)
what is the skeletal anatomy of brachiopod order strophomenida
- commonly thin, typically concavo-convex shells with straight hinge lines
- pedicle opening (foramen) atrophied during ontogeny
what is the skeletal anatomy of brachiopod order Rhynchonellida
commonly thick, biconvex shells with curved hinge lines, marked costae, attached by a pedicle, circular foramen, zig-zag commissures
