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