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BIOL 214 > Lecture 3 Exam 1 > Flashcards

Lecture 3 Exam 1 Flashcards

1
Q

When did O2 enter the atmosphere and how did this change life on earth?

A
  • appeared 2.5 billion years ago
  • O2 supports multicellular life
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2
Q

What is a fossil?

A

Any trace left by an organism that lived in the past

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3
Q

What is a trace fossil?

A
  • footprints, burrows, feces, anything left behind by an organism
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4
Q

What is a compression fossil?

A
  • a fossil that has undergone compression in a sedimentary rock (mostly plants)
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5
Q

What is a cast and mold fossil?

A

cast: fossilized imprint made in rock that are filled with minerals

mold: fossilized imprint made in rock.

  • mostly organisms with exoskeleton: shell, rigid structures
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6
Q

What is a permineralized fossils

A
  • deposit of minerals within cells (crystallized fossils)
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7
Q

What are unaltered remains?

A
  • also known as frozen remains: mostly found in permafrost
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8
Q

What are the biases of the fossil record

A
  1. Geography: depositional areas (lowlands, marine)
  2. Taxonomic bias: bones and shells amenable to fossilization. Best fossil records have been left by marine invertebrates with hard skeletons. Not all organisms make good fossils
  3. Temporal bias: earth’s crust is recycled so older rocks are rarer, so older fossils are harder to find
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9
Q

List reasons why origins of higher taxa have not been documented

A
  • many organisms are completely consumed by other organisms
    -sediments usually form only sporadically at a given location
  • there is little reason to assume that all evolutionary changes in which we are interested occurred at the few localities of a time interval that actually allowed fossilization
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10
Q

How do we know that the fossil record in incomplete?

A
  • many periods are represented by few known sedimentary formations and strata are often separated by more than 10,000 years
  • many lineages are represented by only at very widely separated time intervals
  • many extinct species of large conspicuous organisms are known from only one or a few specimens
  • new fossil taxa are discovered at a steady rate
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11
Q

What are the 2 difficulties in the interpretation of fossils?

A
  • age can only imprecisely be estimated by their location in strata
  • many fossils are crushed or fragmented
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12
Q

What are chronospecies

A
  • successive phenotypically different forms of a single evolutionary lineage
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13
Q

What is speciation?

A

The splitting of a lineage (cladogenesis)

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14
Q

What is pseudoextinction or taxonomic extinction

A

when a lineage changes so much that its original name disappears. Also known as anagenesis

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15
Q

What are the different ages?

A
  • proterozoic
  • paleozoic
  • mesozoic
  • cenozoic
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16
Q

Describe the proterozoic era

A
  • characterized by prokaryotes and eukaryotes
  • Ediacaran fauna (635-543 mya): soft bodied, lacking skeletons, crept or stood upon the sea floor. Simple morphology, radial/bilateral symmetry, mainly sponges/jellyfish. Thought to may be a “failed” metazoan lineage
  • in paleozoic era
17
Q

Describe the cambrian period

A
  • Cambrian explosion started (paleozoic era)
  • almost all modern phyla and classes of skeletonized marine animals suddenly appear in the fossil record
  • Burgess Shale has the best record of this period
  • large animals, complex morphology (developed segmentation, head, appendages), and bilateral symmetric
  • chordates (first vertebrates and jawless):
  • the number of phyla existing in the cambrian is equivalent to the diversity observed today
18
Q

What precipitated the cambrian explosion?

A
  • diversification may have been promoted by increasing oxygen levels in the atmosphere and ocean
  • vacant ecological habitats
  • key innovations related to multicellularity and the organization of developmental processes may have evolved (collagen, gene action)
  • maybe there was no such thing
19
Q

Describe the Ordovician era

A
  • in the paleozoic era
  • first land plants and jawed fish
20
Q

Describe the Silurian and Devonian era

A
  • in the paleozoic era
  • origin and diversification of bony fishes (silurian)
  • first fungi, tetrapods and insects (devonian)
21
Q

Describe the carboniferous and permian era

A
  • in the paleozoic era
  • widespread tropical swamp forests, gigantic dragonflies, reptiles, mammal like reptiles
  • Appalachian mountains rise
22
Q

What is the mesozoic era divided into?

A
  • triassic
  • jurassic
  • cretaceous
23
Q

What is the Pleistocene epoch

A
  • pleistocene epoch
    -repeated glaciations, origin of modern humans, repeated extinctions/glaciations
24
Q

What is the triassic period?

A
  • first dinosaurs and mammals
25
Q

What is the jurassic period

A

-first eutherian mammals and first bird

26
Q

What is the cretaceous period

A
  • first flowering plants
  • KT extinction
27
Q

What is the pleistocene epoch

A
  • repeated glaciations
  • origin and extinction of large mammals
  • origin of modern humans
  • extinction of many taxa
28
Q

what is pseudoextinction?

A
  • when a lineage changes so much that the original name disappears
29
Q

What is anagenesis

A

new species is transformed into a different species

30
Q

What is the cenozoic era

A
  • mammal radiation after extinction of dinosaurs
  • pollinating insects
  • first apes
  • humans appear
31
Q

what is the holocene epoch

A

agriculture, domesticated animals, digital watches

32
Q

What is the Pleistocene epoch

A
  • Pleistocene epoch
    -repeated glaciations, origin of modern humans
33
Q

What are the big 5 extinction events

A
  • cretaceous-Paleocene boundary
  • end Triassic
  • end Permian
  • late Devonian
  • end Ordovician
34
Q

What is background extinction?

A
  • the normal extinction rate
  • within any group the chance of extinction is constant but rates may vary among taxa
  • rate of extinction and ability to survive the mass extinctions may be related to geographic range

BIOL 214 (7 decks)

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