Ch 4 - Fossils and Timescales

Question 1

Alfred Wegener

Answer 1

Proposed continental drift in 1915

Question 2

Fossils and methods of formation

Answer 2

Animals trapped in sediments; compression (imprint), permineralisation (precipitation of mineral replaces the tissue), unaltered remains

Question 3

Dating

Answer 3

Isotopes half life (1/2^n, n = # half lives); formed by nuclear reactions in magma core

Question 4

Geological time periods

Answer 4

Paleozoic: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian; Mezozoic: Triassic, Jurassic, Cretaceous; Cenozoic: Tertiary, Quaternary

Question 5

Cambrian

Answer 5

542 Mya; marine animals diversify

Question 6

Odrovician

Answer 6

488 Mya; Echinoderms and invertebrate diversify, cephalopods; extinction at end of period (Gondwana over south pole)

Question 7

Silurian

Answer 7

444 Mya; Jawed fish, early terrestrial plants and arthropods

Question 8

Devonian

Answer 8

416 Mya; Bony fish diversify; amphibians, insects, ferns, seed plants originate; mass extinction near end

Question 9

Carboniferous

Answer 9

359 Mya; small continents; plants increase, winged insects, amphibians diverse, first reptiles

Question 10

Permian

Answer 10

299 Mya; Pangaea; glaciations; reptiles and mammal forms diversify; mass extinction (esp marine)

Question 11

Triassic

Answer 11

251 Mya; separation of Pangaea starts; gymnosperms dominant, first dinos and mammals

Question 12

Jurassic

Answer 12

200 Mya; separation continues; dinos; first birds; Mesozoic marine revolution

Question 13

Cretaceous

Answer 13

145 Mya; most continents separated; mammals, birds diversify; mass extinctions of ammonoids and dinos

Question 14

Tertiary

Answer 14

65.5 Mya; Cooling, drier climate; mammals, birds, insects radiate

Question 15

Quaternary

Answer 15

1.8 Mya; Continents in modern places; glaciations and extinctions; Homo sapiens, agriculture, civilization

Question 16

Burgess Shale

Answer 16

Many cambrian species, most phyla; used to be bottom of sea until the mountains rose up

Question 17

Trilobites

Answer 17

Extinct arthropod. Segmentation, eyes, 3 body sections.

Question 18

Canadaspis

Answer 18

Crustaceans, most abundant in Burgess shale

Question 19

Sanctacaris

Answer 19

Gave rise to spiders

Question 20

Reasons for Cambrian explosion

Answer 20

Environment: Oxygen; development: hox genes, more diverse body plans. Leads to predation, hard shells