Paleontology and Macroevolution

Question 1

What is a fossil?

Answer 1

A fossil is any trace left by an organism that lived in the past

Question 2

What are the 4 general categories of fossil formation?

Answer 2

o Compression fossils
o Casts and molds
o Permineralized fossils
o Unaltered/minimally altered remains

Question 3

What is preserved in compression fossils?

Answer 3

External structures

Question 4

How do compression fossils form?

Answer 4

Compression and compaction from overlying sediment, leaves behind a carbon film

Question 5

What do casts and molds preserve?

Answer 5

External and internal structures

Question 6

How are casts and molds formed?

Answer 6

Originates when buried remains decay. Molds consist of unfilled spaces; casts form when new material infiltrates the spaces and hardens into rock

Question 7

What do permineralized fossils preserve?

Answer 7

Internal and external structures (e.g., petrified wood)

Question 8

How do permineralized fossils form?

Answer 8

Dissolved minerals precipitate in the tissues of organisms buried in sediment

Question 9

What are unaltered remains?

Answer 9

Intact tissue and skeleton

Question 10

How are unaltered remains preserved?

Answer 10

Organic matter preserved in place not conduce to decay by bacteria and fungi (e.g., peat bogs, resin, ice, etc.) (little oxygen, protective environments)

Question 11

What are the three components that successful fossilization relies on?

Answer 11

Durability of material
Burial (usually in wet sediment)
Lack of oxygen

Question 12

Give examples of materials that are particularly durable for fossil formation. (5)

Answer 12

 Calcified structures (shells)
 Skeleton
 Exoskeleton
 Wood
 Leaves

Question 13

Why is burial important for fossil formation?

Answer 13

No exposure to oxygen or scavengers

Question 14

Why is lack of oxygen important for fossilization?

Answer 14

Most bacteria and fungi need oxygen

Question 15

What is fossilization biased by? (3)

Answer 15

Geography
Taxonomy
Temporal/age

Question 16

What geographical areas are fossils biased towards?

Answer 16

Lowland marine habitats

Question 17

Describe the taxonomy bias of the fossil record.

Answer 17

Marine organisms with hard parts

Question 18

How is fossilization biased with age?

Answer 18

Older fossils are rarer

Question 19

What area is said to have the best preservation of the earliest life forms?

Answer 19

Burgess Shale

Question 20

What is a whale?

Answer 20

o Living and extinct whales are all in the Mammalian order Cetacea
o Delimited based on cranial skeletal morphology, especially dentition and ear bones

Question 21

Are whales artiodactyl or non-artiodactyl ungulates?

Answer 21

 Astragalus of Artiodactyl ungulates is a double pully formation
 But whales lost astragalus
o Looking back…
 Ambulocetus (48-47 MYA)
* Earliest +/- complete whale
* Walked on land but spent time in water
* Swam much like an otter
 Artiodactyl Astragulus bones 40-6 MYA
* Pulley form
o Therefore, whales are artiodactyl ungulates, sister to hippos

Question 22

List the three geological eras.

Answer 22

Paleozoic (ancient life)
Mesozoic (middle life)
Cenozoic (recent life)

Question 23

What is the timeline of the Paleozoic era?

Answer 23

543-251 mya

Question 24

What are the periods within the Paleozoic era? (6)

Answer 24

Cambrian
Ordovician
Silurian
Devonian
Carboniferous
Permian

Question 25

What are the 3 periods within the Mesozoic era?

Answer 25

Triassic Jurassic Cretaceous

Question 26

What are the two periods within the Cenozoic era?

Answer 26

Tertiary Quaternary

Question 27

What were the major evolutionary events within the Cambrian period? (2)

Answer 27

Arthropod radiation 1st vertebrates

Question 28

What were the major evolutionary events in the Ordovician period? (3)

Answer 28

1st land plants 1st jawed fish Ends with mass extinction

Question 29

What were the major evolutionary events within the Silurian period? (2)

Answer 29

1st bony fish 1st vascular plants

Question 30

What were the major evolutionary events within the Devonian period? (3)

Answer 30

1st tetrapods 1st insects Ends with mass extinction

Question 31

What were the major evolutionary events within the Carboniferous period? (2)

Answer 31

1st winged insects 1st synapsids

Question 32

What were the major evolutionary events within the Permian period? (1)

Answer 32

Ends with mass extinction

Question 33

What were the major evolutionary events within the Triassic period? (4)

Answer 33

1st dinosaurs 1st mammals 1st dinosaur radiation Ends with mass extinction

Question 34

What were the major evolutionary events within the Jurassic period? (2)

Answer 34

1st eutherian mammals 1st birds

Question 35

What were the major evolutionary events within the Cretaceous period? (5)

Answer 35

2nd dinosaur radiation 1st flowering plants Flowering plant radiation Mass extinction Mammal radiation

Question 36

What were the major evolutionary events within the Tertiary period? (1)

Answer 36

1st primates

Question 37

What were the major evolutionary events within the Quaternary period? (1)

Answer 37

1st humans

Question 38

During which period did arthropod radiation occur and the first vertebrates were formed?

Answer 38

Cambrian

Question 39

During which period did land plants and jawed fish emerge?

Answer 39

Ordovician

Question 40

During which period did vascular plants and bony fish first emerge?

Answer 40

Silurian

Question 41

During which period did tetrapods and insects first emerge?

Answer 41

Devonian

Question 42

During which period did winged insects and synapsids first emerge?

Answer 42

Carboniferous

Question 43

During which period did dinosaurs and mammals first emerge?

Answer 43

Triassic

Question 44

During which period did eutherian mammals and bird first emerge?

Answer 44

Jurassic

Question 45

During which period did flowering plants first emerge?

Answer 45

Cretaceous

Question 46

During which period did primates first emerge?

Answer 46

Tertiary

Question 47

During which period did humans first emerge?

Answer 47

Quaternary

Question 48

List the five mass extinctions by period.

Answer 48

Ordovician-Silurian Devonian-Carboniferous Permian-Triassic Triassic-Jurassic Cretaceous-Tertiary

Question 49

What is a mass extinction?

Answer 49

events that lead to extinction >60% of species

Question 50

How many mass extinctions have occurred since the Cambrian era

Answer 50

5

Question 51

On average, how many species do we lose every million years?

Answer 51

20%

Question 52

Are we currently experiencing a 6th mass extinction?

Answer 52

Maybe o In recent times extinction rates do not approach 60% of known taxa o HOWEVER, in the last 100 years human population growth and habitat loss have accelerated o Biologists predict 100-1000x normal background rates