Chapter 23: History Of Life

Question 1

Stratigraphy

Answer 1

• Study of rock layers
• Layers reveal patterns of evolution and age of fossils
• Fossils toward the top are younger and are more similar to modern organisms

Question 2

Radiometric dating

Answer 2

-measures the amount of radioisotopes and daughter element, tells the age of material

Question 3

Fossil record

Answer 3

• how long animals and plants lived in the past

- how they are related to each other

Question 4

Magnetic field

Answer 4

Related the age of rocks to patterns in earths magnetism

• magnetic poles move and can reverse themselves
• iron on rock can align w/ magnetic north and preserves the record of magnetic field at the time

Question 5

What is continental drift? How does it explain environmental change and the distribution of organisms/fossils?

Answer 5

• continental drift is land masses changing position overtime due to plate tectonics moving
• altered ocean patterns, heat in the atmosphere, and formed mountains
• explains why same fossils are found in different continents

Question 6

Why is continental drift considered a driving force of evolution

Answer 6

Animals had to adapt to the change of environment in order to survive

Question 7

What are plate tectonics? How does it tie into continental drift?

Answer 7

-mechanism to continental drift
-sea floor spreading/ rifts: new rocks comes from earth interior and pushes the old rock outward
Subduction zones/trench: old rock plunged into trench and remelts into earths interior and one plate is pushed under the other

Question 8

How does a change in the geology of earth affect the environment? How does it affect organisms

Answer 8

• it affects ocean circulation/ patterns,global climates, glacial patterns
• glaciers form(glacial advance) causes cooler climates
• glaciers melt releases water causes warmer climates
• change in ocean depth/sea level
• animals have to adapt

Question 9

Climate vs weather/ causes of current climate shift

Answer 9

• weather are daily events at a specific location(changes fast)
• climate is long term and averages over seasons at a specific location (changes slowly)
• current climate is rapid change organisms don’t have time to adapt, temperatures fluctuate due to negative impacts on environment

Question 10

Major climate/ environmental disruptions/ how do they change environment

Answer 10

-volcanoes: the larger the eruption the more effect on life. They block sunlight from plants(affects the food chains) lower global temp, Change in weather patterns
Meteor impacts: brought new elements to earth, caused the K-T extinction

Question 11

What is the K-T(Cretaceous-Tertiary) extinction event? How did it change the environment and what is the evidence?

Answer 11

• meteor that killed the dinosaurs by blocking sunlight heated debris caused massive fires across earth and tsunamis
• the evidence is there is an iridium layer that can be found by Mexico, layer of soot w/ composition, SUDDEN DISAPPEARANCE OF ORGANISMS not found in the fossils or strata

Question 12

What are the 2 eons

Answer 12

Precambrian and Phanerozoic

Precambrian: Snowball earth, seas and continents were covered by ice life was confined to warm areas limited diversity

Phanerozoic: we live in this period oxygen concentrations increased, continents formed many species appeared(Cambrian explosion)

Question 13

Order of era and periods

Answer 13

Eras: Paleozoic, Mesozoic, Cenozoic

Periods: (first to last) 
Cambrian 
Ordovician 
Silurian 
Devonian 
Carboniferous 
Permian 
Triassic
Jurassic 
Cretaceous 
Tertiary (ice age)
Quaternary (current)

Question 14

Cambrian

Answer 14

• life is in the ocean
• restricted to microorganisms
• most diverse were crustacean arthropod (trilobite species)

Question 15

Ordovician

Answer 15

• land has no multicelular life
• evolutionary radiation of marine life (mollusks and brachiopods)
• was ended bu the Ordovician mass extinction( massive glaciers formed, 75% of population extinct)

Question 16

Silurian

Answer 16

• animals fed above ocean floor
• jawless fish
• first vascular land plants
• first terrestrial Arthropods( scorpions and millipedes)

Question 17

Devonian

Answer 17

• accelerated rate of evolutionary change
• jawed fish some with bony armor
• forests on land
• first seed producing plants
• first insects
• early terrestrial vertebrates
• Devonian mass extinction( 75% of marine animals, 2 large meteorites)

Question 18

Carboniferous

Answer 18

• tropical areas and swamp forests
• marine areas: crinoid meadows
• insects developed flight
• large amphibians
• amniotes

Question 19

Permian

Answer 19

• Pangea
• amniotes 2 groups (reptiles and lineage that led to mammals)
• mammal like reptile (dimetrodon)
• Permian mass extinction (the largest mass extinction event, volcanic eerily ions, low oxygen, animals could not live in land, glaciers)

Question 20

Triassic

Answer 20

• Pangea starts to break up
• conifers( seed producing plants dominate)
• frogs and turtles
• more reptiles
• mass extinction event ( meteor strike loss of 65% of species)

Question 21

Jurassic

Answer 21

• Pangea= 2 continents: Laurasia (north) and Gwandana(south)
• first lizards
• Dinosaurs dominated
• first mammals
• first flowering plants

Question 22

Cretaceous

Answer 22

• laurasia and Gwandana break into continents we know today
• first snakes
• everything diversified
• mass extinction (K-T caused by meteorite)

Question 23

Tertiary

Answer 23

• grassland spread
• ungulates
• flowering plants developed non woody forms
• rodents, hoofed animals, marsupials, primates first appeared in North America

Question 24

Quaternary

Answer 24

• 4 major and 20 minor ice ages
• evolution of hominoid lineages
• major civilization current time