1. Mammals Evo Final Flashcard Set

Front 1

A major extinction that included all dinosaurs except birds occur at____1____ end of the ___2___

Back 1

1. K-T boundary
2. Mesozoic

Front 2

Major Current theories for extinction of Dinosaurs, (2)

Back 2

1. World Wide Cooling of Climates
2. Impact of a large meteorite whose dust may have caused sudden cooling and lack of sunlight.

Front 3

Evidence for meteorite impact in K-T boundary rocks: (4)

Back 3

A. High iridium spike in boundary clays
B. Possible impact site Yucatan Mexico
C. Mircrotektites
D. Shocked Quartz

Front 4

High iridium spike in boundary clays is :

Back 4

important because iridium is otherwise rare on Earth, but concentration of it is found at the clay boundry

Front 5

Possible impact site:

Back 5

Yucatan, Mexico

Front 6

Shocked Quartz is

Back 6

crystal matrix deformed under pressure

Front 7

Mircrotektites

Back 7

hardened blobs of molten meteorite thrown into atmosphere

Front 8

Extinction and opportunity

The evolution of synapsids has been strongly affected by major extinctionsey:

Back 8

1. At the end of the Paleozoic (Permian-Triassic boundary)
2. The K-T boundary. When all dinosaurs except birds went extinct at the K-T boundary,
mammals had the opportunity to begin an adaptive radiation that continues today.

the only snapsids to survive the triassic were mammals

Front 9

Synapsids

Back 9

Major defining feature is the presence of a single pair of positioned temporal fenestrae (openings) on the skull behind the eye

Front 10

Early synapsids

Back 10

The best known of these included several groups of "sail backs", with a membrane covering elongated vertebral spines

Front 11

Early synapsids

Probable function of "sail backs" structure:

Back 11

increased their body surface area for picking up and getting rid of heat by this membrane-covered structure.

Front 12

Therapsids

This more mammal-like group included:

Back 12

1. numerous herbivores
2. several groups of carnivores

Front 13

Therapsids:

The temporal fenestrae are typically__1__ in therapsids

Back 13

1. larger

Front 14

Mammals - evolved from carnivorous therapsids called __1__ in the late Triassic

Back 14

cynodonts

Front 15

Important Mammal Characters (9)

Back 15

1. Hair for insulation and mammary glands for nutrition of young.
2. Differentiated teeth for complex chewing
3. Limited tooth replacement.
4. A single bone in the lower jaw, the dentary.
5. Three bones in the middle ear to improve hearing
6. Secondary Plate
7.Diaphragm
8. Posture less sprawled and increasingly upright
9. Enlarged brain

Front 16

Important Mammal Characters

1. Hair for insulation and mammary glands for nutrition of young


in refernce of fossils

Back 16

Neither structure is usually preserved in fossils, though fossil hair has been found in a few special cases.

Front 17

Important Mammal Characters

2. Differentiated teeth for complex chewing: (4)

Back 17

1. Incisors
2. Canines
3. Premolars
4. Molars

Front 18

Important Mammal Characters

4. A single bone in the lower jaw, the dentary.

Back 18

This bone articulates with the squamosal on the skull to form the mammalian jaw joint.

Front 19

Important Mammal Characters

5. Three bones in the middle ear to improve hearing

Back 19

1. malleus and incus, hammer?

2. The transition of the articular and quadrate to malleus and incus is well documented through both fossils and embryological development of modern mammals

Front 20

A classic case of evolutionary change in homologous structure:Diarthrognathus

Back 20

a fossil theraspid close to mammals with two jaw joints

Front 21

Important Mammal Characters

6. Secondary Plate

Back 21

1. separates the air passage from food during chewing, thus allowing mammals to eat and breathe at the same time

2. helpful for the higher food and oxygen requirements necessitated by endothermy (metabolically controlled constant temperature)

Front 22

Important Mammal Characters

7. Diaphragm

Back 22

1. makes breathing more efficient

(a shortened ribcage indicates this in fossils)

Front 23

Important Mammal Characters

8. Posture less sprawled and increasingly uprightng

Back 23

walking, able to use forearms for other purposes

Front 24

Important Mammal Characters

9. Enlarged brain

Back 24

1. Neocortex: the anterior region
2. greater intelligence

Front 25

Mesozoic Mammals

Back 25

1. Most remained small
2. probably nocturnal insectivores to the end of the Cretaceous
3. developed unusual adaptations respectively for digging, gliding, beaver-like swimming, and rodent-like feeding