Mammal Evolution and Characteristics
What are Amniota and when did they first appear?
- Early Carboniferous Period -They are animals with Cleidoic eggs (shelled eggs) -common ancestor of all mammals and reptiles
What are synapsids?
Mammals
What group of muscles do herbivores use to chew?
Masseter
When were most extant families recognized to have existed?
Miocene
What were the first herbaceous/omnivorous mammals called?
Multituburculate
Definition of Edentulate
No permanent teeth
Definition of Edentate
No teeth
When was the great mammal radiation?
Paleocene Epoch of Tertiary period (65 mya)
What are carnassial teeth?
Sectorial shearing teeth (dogs and cats)
What group of muscles do carnivores use to chew?
Temporalis
What is Cementum
The covering root of teeth that allow us to age them
What is the diastema?
The gap between the tooth row, such as in deer
These carnivorous creatures were the first "mammals"
Therapsida
When did mammals first appear on Earth?
Triassic Period
True or false - Walrus tusks are canines
True
True or false: Mammals did evolve from reptiles
True, they shared a common ancestor
What are anapsids?
Turtles
What does diphyodont mean?
Two sets of teeth
Do rodents have open- rooted teeth?
Yes
True or False - Narwhal tusks are canines
False, they are incisors
True or False- Elephant tusks are Canines
False, they are incisors
What are diapsids?
Lizards and Snakes
What animals have Homodont teeth?
-Armadillos, whales
6 Characteristics of modern mammals (REMEMBER - Hairy Enchiladas Make Mrs. Piggy Die)
-Hair -Enucleated blood cells -Mammary glands -Muscular diaphragm -Placenta in Therians (and poorly developed in others) -Dentition
Benefit of soft tissue changes in mammals
-Increased metabolism efficiency -Better food gathering and processing methods -Increased auditory acuity
What makes a mammal jaw different from a reptiles?
-Mammals have an enlarged dentary bone instead of multiple lower jaw bones
What the 2 infraclasses of Theria?
-Metatheria (Marsupials) -Eutheria ("Placental" Mammals)
What are the 3 subclasses of mammals?
-Prototheria (monotremes) -Multituburculate (Extinct) -Theria
Anatomical trends leading to mammals and seperating them from reptiles (REMEMBER- Tigger Didnt Meet Christopher Later Since pooh Fell inTWO Honey)
-Temporal opening enlarged -Dentary bone enlarged -Middle ear resulted from remaining jaw bones -Carpal and tarsal bones reduced -Limbs rotated 90 degrees -Soft palate for breathing while eating -Flexibility increased due to loss of ribs -Two occipital condyles for improved head movement -Heterodont dentition
What were the 3 subcontinants called after the breakup of Pangaea?
-West Godwana -East Godwana -Laurasia
When were most extant orders recognized to have existed?
Eocene
What teeth in marsupials are diphyodont?
Last premolars