Lecture on Mammalia - Overview and Characteristics

This set of flashcards covers key concepts and terminology related to the overview and characteristics of Mammalia as presented in the lecture.

Mammalia

A class of endothermic vertebrates characterized by the presence of hair, mammary glands, and differentiated teeth.

Endothermy

The ability of mammals to generate heat from within the body, differing from being homeothermic which refers to maintaining a constant body temperature.

Diphyodont

Refers to mammals that have two sets of teeth in their lifetime: deciduous (milk) teeth and permanent teeth.

Thecodont

A dental structure where teeth are rooted in sockets in the jaw bone, characteristic in mammals.

Viviparous

Refers to animals that give birth to live young instead of laying eggs; most mammals are viviparous.

Oviparous

Refers to animals that lay eggs; monotremes like the echidna and platypus are oviparous.

Cranial fenestrae

Openings in the skull that accommodate muscle attachment and reduce the weight of the skull.

Anapsid

A term describing a skull type without temporal fenestrae, characteristic of some extinct reptiles.

Diapsid

A term describing a skull type with two temporal fenestrae, characteristic of reptiles such as dinosaurs and birds.

Synapsida

A group of amniotes characterized by having a single temporal fenestra; ancestors of mammals.

Tribosphenic molar

A type of molar tooth in mammals characterized by a specific arrangement of cusps that allows for effective slicing and grinding.

When did mammalia originate?

The Triassic (around same time as dinosaurs); after K-T extinction

Why has there been a resurgence in mammal species as of 2010?

Genetic sequencing

What species accounts for 40% of all mammals?

Rodents

What species accounts for 22% of all mammals?

Bats

What species accounts for 8% of all mammals?

Primates

Characteristics of mammalia (13)

endothermy, hair, skin glands, ears w/ pinnae, solid exoskeleton, differentiated dentition, determinant growth of bones, highly differentiated vertebral column, differentiated skull, muscular diaphragm to support negative pressure to lungs, 4-chambered heart, anucleate red blood cells, most are viviparous

Function of skin glands

Serve to produce oil, scents, facilitate cooling (e.g. mammary, sweat, musk, etc.)

Are mammal limbs arranged beneath the body or splayed out?

Beneath the body (splayed out = reptiles)

What differentiation is there in mammalian teeth?

Incisors, canines, premolars, molars

How many sets of teeth are there in mammals?

2 (diphyodont)

Define thecodont

Well-rooted