Mammology Exam 1

What makes mammals unique

mammals have hair, mammary glands, and three middle ear bones

How do we study mammals

From a taxonomical and fucntional perspective

Why do we study mammals

because they were important to early and modern humans as food, pets, recreation, health impacts, environmental impacts, mammal conservation, and to learn more about ourselves

what is the range of weight mammals can be

3 Oz to 160 tons

What is the range of mammal lifespans

well under a year to 200+ years

What is the range of mammalian gestation

12 to 770 days

mammalian evolution is

fluid and it changes

what are amniotes

fish like creatures that crawled to land 400 million years ago that arose from amphibian like tetrapods

Which animals can trace their liniage bac to amniotes

reptiles, birds, and mammals

What was the first step to settling on land

evolution of the cledoic egg with a hard shell porus to air

What are the groups of amniotes

Anapsid (no openings), diapsid (two openings), euryapsid (extinct two openings), and synapsids (two openings seperated by postorbital and squamosal bone)

What group of amniotes gave way to mammals

Synapsids

What continuum emereged in 166 mya where we define mammamls

articulation of the squamosal and dentary bone

what are the shared characteristics of amniotes (synapsids) and mammals

shared dentary bone, shared position of the ear capsule, shared staped, shared quadrate

If you believe in a polyphyletic origin of mamals what do you think (even though it is less supported)

polyphyletic origins of mammals believe egg-laying mammals originated differently from live-birth mammals because of large differences

How is monophyletic supported by the fossil record

shared characteristics of egg-laying and live-birth mammals such as articulation betweeen dentary and squamosal along with diphydont dentition with complex occulsion

What are characteristics of mammals that aren’t defining

live-births and the ability to thermoregulate,

A protrusion off the frontal bone that forms the posterior portion of the eye socket in many mammals.

Postorbital process

Which events led to the radiation of modern mammal lineages?

break up of the continents and the extinction of the dinosaurs

The zygomatic arch, when present, can be formed by which 3 bones?

jugal, squamosal, and sometimes the maxillary

Describe 3 important evolutionary trends in the evolution from amniotes to mammals

1. The 3 inner ear bones

2. Articulation of the squamosal and dentary

3. Diphydont dentition with complex occlusion

early mesozoic mammals were

squirrel-sized, lived in trees, nocturnal, likely insectivores, and spread far apart

what is an occipital condyle

projection on either side of the hole that connects their spine and their legs beneath them

what are the charcteristics of mammals soft tissues

hair, 4 chambered heart with functional left aerotic arch, biconcave erythrocytes enucleate, mammary glands, and muscular diaphragm

What are the skeletal characteristics of mammals

a single dentary bone, 2 occipital condyles, 3 inner ear bones, epiphyses (growth plates) on long bones

What are biconcave erythrocytes, enucleate

the shape of our blood cells have two indentations making them more efficient at carrying oxygen and no nucleus

What can dentition reflect

trophic level and feeding specialization

the basic tribosphenic dental pattern

is well adapted for eating insects and most adaptations are rendered from this

what are the 3 bones teeth can occur in mammals

premaxilla, maxilla, and dentary

What is dentine and what is it protected by?

dentine is in the middle of the tooth in both crown and root and is the growing portion of the tooth. It is protected by the enamel

what can centium be used for

the protective layer under the tooth and can be used to age an animal

where are th nerves and blood cells found in the tooth

pulp cavity

what teeth never stop growing

open-rooted teeth with enamel only on one side

what are the layers of the epidermis

stratus corneum, stratus granulosum, stratus germatavium, melanocytes

what makes up the dermis

connective tissue, blood vessels, hair tissues, and sensory endings of nerves

what does the hypodermis consist of

primarily fatty tissue with some vascular tissue and structures for temperature upkeep

what layer of skin does the papilla protrude into

hypodermis

what does the erector pilli do

helps hair stand up for insulation and to look bigger

what are the structural layers of hair

medulla, cortex, and cuticle

what is the difference between angora and definitive hair

angora grows forever while definitive reaches a certain length and stops

what type of hair is vibrissae

whiskers that are long stiff hair with definitive growth

what are the three types of guard hairs (over hairs)

spines which are stiff and enlarged guard hairs with definitive growth, bristles which have angora growth and are generally long, and awn with weak base and stiff ends that exhibit definitive growth

what are the three types of under hair which is used for insulation

wool that is long and soft and exhibits angroa growth, fur which is closely spaced fine short hairs with definitive growth, and villi which have definitive growth and are short and fine

what melanin is responsible for blonde hair, which is responsible for black

pheomelanin is for red and yellow hair, while eumelanin is responsible for black and brown

what are agouti hairs

long hairs appear eumelanin and short appear phenomelanin

what is Gloger’s rule

places with more UV exhibit more pigmentation

what are countershading, disruptive coloration, and cryptic coloration used for

to avoid being targetted and detected

what are the different types of molting

postjuvenile molting, annual molting, and seasonal molting

what are the different types of glands

sweat glands, mammary glands, sebaceous glands, and scent glands

arboreal arboreal locomotion has what kind of digits

opposable digits and prehensile tails

gliding locomotion makes use of what feature

patagium which is skin between hind and forelimbs that act as a sail

what is a fusiform body shape

a torpedo shaped body

what is the difference between eccrine and apocrine sweat glands

eccrine is odorless and not all mammals have this while apocrine is odorful and thicker with pheromones

what gives claws, nails, and hooves a curved appearance

the straight unguis on top and soft subunguis underneath

what are head ornaments used for

horns or antlers that only occur in ungulates and are used for ornamental, sexual selection , or defense

what defines true horns

an inner core of bone and a sheath of keratenized material that never branch and never shed

what does the axial contain

the vertebral column and ribs

what does the appendicular conatain

limbs and stuff

what are the types of muscles of mammals?

striated (voluntary muscle), smooth (involuntary muscle), and cardiac (heart muscle)

what is ambulatory locomotion

metacarpals and metatarsals unmodified with limbs equal length

what is cursorial locomotion

increased limb length and stride to allow very high speed usually for digitgrades or ungulagrades

what is the difference between plantigrade, digitgrade, and ungulagrade

plantigrade walks on heels, digitgrade walks on toes, and ungulagrade walks on nails (hooves)

what is saltitorial locomotion

enlarged hind limbs that are good at zig-zagging and either spring (on all 4s) or ricochet (bipedal)

what are fossorial adaptations

reduction of external body projections, development of valvular body openings, reduction of vision, enlargement of the forefeet and claws, reduction in the length of the tail and neck

what is the gradient of aquatic adaptations

semi-aquatic (mostly land, forelimb propulasion), semi-aquatic (mostly aquatic, either propulasion), fully aquatic (back propulsion)

what are the major skeletal modification of aerial motion

bones and forelimbs elongated, kneeled sternum, knee directed backwards, calcar, and slender and light bones

why do mammals require food

because they require energy and nutrients, especially to maintain their high body temperature

what does insectivores intestines look like

simple without complex folding

what type of teeth do insectovores have

teeth with sharp cones or blades with specialized lower inscisors

arboreal locomotion is adapted for what

tree living

scansorial locotmotion

has sharp claws and fluffy tails like squirrels

what are the types of insectovores

aerial, terrestrial, and semi-aquatic

how many orders are insectovores

9

what do carnivores intestines look like

small stomachs without complex folding but a secum is sometimes present to alow more fermentation

carnivores jaws are designed for what motion versus herbivores which are designed for what other motion

carnivores have strength in up and down while herbivores are strong side to side

what specialized teeth do carnivores have

sharp inscisors and canines along with carnassials

what do herbivore intestines look like

lots of complex folding and a medium to large secum

what is brachiation locomotion

swinging locomotion from arms that are often

Why is foods and feeding important

mammals require energy and nutrients especially since they have high body temperatures, size variability, and energy content variability

what are the dietary adaptations of insectovores

small intestines no cecum

What does the dentition of insectovores look like

sharp cone or blade teeth with specialized inscisors

what are the types of insectovores

aerial, semi-aquatic, and terrestrial

what are the dietary adaptations of carnivores

simple stomach, occasional cecum, large and powerful temporalis muscle

What does the dentition of carnivores look like

sharp inscisors and canines, carnassials, and crushing molars in canines

What orders exploit carnivory

Carnivora, chiropetra, and marsupial dasyurids

What are the types of carnivores

terrestrial, aerial, and aquatic

What is sanguinivorous

blood-eating diet, often have reduced rostrum, sharp incisors, and straw like tongue

what is piscivorous

fish eating diet

what are the types of herbivores and give examples of each

browsers like deer or elk, grazers like bison, and gnawers like voles

what mussel is very strong in herbivores that helps with their side to side jaw motion

masseter

what is the dentition of herbivores

reduced or absent canines, lophadont dentition, with broad molars

what are the two digestive stratagies of herbivores

foregut fermentation (ruminant) and hindgut fermentation (non-ruminant)

what direction does a ruminat herbivores digestive system go

both directions so it is digastric

what are the digestive adaptations of a ruminant herbivore

large 4 chambered stomach, folding intestines, large cecum

Describe the path food goes in foregut fermentation

1st to the rumen →goes back into the mouth → 2nd chamber is reticulum with its honeycomb structure → 3rd chamber omasum with folding smoothed walls →4th chamber abomasum which has stomach acid and was the original stomach → intestines → rectum

what is the cellulose utilization comparison of ruminant to nonruminant herbivores

ruminant has 60% while nonruminant has 45%

About how long does foregut fermentation take and how much of the available food do they gain

takes around 72 hours and only gain like 70% of food available

what are the digestive adaptations of hindgut fermentation

digestive enzymes in salvia, large cecum, most nutrietn absorption happens in intestines, monogastic direction (one way)

what are some specializations in herbivory

grainivory (seed eating), folivery (leaf eating), frugivory (fruit eating)

how many mammals have some level of omnivory

most