Mammology Unit 1

What is the definition of mammalology?

science that utilizes knowledge and investingting by making observations and posing questions and testing through experimentation.

Why is mammalogy important?

Economically, socially, and environmrntal/ecological

Why is mammalogy economically important?

prey items, hunting, and livestock

Why is Mammalogy Sociallly and culturally important?

• pets

• predators on humans

• psychological aspects of humans (understand other mammal behavior understand ours

• pest control

• understand transmit of diseases

Why is mammalology important enviromentally/ecologically?

• Understand evolution

• understand ecoligcal and behavioral conservation

• mammals are often keystone species

What is the taxonomy for Mammals?

Dmoain Eukarya, Phylum Chordata, subphylum vertebrata, class Mammalia

How many species are recognized as mammals? what are the two animals that are majority of species?

over 6,800 species currently recongnized, majority are bats and rats

What are shared evolutionary traits of all mammals?

hirsute, lactogenic, endotherms

What are the soft anatomy features of mammals?

• hair

• mammary gland

• endothermy

• viviparity (except monotremes)

• 4 chambered heart

• enucleated red blood cells

• muscular diaphragm

• no renal portal system

• complex integumentary structures

• nitrogenous waste excreated as urea

• complex facial dermal muscles

• Extreme expansion of the cerebral cortex of the brain

What traits for mammals that helps oxygen levels?

• 4 chambered heart

• enucleated red blood cells

• muscular diaphragm

What is the evolutionary benfit to having complex facial dermal muscles?

Whiskers having more sensory inputs to help navigate the enviroment

What are the two ways shared mammal traits are split into? What is pro and con of each?

Soft and Hard anatomy

What is the Renal portal system comparison between mammals and other tetrapods/fish? Why is it important?

The mammal renal portal system in mammals, compared to tetrapods and fish, has less branching main veins/arteries or “pitstops” on the route to the kidneys. This is due to mammals already more efficent oxygen systems so “pitstops” would have an inverse efficiency in carrying oxygen. Overall it is an important distinction due to faster and more effective movement of blood.

What type of anatomy are more efficient for identifying fossils?

Hard Anatomy

What is the trait that helps mammals have a larger rotation radius in the neck?

Double occipital condyle

What is the Epiphyseal line on long bones? Why is it important?

a line visible on the bone that is the remnants of the completed growth plate. Goes from cartilage of growth plate to solid bone. Important because it helps to identify adolescents in mammals

What does monophyletic mean?

taxon that includes all organisms desscended from a single most recent common ancestor

What does polyphyletic mean?

Taxon that is composed of unrelated organisms descended from more than one common ancestor (not most recent common ancestor), distantly related

What does paraphyletic mean?

taxon does not include all organisms descended from a common ancestor, talks about portion of a group

What are different ways a phylogenetic tree is built or constructued?

• synapomrphy

• traits

• sympleisiomorphy

• homology

• analogy

• morphology

• karyology

• molecular data

What is karyology?

isolation of chromosomes; infer relationships on morphology of chromosomes

What is an evolutionary trend?

directional change through time withing a lineage

What is the differnce between homologous vs Analogous structures?

Analogous are structures that have similar functions but have no ancestor shared it was an independent evolution.

Homologous structures that are derived traits from a shared ancestor that may not retain similar functions.

What is convergent evolution?

evolution of traits based on similar environmental cues and functions

What implications does continental drift have on the earth?

• position and orientation affect climate

• position and orientation affect circulation of the oceans

• influences mammalian evolution and diversification

What were major events in paleozonic era?

• devonian period had first land tetrapods

• paleozoic first vertbreates and land plants, first jawed fish

• early carboniferous 1st ancestor that led to mammals

• permian period mountain building, Permo-triassic crisis (largest extinction event)

What period had the first jawed fish?

paleozic

What were major events in the mesozoic era?

• triassic: warming period, age of dinosaurs and mammals,first part of vicariance due to contients breaking up

• Jurassic alatic and pacific ocean formations, higher water levels, oceans start to seperate continents

• Cretaceous: high water levels, no ice caps, marsupials in north america, placentals in asia

• K/T boundary: organism diversification high, second building of rockies, inland seas disappear, asteroid impact caused extinction from dust clouds, volcanos, or microbes

Which period was the major diversification mammals (age of mammals)?

Triassic

What evidence do we have for the aesteriod impact in the K/t boundary?

iridum in soil profile 

What are major events for cenozoix era?

• Eocene: himilayans formed, grassland and grass-eating mammals, India runs into asia, marsupials dispersing due to landmass connection

• Glacial maximum: rapid coolign period, incremental melting and glaciation (mammal movement)

• late creaceo

How do glacials effect mammals?

• Move adapt or go extinct

• creates species pump

what is biogeography?

study of geographical distributions of living things in time and space

What are questions does biogeography ask?

What does biogeography realms indicate for mammals?

various regions that are unique across the globe and create niches for mammals

What is the gondwana effect?

What were dispersal methods due to continents?

• corridors

• filter zones

• sweepstakes routes

What are barriers to dispersal?

oceans, deserts, mountains, climate, and vegetation changes, rivers

What happened to marsupial dispersal during the middle eocene?

Marsupials dispersed to south america, antarctica and australia sea levels rise and cut off dispersal route

What is the pattern of mammal diversification in North America?

Latitudial gradient with higher diversification towards equater

What is other data history is used to predict biogeography of mammals in North America?

• geologic history

• floral history

• glacial history

How did geologic history influence mammal biogeography in North America?

Creation of Basin and Ranges by tectonic plate pulls caused barriers to dispersion, which caused isolation of species), Ranges effect water patterns which effect niches (think warm and cool side of mountains)

How did glacial history effect mammal biogeography in North America?

•  change dispersal routes: caused kettle lakes, ice dams and Pluvial lakes

• change orintation, location, or extent of their landscape

• effect climate; local precipitation, local temperature

What are kettle lakes?

as glaciers move they scrap away land causes water to fill dips and creates lakes

What are ice dams?

Ice from glaciers cause natural redirction of water through dams

What are Pluvial lakes? What is an example?

lakes that are reminents during pluvial or wet periods, Great Salt Lake

What is a species pump?

cycle of repeated isolation and reconnection of species

Barriers effects are ____ by species.

variable

How do islands effect biogeography?

• bigger patches = more species

• once on an island, extinction is tied to patch size

What is the full classification for mammals?

Domain: Eukarya

Kingdom: Animalia

Phylum: Chordata, Craniata

Subphylum: Vertebrata, Tretrapoda, Amniota

Class: Mammalia

What are traits for Chordata?

• bilateral body

• notochord

• dorsal neural tube

• pharyngeal gill slits

• post anal tail

• endostyle

What is a trait that connects mammals and reptile as a closer sister taxa?

Amniotic egg

What is synapomorphy of all mammals?

Synapsod condition in the skull

Who were the first amniotes to radiate in terrestrial habitats?

Synapsids

When did synapsids first appear?

Paleozoic- Late carboniferous

When did synapsids first become the most abundant?

Permian- early mesozoic

When did synapsids become top carnivores?

Triassic

What are the 3 large groups of ancestral lineages that gave rise to mammals?

• therapsida

• pelycosauria

• synapsida

When did the pelcosauria live?

carbniferous to permian

Pelycosauria

• paraphyletic

• dimetrodon- sail back

• new form of eating by dismember prey, came with new muscle attachment

• heterodont dentition

What group gave rise to therapsids?

dimetrons

Therapsids

• replaced pelcosaurs

• “more mammal-like”

Synapsida

• small and agile

• tied to water even with amniote egg

• top predators 

What are major gorups of therapsids?

• Dinocephalia

• anomodontia

• theriodontia

What were traits that moved ancestoral species to more “mammal-like”?

• enlarged temporal opening

• lower temporal bar

• sagittal crest with zygomatic arches

• jaw joint with occiput

• upper canine enlarged

• heterodonty and diphyodonty

• hard secondary palate

• upright limb posture

• deep acetabulum

• shortened feet

• loss of lumbar ribs

• shorter tail

Dinocephalia

• large in size

• interlocking incisors

• dowturned facial region

• lower jaw with sumple hinge movements

• pachyostosis (thickening of bones in skull)

• headbutting mates

Anomodontia

• toothless, beaks for food instead, upper tusks

• herbivores

• temporal opening at back of skull enlarged 

• sliding jaw

• successful group due to skull and jaw changes

Theriodontia

• land dwelling

• predatory, some herbivors

• versatile jaw movement and more precise dental occlusion, wider gape

• lower incisors to pass entirely behind upper incisors

• long canines in carnivores 

• change in ears allow for better hearing

Cynodontia

• most successful of all therapsids

• small creatures to evade predation

• nocturnal

• dependent on hearing and smell

• heterodonty lead to carnivory

• nasal turbinates

• two occipital condyles

• hard secondary palate

• warm-blooded

• hairy

Which group do cynodontia belong to?

therapsida, theriodontia

Which group and family gave rise to all mammals?

Cynodontia Galesauridae

Galesauridae

• first mammals with dentary squamosal jaw articulation

• diaphram

• long body with distinct thoracic and lumbar regions

• hard secondary palate

• large brain for olfactory and auditory bulbs 

What does dentary-squamosal jaw articulation indicate?

true mammals seperates them from synapsids

What is important for dentary-squamosal jaw articulation?

makes a single lower jaw bone which increases strength of jaw

What time period does most mammals history occur?

Mesozoic

What is the importance of squamosal and dentary changes in mammals?

transmission of sound and jaw articulation

What is the main difference between early cynodont jaws and early mammals?

loss of bones in jaw for articulation to inner ear

What bones in the jaw are lost between cynodonts and early mammals?

• quadrate

• angular

Explain how bones in jaw changed from cynodonts to modern mammals.

cynodont lower jaw had dentary, angular, typanum, and articular. To early mammals dentary bone enlarged, angular lost and made to quadrate in inner ear, typanum expaned to add tympanic bone. From early mammal to modern mammal all bones lost in lower jaw move to inner ear, dentary expands to only bone, tympanic bone becomes typanic ring, quadrate becomes incus.

What is a modern mammal that supports movement of jaw bones to ear?

possums

How did jaw bone changes effect muscle attachment?

created masseter muscles, added more and thicker muscles

Why is the secondary palate important in therms for evolution?

• seperation of oral cavity and nasal cavity allows for eating and breathing

• allows for succling by creating negative space

what are bones that form secondary pallate?

premaxillary, maxillary, and 

What is the order of evolution for lactation in mammals

• lactation

• nipples

• secondary palate

• delayed formation of diphyodont teeth

What are the two major groups of class mammalia?

• prototherians

• therians

What are the major groups of prototherians?

• Morganucodontidae

• docodonta

• multituberculata (allotheria)

• monotrmata (prototheria)

What are major groups of therians?

• symmetrodonta

• eupanototheria

What are major groups for eupantotheria?

• dryolestidae

• peramuridae

• boresophenida

• methatheria

• eutheria