Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ANSC2005 > Mammals > Flashcards

Mammals Flashcards

(42 cards)

Start Studying
1
Q

What is a mamma?

A

Tetrapods, Amniotes, Synapsids

Key features:

  • Endothermic
  • Respiration with a muscular diaphragm
  • Hair that provides insulation
  • Mammary glands
  • Differentiation of teeth
  • Refinement of ear bones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Tetrapod

A

A four-footed animal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Synapsid

A

mammals and “mammal-like reptiles” with modifications to skull and skeleton indicative of increase in metabolic rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Amniote

A

An animal that develops embryonic membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Reptiles vs mammals

A

Retiles have one ear bone (Dimetrodon)

Mammals have multiple ear bones (Morganucodon)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3 mammalian groups that remain today

A

Monotremes - egg laying mammals

Marsupials - Give birth to small, embryonic young, have pouch

Placentals - Give birth to fully develop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Australian mammal origins

A

Monotremes and marsupials descend form ancestors that were on the continent when it detached from Antarctica

Eutherian mammals (rodents) came by island hopping from Indonesia and New Guinea via boats and floating vegetation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

2 groups of marsupials

A

Australidelphia: Found in Australia & New Guinea

Ameridelphia: Found in the Americas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Australidelphia (marsupial) four orders:

A

Dasyuromorphia
Peramelemorphia
Diprotodontia
Notorycytemorphia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Marsupial morphology

A

Diverse group (range of sizes)

Morphology reflects function - e.g. dite, locomotion

General mammalian features with modification unique to marsupials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Polyprotodont

A

Multiple pairs of lower incisors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Diprotodont

A

One pair of incisors in the lower jaw

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

-dactyl:

A

A suffix that indicates “fingers or toes of a particular type or number”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Syndactyly

A

The normal occurrence of having two or more fused digits in a mammalian species

In many marsupial species syndactyly is common between digits II and III on the hindfoot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Order: Dasyuromorphia

A

Carnivorous or insectivorous marsupials

Polyprotodont dentition
• Three pairs of ~ equal-sized lower incisors
• Numerous, sharp teeth
• Numbat – teeth reduced in size and fewer incisors

Hindfoot has 5 separate toes (+/- digit 1): NO syndactyly

Forelimb length = hindlimb length

Non-prehensile tail

E.g. Tasmanian devil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Order: Peramelemorphia

A

Bandicoots and bilbies

Omnivorous marsupials

Long pointed heads and compact bodies

Polyprotodont dentition
- Three pairs of ~ equal-sized lower incisors (not as pointed as dasyuroids)

Hindlimb large with 4 toes:
• Syndactyly digit 2 and 3 fused, digit 1 absent/reduced

Forelimb shorter than hindlimb (→ bounding gait) with well-developed claws (digging)

Non-prehensile tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Order: Notoryctemorphia

Study These Flashcards
A

Marsupial mole

Ancient lineage with just two species (Southern and Northern marsupial mole)

Subterranean habit (occurring under the earths surface)
- Unusually low metabolic rate and highly variable body temperature – adaptation for a burrowing lifestyle?

Blind (eyes = non-functional buds beneath the skin)

Absence of external ears, heavily keratinised skin on nose

Tubular body form, with rear-ward opening pouch (females)

Forelimb short and powerful, digits 3 and 4 have developed into large, spade-like claws (digging)

Tail – shortened and immensely strong

Insectivorous/carnivorous – polyprotodont dentition

18
Q

Order: Diprotodontia

Study These Flashcards
A

Koala, wombats, possums and macropods

Most specialised and recently evolved Order ~120 species

Mostly herbivorous or omnivorous

All have diprotodonts dentition

One pair of lower incisors, with NO lower canine teeth

Hindlimb syndactyly digit 2 and 3 (fused together, except at the tip)

Forelimb: Ability to oppose first two digits in most arboreal species (not in wombats, kangaroos and wallabies)

Non-prehensile tail (yes in possums)

Very successful group with two subforms:
•Vombatiformes (koalas and wombats)
•Phalangerida (possums, rat-kangaroos and kangaroos)

19
Q

Diprotodontia: Sub order - Vombatiformes

Study These Flashcards
A

No tail

Adaptation for climbing (koala) or burrowing (wombats)

Rear-ward opening pouch

20
Q

Diprotodontia: Sub order - Phalangerida

Study These Flashcards
A

Morphologically very diverse

Four principle lineages that can be viewed as superfamilies:

  • Phalangeroidea (Brushtail possums, scaly-tailed possum)
  • Burramyoidae (pygmy possums)
  • Petauroidea (ringtail possums, gliders)
  • Macropodoidea (kangaroos, wallabies and kangaroos)
21
Q

Phalangerida - Superfamily Phalangeroidea

Study These Flashcards
A

Noticeably short face, eyes directly forward

Long, prehensile tail

Arboreal – excellent climbers

Variable herbivores (Brushtail possums well adapted to life in suburbia)

22
Q

Phalangerida - Superfamily Burramyoidea

Study These Flashcards
A 
Pygmy possums 
Smallest of the possums 
Long, slender, prehensile tail 
Arboreal 
Insectivorous
23
Q

Phalangerida - Superfamily: Petauridae

Study These Flashcards
A

Possum-like marsupials from four families

E.g. ringtail possums & gliders

Extreme morphological and ecological diversity

Arboreal

All are dietary specialists of one form of another:
•Folivores (e.g. ringtail possum)

  • Sap-eaters (e.g. wrist-winged gliders and Leadbeater’s possum )
  • Omnivorous (e.g. striped possum - wood-boring insects)
  • Nectivorous (e.g. feathertail glider and honey possum)
  • Variations in teeth and digestive tract anatomy
24
Q

Feathertail Glider

Study These Flashcards
A

Belongs to superfamily: petauridae

  • Smallest gliding possum
  • Gliding membrane between elbow and knee
  • Nectivore and communal
25
Sugar Glider
Belongs to superfamily: Petauridae Small, omnivorous, Gliding membrane btw wrist and ankle (termed wrist-winged glider, a trait common to 6 gliding species) Omnivorous: summer = insectivorous; winter = exudativorous (feed on sap, manna and honeydew
26
Greater Glider
Not closely related to other Petauridae gliders Gliding membrane btw elbow and ankle - More controlled glides Folivore, feeding almost exclusively on Eucalyptus leaves Solitary - very vocal
27
Superfamily: Macropodoidea
Kangaroos, wallabies and rat-kangaroos Macropods: strong, powerful hindlimbs and long hindfeet Three families: • Macropodidae: kangaroos and wallabies (<25kg) * Potoroidae: potoroos and bettongs (“rat kangaroos”) * Hypsiprymnodontidae: Musky Rat-kangaroo Adaptations to a hopping lifestyle Syndactyly, with no opposable first digit Terrestrial (except tree-kangaroo) Essentially herbivorous
28
Marsupial morphology
Some common morphological features: - Reproductive traits - Skeletal modifications - Slightly lower body temperature and metabolic rate (expend less energy than eutherian mammals of comparable size and activity) - Brain usually smaller - Most have an opposable 1st digit on hind feet
29
Musculoskeletal Structure of marsupials
``` Compared with eutherians: - Hard palate fenestrated - Epipubic bones present - Lack fully developed patella •Have clavicles ```
30
Skull of marsupials compared to eutherians
Large facial area to small cranial cavity Mandibular symphysis may not be fused (many diprotodonts) Often have narrow oral gape Mandible: internal angular process (so-called “marsupial shelf”)
31
Metabolism of marsupials
Resting body temperature 2-3 degrees lower than eutherians Basal metabolic rate lower (‘primitive’?) but –Nutritional requirements lower for maintenance –Can increase greatly in response to cold (10-11 x) and peak metabolism of some marsupials may be higher than some eutherians –Adaptations to cope with changes in temperature (e.g. torpor)
32
Brain of marsupials
Small Large olfactory bulbs Basic sulci: limited surface area Lacks corpus callosum
33
Hopping (saltation)
Energetic advantages for animals - energy stored in elastic structures e.g. tendons Pentapedal gait: alternately support weight on forelimbs + tail and hindlimbs Top kangeroo speed = 70km/hr
34
Common reproductive features of marsupials
Most polyoestrous Most ovulate spontaneously Pregnancy < or = oestrous cycle length Ovarian activity suppressed by lactation Under-developed offspring at birth Long lactation and short gestation Embryonic diapause in Macropodidae Note: Marsupials also have a placenta (usually more primitive then eutherian mammals)
35
Marsupial pouch
Provides high humidity and stable temperature Formed by invagination of skin of ventral abdomen through a gap in the cutaneous muscles Interior skin relatively hairless, and produces a brown secretion that coats the pouch wall Mammary glands in pouch with long nipples (young initially permanently attached to one teat, and only that teat develops) The pouch is full of bacteria
36
Development of young joey
Small and immature at birth Neonate has circular mouth - Teat expands inside mouth - Can breath and swallow concurrently Remain dependent on mother for some time after leaving pouch/teat
37
Lactation in marsupial
Suckling initiates lactation in suckled mammary gland Milk composition changes during lactation - Protein, lipid and carbohydrate (CHO) concentrations and constituents change - Different glands can concurrently produce different milks to sustain young at different stages of development - Antibodies are transferred across the gut wall for relatively long period of time
38
Embryonic Diapause (marsupials)
Refers to the phenomenon where a female will mate while she has a young in the pouch. The resulting conceptus is held in the uterus in "suspended animation" until the first young has finished suckling Common in kangaroos and wallabies Sucking inhibits corpus luteum = progesterone --> causes diapause
39
Male reproductive anatomy of macropods (kangaroos & wallabies)
Scrotum located cranial to penis Only 2 accessory glands: 1. Prostate 2. Cowper's (bulbourethral) gland Glans penis - Usually bifid ('split') Non erect penis withdrawn into common vestibule in S shaped curve
40
Three basic patterns of sperm production in marsupials
1. Capacity for continuous sperm production e.g. Kangaroos, Koalas, Tasmanian devil 2. Seasonal breeders: only have sperm production during an annual breeding season e.g. greater glider 3. Single cycle breeders: Sperm production over a short breeding season, males die within a short period of females becoming pregnant e.g. Antechinus
41
Marsupial species with continuous sperm production
Sperm production occurs throughout the year, but males often "secondarily seasonal" - If females are seasonal, often see seasonal variation in accessory sex glands and testosterone production, which peak around the time of peak conception
42
Marsupial species with seasonal sperm production
Testis size fluctuated throughout the year

ANSC2005 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions