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Flashcards in Herbert Deck (45)
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What is the difference between prototheria, metatheria, and eutheria?

Prototheria- egg layers (monotremes)
Metatheria- embryonic young (marsupials)
Eutheria- birth more developed young

1

Four traits that distinguish mammals from reptiles?

Homeothermic
Suckling of young
Body hair
Muscular diaphragm

2

What are the origins of marsupials and monotremes?

Breaking off from Antarctica 35-40 million years ago

3

What are the origins of Australian eutherians?

Island hopping 5-6 million years ago

4

What are the most easily recognisable differences between ameridelphia and australidelphia?

Structure of the tarsal bones

Also blood proteins, DNA and sperm morphology

5

What are the four orders of marsupials?

Dasyuromorphia
Peramelemorphia
Diprotodontia
Notoryctemorphia

6

What is the name of the opposable 1st digit on the hind foot present in some marsupials?

Hallux

7

Define polyprotodont

Multiple pairs of lower incisors

8

Define diprotodontia

One pair of incisors in the lower jaw.

9

Define syndactyly

Normal occurrence of having two or more fused digits in a mammal species.

10

Between what two digits is syndactyly most common?

II and III

11

What is the dentition of dasyuromorphids?

Polyprotodont

12

Would a spotted quoll have one or more digits fused together naturally?

No, it is a dasyurid, they do not have any syndactyly

13

Bandicoots have three pairs of equal sized lower incisors.

Yes they are of the order peramelemorphia which are polyprotodonts

14

Syndactyly is a defining aspect of peramelemorphia

True/ False

True

15

What does the order notoryctemorphia include?

Marsupial moles

16

All diprotodonts have one pair of lower incisors

True or false?

True

17

What order do koalas belong to?

Diprotodontia

18

All diprotodonts have syndactyly

True/ False

True

19

What is the significance of the path of the ureters in marsupials?

Prevents the fusion of the vagina into a single structure

20

Define polyoesteus

Multiple cycles in breeding season

21

How is ovarian activity modulated in marsupials?

By lactation

22

Describe the placenta of bandicoots koalas and wombats

Chorioallantoic

23

Structure and function of the pouch?

Structure
Invagination of skin of ventral abdomen through a gap in cutaneous muscles, interior skin is hairless, coated by a brown secretion

Function
High humidity and stable temperature for growing young
Mammary glands with long nipples to suckle young

24

What is embryonic diapause?

A female mates while a young is in her pouch. The conceptus is suspended until the first young has finished suckling.

25

How does embryonic diapause work?

Corpus luteum develops and is then inhibited by suckling stimulus

26

Solitary marsupials are usually...

Small nocturnal carnivores/omnivores

Exceptions include brushtails and koalas

27

What is sexual size dimorphism?

Significant difference in size between the sexes within a species

28

How do marsupials cope with cold conditions?

1 increase metabolic rate
2 huddling in groups
3 torpor (pseudo hibernation)

29

How do marsupials cope with heat?

Panting, sweating, licking paws