Lecture 26 Vertebrates - Mammals Flashcards

1
Q

Three subclasses of Mammals

A

-Eutheria
-Prototheria
-Metatheria

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2
Q

5 orders of the subclass Eutheria are

A

-Carnivora
-Cetacea
-Chiroptera
-Rodentia
-Sirenia

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3
Q

One order of the subclass Prototheria is

A

Monotremata (platypus and short-beaked echidna)

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4
Q

Two orders of the subclass Metatheria (Marsupialia)

A

-Diprotodontia
-Polyprotodontia

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5
Q

The subclass Metatheria of Mammals is also called

A

Marsupialia

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6
Q

All subclasses of mammals evolved from a

A

Common reptilian ancestor

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7
Q

Monotremes evolved in

A

The Southern Hemisphere

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8
Q

Monotremes retained four reptilian characteristics:

A

-oviparity
-meroblastic cleavage of embryo
-production of venom
-electroreception

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9
Q

There are __ species of monotremes

A

5

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10
Q

Which monotremes are found in Australia

A

-platypus
-short-beaked echidna

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11
Q

The echidna has the

A

Widest environment range of any Australian mammal

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12
Q

The platypus exists in

A

Freshwater habitats of eastern Australia

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13
Q

Defining characteristics of monotremes (7)

A

-absence of calcified teeth (have a keratinised dental pad)
-electroreception used to detect prey
-reptile-like stance (limbs held off to side rather than under body)
-cloaca
-oviparity
-no teats (females produce milk through modified sweat glands)
-venom

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14
Q

Crural glands are (4)

A

-venom glands found on the ankle of male platypus
-can move independently
-evolved independently of reptile venom
-used for defence of territories

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15
Q

Electroreceptors are located

A

within the skin of bill/beak in platypus and echidnas

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16
Q

The pectoral girdle of monotremes has

A

Reptilian features: coracoids, epicoracoids, and interclavicle

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17
Q

Monotremes have multiple

A

X and Y chromosomes

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18
Q

In marsupials and eutherian, sex is determined by ___

A

SRY on Y chromosome

19
Q

Monotremes lack

A

SRY on chromosome Y (ie. determines sex)

20
Q

The monotremes sex system is a

A

Link between birds and therians

21
Q

In the platypus, only the ___ is functional

A

Left ovary

22
Q

Monotremes have ___ but no ___

A

Mammary glands; teats

23
Q

The eggs of monotremes are (2)

A

-a porous, leathery shell
-developed in the uterus for ~20 days absorbing embryotrophe

24
Q

Echidnas incubate in ___ while platypus incubate in ____

A

Transient pouch; nest

25
Q

Not all marsupials posses

A

A pouch

26
Q

How many species of Marsupials

A

270

27
Q

Marsupials and eutherian diverged from

A

A common ancestor

28
Q

Marsupial young are born in an

A

Altricial state (ie. not developed yet)

29
Q

Marsupial young depend on ___ rather than ____

A

Lactation; gestation

30
Q

XX chromosome of marsupials results in (2)

A

-female reproductive tract
-pouch

31
Q

XO chromosome in Marsupials results in (2)

A

-female reproductive tract
-scrotum

32
Q

XY chromosome in Marsupials results in (2)

A

-male reproductive tract
-scrotum

33
Q

XXY chromosome in marsupials results in (2)

A

-male reproductive tract
-pouch

34
Q

Pouch OR scrotum development of marsupials depends on ___ and not___

A

X chromosome; hormonal control

35
Q

In marsupials, the ureters pass

A

Medially to Müllerian ducts

36
Q

Marsupials posses ___ from Müllerian ducts and ___ of connective tissues

A

Two lateral vaginae; median vagina

37
Q

Birth of marsupials occurs in the ___ vagina

A

Median

38
Q

In eutherian, ureters pass

A

Laterally to Mullerian ducts

39
Q

The Müllerian ducts is ___ in eutherian

A

Fused at the distal end to form the vagina

40
Q

The Müllerian ducts in marsupials is

A

Not fused

41
Q

The median vagina of marsupials is

A

Formed from connective tissue

42
Q

Marsupials replaced the role of ____ with ____

A

Gestation; lactation

43
Q

Marsupial young are born with (4)

A

-well developed forelimbs and claws
-well developed mouth, tongue, nostrils, and lungs
-no hair
-periderm covering eyes and ears