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Mammalian Diversity > Mammal overview > Flashcards

Mammal overview Flashcards

1
Q

Give the 2 subclasses of the mammal class.

A

Prototheria (Monotremata)

Theria (Metatheria)

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2
Q

Give the 2 infraclasses of the subclass Theria.

A

Marsupialia

Placentalia

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3
Q

What is the difference between organisms in the subclass Prototheria and Theria

A

Prototheria- Lay eggs

Theria- Have live young

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4
Q

What has caused drastic changes in the mammalian phylogeny ?

A

Fossil findings

Molecular analysis

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5
Q

How many mammalian orders are there ?

A

27
1 Prototherian
7 Marsupial
19 Placental

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6
Q

How many species exist in the mammalian order ?

A

5,488

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7
Q

Give a broad description of a mammal.

A 
Group of animals with;
Backbones
Bodies with fur (?) 
Nurse infants with milk
Unique jaw articulation
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8
Q

What is the mammae ?

A

Mammary gland, where milk production takes place

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9
Q

What is a mammillae ?

A

A nipple/teat, delivers milk to the infant

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10
Q

How many mammaries will an organism have ?

A

Generally twice as many mammaries as the average litter size.

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11
Q

What are the benefits of feeding via the mammary system ?

A

Guarantees constant supply of food
Female can redistribute energy into milk production

Little energy required for offspring to feed.

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12
Q

What one species has paternal lactation ?

A

Dayak fruit bat

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13
Q

What bone has articulated to form the mammalian jaw ?

A

Dentary bone

Has met with the squamosal bone in the skull to form jaw.

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14
Q

Which ancestral bones are responsible for an increase in the acuteness of mammalian in hearing ?

A

The quadrate and Articular bone.

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15
Q

The quadrate bone has become the….

A

Incus of the inner ear

decreased in size

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16
Q

The articular bone has become the….

A

Malleus of the inner ear

decreased in size

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17
Q

How many jaw joints do mammals have in the present day ?

A

One jaw joint, giving more efficient chewing.

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18
Q

How do mammalian teeth differ from shark teeth ?

A

They do not continuously grow.

Will replace them once or never.

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19
Q

Give cycle of placental mammal teeth.

A

2 sets
Milk teeth
Adult teeth

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20
Q

Which teeth remain constant throughout a placental mammals life ?

A

Molars, only one set.

21
Q

Give the cycle of marsupial teeth.

A

1 set

Only last premolar will be replaced

22
Q

What enamel is found on mammalian teeth ?

A

Prismatic enamel

23
Q

What is an occipital condyle ?

A

Where the skull meets the top of the neck vertebrate.

24
Q

How many occipital condyles do mammals have ?

A

2

25
Q

What is the advantage to mammals of having 2 occipital condyles ?

A

Decreases tension on skull

Allows greater control of head movement

26
Q

How many occipital condyle do birds have ?

A

1

27
Q

What is the disadvantage of 2 occipital condyles ?

A

Decreased lateral head movement

28
Q

Give the earliest fossil evidence of mammals.

A

160 million years ago

29
Q

Who do mammals share there AMNIOTE common ancestor with ?

A

Reptiles, Dinosaurs, Birds,

30
Q

Give the groups which this amniote ancestor diverged into.

A

Anapsids
Diapsids
Synapsids

31
Q

How can you identify the difference between the Diapsids and Synapsids ?

A

Temporal fenestra

Di= 2 Temp Fen. 
Syn= 1 Temp fen.
32
Q

What is a temporal fenestra ?

What is its function ?

A

Large holes in the sides of the skull.

Enable muscles to expand and lengthen

33
Q

Which group went on to form the mammals, 300 mya ?

A

Synapsids

34
Q

Give the first order of dinasours which mammalian charecteristics.

A

Pelycosauria

E.g Dimetrodon.

35
Q

Describe the limb arrangement of Pelycosaurs.

A

Limbs were sprawled out to the sides

like reptiles

36
Q

What were the pelycosaurs replaced by and when ?

A

Therapsids- More advanced synapsids

Late Permian

37
Q

What occurred in the Triassic to threaten Therapsid survival ?

A

Huge increase in number of other dinosaurs.

Managed to survive

38
Q

Give the key beneficial adaptions of the Therapsids

A

Limbs beneath the body
(rapid locomotion)

Secondary palate
Separate mouth and nasal passage,
(eat and breath at same time.)

39
Q

Describe the positon of the Articular and the Quadrate in the therapsids.

A

Remain in lower jaw

Not incorporated into malleus an incus of ear

40
Q

What other adaptions took place between the Therapsids and the mammals of today ?

A 
Became endothermic
Live young birth
Heterodont teeth (diff.)
Development of temporal fenestra 
Zygomatic arch
Hair and fur
41
Q

What is the zygomatic arch ?

A

A cheek bone- Enables

more efficient chewing

42
Q

What is the advantage of heterodont teeth ?

A

Enable specialisation of organism, can eat diff prey items

43
Q

When did the First mammals separate from the Therapsids ?

A

In the late Triassic,

240 million years ago

44
Q

What feature separated the 1st mammals from the Therapsids ?

A

Dentary bone fused to squamate skull, to form jaw.

45
Q

Give the original niche thought to be occupied by these animals.

A

Nocturnal and insectivores

Only niche left available by dinasours

46
Q

The first mammals actually occupied a wide range of niches. How do we know this ?

A

Jaw analysis.

Comparing jaws of fossils to modern day mammals.

47
Q

Give the progression of mammals from Synapsids.

A

Synapsids
Pelycosaurs
Therapsids
Cycodonts

48
Q

When did the split between marsupial and placental occur ?

A

168 million years ago

49
Q

When did the split between protherian and therian occur ?

A

200 million years ago

Mammalian Diversity (19 decks)

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