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Animal Diversity > 18-19: Mammal origins, Primates > Flashcards

18-19: Mammal origins, Primates Flashcards

1
Q

What sets mammals apart from other animals?

A

Endothermy and homothermy- generate own heat, maintain temperature
Have a placenta (in eutherians) and mammary glands
Heterodony- teeth not all in the same shape
Secondary palate- way of breathing whilst chewing
Enlarged brain

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2
Q

How many extra holes in the skull do mammals have?

A

1 on each side

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3
Q

What is 1 extra hole on each side called?

A

Synapsid

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4
Q

When did ‘mammly’ type things occur?

A

End of Triassic- the start of the dinosaurs

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5
Q

When did mammly things diversify?

A

Cretaceous

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6
Q

What allowed the diversification of mammals?

A

The extinction of the dinosaurs

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7
Q

Synapsida features

A 
From the Permian
Single opening between skull roof and cheek
Large canine-like teeth
Strong, arched palate
Eg. Pelycosaurs
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8
Q

Therapsida features

A

From mid-Permian to Triassic
Expansion of jaw muscles- to chew
Less sprawling gait, more upright
Expansion of cerebellum

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9
Q

Cynodonta features

A 
From triassic to mid-Jurassic
Well developed post-canine teeth
Changes in jaw
Jaw bones change to ear bones
Complete secondary palate- can chew and breathe at the same time
Endothermic
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10
Q

Early mammalia features

A

Late Triassic to present
First evidence of hair- doesn’t fossilise well, could have been earlier
Mammary and skin glands
Teeth when growing, shed and have second set when adult
Closer to modern form

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11
Q

Mammalia features

A

3 ear ossicles
Modified vertebrae
Long bones
Enlarged neopallium (part of brain for sensory perception, cognition, language)

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12
Q

What are theria?

A

Most of the modern mammals- eutherians and marsupials

Have modifications of the braincase

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13
Q

What are eutherians?

A

Give birth to developed offspring

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14
Q

What are marsupials?

A

Undeveloped offspring are kept in pouches

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15
Q

Evolution of the jaw joint

A

Reduction in the number of bones
It is stronger to have fewer bones
Needs to be strong for chewing
Jaw bones become ear bones

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16
Q

Features of the mammal palatte

A

Soft palate separates
The epiglottis stops food going down the airway
Would be better to have nose underneath mouth- evolution is not perfect

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17
Q

Amphibian palatte features

A

Big bony plate

No separation of airway from the oesophagus

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18
Q

Therapsid reptile palatte features

A

Partial bony layer

A bit of separation

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19
Q

Mammal palatte bony layer

A

Completely jointed

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20
Q

Characteristics of the modern mammal

A 
Hair- can be evolved into spines
Sweat, scent, mammary glands
3 ossicles (malleus, incus, stapes)
Usually 7 vertebrae in neck- birds have as many as they need
Heterodont- lots of different shapes of teeth
4 chambered heart
Non-nucleated, biconcave red blood cells
Males are heterogametic (XY)
Milk from mammary glands
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21
Q

Mammal hair features

A

Made of keratin
Usually 2 layers- dense, soft underhair, course guard hair
Varied colours that can change by seasons for camoflague

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22
Q

Sweat gland examples

A

Eccrine- cooling

Apocrine- reproductive

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23
Q

Scent gland uses

A

Marking

Communication

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24
Q

Teeth argument

A

Success of mammals is due to the range of teeth?

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25
What teeth do mammals have?
``` 4 types: 3 Incisors 1 Canine 4 Premolars 3 Molars (on each side) They have these on both upper and lower jaws ```
26
Mammal diets
``` Insectivorous Herbivorous Ruminants Carnivorous Omnivorous Can have special teeth for diet ```
27
Insectivore digestive system
Short intestine | No caecum
28
Ruminant herbivore digestive system
4 chambered stomach with large rumen | Long small and large intestine
29
Non-ruminant herbivore digestive system
Simple stomach | Large caecum
30
Carnivore digestive system
Short intestine and colon | Small caecum
31
Herbivore =
long gut, takes more time to digest vegetation
32
Flight in mammals
Eg. northern flying squirrel Gliders Help us see the process of where flight came from
33
What is echolocation?
Frequency modulated pulses directed in a narrow beam | Allow them to 'see'
34
Reproduction forms
Monotremes- lay eggs (ancestral form) Marsupials- pouched, viviparous Eutherians (placentals)- viviparous, lessaltricial Internal fertilisation
35
Placenta features
Needs to cope with nutrients and waste crossing inside the body Membrane system
36
Which type of mammal produces offspring the quickest?
Eutherians- main advantage But marsupials more flexible- can ditch baby in pouch if no food around Joey in pouch, egg in body
37
Primate limb
Nails rather than claws Grasping hands and feet Upright body posture Retained a lot of primitive features- hands/feet
38
How many digits?
5- a pentadactyle limb | This is the ancestral form
39
Primate hand adaptations
Adapted to grasping | Many don't have a thumb
40
Which primate does have claws?
The marmoset | A secondary derivation that has re-evolved
41
Primate teeth/diet features
Ungeneralised teeth Some have a tooth comb Eat a generalised diet Have incisors, canines, premolars, molars
42
What are tooth combs?
Where incisors point forwards | Eg. in lemurs for grooming
43
Old world monkey teeth
Have big canines
44
Aye-aye teeth
A madagascan lemur | Has huge protruding gnawing teeth
45
Primate senses, brain and behaviour features
``` Short snout Large eyes Big brains Flexible behaviour Extended infant care Large social groups ```
46
What is the only nocturnal monkey?
The owl monkey
47
Features of the proboscis monkey
Can enlarge nose for sexual display Makes a noise Like to swim
48
Example of a monkey with a prehensile tail
Red spider monkey
49
What is a prehensile tail?
Can grasp objects
50
What are primates split into?
Strepsirhini | Haplorhini
51
Features of Strepsirhini
Wet, dog-like nose Split lip Whiskers
52
Features of Haplorhini
No split lip | Dry noses
53
What do tarsiers belong to?
Haplorhini, as they have dry noses, but are also said to be prosimians
54
Haplorhini split into
Platyrrhini- flat noses Catarrhini- round noses Tarsiiformes- tarsiers
55
Lemuriformes are split into
Lorisoidea | Lemuroidea- madagascan lemurs
56
Catarrhini are split into
Cercopithecoidea- old world monkeys | Hominoidea- great and lesser apes
57
What are the old world monkeys called?
Cercopithecoidea
58
What are the great and lesser apes called?
Hominoidea
59
When do we think primates began to appear?
After dinosaurs, but no fossils | See properly in oligocene
60
When does fossil evidence say the earliest hominins appear?
6mya
61
What are hominins?
Human-type Bipedal (walked on two legs) Small canines Vertical face
62
What are hominids?
All human/ape like ancestors
63
What did the common ancestor look like?
Not like a chimp | No idea!
64
Miocene hominins
``` 6.5mya (Miocene) Part of skull found Gorilla-like? Very human-like from the front Don't know if its part of the human lineage ``` 6mya (Miocene) Part of femur suggests that they were bipedal
65
Pliocene hominins
4.5mya Chimpanzee ancestor Not enough evidence to confirm bipedality 3.5mya Skull of an offshoot from the main human lineage? Australopithecus- lots of them! 3-1.5mya Huge teeth for eating tough vegetation?
66
What were Australopithecines?
From Africa, found in 2 places In south african caves, good preservation but difficult to date In east africa, can date but not good preservation Relatively small brain
67
Pleistocene hominin
``` Homo habilis Earliest homo species! Earliest stone tools Similar to Australopithicus but bigger brain Quite small, sexual diamorphism Just in Africa ```
68
What was homo erectus?
``` 1.8mya to 200,000 ya Nariokotome Boy- skeleton of adolescent Long, low skull with broad base Prominent brow ridges Large posterior teeth Apart from skull, looks human Originated in Africa, but have been found outside ```
69
What are Neanderthals?
``` Found in Neander valley, Germany All over Europe Bigger brain than modern humans Tools not as advanced Not separate species- we have lots of Neanderthal DNA ```
70
Neanderthal features
Lack of chin Projecting mid-face Large cranial capacity Low forehead
71
Anatomically modern human features
Definite chin Small anterior teeth Small brow-ridges Vertical forehead
72
What was homo floresiensis?
``` Found on island east of Java 18,000 ya Very small brain 1m tall Related to homo erectus Stone tools ```
73
What were the Denisovans?
Finger bone found in Siberia | Genetically distinct from modern humans and Neanderthals

Animal Diversity (12 decks)

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