Week 8 - Evolution and diversity of mammals 2 Flashcards
(93 cards)
1
Q
Which group of marine mammals includes seals, sea lions and walruses?
A
Pinnipeds
2
Q
What adaptations do Pinnipedes have that make them unique ?
A
They’re adapted for life in water and on land - they feed offshore and give birth on land
3
Q
What do walruses have to defend themself?
A
Both sexes have elongated canine teeth tusks, - Used in battle between males, defence and for hauling themselves out of the water onto the ice
4
Q
What are walruses specialised at eating ?
A
Clams and benthic invertebrates
5
Q
What is the difference between eared seals and true seals ?
A
Eared seals have a flap of skin called a pinna near the external ear opening
6
Q
A
7
Q
What is the purpose of fore-flippers in eared seals ?
A
For propulsion in water
8
Q
What do true seals use to swim?
A
Hind flippers
9
Q
How do seals communicate?
A
Produce click vocalizations under water – may be used in echolocation
10
Q
Describe the elephant seal social organisation
A
- Very resource defensive
- No parental care after mating
- Peripheral, subdominant males hang around edges of harems and intercept females as they return to sea.
- Bulls so aggressive they attempt to mate with pregnant females, or may trample pups.
-Male pups attempt to steal milk from females which aren’t their mothers, so they may grow to be big – not seen in females.
11
Q
What order of marine mammals includes manatees and Dugongs?
A
Sirenia
12
Q
What do sirenia primarily feed on?
A
Plants
13
Q
Do the order sirenia have a compartmentalised stomach or not?
A
No, have long intestine
14
Q
What is inbetween the sirenia small and large intestines?
A
A large mid-gut caecum where cellulose digestion occurs
15
Q
How are Sirenia teeth replaced?
A
Continuously
16
Q
How do sirenia move?
A
Move slowly and expend little energy
17
Q
What is the large group of aquatic mammals called including whales and dolphins?
A
Cetartiodactyla often referred to as cetaceans
18
Q
What are the 2 main suborders of certartiodactyla ?
A
- Baleen whales
- Toothed whales
19
Q
How do Baleen whales feed?
A
Have horny plates instead of teeth to filter plankton
20
Q
What do the toothed whales feed on?
A
Fish and squid
21
Q
What are some features of blue whales?
A
Streamlined
Lost hind limbs
No external ears
Horizontal fins
Boneless tail fluke
22
Q
What is the largest whale ?
A
Baleen whales
23
Q
What type of nostril do baleen whales have ?
A
Paired nostrils separated through to a double holed blow hole
24
Q
How many nostrils do toothed whales have ?
A
1 nostril 1 blowhole
25
What is the jaw like in a toothed whale ?
The jaws are extended as a beaklike snout behind which the forehead rises in a rounded curve
26
How do toothed communicate?
Echolocation
27
How does echolocation in toothed whales work?
- Sound produced by 'monkey lips' in nasal passages
- The melon (whale forehead) focuses sound
- Returning sounds channelled through oil-filled sinuses in lower jaw to inner ear.
- Inner ear isolated from skull by bubbly foam
28
How can echolocation be used in tooth whales for prey capture?
Intense ultrasound can stun squid
29
What kind of frequency do baleen whales use?
Low frequency
30
What travels further low or high frequencies?
Low
31
What is the bat order called?
Chiroptera
32
What are the 2 suborders of chiroptera called?
Megachiroptera and microchiroptera
33
What type of bats are Pteropodidae ?
Fruit bats
34
What type of ears and eyes do fruit bats have?
Large eyes and small ears
35
Which sub order do fruit flies fall under?
Megachiroptera
36
How do microchiroptera communicate ?
Via echolocation - All use laryngeal echolocation for orientation, many for prey detection.
37
What does it mean to say bats are monophyletic?
All bats (both fruit bats and insect-eating bats) come from a single common ancestor.
38
What is the difference between orientation in mega and microchiroptera ?
Micro - use echolocation
Mega (fruit bats) - use visual system
39
What do fossils tell us about bat echolocation?
Cochlea structure suggests capable of echolocation
40
What are the new ways to group bats ?
Yinpterochiroptera = fruit bats + horseshoe bats
Yangochiroptera = other microbats
41
How many times do we think echolocation evolved?
once and was lost in fruit bats
42
What wing shape do fast flying species of bat have?
Long, narrow wings
43
Which limb is the wing a modification of in bats?
Pentadactyl limb
44
What are bats the only mammal capable of ?
powered flight
45
What is meant by the aspect ratio of wings?
Aspect ratio = wing length : wing width
46
What aspect ratio do bats that fly in confined spaces have ?
low and also low wing loading
47
What frequency to bats use to locate prey?
High frequencies used in echolocation have short wavelengths, allow detection of small objects.
48
How have many insects evolved to not be eaten?
Have evolved ears sensitive to ultrasound. Veer away from distant bats, spiral out of flight paths of near ones.
49
What kind of prey do bats use gleaning on?
Non-volant (can't fly)
50
What species of bat uses gleaning?
Myotis myotis = greater mouse-eared bat
51
How might bats frugivory be important economically?
Frugivory may have evolved from bats first catching insects around rotting fruit, then eating prey in fruit, finally specialising on fruit itself.
Crushing/grinding molars.
Critical for succession and forest regeneration
52
What might have caused the evolution of nectarivory in bats?
Insectivory - many insects visit flowers
53
Why are nectar and pollen good for bats?
Balanced diet of carbohydrate & protein.
54
Why are bats economically valuable?
Large colonies may eat many insect pests.
Disperse fruits.
Many economically important plants pollinated by bats – bananas, silk cotton tree, agave (source of tequila
55
How did piscivory (fish diet) evolve?
Bat detects ripples on water surface by echolocation.
56
What does sanguivory mean?
Feeding on blood
57
What is Reciprocal altruism?
Small groups of females associate in roosts.
If one female is unsuccessful in obtaining blood, others will regurgitate.
Females who are regurgitated to will later return the favour. Reciprocity important.
58
What does a bat being heterothermic mean?
Means they can adjust their body temperature in response to different temps
59
When bats hibernate why do they only arouse periodically?
As it is very energetically costly
60
When would a bat enter torpor?
In winter to conserve energy, it is a state of decreased metabolic rate and body temperature
61
Do bats live for a short or long time?
Long
62
What frequencies do most bats use for echolocation?
20-60 kHz
63
What is an example of the order Scandentia?
The tree shrew (small squirrel like mammals of the tropics)
64
How are the tree shrews teeth adapted for feeding and grooming?
Canine teeth are poorly developed, primitive sharp-cusped molars reflect an insectivorous diet and forward-projecting lower incisors are used in feeding and grooming.
65
What is an example of the order Dermoptera?
Flying lemurs / colugos
Dermoptera = skin wing
66
What feature allows lemurs to glide?
A patagium
67
Why is steroscopic vision important for flying lemurs?
It gives them good depth perception required for judging safe landings.
68
Which order is the closest living relatives of primates?
Dermoptera
69
How were early primates adapted to living in trees (arboreal)?
Flexible limbs, prehensile hands and feet, claws transformed to nails, tail often used for balance.
70
What shape molars did early insectivorous species have?
Triangular
71
How did molars change in primates to suit a more omnivorous diet?
Became square and bunodont molars to facilitate crushing food
72
What are 3 trends in the evolution of primates based on eyes, cerebellum and cerebrum?
Eyes faced forwards = overlapping visual fields and stereoscopic vision.
Cerebellum enlarged = more precise muscle movements
Cerebrum enlarged = evolution of greater mental powers
73
What are the main sub orders of primates ?
1. Strepsirrhini (includes lemurs, lorises, and galagos)
2. Haplorhini (includes monkeys, apes, and humans)
74
What are some lemur characteristics ?
Monogamous
Nails not claws
Triangular molars
75
Which 2 infra orders is the Haplorrhini suborder split into?
Tarsiiformes and simiiformes
76
Which infraorder are monkeys, apes and humans in?
Simiiformes
77
What are the 2 parvorders of Simiiformes ?
Parvorder Platyrrhini → New World monkeys
Parvorder Catarrhini → Old World monkeys + apes and humans
78
What are characteristics of new world monkeys (Platyrrhini)?
Have widespread nostrils and flat noses
Retain all 3 premolar teeth in each side of jaw.
Arboreal, many use prehensile tail as 5th limb
79
What are some characteristics of Catarrhini?
Downward pointing nostrils in narrow nose
2 premolars on each side of jaw
80
What are some examples of old world monkeys (cercopithecidae-family)?
Macaques and babboons
81
What are some gibbon characteristics (hylobatidae-family) ?
Arboreal
Some monogamous
Complex vocal system
Air sacs
Arm swinging
82
What family are apes and humans?
Hominidae
83
What are some Hominidae characteristics?
Large, lack tails, tendency towards upright posture.
84
Which ape are we most closely related to?
Chimpanzees and bonobos
85
How does the velvet monkey communicate using alarm sounds?
as different alarm calls for different predators, e.g. different noise depending on eagle or snake.
More based on the type of predator as in flying or on land (not species specific)
86
Who are hominins?
Modern humans + all extinct relations after human chimp split
87
Why did homosapiens survive?
Big brains and social evolution
Abstract language
More glucose transporters in brain
88
What dietary changes occurred in hominins and how did this change their teeth?
Ate seeds, nuts and roots
Had smaller incisors/canines but larger molars
89
What was the oldest hominin fossil and its characteristics?
Sahelanthropus tchadenis (6mya):
Small skull
Smaller canines
Thicker tooth enamel
90
What did another old hominin fossil show about walking?
6mya was a femur adapted for supporting an upright torso
91
In general what traits did fossils show about hominins?
Short, stiff toes for efficient walking
Opposable big toe for climbing
92
What features of the fossil Australopithecines show for bipedalism?
Double curved spine, straighter legs, stout heels, arched soles
93
Why do we think bipedalism evolved?
A changing environment - less trees
