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Diversity of life > Mammal diversity and evolution - Week 22 > Flashcards

Mammal diversity and evolution - Week 22 Flashcards

1
Q

What are the 3 families within the Pinnipeds?

What is a characteristic of Pinnipeds?

A
  • Odobenidae, walrus
  • Otaridea, eared seals
  • Phocidae, true seals
  • Feed offshore, give birth on land
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2
Q

Walrus (Odobenidae) adaptations?

A
  • Both sexes have tusks

- Skull specialised to feed on clams

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3
Q

Eared seals (Otaridea) adaptations?

A
  • Large fore flippers (propulsion)
  • Hand slippers don’t help with sustained swimming
  • Fore and hind limbs used better on land, compared to true seals
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4
Q

True seals (Phocidae) adaptations?

A
  • Hand flipper swimmings

- Muscle mass at the rear

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5
Q

General seal adaptations?

A
  • Produce clicks (possible echolocate)
  • Delayed implantations
  • Limited mother-pup contact
  • Richest milk of mammals
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6
Q

What is significant about elephant seal social organisation?
- brutal cunts

A
  • Highly prolygynous
  • Males 3x mass of females
  • No parental care
  • Bloody fights.
  • Alphas inseminate
  • 14 pups per 12 years per female
  • sneaky mating
  • very aggressive
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7
Q

What are Sirenia and what does this contain?

A
  • 3 manatees, 1 dugong
  • Primarily feed on plants, long intestine (45m in manatees)
  • Caecum midgut cellulose digestion
  • Low nutrition, 1/3 of energy you’d expect, live v slowly
  • constant teeth replacement
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8
Q

What are Cetartiodactyla?

A
  • Whales and dolphins
  • Mystieti, baleen whales: horny plate instead of teeth, filter plankton, double blowhole, largest whales
  • Odontoceti, toothed whales: feed on fish/ squid, single blowhole
  • Artiodactyl, closest living relatives, hippo, 55mya
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9
Q

Why does menopause occur in orcas?

- Live to 90 but stop producing at 40?

A
  • Live in materalinica groups
  • Pass on knowledge
  • Post reproductive females lead hunts
  • When young and old breed at same time, cavlves mortality higher
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10
Q

Why do tooth whales echolocate?

A
  • More effective than vision
  • Possibly stun prey?
  • Fish can locate ultrasound, to avoid whales?
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11
Q

Why do whales use long-distance communication?

A
  • Large baleen whales low frequencies, 20-300 Hz
  • Low travels further
  • Sound stuck in channels, travel 5600km
  • Humpback whale song changes yearly
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12
Q

What are Chiroptera?

What is contained within?

A

Bats!

  • Suborders:
  • Megachiroptera
  • Microchiroptera
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13
Q

What type of bat does not echolocate?

A

Pteropodidae, flying foxes aka megabat

- secondarily lost

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14
Q

First wings/ echolocation appearance in bats?

A

52.5 MYA
Icaronycteris
Wings modified pentadactyl limb
Only powered flight mammals

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15
Q

How does Chiroptera wing shape/ flight style affect it?

A

Wing shape determines speed and manoeuvrability

  • Fast = long narrow wings
  • High wing loading means fast but slow manoeuvrability
  • Low aspect ratio = low wing loading, high manoeuvrability
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16
Q

Feeding biology of Chiroptera?

A

70% Insectivouours

  • Frequencies have short wavelength to detect small objects
  • Wing/ tail membrane increase capture area
  • Insects evolved to hear to avoid bats (negative pona taxis)
17
Q

Different types of feeding techniques used by Chiroptera?

A
  • Gleaning, some bat non-volant, echolocation ineffective on complex surfaces, can crawl and hunt on feet
  • Frugivory, bats important for seed dispersal in ecosystem, possibly evolved through eating prey that ate fruit, crushing grinding molars
  • Nectarivory, could have evolved from insectivory, nectar/ pollen is balanced diet, some flowers have acoustic guides to attract bats
  • Piscivory, 2-3 species bulldog bats detect ripples on water surface
  • Carnivory, eat small mammals, can distinguish small poisonous from not
  • Sanguivory, vampire! evolved from insects around wounds
18
Q

Adaptations of reciprocal altruism?

A
  • Small groups of females associate in roosts
  • If one female in unsuccessful in obtaining blood- others will regurgitate
  • Females will return favour
  • Kin selections patterns
  • Females return to maternity colonies (can live for 30 years)
  • Related females use the same feeding areas
  • Usually breed with same male
19
Q

Chiroptera hibernation adaptations?

A

Temperate zone bats are heterothermic
Hybernate 12 days, arouse to drink, feed, roost, defecate
Arousal energetically costly, must be important?
Possibly to rouse immune system?

20
Q

Chiroptera echolocation adaptations?

A

Frequency 20-60 Hz range 11-121 kHz
Wide range of signal design, help detect/ classify insects
short-range ultrasound = higher resolution but higher absorption

21
Q

Name some trends in primate evolution?

A
  • Eyes face forward
    Stereoscopic vision
    Cerebellum enlarged
    More mental power
22
Q

Primate diversity, what is the infraordera and parvorder for humans?

A

Simiiformes, Catarrhini

Simiiformes, Platyrrhini = new world monkeys

23
Q

Communication adaptations of varvert monkeys?

Cambells monkeys?

Law of brevity?

A
  • Alarm calls for different things/ threats
  • Predatory and non-preditorary calls, possibly pre words?
  • Shorter the word, more likely it’s used
24
Q

What leads to primate social organisation?

A

Large neocortex
Many social dynamics
Determined by food distribution
If food can be defended leads to monogamy

25
Q

Hominin evolution, how humans differ from recent common ancestor?

A
  • Fossil chimp record poor, hominin good
  • 95% DNA identical chimp
  • Amino acid divergence 1.3%
  • Rentention of juvenile characteristics (neoteny) young n old have same skull
  • Gene expression is main differences, 10% in brain
26
Q

What can cause faster evolution?

A

Extra copy of genes, subject to duplication

27
Q

What does the oldest hominin fossil show?

A

6-7 mya
Bipedalism, small cannies, thicker tooth
Femur adapted for an upright torso, short stiff toes for walking, opposable big toe for climbing

28
Q

What caused the evolution of bipedalism?

A

Changing environment, africa 10 mya forest drop in temp less rain, forest turned to grassland

  • hominin move to exploit savannah habitats
  • Bipedal less sun exposure, keep cooler, collect food easier
29
Q

What happened to the other homos?

A

Homo sapians out-competed them

  • Genome support hybridization of us and neonderthalensis
  • co-existed long time
30
Q

Why are sapiens still here?

A

1350cc brain
social evolution
language understanding abstract thoughts

31
Q

Significance of FOXP2 and PU3F2?

A

Affect speach related motor control, could be key to communicate?
Natural selection favoured this after chimp split

Diversity of life (10 decks)

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