Mammal diversity and evolution - Week 22 Flashcards
What are the 3 families within the Pinnipeds?
What is a characteristic of Pinnipeds?
- Odobenidae, walrus
- Otaridea, eared seals
- Phocidae, true seals
- Feed offshore, give birth on land
Walrus (Odobenidae) adaptations?
- Both sexes have tusks
- Skull specialised to feed on clams
Eared seals (Otaridea) adaptations?
- Large fore flippers (propulsion)
- Hand slippers don’t help with sustained swimming
- Fore and hind limbs used better on land, compared to true seals
True seals (Phocidae) adaptations?
- Hand flipper swimmings
- Muscle mass at the rear
General seal adaptations?
- Produce clicks (possible echolocate)
- Delayed implantations
- Limited mother-pup contact
- Richest milk of mammals
What is significant about elephant seal social organisation?
- brutal cunts
- 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
What are Sirenia and what does this contain?
- 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
What are Cetartiodactyla?
- 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
Why does menopause occur in orcas?
- Live to 90 but stop producing at 40?
- Live in materalinica groups
- Pass on knowledge
- Post reproductive females lead hunts
- When young and old breed at same time, cavlves mortality higher
Why do tooth whales echolocate?
- More effective than vision
- Possibly stun prey?
- Fish can locate ultrasound, to avoid whales?
Why do whales use long-distance communication?
- Large baleen whales low frequencies, 20-300 Hz
- Low travels further
- Sound stuck in channels, travel 5600km
- Humpback whale song changes yearly
What are Chiroptera?
What is contained within?
Bats!
- Suborders:
- Megachiroptera
- Microchiroptera
What type of bat does not echolocate?
Pteropodidae, flying foxes aka megabat
- secondarily lost
First wings/ echolocation appearance in bats?
52.5 MYA
Icaronycteris
Wings modified pentadactyl limb
Only powered flight mammals
How does Chiroptera wing shape/ flight style affect it?
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
Feeding biology of Chiroptera?
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)
Different types of feeding techniques used by Chiroptera?
- 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
Adaptations of reciprocal altruism?
- 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
Chiroptera hibernation adaptations?
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?
Chiroptera echolocation adaptations?
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
Name some trends in primate evolution?
- Eyes face forward
Stereoscopic vision
Cerebellum enlarged
More mental power
Primate diversity, what is the infraordera and parvorder for humans?
Simiiformes, Catarrhini
Simiiformes, Platyrrhini = new world monkeys
Communication adaptations of varvert monkeys?
Cambells monkeys?
Law of brevity?
- Alarm calls for different things/ threats
- Predatory and non-preditorary calls, possibly pre words?
- Shorter the word, more likely it’s used
What leads to primate social organisation?
Large neocortex
Many social dynamics
Determined by food distribution
If food can be defended leads to monogamy
