marine mammals

Question 1

outline some characteristics of marine mammals

Answer 1

• heterotrophic
• homeothermic= constant temp
• endotherms
• airbreathing
• viviparous - give birth to young
• k-selected species

Question 2

where in the world are marine mammals found

Answer 2

Widley distributed but can be patchy depending on ocean productivity and food availability
richness usually peaks in colder, temperate waters

Question 3

what are the main taxonomic groups of marine mammals

Answer 3

1) cetaceans = whales, porpoises and dolphins
2) pinnipeds= seals, sealions and walruses
3) sirenians= manatees and duogongs
4) marine fissipeds= sea otters and polar bears

Question 4

outline some characteristics of cetaceans

Answer 4

• piscivores and carnivores
• spend lives in waterer with many adaptations
• 28 recorded UK species
• variety of feeding tatctics

Question 5

give some examples of feeding tactics demonstrated by cetaceans

Answer 5

lunge feeding
bubble netting
shore chasing
tail slapping

Question 6

give some examples of species found in the mysticeti

Answer 6

blue, fin, grey, humpback and minke whales

Question 7

give some characteristics of odontoceti

Answer 7

more than 70 species
diet consists of fish, squid and bottom inverterbrates
includes dolphins, porpoises etc

Question 8

outline some characteristics of pinnipeds

Answer 8

36 extant species
fin footed
majority of lives swimming and feeding in water
come to land to birth, rest and moult

Question 9

give some characteristics of sirenians

Answer 9

spends whole lives in water
only entirely herbivorous group of marine mammals
all four species endangered or threatened

Question 10

outline some characteristics of sea otters

Answer 10

full aquatic
adults may eat as much as 9kg food each day
marine otters a small species found in south america live in costal areas

Question 11

outline some characteristics of polar bears

Answer 11

largest land carnivore
need avergae of 2kg fat per day to maintain weight
diet consists of moslty seals, walrus, beliga whale and fish

Question 12

what are some ecological functions of marine mammals

Answer 12

• transfer of nutrients
• benthic habitat modifiers e.g. sediment turnover
• ## community structure e.g. sea otters feed on urchins helping kelp forests develop

Question 13

outline convergent evolution in marine mammals

Answer 13

the independent development of similar traits or features, fossil records show that mammals re-entered the marine realm on at least seven separate occasions

Question 14

list some challenges of living in an aquatic environment

Answer 14

• breathing
• regulating body temp
• movement
• diving
• communicating
• sound underwater
• low light environment
  sleeping

Question 15

outline some respiratory adpatations

Answer 15

migrations of nostrils to the top of the body e.g. seals and dolphins

Question 16

outline some adaptations to skeletal structure and locomotion

Answer 16

• streamlining
• legs into paddles or fins
• loss of hindlegs
• skin and blubber reducing drag
• paired flipper movement

Question 17

outline some diving adaptations

Answer 17

resistance - streamlined body shape to reduce drag, paddle shaped forelimbs

water conservation - use water in food and inspired air, specialised kidney

sensory adaptations - specialised vocal production

thermoregulation- large body with small surface to volume ratio to reduce heat loss

pressure and o2 collapsible lunsg to force air into tissues to recude bends

Question 18

outline echolocations in odontocetes

Answer 18

high frequency, short duration and directional pulsed sounds with returning echoes used for navigation and foraging

Question 19

what are some acoustic methods used to investigate

Answer 19

passive/active
static/mobile
hydrophones
DAT recorders
click loggers
sound traps
animal attached tags

Question 20

what are some conservation concerns for marine mammals

Answer 20

whaling
seismic exploration
military sona
shipping entanglement
bycatch
pollution