marine mammals Flashcards
outline some characteristics of marine mammals
- heterotrophic
- homeothermic= constant temp
- endotherms
- airbreathing
- viviparous - give birth to young
- k-selected species
where in the world are marine mammals found
Widley distributed but can be patchy depending on ocean productivity and food availability
richness usually peaks in colder, temperate waters
what are the main taxonomic groups of marine mammals
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
outline some characteristics of cetaceans
- piscivores and carnivores
- spend lives in waterer with many adaptations
- 28 recorded UK species
- variety of feeding tatctics
give some examples of feeding tactics demonstrated by cetaceans
lunge feeding
bubble netting
shore chasing
tail slapping
give some examples of species found in the mysticeti
blue, fin, grey, humpback and minke whales
give some characteristics of odontoceti
more than 70 species
diet consists of fish, squid and bottom inverterbrates
includes dolphins, porpoises etc
outline some characteristics of pinnipeds
36 extant species
fin footed
majority of lives swimming and feeding in water
come to land to birth, rest and moult
give some characteristics of sirenians
spends whole lives in water
only entirely herbivorous group of marine mammals
all four species endangered or threatened
outline some characteristics of sea otters
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
outline some characteristics of polar bears
largest land carnivore
need avergae of 2kg fat per day to maintain weight
diet consists of moslty seals, walrus, beliga whale and fish
what are some ecological functions of marine mammals
- transfer of nutrients
- benthic habitat modifiers e.g. sediment turnover
- ## community structure e.g. sea otters feed on urchins helping kelp forests develop
outline convergent evolution in marine mammals
the independent development of similar traits or features, fossil records show that mammals re-entered the marine realm on at least seven separate occasions
list some challenges of living in an aquatic environment
- breathing
- regulating body temp
- movement
- diving
- communicating
- sound underwater
- low light environment
sleeping
outline some respiratory adpatations
migrations of nostrils to the top of the body e.g. seals and dolphins
outline some adaptations to skeletal structure and locomotion
- streamlining
- legs into paddles or fins
- loss of hindlegs
- skin and blubber reducing drag
- paired flipper movement
outline some diving adaptations
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
outline echolocations in odontocetes
high frequency, short duration and directional pulsed sounds with returning echoes used for navigation and foraging
what are some acoustic methods used to investigate
passive/active
static/mobile
hydrophones
DAT recorders
click loggers
sound traps
animal attached tags
what are some conservation concerns for marine mammals
whaling
seismic exploration
military sona
shipping entanglement
bycatch
pollution
