Week 10: Navigating the environment Flashcards
1
Q
Methods of seabird navigation
A
- Sun/star navigation hypothesis
- Memorising visual landscape
- Geomagnetic field (poles)
- Olfactory/smell (chemical cues relating to albedo and chemicals from runoff)
- Experience
- Sound and infrasound (earthquakes and wavefields)
2
Q
How do benthic foragers, such as penguins, navigate
A
Follow consistent routes to revisit discrete locations
3
Q
Penguins follow linear path when foraging because
A
Fish are abundant along these linear trawl marks which stir up sediment and therefore food.
4
Q
Linear foraging =
A
Poor breeding success
5
Q
What is a mammal
A
- Amniotes
- Endothermic
- Give birth to live young that suckle from mammary glands
- Have hair at some time in life
6
Q
3 orders of marine mammals
A
- Carnivora
- Cetacea
- Sirenia
7
Q
Carnivora: 6 Otter adaptations
A
- Most aquatic of all carnivora
- Flipper-like hind paws and flattened tail
- Dives 5-35m (max. 100m)
- Opportunistic diet, mostly benthic invertebrates
- High heat production and insulating fur (maintained by grooming)
- Large, lobular kidney facilitates osmoregulation
8
Q
Pinnipeds 3 extant families
A
- Phocidae - True seals
- Otariidae - Eared seals, fur seals and sea lions
- Odobenidae - Walrus
9
Q
Pinnipeds evolved from
A
Terrestrial bear like ancestors
10
Q
5 Adaptations in Pinnipeds for an aquatic life
A
- Limb modification into flippers
- Streamlined body shape
- Insulation (hair/fur, blubber)
- Physiological adaptations for diving
- Osmoregulation
11
Q
How do pinnepids maintain a streamlined body shape
A
- Reduced/absent ear pinnae and tail
- Genitals/mammaries retracted
12
Q
What are pinnipids physiological adaptations for diving
A
- High concentrations of myoglobin in muscle
- Large blood volume with high concentration of haemoglobin
- Bradycardia and reduced organ function
13
Q
How do pinnipeds undergo osmoregulation
A
- Water from dietary intake and metabolism
- Excrete concentrated urine (chloride)
14
Q
Food and foraging activity of pinnipeds
A
- Diet mainly fish, molluscs and crustaceans
- Broad diets, opportunists, e.g leopard seal (krill, fish, birds, seals, scientists)
- Some specialists (walrus: benthic invertebrates, crabeater seal: krill)
- Sight important for finding food
- Vibrissae (whiskers) allow following of hydrodynamic trails
15
Q
2 extant families of sirenia
A
- Trichechidae (manatees)
- Dugongidae (dugongs)
16
Q
10 Sirenian adaptations
A
- Only herbivorous marine mammals
- Fusiform body shape
- Paddle-like pectoral limbs, absent hind limbs
- Flattened flukes
- Dorsal nostrils
- Thermal stress 17-19 degrees
- Large body size, reduced extremities
- Blubber
- Behavioural adaptations (migrate to warm water, e.g hot springs, power stations)
- Superficially lobular kidneys able to produce hyperosmotic urine
17
Q
2 sub orders of cetacea
A
- Mysticeti (baleen whales)
- Odontoceti (toothed whales)
18
Q
Mysticeti characteristics
A
- Baleen whales
- 2 blowholes
- 4 families
- 13+ species
19
Q
Odontoceti characteristics
A
- Toothed whales
- Single blowhole
- 10 families
- 70+ species
20
Q
How do Cetaceans control thermoregulation
A
- Polar to tropical distributions - maintain body temperature apprx 37 degrees
- Low surface area:volume
- Insulated with blubber
- Must be able to retain heat and dump heat
- Blubber highly vascularised
- Counter-current heat exchangers in flukes
21
Q
Myticetes characteristics in food and foraging
A
- Baleen - 0.2 to 4m long
- Rorqual whales are fast swimming lunge feeders (diet - zooplankton and small fish)
- Right whales are ram or skim feeders (diet - zooplankton)
- Prey detection through olfaction
22
Q
How do Rorqual whales enhance their feeding methods through lunge feeding
A
- Throat pleats and a flexible lower jaw
- Behavioural adaptations to concentrate prey
23
Q
How do right whales enhance their feeding methods through ram feeding
A
Filtration enhanced by venturi effect
24
Q
Odontocetes characteristics in food and foraging
A
- Teeth for gripping prey or suction
- Diet - fish, cephalopods, birds, pinnipeds, cetaceans
- Find prey by echolocation: sound production and listening for echoes reflected off objects in environment
25
How do Cetaceans control osmoregulation
1. Water from diet and metabolism of fat
2. Kidney structure facilitates production of hyperosmotic urine
3. Hormonal control
26
Threats to conservation of NZ sea lion
1. Bycatch in squidfishery (est. 1571 deaths 1995-2015)
2. Resource competition resulting in female and pup weights declining
3. Epizootics/disease 1998, 53% pup mortality
27
Main threat conservation of hectors dolphin
Bycatch in gillnets (trawls)
28
Main management of conservation issues
Extensive MPAs to restrict gill netting
29
Orientation definition
Understanding of where tou are in space relative to another location
30
Navigation
Charting a course to a remote goal
31
Migration
Animals moving between locations for different life-history stages
32
Homing
Movement back to a known site after displacement e.g a foraging trip
33
Navigation enables animals to effectively find specific locations for
1. Food
2. Conspecifics
3. Safety
34
Humpack whale migration traits
1. 14-17 long baleen whale
2. Cosmopolitan distribution
3. Feed in polar waters
4. Breed and nurture in tropical waters
5. Longest known mammalian migration
6. Average migration = 51 days
35
Northern elephant seal migration traits
1. Breed on california coast
2. Feed in north pacific
3. Annual migration = 20,000km
36
Why do marine mammals spend summer at polar latitudes
1. Foraging in areas of seasonal productivity
2. Extensive food resources to replenish body condition
37
Why do marine mammals spend winter at tropical latitudes
1. Warmer temperatures
2. Less harsh conditions for young
3. Fewer predators
38
4 methods of marine mammal navigation
1. Magentic compass (magnetite particles in brain, to magnetic fields/poles)
2. Celestial compass (well developed vision/migrate at surface)
3. Sound as orientation (coastlines)
4. Learn routes from conspecifics (young learn from mother)
39
Southern right whale unique migration pattern
Migrate from sheltered coastal areas during winter (calving and mating) to productive offshore waters during summer (foraging)
