All Of MARI112

What 4 traits define vertebrates

Dorsal hollow nerve cord, notochord, pharangeal pouches, post-anal tail

What are the 3 subphyla

Urochordata (Tunicates), Cephalochordata (Amphibians), Vertebrate (Mammals)

What was the benefit of jaw/dental development

Fish could move up the food web

What are Agnatha

Primitive vertebrates

Cartilagenous, no jaws or paired fins

Benthic predators, parasites, scavengers

Slime!

What are Chondrichthyes

Cartilagenous fish

Paired fins, nares

Scale

What are Holocephali

Sub-class of chondrichthyes (Chimeras)

Take on morphology of other animals (E.g. elephant shark)

What are Elasmobranchii

Sub-class of chondrichthyes (Sharks, skates, rays, sawfish

Characteristics of Rays/Skates

Modified pectoral fins

Dorso-ventreally flattened body

Ventrally located gill slits and mouth

Large flattened teeth

Whip like tales with poison gland

Food source of rays/skates

Molluscs and arthropods

What are osteoichthyes

Bony fish

Strong + Flexible

Support + muscle attachment

What are Sarcopterygii

Lobe-finned fish

Primitive (Coelacanth + Lungfish)

Ancestors of tetrapods

What are Actinopterygii

Ray-finned fish

Flexible fin design

Stugeons, gars, teleosts

What percentage of fish does the order teleost account for

90%

Challenges for life in sea water

Feeding strategies

Movement + Propoulsion

Position in the water column

Gas exchange

Osmoregulation

Differe mouth types

Mouth with teeth

Protrusible

Superior

Terminal

Inferior

How dense is water than air

800x denser, 100x more viscous

Propulsion

Propulsion occurs from tail or fins

Caudal fin alignment

Homoceral = symmetrical

Heteroceral = asymmetrical

Caudal fin shapes

Truncate

Rounded

Pointed

Forked

Lunate

Heterocercal

Chondrichthyes position in water column

Cartilage skeleton reduces density

Pectoral fins generate lift

Produce and stoe squalene

Osteichthyes position in water column

Gas filled bladder for buoyancy

Swim bladder (primitive lung)

Gas volume adjusted by gas gland and muscular contraciton

Gas exhcange in fish

Unidirectional water flow by ram ventilation, buccal or opercular pumping

Countercurrent flow of water against flow of blood in fish’s gills

Diffusion constantly taking place

Fish fixes for osmoregulation

Kidneys - conc. urine

Active secretion of salts across gills

Elasmobranchs reabsorb urea into blood

Urea kept in bloodstream

Mechanoreceptors

Sensorys receptors that respond to mechanical pressure or distortion

Lateral line + inner ear systems (acoustico-lateralis)

Hair cells in both systems

What are otoliths

Deposition of calcium carbonate

Can be used to age fish

Sound and the swim bladder

Swim bladder compressed by soun waves, transmitting sound to otoliths

Importance of hearing/sound

Used to sense surrounding, communicate, locate food, protect themselves underwater

What is the lateral line system

System of tactile sensory organs

Neuromasts form interconnected network along the head and body

What is Electroreception

Capacity to percieve weak electric fields

Why is electroreception important

Prey detection, predator avoidance, mate detection, geo-navigation, communication

How does electroreception occur

Ampullae of Lorenzini

What are the ampullae of lorenzini

Special sensing organs called electroreceptors

Form a network of mucus-filled pores

How do fish emit electrical signals

During osmoregulation

Concentration of ions within an animal’s body is lower than that of sea water

Olfaction in larval fishes

Important for finding habitat and avoiding predators

Importance of olfaction

Identifying predators, prey, chemical alarm cues (conspecifics)

Vision

Fish retinas have both rod cells and cone cells

Importance of vision

Avoid predation, find food, find mates, select habitat

What is an apex predator

Species that occupy the top trophic position in a community

What do apex predators do

Have strong effected on trophic dynamics + diversity of systems

Affect abundance of mesopredators via lethal encounters or influencing behaviour

Kill smaller predators for food + avoid comp.

What is a mesopredator

Any mid-ranking predator in food web regardless of size or taxonomy that occupies trophic positions below apex predators

What do mesopredators do

Better at exploiting shared food resources

Less specialised hunters than apex predators

Have less influence on the behaviour of other species

What is a dominant species

The most abundant species in a community

What is a keystone species

Have effects on communities that far exceed their abundance (e.g. sea otters)

What is a foundation species

Exert influence on a community not through their trophic interaction, but by causing physical changes in the environment (e.g. corals)

What is mesopredator release

increment in density of mid-ranking predators due to loss of top predators

What is pursuit predation

Predators give chase to fleeing prey

What is Ambush predation

Predators use a combination of senses to assess the rey and to time the strike

Adaptions for predation

Visual acuity

Teeth

Streamlined body

Camouflage

Venom

Adaptations for prey

Camouflage/Crypsis

Speed + senses

Mimicry

Venom + spikes

Warning colours, pattern + eyespots

What is prey masquerading

Occurs when an organism uses its colouration or shape to resemble an inedible object

What is chemical crypsis

Alteration to the olfactory cue of an animal to match the olfactory cue of another organism

What is a C-start

Flow stimulus produced by predator gives prey a fast start to escape

What are non-cinsumptive effects

Changes in morphology and behaviour because of predation pressure

Animals released from predation pressure may shift energetic resources from somatic growth or reproduction

What are the three orders of marine mammals?

Carnivora, Cetabea, Sirenia

What are mammalian traits?

Amniotes

Endothermic

Give birth to live young that suckle from mammary glands

Have hair at some time in life

What are the common challenges marine mammals must face?

Locomotion

Thermoregulation

Respiration

Osmoregulation

How do marine mammals overcome locomotion challenges?

Fusiform body shape with limbs adapted for swimming

How do marine mammals overcome thermoregulation challenges?

Generate internal body heat and converse with blubber and/or fur

How do marine mammals overcome respiration challenges?

Respiratory system modified to collect and retain large volumes of oxygen

How do marine mammals overcome osmoregulation challenges?

Osmotic adaptations free them from need for fresh water

Polar Bears

Only marine bear species

Top of arctic food-web

Primarily hunt ringed seals (only solely carnivorous bear species)

What adaptations do polar bears have?

Large fore-paws, thick fur, reduced ears

Ability to lay down fat stores quickly, and metabolise slowly

What are the implications of climate change for polar bears?

Arctic warming is 3x the global average

Polar bears must move greater distances to survive, overlapping less with seal distributions and predate ground nesting birds

More overlap with humans

Sea Otters

Most aquatic of all carnivora

Oppotunistic feeder

Dives 5-35m

What are the adaptations of sea otters?

Flipper-like hind paws and flattened tail

High heat production and insulating fur

Modified respiratory system

Large, lobular kidney facilitate osmoregulation

Pinnipeds

Semi-aquatic carnivorous mammals with limbs modified into flippers

What are the three families of Pinnipedia?

Phocidae - ‘true’ seals

Otariidae - ‘eared seals’, fur seals, and sea lions

Odobenidae - walrus

What is the distribution of pinnipeds?

From arctic to antarctic

What different salinities can pinnipeds withstand?

Marine, Brackish, and Freshwater

What are the two breeding patterns for pinnipeds?

Solitary or Colonial

How many species of pinnipeds are in the worlds?

33 species

What adaptations do pinnipeds have for aquatic life?

Limb modification into flippers

Streamlined body shape

Insulation

Physiological adaptations for diving (high myoglobin in muscle, large blood vol. with high haemoglobim, bardycardia)

Osmoregulation (excrete conc. urine)

What is the importances of vibrissae to pinnipeds?

Vibrissae allow following of hydrodynamic trails for finding food

What are the two families of Sirenia?

Trichechidae - manatees

Dugongidae - dugong

What structural adaptations do Sirenia have?

Fusiform body shape

Paddle-like pectoral limbs, absent hind limbs

Flattened flukes

Dorsal nostrils

Large body size (including large kidneys and intestine)

Blubber

What are the two sub-orders of cetacea?

Mysticeti - Baleen whales

Odontoceti - Toothed whales

What is the difference in blowholes between Mysticeti and Odontoceti?

Mysticeti have two blowholes whereas Odontoceti have a single blowhole

Cetacea ranges

Cosmopolitan or restricted

Cetacea habitats

Coastal

Continental shelf

Pelagic

Cetacea salinity

Marine

Freshwater

Cetacea sociality

Solitary

Social - fission/fusion

Social - stable groups

What adaptations do cetacea have for locomotion?

Streamlined body shape

Reduced/absent extremities

Appendages long and narrow

Dorsal blowhole

Thrust from movement of flukes

Skin sloughing eliminates fouling

What adaptations do cetacea have for thermoregulation?

Low surface area: volume ratio

Insulated with blubber

Blubber is highly vascularised

Counter-current heat exchange in flukes

What adaptations do cetacea have for respiration?

Deep divers store large volumes of oxygen in blood and muscle

Netaceans rely more on muscle storage than pinnipeds

What is primary productivity

The synthesis of organic materials from inorganic substances by photosynthesis or chemosynthesis

What are the two types of primary producers

autotrophs and lithotrophs

What is the purpose of the light reactions

Trap light enrgy and convert it to chemical potential energy

What is the purpose of the dark reactions

Use the chemical potential energy to fix carbon via the carbon cycle

What is taken up during photosynthesis

CO2 (to become glucose)

H20 (becomes an electron donor)

What are the accessory pigments

Chl a is universal

Green: Chl b

Browns: Fucoxanthin, Carotenoids

Reds: Phycoerythrin and Phycobillins

What is chemosynthesis

The conversion of one of more carbon molecules into organic matter using the oxidation or inorganic compounds or methane as a source of energy

Why is chemosynthesis important

Chemosynthesis supports fisheries

What is primary productivity expressed by

gram of carbon bound into organic material per square metre of ocean surface area per year

How much of the oceans surface does the open ocean make up

93%

What is the importance of oceanic productivity

Oceanic productivity plays a large role in moderating the global environment

Why are coasts more productive

25% marine productivity, 90% of fish caught

Coasts have better light, weather, upwelling

What is the sensitive margin between the land and the ocean

Run off for the land

Dump sit

Accessible for fishing

Degraded

What is the importance of primary productivity

Fixes carbon and is the base of marine food webs

Provides oxygen

Role in carbon controlling atmospheric CO2 and climate