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61 Cards in this Set
- Front
- Back
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Describe the Agnathan fish (Hagfsh & Lampreys) |
Agnatha (jawless fish) * No jaws * No paired fins * Some species (now extinct) had "bone" armour Hagfish * Rasping toungue, no real jaw, blind * Produce A LOT of slime * Can tie themselves into knots to tear portions from food Lampreys * Anadromous (go to frshwater to breed) * Usually parasitic on fish * Functional eyes, 7 pars of gills |
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Describe the Gnathostoma fish. |
Gnathostoma (Jawed fish) * Cartilagious jawed fish * No swim bladder * Heterocercal tail that generates lift * Large oily liver for buoyancy * Denticles instead of scales * Claspers in males * Paired fines * Fast, manouverable and strong (Elasmobranchii- Sharks & rays. Holocephalii- Chimaeras and ratfish) |
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Describe the Osteichthyes. |
Sarcopterygii (Lobe finned) - Fins supported by basal bones - Ancient - Lung fish Actinopterygii (Ray finned) - No bones supporting the rays |
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How do you identify ray finned fish species? (Arctinopterygii) |
* Body measurements * Strctures of head and body * Spine and fin ray counts * Scales * Lateral line |
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What is weird about reptiles? |
They are not a true taxon, they are polyphyletic. |
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What are the reptilian orders? |
Testudines(Sea turtles) Squamata(Snakes and lizards) Crocodilia(Crocodiles) Aves(Birds) |
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What are the characterisitcs of Odontoceti? |
Toothed whales. * Teeth * Single blowhole * Fused bottom jaw |
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What are the characteristics of Mysticeti? |
Baleen whales. * Longer than 7 m * Lack teeth but have a mesh of bumpy plates that hang from upper jaw (baleens) * Double blowhole * Unfused lower jaw |
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How are cephalochordate Acraniatans limited to movement by size? |
They use their notochord for muscular attachment and it helps the body to move. They swim using wave contractions. The bigger they get, the better they are at swimming and getting resources. BUT at some size, the notochord won't be able to support it anymore. This is how vertebrates developed. They replaced the notochord with a vertebral column that is much stronger. |
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How did the formation of the hinged jaw occur in gnathostomes? |
The agnathans had gill pouches that were supported by simple cartilaginous gill bars, firsstly, the anterior gill bars became jaws and the posterior bars retained respiratory function. |
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What was the significance for gnathostomes to develop a jaw? |
* Larger food could be eaten or dismembered * Fascilitated development of teeth * Active predator defence * Passive predator defence (can manouver better and exploit a wider range of habitats) |
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Describe the four classes in Gnathostoma. |
* Class Acanthodii (spiny sharks) - Estinct - Small (20 cm to 2 m) - Paired spines/fins - Body covered in scales - Large eyes, string teeth and jaws - Pelagic * Class Placodermii (plate-skinned) - Extinct - Large (up to 10 m) - No true teeth, large jaw - Bony plates (dermal bone) overing 1/3-1/2 of their body - Benthic * Class Chondrichthyes (Cartilaginous fishes) - Internal skeleton is entirely cartilaginous - Reduced passive predator defence - Teeth formed of dermal bone - No swim bladder or gill covers - Moves through hyrodynamic lift/buoyancy * Class Osteichthyes (Bony fishes) - 75% of all fishes - True bone (perichondral) skeleton - Operculum (gill cover) - Segmented fin rays - Swim bladder for byoancy control |
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What is hydrodynamic lift and buoyancy? What are the disadvantages of each? |
Lift: Arises from flattened ventral surface of pectoral fins. Water flows faster over the upper surface which reduces the pressure and gives the animal an upward lift. Disadvantage: Must keep swimming to stay afloat Buoyancy: Low density fats accumulate in the liver and pectoral fins, giving the shark as low a density as the seawater. Disadvantage: Large bodysize, which is energetically expensive, but the solution to that is being streamlined |
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Describe the lungfish and Coelacanth (sub groups of Sarcopterygii) |
Lungfish: -Thoguht to be extinct, but there are 3 remaining genera (Australia, Africa & South America) - Bony skeleton, but part of the braincase is cartilaginous - Large scales - "lungs" to breathe air Coelacanth - Discovered in 1938 - Large, thick bony scales - Fleshy fins - Vestigial lungs filled with fat |
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How did the Class Actinopterygii get advantageous development from sarcopterygii? |
* They reduced the thickness of the scales to reduce drag * Fin rays were reduced in number and jointed * Tail where symmetrical, more flexibility for swimming * Jaw develop greater strength and movements |
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Desribe the three major radiations from Atinopterygii |
Chondrostei: e.g. sturgeon Holostei: e.g. gar-pike Teleostei: Mostly cycloid scales and fins are oriented for precision of movement These succeed in the evolution due to their diversification of form. |
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Desribe the three families in Teleosts of Parrotfishes, Damselfishes and Trevallies. |
Scaridae (Parrotfish): Small mouth, fused theeth. Herbivores. Laterally compressed. Slow movement. Small eyes. Pomacentridae (Damselfish): Small mouths, herbivores. Weak jaws, laterally compresed. Slow movement. Small eyes. Carangidae (Trevallies): Can grow large (170cm), Carnivores. Larger mouth and eyes. Laterally compressed. Streamlined. Can go long distances and are camouflagued for open waters. |
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What has driven the feeding adaptations of fish? |
- Fish size (age) - Food type/behviour - Habitat - Trophic level |
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What are he characeristics of Reef planctivores? |
E.g. Damselfish. Small, elongate/oval shape. Often solid or banded colours Often stay close to their habitat/substrate. May stay hidden in branched corals. |
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what are the characteristics of ocean planctivores? |
E.g. Herrings and most fish larvae. Minute or abcent teeth. |
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What are the characteristics of diurnal planktivores? |
Visual feeders, so they are light dependent. Feed mostly on copepods, larvaceans and fish eggs with their ramjaw. Small mouths, gill rakers. |
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What are the characteristics of nocturnal planktivores? |
Typically reef associated (specialists), usually larger eyes, that are often red ish. Feed mostly on vertically migrating copepods, amphipods, isopods, mysids, polychaets and ostracods. Most lack protusible jaws because they can get closer to their prey in the dark. |
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What effets do herbivore fish have of seagrass beds? |
Herbivorian fish that mostly feed on algae can revers the effects from eutrophication by eating the epiphyte algae from the grass, which increases the light penetration and allows the grass to grow. |
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What does it mean if a fish is a "gardener"? |
Often territorial fish (damselfish) that are seletive feeders. This is called "gardening" or "differential grazing". These recycle nutrients really fast and enhance the productivity of the envionment around them. |
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What are the positive and negative effetcs of reef grazers? |
+ Grazers creates space for new recruits and are a keystone group on coral reefs - newly recruited corals can be reomved by grazers |
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What are the problems with with being an herbivorian fish? |
Algae are easier to digest than the non-nutritious seagrass. And the abbsorption efficiency is low. So they have to eat all the time and have specialised adaptations. |
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What are some adaptations to seagrass herbivory? |
* High feeding rate and increased gut length * Low stomach pH * Chemical digestion with enzymes * Mechanical digestion * Muscular stomach * Pharyngeal mill |
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What does the pharyngeal mill work? |
The plant food is trapped in mucus and entangled in teeth, the food will be broken into smaller pices while it mves into the oesophagus. |
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What does ontogentic diet shift mean? |
Developmental diet change, so the diet changes with age/size |
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Describe the reproduction of sharks |
Gonohoristic, clear sexual dimorphism. (Males have claspers, formed from extension of the pelvi fin. Internal fertilisation (males use clasper to transfer spermatophores). Bottom dwelling sharks usually lay eggs in cases (oviparous). large- mobile sharks often have live birth. (vivparous) |
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What are the differenes between oviparous sharks and vivparous sharks? |
Oviparous: Eggs are attached to substrate or wedged inte crevices. Newly hatched young are mini adults and are very well developed. No parental care after eggs are laid. Viviparous: Embroys can be nourished by placenta like attachment, some have mily secretion from females. Some have rich yolk sac that ruptures just before bith. Eggs and less developed embryos can be consumed. |
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What does Protandous and protogynous mean? |
Protoandrous: Male to female Protogynous: Female to Male |
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How do Acanthuriade (Surgeonfish) reproduce? |
Gonochoristic, floating eggs. Have a relatively long planktotrophi larval stage. Juvenile settles when they are close to reefs, when they settle, they eat the same diet a the adults. |
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What control/stimulates sex change in fish? |
Age/Size: Change to other sex at a cenrtain stage/age. Social suppression: Can change if other sex is lacking Social induction: Change sex due to precence of other sex |
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How do Labridaens (Cleaner wrasses for example) change sex? |
Potogynous. Single dominant male in a group of females. If male dies or is removed, the most dominant female will change sex. The change is very rapid, the olours change in a few hours and will be a functional male in a few days. |
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What is polyandry and mongamy? |
Polyandry: Many males to one female Monogamy: One male to one female. |
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Why do some fish species change sex? |
* Individuals gets two chances to reproduce * Ability to reproduce while sill growing * Maxmimise reproductive potential of the species * Successful fish will dominate fertilisation of the rest of the group. |
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What does the size advantage model mean? |
There will be a reproductive success that increases with size, so an individual with a particular size will adopt the sex that is most favourable for that size.
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What are the size advantages of protandry? |
* Females with a larger body cavity will lay more eggs * Large individuals have a higher fecundity as females * Males change to females after reaching a certain size. |
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What are the size advantages of protogyny? |
* Larger males have greater reproductivity success (gains control of harem and can protect nest sites) * Females can change to males after reaching a certain size. |
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Describe two spawning modes within fish and what chracteristics they have |
Broadcast spawning: High fecundity, floating eggs and no parental care. Demersal spawning: lower fecundity, sinking eggs and some parental care (nesting/brooding) |
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What are the risks with pelagic spawning and why is it still done? |
* mortality is very high * The mortality and movement of pelagic stage controls adult populations Why; * Patchy environment, they can only do this * Energy saving * Dispersal increases likelyhood of locating patchy food or habitats * Avoid local extinction in long term |
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Describe the distribution of saltwater crocodiles. How can they live in saltwater conditions? |
Found i open brackish water around coastal areas and in freshwater systems. They have a high tolerance for salinity thanks to salt excretion glands (concentrated urine) |
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Crocodiles are Ectotherms. What does this mean? |
They rely on surroundings to control body temperature. They prefer to have a body temperature of 30-33 C so they use water, sun and shade to regulate it. |
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Describe the senses and jaws of crocodiles and how they use locomotion. |
Eyes: Have good eyesight and can see colours, they also have excellent night vision. They have a transparent eyelid that proctects the eye but limits udnerwater vision. ISOS: Integumentary Sense Organs. Pressure sensors located around jaw and body. Jaws: Have 60+ teeth that are constantly replaced. Have a bite force of 3447 kg. Locomotion: -Swimming: Feet are tucked in alongside body, tail is used for swimming. - High walk: Can lift the entire bdy off the ground on their feet. Can walk up to 5km/h -Gallop: employed when scared or trying to flee. 17km/h. |
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What are the diet of saltwater crocodiles? |
Young ones eat small animals (crabs, prawns, fish, frogs and insects.) Larger crocodiels eat pigs, birds, reptiles, sea turtles, wallabies and even other crocodiles. They are generallly sealth predators. They can live several months without food because they have a slow metabolism. |
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How do saltwater crocodiles reproduce? |
Underwater. Male lies on back of the female and wraps his hind legs and tail under her. Internal fertilisation. Eggs will be laid 2-6 weeks after mating and will be guarded for 2-3 months. The incubation and sex determination is temperature dependent. Eggs hatch 11-13 weeks after being laid and will die if it is more than 34C. |
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What are the population threats on saltwater crocodiles? |
Habitat destruction, mortality due to eating cane toads and ess eggs laid by overheating, flooding and boat strikes. Also drowning in nets and hunting. |
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What are some adaptations sea snakes have adapted to live in marine environments? |
External: Laterally compressed body and flattened tail on some. Valves on nostrils, frequent skin shedding and reduced ventral scales. Internal: Extended lung and cutaneous respiration |
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how do sea snakes osmoregulate? |
Their kidneys cannot concentrate salt in urine like crocs, so they have a concentrated brine solution produced by a salt gland under the tongue that is the pushed out when they flick the tongue. |
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What are: Sphenisciformes Procellariiformes Pelicaniformes Suliformes |
Sphenisciformes: Penguins, completely depending on the sea for food. Flightless. Procellariiformes: Tube-nosed seabirds: albatrosses,petrels, shearwaters. Albatrosses nest in isoleated islands and are specialised seabirds. Pelicaniformes: DUH Suliformes: Plunge divers, reinforced face |
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What is the biggest threat to penguins? |
Climate change. They need fast ice to breed and it is less and less habitat space for each year. |
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What is the biggest threat to albatrosses? |
* The ocean is patchy, so the need to fly long distances for food. They also have a low fecundity. * Long line fishing, esp. pelagic fishery * Depleting stocks due to overfishing * Plastic ingestion * Predation on chicks * Introduced species |
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Ho can we adapt fishing to reduce bicatch of diving birds? |
* BaitStaining – not palatable / visible * BirdScaring – streamers and other devices * Changetime to avoid birds (night / season) * Limitingbird access to baited hooks – dipper poles |
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What are the threats to sea turtles? |
* Habitat loss and degradation * Egg collecting for human food * Incidental capture in fishing gear * Harvesting for human food * Boat strikes * Trade of turtle products * Chemical pollution in marine environment * Plastic * Light pollution * Tourism |
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What are some conservation and management methods to preserve sea turtle populations? |
*Legislation * Enforcement of laws * Protected areas * Research * Public education * Technology (turtle excluder devices in fisheries, 97% turtles released alive) |
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What are the differences between marine otters and sea otters? |
Marine: No sexual di-morphism and smaller(90cm). West coast of South america in kelp forests. Need rocky shores to breed. More vulnerable than sea otters because they spend more time on land. Sea: Sexul di-morhpism and larger (120-130 cm). Keystone speies in kelp forstes. Polygamous, no regular mating season. 1 pup/birth. Give birth in the ocean. |
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What are the differeces between Otariidae and Phocidae? |
Otariidae (Fur seals and sea lions) : Have "legs" and ear flap. Swim with front flippers, like turtles or penguins. Phocidae ("true" seals): Have tail and no ear flap. (More adated to swim. Swim with the tail, like a fish. |
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How did the stellars sea cow become extinct? |
Overharvested and killed off in 27 years by modern man... Overharvesting of sea otters started at the same tie---> more urchins. |
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What are the differences between dugongs and sea cows? |
Manatees (Sea cows): More river dependent. Eat plants, algae and seagrass. Dugongs: "dolphin" tail and only eats seagrass. |
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Explain the following definitions: Polydont Homodont |
Polydont: Many teeth Homodont: Teeth are all similar in size and shape |
