Keywords Flashcards
Protogyny
Fish starts off as female and changes to male at a later stage.
Protandry
Fish starts off as male and changes to female at a later stage.
Monomorphic
One form, (sexes are similar in size and appearances).
Dimorphic
Two distinct forms, (sexes look different).
Sequential hermaphrodites
Changes sex at a certain point in its life
Egg Scatterers
Fish scatter their eggs onto the substrate/plants. The fry hatch very quickly. No parental care. Lay a large group of eggs to offset predation.
Egg Buriers
Usually inhabit areas of drought. Spawning takes place in the dry season. Eggs are buried in the mud, and rain stimulates eggs to hatch.
Egg depositors
Fish deposit eggs on substrate. The fish lay less eggs, but eggs are larger. Two groups;
Parental carers
Non-parental carers
Mouth brooders
Fish brood offspring in mouths, so predators will not eat the eggs/fry. Parental care is given. Female does not eat whilst brooding. Incubation takes place in the throat. Two groups;
Ovophile; eggs are laid then the female sucks them up. The male has egg shaped spots on his anal fin, the female tries to such them up but receives a mouthful of sperm (milt). Eggs are then fertilised.
Larvophile; Lay eggs on substrate, and are guarded by parents. Once hatched, the female picks the fry up and keeps them in her mouth.
Nest builders
Fish construct nests where fertilised eggs are guarded. Male tend to build the nest; either a bubble nest or a nest on the ground.
Livebearers
Two groups;
Ovoviviparous; the eggs form and hatch within the female before birth, once hatched in the body, live young is born.
Viviparous; no eggs are formed, young are nourished within the body.
Some females can store milt in the body for several months.
Anterior
Towards the head
Posterior
Towards the tail
Cranial
Head region
Caudal
Pertaining to the tail region
Dorsal
Towards the top of the animal
Ventral
Towards the belly of the animal
Placoid scales
Found in rays and sharks. Resemble small teeth like projections from skin.
Ganoid scales
Usually mosaic in arrangement with little overlaps. Seen on sturgeons and gars.
Ctenoid scales
Spiny comb or teeth-like extensions to the outer edge
Cycloid scales
Round and oval shaped
Scutes
Don’t have scales. Instead have 2 or 3 overlapping bony plates called scutes
Photoreceptors
Fish eyes that have rods and cones.
Fins
Used for stability, propulsion, steering and balance.
Dorsal fin
Located along the back of the fish between the tail and head - provides lateral stability so the fish can swim in a straight line and prevent it rolling over.
Caudal fin
Tail fin - responsible for propulsion, sudden forward movements and very fast swimming patterns
Anal fin
Located on the underside of the body between the pelvic and caudal fin - helps with stability and prevents the dish from rolling over.
pectoral fin
Paired located near the bottom of the fish directly beneath the gill openings - used for navigation and stability, provides upward lift that helps fish maintain depth, enables flight of flying fish, some species also have defensive spines.
Pelvic fin
Located in front of the anal fin on the abdomen of the fish - used for braking, stabilising their bodies and changing their direction.
Adipose fin
Some fish e.g. tetras have an extra adipose fin - located between the dorsal and caudal fins.
Ventral fin
Some fish e.g. catfish use them to hold eggs during spawning.
Lateral line
Helps detect vibrations, water pressure and currents, visible as a line of tiny perforations in a row of scales down the fish. Pressure around objects is distorted allowing fish to change direction quickly to avoid predators, catch prey and shoal.
Swim bladder
Bag-like organ filled with gas controlled by the blood. Located below the backbone. Most bony fish (except bottom-dwellers) have one. Provides buoyancy, allowing fish to remain at a certain depth in water. Lungfish use it to breathe air, and catfish use it to produce sounds and provide buoyancy.
Gills
Diffuse oxygen from the water. Take in water and expel through gills.
Respiration
Breathing process begins when the gills covers close and the mouth opens.
heart
2 chambers - atrium and ventricle.
Liver
Secrets enzymes that break down fats. Storage area for fat. Production of bile. Also involved in waste excretion.
Kidney
2 kidneys, located near the spine. Produces urine and helps regulate the salt levels.