The Perch Flashcards
1
Q
Classification
A
- perch are vertebrate animals (they have backbones)
* most bony fish have a swim bladder used to maintain buoyancy or as a lung
2
Q
Digestion
A
- perch eat smaller fish, aquatic insects, crayfish and snails
- they feed by creating a partial vacuum in their mouths and sucking in prey
- they have pyloric ceca at the junction of the stomach and intestine to increase the surface area for absorption
3
Q
Gas exchange
A
- perch get their oxygen from water
- it would take too much energy to inhale and exhale water into lungs, therefore fish have gills
- gill filaments are made of small thin walled lamellae
- water is gulped into the mouth while the gill covers are closed, then the mouth closes, forcing water through the gills
- deoxygenated blood flows through the gills from back to front, the counter-current system maximizes gas exchange
4
Q
Circulation
A
- perch have a closed circulatory system
- their hearts have only one pump
- a single atrium collects blood and a single ventricle pumps it back out
5
Q
Reproduction
A
- sexes are separate in perch
- females lay eggs on the bottom and males release sperm over the eggs
- the eggs hatch in 2 or 3 weeks, depending on the temperature
- perch don’t care for their young
6
Q
Excretion
A
- nitrogen wastes diffuse into the water through the gills
- perch skin is waterproof but the mouth and gills freely allow water to diffuse into the blood
- the perch kidney produces large volumes of dilute urine, to eliminate all this extra water
