BIOL 1108 1st Edition Lecture 12 Outline of Last Lecture I Locomotion II Feeding III Reproduction and Development Outline of Current Lecture I Oviparous Viviparous OvoviparitySpecies II Development III Sensory Systems Current Lecture I II Oviparous Viviparous OvoviparitySpecies Oviparous egg laying o Eggs are layed outside the body and nourishment comes from yolk in the egg o Most fish have a larval stage Viviparous live bearing o Young develop inside the mother and get nourishment from the mother o Nourishment from fish placental connection Secretions in the reproductive tract Nutritive eggs additional eggs are food for fertilized eggs o Skip the larval stage o Typically follow internal fertilization Ovoviparity both o Eggs are produced but are retained inside the female until around the time of hatching o Nourishment from the egg yolk Development Larval stage starts when young switch from yolk to an external food source Juvenile stage miniature version of the adult form These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute III Deviations o Flatfishes flounders halibut sole young are bilaterally symmetrical eyes are not on one side of head Asymmetric development o Smoltification of Anadromous Salmonids Migrating individuals from the Salmonidae family Egg Larvae Fry Parr Smolt Adult Transition from freshwater to saltwater changes in environmental conditions Adult stage attainment of sexual maturity age depends Sensory Systems Gain information from the environment o Hearing range varies Otoliths Gas bladder o Lateral Line System detects vibrations and changes in water pressure Consists of neuromast cells along the side of the fish s body Provides spatial awareness Allows them to navigate in space o Vision Eye Structure Cornea Iris Pupil Lens held by ligaments Retina where photoreceptors are located Optic nerve Fish have round lens whereas terrestrial vertebrates have more elliptical lens Effects the focusing of light through the eye Very little refraction difference in aquatic environment 2 types of photoreceptors Rods light reception o More rods in nocturnal fish Cones color reception o More cones in coral Tapetumlucidum layer of guanine crystals behind the receptor layer of the retina Reflect light o Smell olfaction Nasal sacs contain olfactory receptors that detect chemical cues in the water Complexity depends on feeding habits of fish
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