I. Fishes – Biology

J. Migration• Generally related to feeding and/or reproduction• Diel

• Horizontal• Ex: Grunts (day on reef, night feeding in seagrass

beds)• Vertical

• Ex: Mesopelagic fishes

• Large Scale• Ex: Skipjack tuna feed in Eastern Pacific, spawn in

Western and Central Pacific

I. Fishes – Biology

J. Migration1. Anadromous

• Spawn in fresh water• Spend most of life in ocean• Ex: Salmon (seven species) in Pacific Ocean

• Spawn in shallow areas of rivers/streams• Semelparous (adults die after spawning)• Young migrate downstream to ocean after 0-5

years• Spend 3-7 years in ocean before returning to

home stream• Homing behavior enabled by olfactory imprinting• Important source of nutrition for wildlife, forests

I. Fishes – Biology

J. Migration2. Catadromous

• Spawn in ocean• Spend most of life in fresh water• Ex: Eels (16 species) in Atlantic Ocean

• Spawn in Sargasso Sea (400-700 m or deeper)• Semelparous• Eggs hatch into leptocephalus larvae• Larvae spend a year or more as plankton then

undergo metamorphosis into juveniles• Adults spend 10-15 years in fresh water before

migrating to Sargasso Sea to spawn

Fig. 10-37

Fig. 11-1

II. Tetrapods

• Amphibians (Amphibia)• Terrestrial, freshwater• Live near/in water; some species entirely aquatic• Reproduce in water; most with external fertilization• Ectothermic

• Reptiles (Reptilia)• Terrestrial, “freshwater”, marine• Adapted to life out of water; some species entirely aquatic• Ectothermic

• Birds (Aves)• Terrestrial• Some species dependent on aquatic systems• Endothermic

• Mammals (Mammalia)• Terrestrial, “freshwater”, marine• Some species entirely aquatic• Endothermic

Aquatic-Terrestrial Transition

Challenge Aquatic TerrestrialDesiccation Few adaptations to

resist desiccation

Water-retaining skin

Gas Exchange Gills Lungs

Mechanical Support Thin, flexible bones Stronger bones Ribs, girdles

Locomotion Caudal or fin propulsion; glide

Walking; no glide Limbs with digits

Feeding Suspension feeding Suction feeding

Modification of jaws, teeth, tongue

Thermoregulation Ectothermic Poikilothermic

Excretion Ammonia Urea

Sense Organs Lateral line, otoliths Inner ear

Reproduction External fertilization Aquatic eggs

Internal fertilization Amniotic egg

evolution.berkeley.edu/evolibrary/article/evograms_04

Tiktaalik

Evolution of Limbs

Tiktaalik Sea-Land Transition

III. Amphibians

A. Urodela (salamanders, newts)• Terrestrial, aquatic: ~550 species• Retain tails as adults (paedomorphic character)• Fertilization usually internal

B. Anura (frogs, toads)• Terrestrial, aquatic: ~5400 species• Possess tails as juveniles; not in adults• Fertilization usually external

C. Apoda (caecilians)• Terrestrial (mostly), aquatic: ~170 species• Legless (secondary)• Fertilization internal