Term | Definition |
fish | ancestors of all land animals |
agnatha | jawless fish that is no longer a taxonomic term |
530 million | fish evolved __________ years ago |
41 percent | percentage of freshwater fish species |
26,000 living species; more than all other vertebrate groups combined | how many living fish species? |
800 x more | fish adapted to lived in a medium __________ dense than air |
salt and water balance | fish can adjust to _____________ of environment |
1/20th | gills extract oxygen from water that has ___________ the oxygen of air |
aquatic | environment both shaped and constrained fishes evolution |
free-swimming protochordate | fish descended from __________________ ancestors |
agnathans | earliest fish-like vertebrates include extinct ostracoderms, and living lampreys and hagfishes |
placoderms | fish with paired appendages and jaws that went extinct in Carboniferous with no living descendants |
cartilaginous fishes | lost heavy armor and adopted cartilage as skeleton; flourished during some periods, becoming nearly extinct during others |
bony fish | dominant fishes today |
ray finned and lobe finned | two distinct lineages of bony fish |
ray finned bony fish | radiated to form modern bony fishes |
lobe finned | sister group to tetrapods; include lungfishes and the coelacanth |
oviparous sharks and rays | lay an egg capsule immediately after fertilization that attaches to kelp with tendrils; may take up to two years before mini adult hatches |
ovoviviparous sharks | retain fertilized eggs in reproductive system where they are nourished by yolk of egg; "live" birth |
viviparous sharks | nourish embryos with maternal bloodstream; "live" birth |
live births | make it more likely more of the young survive but no other care is given after birth |
trunk and tail muscles | propel fish forward by undulations |
large, rigid head | minimizes yaw |
less yaw and a fast fish | created by a very rigid body |
tail or caudal fin | largest fin is the ___________ for rapid forward movement |
dorsal fins and anal fins | assist with lateral stability |
gill covers | operculum |
pectoral fins | assist with hovering and slow turning |
pelvic fins | often small for open water swimmers but larger on bottom dwellers which use them for resting on |
heavier | fish are slightly ___________ than water |
fatty liver | a shark has a very ____________ that makes it a little buoyant; must also keep swimming to move it forward and angle itself up |
swim bladder | bottom dwelling fishes lack a ______________ |
volume of gas | fish an control depth by adjusting ______________ to bladder |
gulp air | some fish _____________ to fill swim bladder |
gill filaments | folds of tissue inside the pharyngeal cavity covered by the operculum |
85% of O2 from H2O | continuous water flow opposite blood flow through capillaries maximizes gas exchange allowing some fish to remove ________________ |
ram ventilation | forward movement pushes more water over gills |
lungfish | use lungs |
eels | use skin |
bowfin | use gills at low temperatures and air bladder at higher temperatures |
electric eel | has degenerate gills and must gulp air |
searching for food and eating | fish spend most of their time __________________ |
zooplankton, insect larvae, and other aquatic animals | most carnivores feed on ______________________ |
swallow food whole | since it would block flow of water across gills, most fish ________________________ although a few have teeth that crack prey or have some molars in throat |
plants and algae | some herbivores eat ______________________ |
suspension feeders | eat plankton using gill rakers to strain food; these fish swim in large schools |
stomach | used for storage |
intestines | absorb and digest nutrients |
catadromous | develop in freshwater but spawn in seawater |
anadromous | living in sea but spawing in freshwater |