fishes chapter 11 section 2. characteristics of fishes vertebrate lives in the water uses fins to...
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Fishes
Chapter 11 Section 2
Characteristics of Fishes Vertebrate Lives in the water Uses fins to move Ectotherms Obtain oxygen through gills Have scales
Obtaining Oxygen Fishes get oxygen from the water
Fish gulps water (water contains oxygen) Moves through openings in fish’s throat to
the gills Water flows over gills Oxygen moves from water into the fish’s
blood
Circulatory System Closed circulatory system
Heart has two chambers, or inner spaces Pumps blood in one
loopHeart to the gillsGills to rest of the body
Back to heart
Movement
Fins help fish swim Thin membrane
stretched across bony supports
Fin provides large surface to push against the water (canoe paddle)
Movement is related to obtaining food and reproduction
Reproduction External fertilization: the eggs are
fertilized outside the female’s body Male hovers close to female and spreads a cloud of sperm cells over the eggs
Internal fertilization: giving birth to live young Sharks Guppies
Nervous System Nervous system and sense organs of
fishes help them find food and avoid predators
Keen sense of touch, smell, and taste help fishes capture food
Major Groups of Fishes
JawlessCartilaginousBony
Jawless Fishes
No jaws or scales Have mouths instead (scraping, stabbing,
and sucking their food) Cartilage: tissue that is more flexible than bone Examples
Hagfish Look like large, slimy worms
Lampreys Can be parasites Use sharp teeth and suction
cup mouths to feed on other fishes Eel-shaped bodies
Cartilaginous Fishes Have jaws and scales, and
skeletons made of cartilage Most sharks cannot pump water
over their gills, rely on swimming or currents to keep water moving across gills
Rays and skate take in water through small holes located behind their eyes
Usually carnivores Sharks: attack and eat nearly
anything that smells like food, many rows of teeth
Rays and skates: hunt on ocean floor, crushing mollusks, crustaceans, and small fishes with their teeth
Bony Fishes Examples: trout, tuna, goldfish Have jaws, scales, a pocket on each side of the head that holds the gills, and a skeleton made of hard bones
Fins: help the fish stay upright Scales: cover the body by overlapping
each other Gill Pocket: holds the gills Swim Bladder: helps stabilize the fish
at different depths in the water
Diversity of Bony Fishes