Download Mendel`s Work Section 1 Chapter 4

11-2 Fishes
Fishes
vertebrate that live water, use fins to
move,
most are ectotherms, obtain oxygen
through gills, and have scales
largest group of vertebrates (nearly 50%)
gills
remove oxygen from water (feathery)
remove CO2 from blood stream
fish open mouth water flows over gills
and out slits below
circulatory system
closed
heart with two chambers that pumps
blood in a closed loop ...heart to
gills...gills to rest of body and back to
heart
movement
fins... thin membrane stretched across
bony supports
act like paddles
large surface area allows for faster
movement
reproduction (external)
most fishes have external reproduction
eggs are laid...sperm is deposited
reproduction (internal)
sharks and guppies
eggs are fertilized inside female ...young
develop inside
birthed when able to live on their own
nervous system
nervous system and sense organs help
fishes find food and avoid predators
most can see well in water.... good sense
of touch...and smell ...some taste with
whiskers...
Three Main groups
jawless, cartilaginous, and bony
Jawless Fishes
have no jaws or scales, skeletons are
cartilage
hagfish (large slimy worms) and
lampreys (parasites to other fishes)
mouth openings made for scraping,
stabbing and sucking their food
Cartilaginous Fishes
Sharks, rays, and skates
jaws, scales, and skeletons made of
cartilage
scales are pointed, tooth like...rougher
than sandpaper.
obtaining oxygen
most cannot pump water over gills and
rely on swimming or currents to move
water to gills
rays and skates .. lie around a lot.. take in
water through small holes located behind
eyes...water leaves through gills on
underside ....
obtaining food
usually carnivores
rays and skates hunt the ocean floor
crush mollusks, crustaceans, and fishes
with their teeth
sharks will attack anything that smells
like food they can smell and taste even a
small amount (one drop of blood per 115
liters)
rows sharp teeth that replace lost teeth
...flip up and move forward
Bony Fishes
have jaws, scales, a pocket on each of
head that hold gills, a swim bladder,
and a skeleton made of hard bone
huge variety
95% of all fishes are bony fishes
live in both salt and fresh water
swim bladder
gas-filled sac that helps the fish stay
stable at different depths in the water
the gas adjusted after the fish reaches the
desired depth