Transcript Behavior & Reproduction in Sharks

Behavior & Reproduction in
Sharks
Kevin T., Yazel M., & Rickeeta R.
Structures & Behavior
• Survived over 300 million years. Resemble early ancestral forms of
sharks; called “living fossils”
• Lateral line organ can pick up sound.
• Can detect a small amount of blood ½ kilometers away.
• 2/3 of their brain is devoted to it’s smell.
• Can detect weak electric fields given of by other organisms.
• Have tiny pores called “ampullae of Lorenzini”; which sense electric
generated from the muscles of other fish.
• Streamlined body allows them to move quickly. Tail fin produces
speedy acceleration. Quick to catch prey.
• Several rows of teeth, move forward to replace lost teeth, may have
100’s of teeth at a time.
• Have to be in constant motion because they don’t swim, if they
stop they will sink to the bottom, swimming provided continuous
stream of oxygenated water for the gills.
Reproduction
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Fertilize internally.
Males have 2 organs called claspers by their pelvic fins. Transfers sperm into the
females reproductive tract.
Some sharks develop internally & live-bear their young.
Some sharks begin their predatory behavior while still developing.
Others have external development, where 1 or 2 embryos develop within a black,
leathery egg casing called “mermaid’s purse” they take 1 or more years to develop.
Their empty egg casings are often seen washed up on the shore of the beach.
jawless fish
Arynn Washington Myron
Williams Paula Mombeh
Groups of Fishes
• Jawless Fish which by their names imply that
they have no jaws.
• Sharks and their relatives, who belong the
class Chondrichthyes which include sharks,
rays, skates and a fer uncommon fish like
sawfishes.
• Bony Fish which make up the class of
Osteichthyes.
Jawless
• Skeletons are made of fibers and cartilage
• Lack vertebrae
• Modern jawless fish are divided into to
classes: lampreys and hagfishes
• Lampreys are typically filter feeders as larvae
and parasites
• Hag fishes have wormlike bodies lack eyes and
have light detecting sensors scattered around
their bodies and they have six hearts
Sharks and Relatives
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Chrondros is the Greek word for cartilage
Have tooth like scales covering their skin
Large curved tails and torpedo shaped bocies
The most noticeable part is their thousands of
teeth
Bony Fishes
• Have hard calcified tissues called bone
• Almost all bony fishes belong to the group
called ray finned fishes which means slender
bony spines
• Only 7 living species of bony fishes do not
belong to the ray finned group
By Destiny Stokes
DeMarco Hicks II
Malik Cheeks
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Fish whose entire skeleton is composed of
cartilage are called cartilaginous fish
Placoid scales: tiny teeth that are deeply
embedded in the skin(Point backward)
Visible gill slits for breathing
Mouth located on the ventral side
Fins are very rigid
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Class :Chondrichthyes
1st jawed fish & has several unique
characteristics
Relies on the lift by the pectoral fins to help
prevent sinking & to glide in the water
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There are about 350 known species of sharks
Vary greatly in size
Filter feeders
Whale shark: largest fish in the
world(harmless to humans/vertebrates
Hammerhead: predatory shark( two lateral
projections on its head with an eye at each
end)
Kassandra Randall
Michael Williams
George Jones
 Except during mating season, Rays are not known to
be social
 Rays regularly attend cleaning stations where certain
species of fishes pick parasites from their hovering
bodies
 Rays give birth every other year to a single pup, or a
pair of four-foot pups that arrive rolled up like burritos
 Male rays leap out of water to impress females, to help
control parasites, to escape predators, or as a means of
intraspecific communication.
 Rays can grow to nearly 25 feet from wingtip to
wingtip, live for a quarter century, and will consume
about 60 pounds of plankton and small fish each day
by filter feeding.
 Only two species of mantas have been scientifically
described, although a third, similar-appearing species
inhabiting the Caribbean and Atlantic is suspected.
 Although useless and nonfunctioning, a manta has
approximately 300 rows of skin-covered teeth in its
lower jaw
 They swim in tropical waters
 Open oceans
 Oral reef.
 Near the coast
 Up to 29.5 ft (9 m) wide
 Dark brown to black on top with paler margins; they
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are mostly white underneath
Eat microscopic plankton, small fish, and tiny
crustaceans
Mantas have no teeth; they sieve their food
Reproduces via aplacental viviparity (embryos develop
inside eggs that are retained within the mother's body
until they are ready to hatch)
Harmless to people and usually indifferent to divers
Life Span Is unknown
Morgan B, Shawn S.
Shark facts
 93% of shark attacks from 1580 to 2010 worldwide were on males.
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In 2010, North American waters had 42% of all confirmed unprovoked
shark attacks worldwide (32 attacks).
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Surfers accounted for 50.8% of all attacks in 2010.
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Swimmers and waders accounted for 38% of all attacks in 2010.
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Snorkelers and divers accounted for 8% of all attacks in 2010.
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Inflatable rafts and inner tubes accounted for 3% of all attacks in 2010.
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2010 was the most dangerous year for unprovoked shark attacks in a
decade, with 79
Why sharks attack ?
 There are four basic types of shark attacks on humans.
The first and, by far, the most common are provoked
attacks.
 These occur when people in some way touch, or
otherwise disturb, sharks.
 Fishermen removing sharks from their nets, for
example, might lose a finger or limb if not careful.
 Sometimes divers have taunted or tried to grab a shark,
with not-surprising consequences.
Ways of preventing shark attacks
 Stay in groups and do not wander away from your
companions, since sharks are more likely to attack
individuals.
 Avoid being in the water during early morning and late
afternoon, since sharks actively feed at those times.
 Never go into the water if you are bleeding, even if the cut
or injury is minor. Sharks possess very keen senses, and
blood could attract one from several feet away.
 Don't wear shiny jewelry when in the water. The glisten
mimics fish-scale sheen and visually labels you as shark
prey.