Presentation on theme: "Behavior & Reproduction in Sharks Kevin T., Yazel M., & Rickeeta R."— Presentation transcript:
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 its 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 100s of teeth at a time. Have to be in constant motion because they dont swim, if they stop they will sink to the bottom, swimming provided continuous stream of oxygenated water for the gills.
Reproduction 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 mermaids 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 WashingtonMyron 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 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
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
Class :Chondrichthyes 1 st jawed fish & has several unique characteristics Relies on the lift by the pectoral fins to help prevent sinking & to glide in the water
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 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. In 2010, North American waters had 42% of all confirmed unprovoked shark attacks worldwide (32 attacks). Surfers accounted for 50.8% of all attacks in Swimmers and waders accounted for 38% of all attacks in Snorkelers and divers accounted for 8% of all attacks in Inflatable rafts and inner tubes accounted for 3% of all attacks in 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.