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All About Sharks!
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|Introduction to Sharks||Introduction to Rays||Anatomy||Shark and Ray Species||Extreme Sharks||Extinct Sharks||Classification||Shark Glossary||Shark Index||Printables, Worksheets, and Activities|
These sharks are fast, strong swimmers and include the great white shark and the mako. A type of Lamniformes shark, family Lamniformae.
The Earth's magnetic field is aligned with the north and south poles, and has reversed many times during geologic history. Sharks may use the magnetic field of the Earth for navigation purposes on migrations.
The shortfin mako shark (Isurus oxyrinchus) has a conical snout and long gill slits. It is the fastest swimming fish. These sharks reproduce via aplacental viviparity (they bear live young but the babies are not nourished via a placenta in the womb; cannibalism often occurs within the womb). Makos can maintain a body temperature higher than that of the surrounding water.Order: Lamniformes.
Mammals are warm-blooded animals with hair that nourish their young with milk. Primitive mammals evolved during the Triassic period. Whales are mammals.
Manta rays (Manta birostris) are the largest rays and are closely related to sharks. These graceful swimmers are up to 29.5 ft (9 m) wide, but average about 22 ft (6.7 m) wide. Mantas are dark brown to black on top; they are mostly white underneath. These harmless rays have a short tail and no stinging spine. Mantas eat microscopic plankton, small fish, and tiny crustaceans.The largest weighs about 3,000 pounds (1350 kg). They are very acrobatic; they can even leap from the water. Mantas are common and are found worldwide in tropical seas, living both close to shore and in open seas.
Marine mammals are mammals that live in the sea and breathe air. Whales, dolphins, seals, sea lions, and sea otters are marine mammals.
Mass extinction is the process in which huge numbers of species die out suddenly. The dinosaurs (and many other species) went extinct during the K-T extinction.
Megalodon was an ancient shark, living between 25-1.6 million years ago; it is extinct. It may have been 40 feet (12 m) long or more. Only fossilized teeth have been found.
Discovered in 1976, the Megamouth is a filter feeding shark that grows to be 16.5 feet (5 m) long. This nocturnal feeder eats small fish, shrimp, plankton, and jellyfish. Only 14 examples of this rare species have been found, mostly in the Pacific Ocean! Off the coast of Indonesia, three Sperm whales were observed attacking a megamouth shark (the 13th observed megamouth). Classification: Order Lamniformes, Family Megachasmidae, Genus Megachasma, species pelagios.
Mermaid's purse is a common name given to shark's eggs, which can have unusual and beautiful shapes.
The Mesozoic Era ("The Age of Reptiles"), occurred from 245-65 million years ago. It is divided into the Triassic, Jurassic, and Cretaceous periods. Dinosaurs, mammals, and flowering plants evolved during the Mesozoic, and Pangaea broke up. The era ended with the K-T mass extinction.
Metamorphic rocks are compacted by pressure and heat from deep inside the earth.
The Milk Shark (Rhizoprionodon acutus) is a common requiem shark that is found in the Eastern Atlantic Ocean and the Indo-West Pacific Ocean. It grows to be up to 6 ft (1.8 m) long, and has a long, slim body. The mouth has long, characteistic labial folds at the corners that differentiate it from other requiem sharks. It is gray above and white below. The milk shark eats small fish (like sardines, herring, and flatfish) and invertebrates (like squid, octopus, shrimp, and crabs). This shark is harmless to humans. It is called the milk shark because in India, it is believed that eating its meat will improve the milk production of a mother. Classification: Order Carcharhiniformes, Family Megachasmidae, Genus Rhizoprionodon, species acutus.
A migration is a seasonal journey from one region to another. Many sharks migrate yearly from cold feeding waters to warm breeding waters.
A million is a thousand thousand. The dinosaurs lived millions of years ago.
A mineral is a naturally-occurring solid of definite chemical composition whose atoms usually form a regular pattern.
The Miocene epoch was a geologic time span that lasted from 24 million to 5 million years ago. During the Miocene, modern birds and many mammals evolved (including the horses, dogs, bears, South American monkeys, and apes in southern Europe). Ramapithecus appeared; this primate was pehaps an ancestor of man. The climate was relatively warm (as compared to the earlier Oligocene or the later Pliocene). There were extensive grasslands (and grasses diversified), and the interior of the continents were relatively dry; northern coniferous forests expanded. Kelp forests appeared in the seas. In North America, the Sierra Nevada Mountains and the Cascade Mountains were formed; in the South America, the Andes Mountains arose. The Bering land bridge formed during the Miocene, connecting Russia and Alaska, allowing many animals to migrat across continents. The Isthmus of Panama also formed during this time. Australia became very dry (but went through wet and dry periods). In Europe, the Mediterranean Sea and Indian Ocean were separated (they had been connected by the Tethys Sea).
Mollusks are marine invertebrates with a soft, unsegmented body. Many have a calcerous shell around the body. Mollusks include squid, octopus, chitons, snails, and bivalves (like clams).
Squatina, also known as angel sharks, are flat-bodied, bottom-dwelling sharks. They have a blunt snout and have teeth that can crush the shellfish that they eat.
Mutualism is an association between two different species of organisms in which both benefit from the association. An example of mutualism is the relationship between bees and the flowers they sip nectar from- the bees get nectar from the flower and the flower gets pollinated by the bees. Mutualism used to be called symbiosis (which is now a more general term).
"mya" stands for millions of years ago.
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