Biology is such a broad field, covering the minute workings of chemical machines inside our cells, to broad scale concepts of ecosystems and global climate change. Biologists study intimate details of the human brain, the composition of our genes, and even the functioning of our reproductive system. Biologists recently all but completed the deciphering of the human genome, the sequence of deoxyribonucleic acid DNA bases that may determine much of our innate capabilities and predispositions to certain forms of behavior and illnesses. DNA sequences have played major roles in criminal cases O.
Fossil shark teeth Cretaceous from southern Israel. A shark tooth is one of the numerous teeth of a shark.
A shark tooth contains resistant calcium phosphate materials. Sharks continually shed their teeth; some Carcharhiniformes shed approximately 35, teeth in a lifetime, replacing those that fall out. There are four basic types of shark teeth: The type of tooth that a shark has depends on its diet and feeding habits.
In some formations, shark's teeth are a common fossil. These fossils can be analyzed for information on shark evolution and biology ; they are often the only part of the shark to be fossilized. Fossil teeth comprise much of the fossil record of the Elasmobranchiiextending back to hundreds of millions of years.
Shark teeth are also useful in conducting research about the structure of teeth, shark migration patterns, and identifying shark species.
A finetooth sharkCarcharhinus isodon Carcharhiniformesthe ground sharks, with over species, are the largest order of sharks.
They include a number of common types, such as catsharksswellsharksand the sandbar shark. Members of this order are characterized by the presence of a nictitating membrane over the eye, two dorsal finsan anal finand five gill slits.
There are a range of shark attack prevention techniques employed to reduce the risk of shark attack and keep people safe. They include removing sharks by various fishing methods, separating people and sharks, as well as observation, education and various technology-based solutions.
Techniques that involve culling sharks are contentious. Environmental groups have voiced concern over the impact of reduced shark numbers on ocean ecosystems and the problem of by-catch of other marine life, particularly endangered species.
Because sharks are important to the ecosystem, killing them harms the ecosystem. Shortnose sawsharkPristiophorus nudipinnis A sawshark or saw shark is a member of a shark order Pristiophoriformes bearing a unique long, saw-like rostrum snout or bill edged with sharp teeth, which they use to slash and disable their prey.
There are eight species within the Pristiophoriformes, including the longnose or common sawshark Pristiophorus cirratusshortnose sawshark Pristiophorus nudipinnisJapanese sawshark Pristiophorus japonicasBahamas sawshark Pristiophorus schroederisixgill sawshark Pliotrema warreniAfrican dwarf sawshark Pristophorus nancyaeLana's sawshark Pristiophorus lanae and the tropical sawshark Pristiophorus delicatus.
Sawsharks are found in many areas around the world, but is most commonly found in waters from the Indian Ocean to the southern Pacific Ocean. The Bahamas sawshark was discovered in deeper waters m to m of the northwestern Caribbean. The whale sharkthe world's largest fish, is classified as Endangered.
Binding legislation and harvest management strategies It evaluates threatened species, and treats threatened species not as a single category, but as a group of three categories, depending on the degree to which they are threatened: Frilled sharkChlamydoselachus anguineus The Hexanchiformes are the order consisting of the most primitive types of sharksand numbering just seven extant species.
Fossil sharks that were apparently very similar to modern sevengill species are known from Jurassic specimens. Hexanchiform sharks have only one dorsal fineither six or seven gill slitsand no nictitating membrane in the eyes.Figure 2 shows the landing composition of sharks by the different types of fishing gear in for the west and east coast of Peinsualr Malaysia, East Malaysia (Figures 2a, 2b and 2c, respectively), and for the whole waters of Malaysia combined (Figure 2d).
Carpet Sharks derive their name from both their bottom-dwelling nature and varied coloration.
Taxonomy,Carpet Sharks,Whale Shark BECOME A SHARK SAVER. Join our email list for the latest news and help make a difference. SIGN UP NOW. Share this page with a friend.
Get social with Shark Savers. Join us on Facebook, Twitter, YouTube and Vimeo. There are over different types of sharks in the World.
Come learn about them all in this super list of different shark breeds. This is cool stuff! Although sharks belong to the class Chondrichtyes, there are many different types.
Sharks arose about million years ago and have remained virtually unchanged for the past 70 million years and still comprise a dominant group. It is thought that sharks almost certainly evolved from placod. Unlike most editing & proofreading services, we edit for everything: grammar, spelling, punctuation, idea flow, sentence structure, & more.
Get started now! Introduction The legendary great white shark is a cartilaginous fish that has caused fear and admiration for many years. It is considered one of the biggest predators of the oceans and the fiercest, but there is more imagination than truth in this sentence.