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Sharks and swordfish have circulatory mechanisms that keep their body temperature warmer than the surrounding area maintaining thermal homeostasis.

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1. Sharks generally have about 45 to 50 teeth – but that’s just the “front row” teeth. They also have, on average, as many as seven replacement rows of teeth behind the front row, ready to move into place if a tooth is damaged or falls out. With all the action a shark’s mouth sees throughout its lifetime, an individual might go through as many as 30,000 teeth.

2. Even though we associate sharks with big, sharp chompers, some species barely need their teeth. Whale sharks and basking sharks, two of the largest species, are both filter feeders and have numerous, tiny teeth – a whale shark might have up to 300 rows of teeth .

3. While sharks don’t use sounds to communicate, they do rely on body language. If you’re snorkeling or diving, it’s good to be aware of the body language sharks use to communicate that they’re uneasy. Hunched backs, lowered pectoral fins, sharp movements (in zig zag or back-and-forth patterns), and diving down to touch the bottom are all good indicators that a shark is feeling uncomfortable.

4. Some large sharks have dramatically longer lifespans than small sharks. For instance, whale sharks (which generally range from 18 to 32 feet/5.5 to 10 meters in length) can live up to 100 years, while the smooth dogfish (with an average length between 2 and 4 feet/0.6 and 1.2 meters) might only live for 16 years.

5. Whale sharks claim the title of largest shark species, and are also the largest species of fish in the world.

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Many of the early forms of sharks were quite small. There is evidence to suggest they looked more like fish. Many of them were similar to eels as well. Their faces featured noses that were round rather than pointed. They also didn’t have a brain as large as it is today. That is a very important point to make though. More than 2/3 of the size of a brain today for a shark is for the senses. Mainly their ability to smell. This is one of the areas where sharks have significantly been able to evolve and to become a more intelligent species.

Their teeth were also quite different than they are today. Instead of being razor sharp they were smooth. However, these early ancestors definitely had the rows of teeth that were replaced like they do today. This could indicate that early sharks fed upon plants in the water instead of being meat eaters as we know them today. This could be an indication that something occurred that made it impossible for plant life to grow for a while. In order to survive they started to consume other living creatures in the water.

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how do sharks maintain a stable internal environment

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how do sharks maintain a stable internal environment

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Shark needs a supply of water and dissolved materials inside its body to carry out the exquisite chemical choreography needed to maintain its life processes. Dissolved in the Great White's bodily fluids is a complex mixture of salts, including sodium, potassium, and calcium chloride, sulfates, and many others. Outside the shark's body, the seawater contains a similar but more concentrated mixture of dissolved salts. Since water is among the smallest of biologically-important molecules, it requires less energy to move water than salt. Thus, if relative salt concentrations were the only important factor, a White Shark would continually lose its vital supply of internal water to the outside marine environment through the relentless process of osmosis. But there is more to saltiness than just salt.

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how do sharks respond to their environment 

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how do sharks respond to their environment 

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The adaptive features of sharks have enabled the species to survive in waters all over the world for more than 400 million years. Although the shark is a capable predator in many waters, sharks mainly change their environment when in search of food. Sharks can also detect aquatic wildlife in the area by utilizing electromagnetic fields; this makes it easier to protect themselves and spot potential meals at any time. They readily travel long distances to another region to survive when food in one environment becomes scarce.

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how do sharks obtain and use material and energy

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how do sharks obtain and use material and energy

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In most mammals it’s relatively easy to observe animals preparing for food scarce times by putting on body fat — bears, sea lions, whales, etc, all simply get externally larger. But with sharks it wasn’t immediately as clear, as the energy was stored internally in the liver — carrying fat stores in their massive livers rather than external blubber.

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sharks are long lived and some species of sharks lay eggs with the developing embryo covered by a tough, protective case. This is known as oviparous reproduction. The embryos of these sharks are well supplied with nutritious yolk, unlike the tiny eggs of most bony fish. After some time, the egg hatches and a young shark emerges. Bullhead sharks, whale sharks, and zebra sharks are examples of oviparous species.

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The first large-scale exploration of the genetic code of the great white shark has revealed some unexpected insights into what makes the iconic apex predator so distinctive.The first large-scale exploration of the genetic code of the great white shark has revealed some unexpected insights into what makes the iconic apex predator so distinctive.Seeking genetic similarities and differences that might explain the characteristics of the white shark, the researchers compared the genetic makeup of the great white to that of zebrafish and human genes, focusing on the RNA sequences expressed by organism's genes (known as the transcriptome). Zebrafish are, genetically, one of the best understood fish, and human genes have long been a point of important research.

All three species have gene products common among them, so the researchers were able to focus on those and establish a common comparative base.

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Unlike most bony fish, sharks's eggs are fertilized inside the female's body. The male shark has "claspers," extensions of the pelvic fins that are used to transfer sperm to the female and fertilize her eggs. Most sharks give birth to live young, but some release eggs that hatch later.

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All living things are made up of cells and the sharks make red blood cells by the spleen

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The selachimorpha is a fearless predator which is most commonly known as a shark.