A crayfish has an open circulatory system while humans have a closed circulatory system. "Closed" means that we have true blood vessels that carry blood to and from the heart. "Open" means that the organs are simply bathed in blood that freely circulates around the body. Sometimes the heart can move the "blood" by creating pressure waves in the fluid.
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The main difference between the circulatory systems of humans and giraffes is the length of their blood vessels. Giraffes have very long necks, so their heart must pump blood with enough force to reach their brain. This results in higher blood pressure and a larger heart compared to humans. Additionally, giraffes have specialized valves in their neck to prevent blood from rushing to their brain when they lower their heads to drink.
There is only a small percentage of genetic difference between male and female humans, estimated to be around 0.1%. The majority of genes are shared between males and females, with the differences mainly located on the sex chromosomes (X and Y).
Humans didn't develop a circulatory system. Early forms of circulatory systems developed in the first animals and organisms to roam the earth. As these species evolved through speciation and genetic variation, new species came to exist that also had circulatory systems. Over time, the systems became more complex and efficient (compare the cardiopulmonary circulatory system of the human compared to the circulation of a fish). Therefore, without circulatory systems there would be no humans nor would there be life as we know it
The difference is the same as in other contexts.* "Artificial" means that something was created by humans. * "Natural" means that it was NOT created by humans.
Exoskeleton: Crayfish have a hard shell, and no bones. That makes crayfish invertebrates (no spine). Gills: Crayfish respire underwater through gills, where humans use lungs. The circulatory system is the second one, the reason for this being that crayfish have no blood vessels (and humans obviously do).
Both are close circulatory system.
The excretory system of crayfish, which involves specialized structures called green glands for waste removal, is unlike the human excretory system, which primarily relies on the kidneys. The respiratory system of crayfish, which involves gills for gas exchange, differs from the human respiratory system that uses lungs.
Humans
Closed circulatory systems have blood that does not flow in defined blood vessels. Examples are insects and how their organs are bathed continually in "blood". Open circulatory systems have blood that flows in vessels. Humans have this system as blood flows in veins, arteries and capillaries.
Quite obviously crayfish, humans, and many other animals have apendages. Snails, however do not.
Closed circulatory systems have blood that does not flow in defined blood vessels. Examples are insects and how their organs are bathed continually in "blood". Open circulatory systems have blood that flows in vessels. Humans have this system as blood flows in veins, arteries and capillaries.
Unicellular: Exchanges occur directly with enviroment Multicellular: Diffusion is not possible unless diffusion across body surface. Transporting substances over long distance in animals.
Humans
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The perch has a single circulatory system that consists of a two-chambered heart and blood vessels, while humans have a double circulatory system with a four-chambered heart. In the perch, blood flows from the heart to the gills for oxygenation and then to the body tissues, while in humans, blood circulates from the heart to the lungs for oxygenation and then back to the heart before being pumped to the rest of the body.
There is very little difference between the circulatory system of a horse and a human other than size. The other primary difference would be that the human system functions on a vertical plane and the horse system functions on a more horizontal plane because of the natural orientation of their bodies.