The different species of dolphins are spread across every ocean and several major rivers around the world. While they may range in size, geographical location and looks, humans are captivated by all the dolphin species. more »
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The different species of dolphins are spread across every ocean and several major rivers around the world. While they may range in size, geographical location and looks, humans are captivated by all the dolphin species. more »
Endangered species are at risk of extinction. This means that they would no longer exist upon this planet. It is estimated that 40% of the earth's species are endangered. It is important that steps are taken to preserve these species as they are all important parts of our natural ecosystem. more »
Trees produce wood, and it's pretty easy to identify a type of tree by noticing the shape of the tree at the bark and at the leaves. Pick up a field guide to trees if you're uncertain. Wood is another story--by the time it winds up in the lumber yard or your kitchen, it has lost its bark and leaves, and its shape is mostly... more »
With Zoo Tycoon 2, you can create your dream zoo and then wander with the guests among the animals and attractions. You have to keep the wildlife content in naturalistic environments and ensure that the visitors are happy with rides and refreshments. The Endangered Species expansion adds more options to your creation. more »
Pokemon Fire Red is Gameboy remake of the original Pokemon Red and Blue that was made for the first black and white Gameboys. The game features all of the Pokemon Ruby/Sapphire additions. The game allows you to breed, specify gender and has hold items. The original 150 Pokemon are on this video game, along with a few extras such as... more »
Bird watching is a favorite hobby of many because it can be done almost anywhere. Whether you...
Abalone is a mollusk that has been used for food since before recorded history. Modern Asian...
If nature is calling but the woods are too far away, invite some wildlife into your backyard...
Bass fishing is not just a relaxing recreation; it requires a great deal of skill and...
Many of us tend to think of animals like sea turtles, elephants, tigers, rhinos and gorillas when we hear the word "endangered species." However,... more »
Owl species are separated into two subfamilies, barn and bay owls, and other owls. They are nocturnal and can be observed in the late morning or... more »
The narwhal is an arctic whale species noted for its long, horn-like tusk. It is classified by the International Union for Conservation of Nature... more »
Fruit flies are one of the most widespread and diverse creatures on earth. With hundreds of genera containing many thousands of species of fruit... more »
Everyone loves nature, but sometimes travel spreads opportunistic plants and animals that choke out native wildlife. With a few simple tips, you... more »
In biology, a species is:
* a taxonomic rank (the basic rank of biological classification) or
* a unit at that rank (in which case the plural is "species". This is sometimes abbreviated: "spec." or "sp." singular, or "spp." plural).
There are many definitions of what kind of unit a species is (or should be). A common definition is that of a group of organisms capable of interbreeding and producing fertile offspring of both genders, and separated from other such groups with which interbreeding does not (normally) happen. Other definitions may focus on similarity of DNA or morphology. Some species are further subdivided into subspecies, and here also there is no close agreement on the criteria to be used.
Biologists working definition
A usable definition of the word "species" and reliable methods of identifying particular species is essential for stating and testing biological theories and for measuring biodiversity. Traditionally, multiple examples of a proposed species must be studied for unifying characters before it can be regarded as a species. It is generally difficult to give precise taxonomic rankings to extinct species known only from fossils.
Some biologists may view species as statistical phenomena, as opposed to the traditional idea, with a species seen as a class of organisms. In that case, a species is defined as a separately evolving lineage that forms a single gene pool. Although properties such as DNA-sequences and morphology are used to help separate closely-related lineages, this definition has fuzzy boundaries. However, the exact definition of the term "species" is still controversial, particularly in prokaryotes, and this is called the species problem.Queiroz> Biologists have proposed a range of more precise definitions, but the definition used is a pragmatic choice that depends on the particularities of the species concerned.Queiroz/>
Common names and species
The commonly used names for plant and animal read more at » http://en.wikipedia.org/wiki/Species
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