diversity observed in the entire geographical are,is called gamma diversity,true or false?
599575
Depends on what you mean by "the entire geographical areas"... Gamma diversity describes the diversity seen in an exremely large biome, such as an island, continent, or the arctic tundra, for example.\nAlpha, beta and gamma diversity all refer to the diversity "within a region", the difference is the size of the area being described. Gamma diversity is the diversity in the largest areas examined, as stated above-an entire biome covering a very large area- the Amazon rain forest, for example, while alpha and beta are smaller areas.
694233
Is it really so? On my opinion the only explanation of this phenomenon is Gulf-stream, that flows to the Northern semi-globe and brings much warmth from equatorial zone, while nothing like this exists in Southern semi-globe.
1139774
That would be absolutely impossible to answer with an exact number.  First, if you mean insect species, there are many that are undiscovered.  If you mean absolute total number of every insect, well, I don't know that anyone could even come close to a real estimate, let alone an actual number.
1024578
Descriptive...Statistics that are based on entire populations\n\nInferential....Statistics that are base on samples from a population\nCharacteristics about the whole population are inferred from the samples\n\nI think this is right.
404820
It's based on probability and logic, If you went into a field where there were 1000 rocks on the ground, you randomly chose one of them to roll over and took peek under. You saw 3 centipedes, 7 grubs, 14 ants, 3 roaches and a spider, without disturbing any of the other rocks you can logically conclude that, given the same conditions, there is a high likelihood of finding life under the majority of these rocks.
1169797
There are about 250,000 angiosperm species (flowering plants and trees), and about 80,000 gymnosperm species.  Include the other groupings, and the total comes to about 370,000.\n\nThat said, it is estimated that we have discovered only between 10 and 40% of all known species (and we probably never will discover them given the rate of destruction of habitats such as rain forests.\n\nSo the total is probably between 1.5 and 3.7 milliion, though it's a moot point because we'll never, ever know!
1134630
yep...our earth does have a diverse environment!
659956
We have catalogued an estimated less than half the species out there- And once catalogued, we don't have an active system to determine populations of most species.  Thus, we are in the dark about what species are there, how many there are in the population, etc.  GIven that, we have only vague guesses about the number of species lost.  In a similar vein, we assume new species are being born each year, or at least each decade, but since we don't know what species were there before, we certainly can't tell if a species is newly evolved, or is just one we have never seen before.
858483
"DIVERSITY INDICES: SIMPSON'S D AND E \nIntroduction: A diversity index is a mathematical measure of species diversity in a community. Diversity indices provide more information about community composition than simply species richness (i.e., the number of species present); they also take the relative abundances of different species into account. Consider two communities of 100 individuals each and composed of 10 different species. One community has 10 individuals of each species; the other has one individual of each of nine species, and 91 individuals of the tenth species. Which community is more diverse? Clearly the first one is, but both communities have the same species richness. By taking relative abundances into account, a diversity index depends not only on species richness but also on the evenness, or equitability, with which individuals are distributed among the different species. \n\nImportance: Diversity indices provide important information about rarity and commonness of species in a community. The ability to quantify diversity in this way is an important tool for biologists trying to understand community structure."\n\nP1(flies) = 20/143\nP2(rats) = 3/143\nP3(cockroaches) = 20/143\nP4(ants) = 100/143\n\nS = 4 (there are only 4 species)\n\nD = 1/(Σ (i = 1 to 4) Pi²)\n= 143²/(20² + 3² + 20² + 100²)\n= 20449/10809\n≈ 1.89\n\nEp = D/Dmax where Dmax = S = 4\nThus Ep ≈ 0.473
997050
Sure there are. There are many as-yet undiscovered species within out own world. Remember also, that we are but one of thousands of "species" living on the earth. While not provable at this point, given the vastness of our universe, it is likely that there are other forms of life elsewhere. I'd not imagine "little green men" as much as simple-cellular forms.
13201
We need different shelters for different environments.  The major geographical regions are desert, mountain, forest and aquatic.  Now, think what shelters are typical of each area, and tell how they each shelter the organism effectively.  (To contrast, tell how each shelter is different from the other, and why it must be so.)  Start with yourself.  Where do you live?  What does your home look like?  Why?
1087532
What an interesting tropic for discussion. Let's take this one steppe at a time. First, most geographers feel they are on an even plain. Sure, they have tundra work to do. But they never desert their responsibilities. As a result, the climate they maintain in their workplace is very balanced. So no, geographers never feel out of place. They just take more latitudes.
388403
Yes, indeed they did. In order for differentiation to occur, there must be physical segregation from the main gene pool as well as sufficient time for adaptation, through random mutation and natural selection to occur.\nDarwin observed that different species of finches exist on each of the Galapagos Islands, which, geologically speaking, are quite recent. He reasoned that these differing species all had a common ancestor from South America. Being isolated from the main gene pool has allowed each species to evolve specific genetic characteristics consistent with their new environment.
193198
While it might be possible that some of these creatures exist, it certainly can't be said to be 'probable'.\n\nWe are still finding new species of mammals and birds all the time.  Genetic studies have even shown us that some of the critters we thought we knew are more diverse than we thought.\n\nRecently it was discovered that the species we know as the African elephant is in fact two species, a savannah species and a forest species.  So we have 'found' one of the largest species of land mammal just in the last few years.  Another study found that there was a population of the Bactrian camel (the one with two humps) that was actually a separate species too.\n\nSo it is possible that there may be some critter hidden off in the deep forest somewhere that we've never seen before.  But the chances of something like Bigfoot/Sasquatch remaining undiscovered in the rather well explored forests of North America are rather low.\n\nThe best chance for new, exciting and incredible discoveries are in the seas.  We really have barely scratched the surface in our exploration there, and there could be all kinds of new, even huge and exciting finds down there.\n\nJust in the last few years, the Megasquid was described, whose body is larger than that of the Giant Squid (although the tentacles aren't as long), actual live footage of the Giant Squid was finally taken, and Coelacanths were found off the coast of Indonesia, 10 000 km from where it was thought was the only place they existed.
230027
Diversity is a term that refers both to the different classes of items in a given system, and also to the distribution of those items in those classes.\nBiological diversity or biodiversity is related to the concept of biocomplexity, that is, the web of interelationships and fluxes circulating in the ecosystem. It is usually measured at three levels: ecological biodiversity, species biodiversity and genetic biodiversity.\n\nSpecies biodiversity is not only the number of species in a given ecosystem, but also the proportion of individuals that belong to each species. \nExample: \nIf you have 10 species, but out of a 100-individuals sample, 91 belong to a single species, then the biodiversity is not that high. In probabilistic terms, you  could say that the chances of finding 9 of the 10 species in any sample is low. \n\nThe rainforests of the world are classical examples of high diversity ecosystems. In contrast, most ecosystems that are under continuous stress are less biodiverse, for example deserts, or grasslands. However, low biodiversity does not necessarily mean "less healthy" ecosystems. Although a grassland is less biodiverse than a rainforest, it's a stable biome all the same.\nA related concept, ecological biodiversity, refers to the variety of ecosystems in a given area, and the pattern of distribution of communities in a given landscape. No ecosystem is completely isolated from others and the health of each one depends partly on the interrelationships with other areas, therefore, the loss of ecological biodiversity due to the disappearance of certain environments can lead to greater unbalances.\nGenetic biodiversity refers to variety at genetic level. In a population, it refers to the different alleles (variations of a single gene) that are present. We know that evolutionarily speaking, polymorphisms (presence of different alleles) are a sign of a healthy population, because a greater source of variation is a better resource to respond to environmental changes. Populations that lose their genetic biodiversity (for example, because the number of individuals is severely reduced) may be more exposed to extinction. \nBiodiversity can be measured at all the organization levels studied by Ecology, but is especially focused in communities and ecosystems.
375174
What is a Biome?\n\nA biome is a large geographical area of distinctive plant and animal groups, which are adapted to that particular environment. The climate and geography of a region determines what type of biome can exist in that region. Major biomes include deserts, forests, grasslands, tundra, and several types of aquatic environments. Each biome consists of many ecosystems whose communities have adapted to the small differences in climate and the environment inside the biome.\n\nAll living things are closely related to their environment. Any change in one part of an environment, like an increase or decrease of a species of animal or plant, causes a ripple effect of change in through other parts of the environment. \n\nThe earth includes a huge variety of living things, from complex plants and animals to very simple, one-celled organisms. But large or small, simple or complex, no organism lives alone. Each depends in some way on other living and nonliving things in its surroundings.
788407
This is only a theory, no amount of evidence has proven it fact. The only way scientists verify it is through fossil records which show the existence of marine creatures and plants existing at one point in the middle of the dry land continents that we see today. Also, scientists believe that the continents were once one huge land mass that came into existence similar to the way Hawaii did (aka. with a lot of volcanic activity).