What were the advantages of life on land for early amphibians?
597417
greater oxygen levels than today, less threat of predators, untapped food sources.
855946
1)  By producing heat, organisms can stay active throughout the cold winter months, thereby allowing them to breed and claim new habitats.  They can also feed on the slower, cold-blooded creatures!\n\n2)  Warm-blooded animals can stay more active during night time hours - an advantage for many of the same reasons in (1).\n\n3)  Warm-blooded animals can change their metabolisms much faster than can cold-blooded animals.  This allows them to adapt to environments and to increase their range.  Cold-blooded animals are much slower to adapt to changing environmental conditions.\n\n4)  Exothermic reactions within the body allow for greater metabolic efficiency.  Therefore, warm-blooded animals get greater benefit from the food that they eat, or conversely, do not need to eat as often to get their nutrional requirements.  This gives them an evolutionary advantage in terms of what they can eat and the ability to thrive during famine.
832178
Advantages:\n* You get to know more about the world around you.\n* More species would be discovered.\n* More scientists on the planet Earth.\n* More subjects for you to study in school.\n* More technology for our convenience.\n\nDisadvantages:\n* Scientists die in labs because of accidents.\n* Too many species to keep track of.\n* Animals disturbed from habitats.\n* Plant species taken from environment.\n* Rare species threatened.
633471
they live in different environments
9475
I don't have any solid research but I imagine there were at least a few general reasons:\n\nTo spread out a kingdom because individuals and their livestock needed more land, OR to accomodate growing populations in a certain kingdom/city/empire.\n\nTo provide a safer buffer from enemies, that is, cities in the center of an increasing territory for better protection.\n\nTo secure resources or trade routes\n\nTo convert other people to the expanding religion\n\nTo populate newly/randomly discovered territories\n\nI am editing now, I suppose those things could have been the reason in the very earliest of times but in prehistoric societies, I bet survival sums it up pretty well. Maybe not expansion but certainly the nomadic thing...pick up and move to beat the weather or a threatening pack of animals, to find food or land appropriate to grow food and support livestock. Territory would certainly have had something to do with it, if there was a serious enough pissing contest with a threatening enough adversary, such as an unfriendly neighboring clan, a settlement of people might pick up and move to give themselves more safety by giving the big guy wider berth.
1041464
It has long been held that the parathyroid glands and parathyroid hormone evolved with the emergence of the tetrapods, reflecting a need for new controls on calcium homeostasis in terrestrial, rather than aquatic, environments.\n\nNice to see you've corrected the spelling mistake in your 'nickname', after we all pointed it out, of course...there's a good girl!\n\n;)
110876
Reptiles and many other animals, particularly most insects live at the temperature of the world around them - cold when it is cold and hot when it is hot - this is called poikilothermy, or being poikilothermic. Endothermy means generating heat internally. All mammals are endothermic and most are homeothermic. \n\nWe maintain our inner temperature by burning food (oxidation) within ourselves and we stay cool by sweating, panting and changing our postures and place in the world. Sweating and panting work by generating heat loss through evaporating water; changing posture allows us to control to some extent the heat absorbed from the world around us; while changing position simply means seeking shade or shelter when it is too hot. Mammals are unique in possessing hair and in many mammals hair varies throughout the year. these mammals possess a thick insulating coat of hair during winter and a much thinner one during summer.\n\nBeing warm blooded gives mammals a distinct advantage in may habitats, allowing them to be active when reptiles are hardly able to move. It also allows mammals to live in habitats where reptiles cannot live at all, such as the arctic, mountain tops, etc. The reason behind this is that muscle activity is basically dependent on chemical reactions, as are all biological functions. Chemical reactions run slowly when it is cold, but quickly when it is hot. This is because heat is synonymous with (the same as) energy. The more energy you have the faster the chemical reaction occurs. In the early mammals being endothermic probably allowed them to be active at night when competing reptiles were forced to rest or be sluggish.\n\nBeing warm blooded is costly. Mammals and bird have mush greater energy requirements than reptiles of a similar weight.
791117
Like any structure in an organism, tongues evolved over time through small changes (mutations) which placed each successive individual at a slight advantage within the species.  That individual had some advantage, probably longevity, which allowed for greater success in reproduction.  This allowed the mutation to be passed on to future generations.  The tongue as we know it today, is the result of accumulations of countless mutations over a long period of time.\n\nIn terms of what they might look like in a million years - who knows?  It is pure speculation - can you think of a new 'model' of the tongue that would place an individual at an advantage over other members of the species and allow them to be more successful in terms of reproduction/survival etc..?
930792
One main advantage is the ability of the offspring to take advantage of the parent's resources while the young tree is growing. Trees growing from seeds are limited to the resources in the seed to get their start; trees from root-shoots can borrow from the parent until they can make it on their own. Think of a redwood: most of their reproduction is asexual. Their seedlings have little chance in the deep shade of a forest, but when root-sprouts can take advantage of resources from an already-mature tree getting light in the canopy, the sprouts can grow 3 feet a year.\nSome trees can also root-sprout or stump-sprout if they are cut or fall down. That's another big advantage--to be able to reproduce almost after you're dead.\nAnother advantage is that an asexually reproducing tree is assured of a good environment for its offspring--if it has enough energy to reproduce, it must be doing well. Of course that advantage is shared by non-dispersing sexually reproducing trees.
423906
There's a hypothesis called the aquatic ape hypothesis that proposes that several of our characteristics (reduced body hair, layer of subcutaneous fat, poor kidneys, bipedal stance) and even our brains (fish are an important source of omega-3 fatty acids and great brain food) were the result of our evolving in or near water for a key period after we split from chimps.  Note that this is just a hypothesis not a theory.  There are alternate hypotheses that involve movement out of the forest and into savannah habitat and the same features are connected to that transition to savannah.  A theory, in contrast, is a type of hypothesis that is widely accepted and has loads of support from observations and experimental data.  Examples of theories are gravity and evolution.\n\nIf the aquatic ape hypothesis proves false, there is plenty of data to support our origin from water-dwelling amphibians prior to the Permian-Triassic extinction event.
252440
A tadpole is just a juvenille version of a frog, which is a vertebrate.  This would be like saying that you weren't a vertebrate until you were an adult, which you know is false.\n\nPegnuin feathers are very small and have been selected by evolution to keep the birds as warm as possible.  See a picture of them in the sources link.
661985
Few complex life forms we know of can survive exposure temperatures that low for more than a moment. However, if pockets of milder temperatures could be found (thermal vents, well isulated hybernation dens, etc) some life would likely adapt. Life forms that could mature and reproduce in one warm season (such as a plant that produces spores capable of surviving such a harsh winter) would have a great advantage. Plants such as trees woudn't stand a chance, as is true of many things humans and other complex life depend on for food and shelter. \n\nAnother consideration would be the erosion due to lack of any plants capable of maintaining a root system to stablize soil. Between the turbidity from erosion and likelyhood that all rivers would freeze solid through most of the winter, most life in rivers and lakes would become extinct. Since the upper temperature is not much if any higher than what we have now, the average temperatue is much lower. This would concentrate vast amounts of water in the icecaps, possibly enough to greatly increase the salinity of the oceans, which would also see a major drop in temperature. Most marine life is more sensitive to temperatue changes than terrestrial or freshwater life, so a great number of extinctions there also.\n\nSo no, life would not survive other than perhaps a few simple life forms. Even a drop of a dozen degrees in average temperature would be devastating in the long run for life as we know it.
731534
It is the place where the species was developed. That determines that each specie requires determined conditions to grow at optimal rates. I.e. eucaliptus requires a lot of water, so you will not find it in a dessert. \nIf you plant a tree outside its habitat it may not grow as much as in its habitat. It may inclusive die.
1006019
Over the last several decades a significant decline in frog populations all over the world have been noticed, they are just not moving to diffrent locations.  Right now thousands of species are considered endangered or extinct.\n\nFrogs have been on this planet for more the three hundred millions years.  They were around at the time of the dinosaurs and out lived them.  They belong to the class amphibia, meaning double life.  This name fits them because they spend part of their life in the water and part of their life on land.  Unlike reptiles amphibians as a whole rely on water a lot more and can never move far from it.  Today there are almost 5900 species of known amphibians, which 4800 are frog species.  Frogs and toads (which are a type of frog) belong to the order anura.  Of this order there are 29 different families.  Many biologists question why frogs are in a state of decline, an answer with more the one apparent culprit.  It seems to be a combination of problems such as habit destruction, cattle grazing, agriculture, pollution, climate change, UV radiation, pesticides, invasive species, and even road traffic.\n\nHumans have caused much destruction to the natural environment.  We reduce the number of habitats suitable for many species to thrive in, causing them to migrate elsewhere, adapt to us, or die off.  Frogs are very fragile creatures that adapt slowly to major change.  They always must maintain wet, moist skin and due to their dependency on water they are unable to migrate long distances to find suitable habitat.  If we destroy the only pond in an area where will the frogs go?  We forget that they are small animals and a distance of a mile might be too much for them.  \n\nForest fragmentation of a few hundred feet is enough to wipe out an entire population of frogs.  Something as simple as a road can devastate a species’ numbers.  If a road blocks them from their mating ground it can be an impossible task to cross it.  Many times on a warm sunny day the road will get very hot, and the frog’s skin will dry out while crossing it, resulting in its death.    Along with forest fragmentation comes the edge effect.  With the edge effect a once cool shaded area can change dramatically.  The edge effect causes greater changes in temperature and moisture that can be unsuitable for many frog species.   Microhabitats can dry out and temperatures inside the forest fragment can become increasing cold due wind patterns.  Along the edge different vegetation can take over resulting in invasive species of both plant and animal.  In Brazil an Amazonian frog species has shown great decline and forest fragmentation seems to play a key role.  Adult survival was not effected by fragmentation but mean clutch size was reduced by 17%.  By experiments it has been shown that the fragmentation of the forest causes increase predation, increase in interspecific competition, and slower growth rate resulting in delayed reproduction.  \n\nNot just forest fragmentation causes frog decline but also other human alterations to habitats is causing declines worldwide.  Wetlands are the homes of many species of frogs and humans over the years have in some way changed the landscape.  The wetting and drying of the wetlands has great influence on many organisms and frogs are no different.  The Murray-Darling Basin of Australia has been modified for irrigation flow and has reduced the overbank flooding into flood plain wetlands.  This degradation of the wetlands has caused all frog species in the area to decline by an average of 23%.\n\nAgriculture is also another way in which humans alter the habitat.  Both rangeland and cropland reduces the population size of frogs.  Cattle grazing greatly alters the habitat.  First off the habitat many times must be made suited for grazing.  This means frog habitat can be destroyed causing a direct effect or the cattle can interfere with frog migration, causing an indirect effect.  By the grazing of livestock migrat
489493
The earth when young was a nice place to live,\nTill man came along, and made the world give,\nNow the land is being polluted, And the air too,\nLets learn to recycle, and keep the earth new.
786518
Don't amphibeous species grow back different limbs?  Besides, I heard they IMPORT their frogs legs from a wide variety of Nations, or at least they could if they ran out (it's not as if they are restricted from free trade, and isolated from the rest of the world).  But logic tells me the bodies would just remain the same, but you would have to do a little research, or actual testing, to find the true answer to your question.   But it is my opinion that my answer is simple enough to make sense to you.
320173
Frogs come in variety of colors but the majority of them are green. Being green when sitting on green leaves has obvious advantages if you want to avoid becoming an easy meal for some hungry predator. \n\nFrogs are not green because they have green pigment in their skin.In their skins they have three types of pigment cells (called chromatophores) stacked on top of each other. At the bottom are melanophores, containing a mostly dark pigment called melanin. These are the same cells that can make human skin various shades of brown. On top of the melanophores are iridophores, packed with highly reflective bundles of purine crystals, and on top of the iridophores are xanthophores, usually packed with yellowish pteridine pigments. In the typical green frog, light penetrates to the iridophores, which act like tiny mirrors to reflect mostly blue light back into the xanthophores above them. These cells act like yellow filters, so the light escaping the skin surface appears green to our eyes.\n\nBy manipulating all three types of pigment cells, a wide range of colors can be produced, although usually the range extends from bright green to various shades of brown and gray. In frogs, all of these changes appear to be mediated by hormones circulating in the blood. The advantage of such color change is obvious. Imagine a frog leaping from a green leaf onto a brown tree branch. Melanin moves, reflective purine crystals shift position, yellow pteridine pigments cluster or disperse, and voila, that green frog that stood out like, well, like a green frog sitting on a brown branch is now a well camouflaged brown frog.