Because nobody has found them or seen them yet
No, it is estimated that we have only identified a fraction of the total number of species on Earth. New species are still being discovered regularly, particularly in remote or unexplored areas. The actual number of species may be much higher than current estimates.
Over 1.5 million species have been identified and described by scientists, but it is estimated that there could be anywhere from 5 million to over 100 million total species on Earth, with many still waiting to be discovered and classified. Each year, new species are being discovered in various ecosystems around the world.
Oxygen was discovered by the very first species on planet Earth.
No, not all organisms on Earth have been classified. There are many undiscovered species, particularly in unexplored regions like the deep sea or remote rainforests. New species are continuously being identified and classified by scientists.
Unknown. They discovered some new species only last month.
4000 species known, but over 3million presumed to be living on the earth 4000 species known, but over 3million presumed to be living on the earth
There really isn't a date the Earth was discovered, as humans have known of the existence of the planet since the species was first capable of symbolic thought.
Scientists have identified and named around 1.7 million species of organisms, but it is estimated that there may be anywhere from 8.7 million to over 1 trillion total species on Earth.
No. Far from it. (An enthusiastic 'ditto')
There are estimated to be around 8.7 million species on Earth today, although the actual number could be much higher due to many species still being undiscovered, particularly in less-explored regions like the deep ocean or tropical rainforests.
Scientists have discovered and described approximately 1.75 million species of organisms. However, it is estimated that there may be as many as 8.7 million species on Earth, meaning that many more species are yet to be discovered.
There are 800 000 identified species, most of which are insects and invertebrates. However, many new species are continually being discovered, and taking into account the huge areas still unexplored on Earth (eg forests in South America, small islands, and most oceans), the true number of animal species on earth is probably far larger.