2006-09-06 09:04:27 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Biology
Exact answers only!
2006-09-06 09:07:37 · update #1
too many that they keep on finding new species
2006-09-06 09:06:19 · answer #1 · answered by car4423 4 · 0⤊ 0⤋
The biggest unknown is the number of insect species, which *dwarfs* the number of all other animals *combined*. There are about 920,000 *named* species of insect. However, the actual number is much higher ... (to quote source #1) "It is estimated that there are 20-30 million species of insects on the earth at present."
Source #2 gives estimates for the other kinds of animal species:
non-insect arthropods (spiders, mites, centipedes, millipedes, crabs, lobsters, crayfish, etc.) - 123,400
molusks - 110,000
fishes - 23,000
earthworms - 12,000 (that one surprised me)
birds - 9,000
reptiles - 6,300
echinoderms (starfish, etc.) 6,100
mammals - 4,500
amphibians - 4,200
Total excluding insects - 298,500 species.
Some people would also add the protozoans (single-celled organisms like amoebas and slime mold ... this does NOT include bacteria). add another 30,800 species.
So with the insects, that's still about 20- to 30-million species of animals.
As for plants, one source I found (#3) listed 276,000 plants (including vascular and non-vascular, flowering and non-flowering plants).
However another source (#4) listed 421,968 species of *flowering* plants alone. However, there are a huge number of non-flowering plants that are not included there.
2006-09-06 22:41:36 · answer #2 · answered by secretsauce 7 · 0⤊ 0⤋
There isn't an exact answer.
There are about 10 million animal species only about one fifth of which are even named.
2006-09-06 16:10:28 · answer #3 · answered by Anonymous · 0⤊ 1⤋
there are probably many species that haven't been discovered yet, so it would be impossible to tell.
2006-09-06 16:08:44 · answer #4 · answered by z 2 · 0⤊ 0⤋
Hi. Fewer and fewer each hour.
2006-09-06 16:06:55 · answer #5 · answered by Cirric 7 · 0⤊ 0⤋