Graphics Reference
In-Depth Information
Animals in Motion
The Richness of Life on Earth
The variety of life on earth is staggering in its enormity. There are an
estimated 8,000 species of mammals, over 6,000 species of reptiles, 9,000
species of birds, and 25,000 species of fish, all either swimming, walking,
flying, or crawling over our planet. The number of individual species of
insects, which make up over 90% of all life forms on earth, is estimated at
anywhere between 6 million and 10 million. That's a lot of bugs. I say these
are estimated figures because, though we live in an increasingly crowded
world, much of it still remains almost completely unexplored. The simple
truth is that no one knows exactly how many undiscovered species exist
in the deeper seas or the remote jungles and forests, even if these last two
are diminishing environments. The number of species that have been lost
to the world, and continue to be lost at an alarmingly high rate, is beyond
imagining.
It is well beyond the scope of this text, or I suspect any other single text, to
cover the dynamics and locomotion of all the different forms of animal life
on earth. To cover the entire animal kingdom would clearly be impractical
for this rather modest project and would possibly take the effort of many
