PRE-CAMBRIAN PERIOD to
million years ago to present day
over 3.5 billion years, life has been growing, dividing, changing and
developing into a myriad of forms. One factor about all life on
Earth that has remained constant though, is that Invertebrates or
creatures without an internal skeleton, have always outnumbered the
quantity of life forms in existence at any one time right up until today.
Invertebrates were the very first complex forms of life. As in the
past and still today, invertebrates are so vital that without their
existence, our entire planet and nearly all of its ecosystems would
cease to function!
of Earth's life history has been relatively uneventful with roughly the first
three billion years only consisting of life forms that were simple single-cell
organisms like bacteria and algae. At times, these organisms amassed
into colonies called Stromatolites but nothing more. About 600
million years ago, complex multi-cellular organisms similar to jellyfish,
approximately 530 million years ago during the Cambrian Period, an event
took place in life's history that has never been repeated. An
incredible diversity of life forms 'exploded' on the scene in
abundance. This occurrence is called the 'Cambrian Explosion' and
also marked the emergence of animals with hard external skeletons like
trilobites. Rumbling the foundation of macroevolution's theory is the
intricacy and sheer numbers of life forms that suddenly 'appeared' on our
planet compared to the crude and simplistic organisms that existed
prior. The Cambrian Explosion is one of the greatest mysteries to
paleontologists as well as evolutionists.
vertebrates, invertebrates never developed a bone or cartilage internal
skeleton. They also lack a cranium, nerve chord brain or hard
braincase. Invertebrate fossils of soft-bodied creatures is rare
but does exist. Certain fossil-bearing deposits have revealed
amazingly fine-detailed anatomy of prehistoric soft-bodied invertebrate
life-forms such as those found in the Burgess Shale of Canada or
Hunsruck Shales of Germany. More commonly found invertebrate
fossils are those of hard-bodied creatures such as crustaceans.
the animal kingdom has a little over a million described species
comprising 32 phyla. The phylum of Arthropoda (insects, spiders,
centipedes and crustaceans, for instance) alone make up 82% of all known
species of life on Earth. If we include all invertebrates (excluding bacteria and
virii), we now are talking about 94% of known species! ALL
vertebrates, that is, creatures with internal skeletons and backbones,
comprise only 3% of all known species on our planet.
their size, INVERTEBRATES are truly the "heavyweights" on our planet!
Invertabrates, Invertebrats, Invertibrates, Invertbrates
- copyright Paleo Direct, Inc.
All images and text on this
site are protected by copyright and may not be used in any way.