The
Diversity of The World of Life
Listings & Biology
for Hundreds of Species, Families, & Higher Groups of Life, with Links
to Webpages with Excellent Photos & Additional Information Elsewhere on the
Internet
Note that you may use the
"Search" feature (at left on every webpage) to quickly find
references within this site to any specific species etc. [Note: Since
I migrated this site from AT&T Worldnet to Earthlink, the Search
feature is no longer functional.] Otherwise,
follow the links below and throughout this section, to systematically
explore the wondrous diversity of the world of life.
Please note that even with
the great diversity presented, this website has omitted many of the less
well known groups of life and almost all of those of species that have
become extinct.
I hope to continually
increase the breadth and depth of information within this section, as with
essays on Featured Topics.
As you will note, this
section also serves as an "internet directory", presenting links to
many other websites from around the world, with photos and other
valuable information. I particularly recommend certain excellent
on-line references (and I also strongly advise you to read a word about
linking). You may always return to this site by simply closing
the window that opens when you click on any of those links.
To
Explore the Diversity of The World of Life,
Please
Click Here.
To
Read About the Science of Making these "Family Trees",
Please
Read On...
"Systematics":
The
Classification of
The
World of Life
There
are well over a million known species of living organisms in the world and
undoubtedly many more as yet undiscovered, particularly in the
ever-shrinking Tropical rain forests or the unfathomable depths of the
seas.
It is
in the nature of Homo sapiens or any other intelligent species to
try to find out how the members of any group of things are alike and yet
different. Although all of us may be alike in that concern, we each
differ in our point of view. Biologists are human, too (!);
so it is not surprising that there are different systems of classifying
and, thus, naming species of living things.
"Systematics"
is the systematic studying of those traits -- from
the largest features of anatomy to the smallest mutations in genes -- that various species do or do not have in common, in order to define
"taxa", named groups in general, and "clades" (rhymes
with "glades"), categories not only named but also based upon
the natural relationships between species -- evidence (to most
biologists) of common ancestors in evolution.
Different
"taxonomists" devise different systems of
classification, each of which usually accounts for most but not all of the
variations between species; and as knowledge grows (particularly in
biochemistry and genetics), these schemes
inevitably change.
However,
it is worth remembering that what does not change -- at least over time
frames too short for natural selection to significantly change
populations, by survival of the fittest -- are the species
themselves -- the fundamental, natural groups of living things (typically
defined as a population of organisms that can at least theoretically
successfully breed with one another and produce fertile offspring).
Species -- and arguably only species -- do naturally exist, regardless
of how we choose to artificially group them (or customarily divide them,
as into "subspecies", "varieties", or
"races").
Even
at the most basic level -- the highest taxa
of classification -- there is considerable disagreement.
Traditionally,
there was the "Two Kingdom" system: Every species was
classified as either a plant or an animal. A plant was characterized
by being typically immobile, with a typically rigid wall around the one to
many cells in its body, and producing its own food molecules, typically by
photosynthesis (with energy typically from sunlight) but sometimes by
chemosynthesis (with energy from minerals etc.). An animal was
characterized by being typically mobile, with no wall around the one to
many cells in its body, and consuming other organisms or their products as
food.
Then
there was the "Three Kingdom" system. Plants were divided
into "Prokaryotes" (bacteria and other cells without a
"nucleus" for their genetic material, typically DNA) and
"Higher Plants" (whose cells, like those of all animals, have
their genetic material housed within a membrane-bound nucleus).
Then
there was the "Five Kingdom" system: "Monera"
(bacteria and other prokaryotes, namely blue-green algae), "Protista"
(various algae, fungus-like "slime molds", and "protozoans"
-- single-celled animals), Fungi, Plants, and Animals.
Today,
the concept of a "kingdom" has been mostly abandoned.
Genetic research has identified three "domains", major groups of
life whose members are more alike one another than like those of the other
groups: "Archaea" (those prokaryotes, previously classified as
bacteria, that typically thrive under extreme conditions, as of
temperature and acidity, as were prevalent in the earliest days on Earth) --
presumably the first forms of life on Earth -- as well as Bacteria
and "Eukaryotes" (organisms whose cells do have a nucleus).
The
Eukaryotes are divided into several major groups plus dozens of other
lineages of "protists" (mostly microscopic, single-celled amoebas and flagellates) whose
relationships to one another are not yet clear. The major groups of
Eukaryotes that have been defined are "alveolates" (including
the familiar Paramecium as well as the organism that causes malaria and
various other protists), "stramenopiles" (water molds, diatoms,
and various algae), red algae (a collection of certain seaweeds etc., now appreciated as a major group in its own
right), green plants (including green algae and all land plants), fungi,
"collar flagellates" (single-celled organisms very reminiscent
of the "collar cells" of sponges, the most primitive animals),
and animals (all multi-cellular).
To
learn more about these major groups of life and hundreds of their specific
members...Please
Click Here.
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