Animals World Part 4

All Animals are members Classification Kingdom of the Animalia, Phylum,Class,Order,Family,Genus..All members of Animalia are multicellular, and all are heterotrophs (that is, they rely directly or indirectly on other organisms for their nourishment). Most ingest food and digest it in an internal cavity.Animal cells lack the rigid cell walls that characterize plant cells. The bodies of most animals (all except sponges) are made up of...
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All Animals are members Classification Kingdom of the
Animalia, Phylum,Class,Order,Family,Genus..All members of Animalia are multicellular, and all
are heterotrophs (that is, they rely directly or
indirectly on other organisms for their
nourishment). Most ingest food and digest it in an
internal cavity.Animal cells lack the rigid cell walls that characterize
plant cells. The bodies of most animals (all except
sponges) are made up of cells organized into tissues,
each tissue specialized to some degree to perform
specific functions. In most, tissues are organized into
even more specialized organs. Most animals are
capable of complex and relatively rapid movement
compared to plants and other organisms.It is estimated that around 9 or 10 million species of
animals inhabit the earth; the exact number is not
known and all estimates are rough. Animals range in
size from no more than a few cells to organisms
weighing many tons, such as blue whales and giant
squid. By far most species of animals are insects, with
groups such as mollusks, crustaceans, and nematodes
also being especially diverse. By this measure our
own group, the vertebrates, is relatively
inconsequential from a diversity perspective.
Most reproduce sexually, by means of
differentiated eggs and sperm. Most animals are
diploid, meaning that the cells of adults contain
two copies of the genetic material. The
development of most animals is characterized by
distinctive stages, including a zygote, formed by
the product of the first few division of cells
following fertilization.