2. General characteristics
Multicellular
Eukaryotic but with no cell walls
Heterotrophs (consumers)
With nervous system to respond to
their environment
Locomotion relates to ability to
obtain food by moving to different
places
Most animals develop from a zygote
to become a new organism (individual)
4. An animal has radial symmetry if it can be
divided along any plane, through a central axis,
into equal halves.
An animal has bilateral symmetry if it can be
divided down its length into similar right and left
halves forming mirror images of each other.
5. Though not all animals have a skeleton, those that do
not have can be divided into two groups:
Those with an exoskeleton – a hard, waxy
coating on the outside of the body that
protects internal organs, provides a
framework for support, and a place for
muscle attachment. Ex. Shrimp
Those with an endoskeleton – support
framework within the body that protects
some organs and a brace for muscles to
pull against. Ex. Squid
41. Ascaris
A large roundworm that lives
in the intestines of pigs, horses
and sometimes man
Females are larger than the
males and may reach a length of
nearly twelve inches
Ascaris eggs enter the human
being in contaminated food or
water
They do not hatch in the stomach, but they
begin to hatch within a few hours when they
reach the small intestine
A mature female lays about 200,000 eggs
each day
Ascaris seems relatively harmless in man,
although occasionally a large number of adult
worms twist together, block the intestine and
cause death
Infections are more common in children
Adults become infected under conditions of
lack of vitamins