Biology lab 1 midterm Flashcards
refers to the ability to divide an organism into two equal halves that are
mirror-images of each other
Symmetry
indicates that the body of an organism is more specialized than it
would be if it were asymmetrical.
Radial symmetry
Sponges are in the phylum
Porifera (pore-bearing animals)
Two reasons that sponges are considered one of the most simplest of all animals
(1) They usually lack symmetry (asymmetrical)
(2) They have achieved only the cellular level of complexity. They have no tissues, organs,
or organ systems.
The body of a sponge is perforated with countless tiny openings called
ostia
Open further
examination one or a few larger openings called
oscula (singular osculum)
Sponges engage in one of the simplest lifestyles commonly known as
filter-feeding
The most unique and important of the several types of specialized cells that
sponges possess are called
choanocytes
The wall of a sponge is composed of a gelatinous
substance called
mesohyl
The mesohyl is structurally reinforced with either a skeleton of
protein fibers called s
spongin fibers
hard spur-like structures
spicules
Sponges do not display movement capability as adults and are said to be
sessile
There are three varieties of sponge as far as structural considerations are concerned:
asconoid,
syconoid, and leuconoid
Countless ostia allow water to enter through the walls of the sponge and then the water passes
through a cavity called the
spongocoel
Sponges often reproduce asexually through a process called
budding
