vocab chapter 25
sessile
organisms that dont move from place to place
mantle
the thin membrane that surrounds the internal organs of a mollusk
setae
tiny bristles on each segment of the worm
what is symmetry
symmetry refers to a balance of proportions of an object or animal
the basic body plan of a segmented worm is a tube within a tube
TRUE
blastula
a hollow ball of cells that form a result from two cells that divide into four.
radula
a tonguelike organ with rows of teeth located within the mouth of the mollusk
what are segmented worms classified in
the phylum annelida
what is radial symmetry
this means that the animal can be divided along any plane through the central axis and be divied into roughly equal parts
fossil records show that mollusks havent lived for that long
FALSE they have lived in great numbers for as long as 500 years
gastrula
a structure mad up of two laters of cells with an opening at the end
nephridia
organs that remove metobolic wastes from an animals body
what is the symmetry of a segmented worm
they are bilaterally symmetrical
what is bilateral symmetry
a barnacle extends its britles from thew shell to catch small organisms
TRUE
deuterostome
an animal in which the mouth developes from cells elsewhere on the blastula
in the open circulatory system
the blood moves through vessels and into openings around the body
what are the only enviorment that segmented worms cant be found in
polar regions and frozen soil
not all animals have some type of symmetry, true or false
false, all animals have some types of symmetry that enables them to survive in their surroundings
earthworms ingest soil and digest the organic matter in the soil
TRUE
protosome
an animal with a mouth that developes from the opening in the gastrula
in the closed circulatory system
blood moves through the body enclosed entirely in a series of blood vessels
how do segmented worms breath
they exchange gasses directly through their moist skin
what is asymmetry
any animal that is irregular in shape
the mesoderm is the 5th cell layer found in the developing embryo between the endoderm and ectoderm
FALSE it is the 3rd layer