Ecdysozoa

symmetry

bilateral

coelom

pseudocoelom

tissue layer

triploblastic

Phylum Nematoda

roundworms

Phylum Nematoda body

eutely

eutely

entire body of adult animal or plant consists of fixed number of cells that is the same in all members of the species

nematoda

thread-like shape

pseudocoelom

mesoderm partially lines coelom

pseudocoelom acts as a

hydrostatic skeleton

nematoda gas exchange

via diffusion

nematoda sex

mostly dioecious

nematoda dimorphism

males often smaller than females

nematoda lack

motile cilia or flagella

trichinellosis

transmitted to humans through consumption of undercooked infected
meat

Phylum Arthropoda coelem

eucoelomate

largest phylum of animals

arthropoda

most diverse phylum

arthropoda

when do arthropoda appear in the fossil record

during early Paleozoic (Cambrian explosion

arthropoda exoskeleton

composed of chitin and proteins; in some groups (e.g., crustaceans), it is
reinforced with calcium carbonate

arthropoda appendages

paired, jointed allow movement of the rigid exoskeleton

arthropoda body cavity

hemocoel

hemocoel

space filled with hemolymph in an open circulatory system

arthropoda circulatory system

in the open circulatory system of arthropods, hemolymph is pumped from
the heart into the hemocoel, where it bathes organs and tissues, and then
returns to the heart through ostia

hemocyanin

a respiratory pigment dissolved in the hemolymph of many arthropods and mollusks

bee waggle dance

communicates the direction, distance, and quality of distant food sources relative to the position of the sun

bee round dance

indicates the presence of a nearby food source but does not convey precise direction or distance