introduction to animals Flashcards
animals have..
an extracellular matrix
what do cells in extra cellular matrix do?
they have proteins specialized for cell-cell adhesion
key traits if animals
- multicellular
- heterotrophs
- move
- neurons and muscle cells
animals are a — group
monophyletic
what are the earliest animals to appear in the fossil record?
sponges
sessile
to be attached to a substrate
eg. choanoflagellates and sponges
epithelium
a layer of tightly joined cells the covers the exterior/ exterior of an animal
what are the major linages of animals?
sponges, comb jellies, Cnidaria, acoela, lophotrochozoa, Ecdysozoan and deuterostomes
bilaterians
triploblastic, bilaterally symmetrical animals
is bilateral symmetry Homologous in all triploblastic animals?
yes
what do ctenophore a and cnidarians have because they are radically symmetric?
a nerve net
what do bilaterally symmetric animals have?
a central nervous system
where neurons are clustered into masses
ganglia
cephalozation
the evolution of a head
acoels have…
no coelom and a net nerve even though they are bilaterally symmetric and triploblastic
what is derived from the ectoderm?
skin and nervous systems
what is derived from the endoderm?
the gut
what is derived from the mesoderm?
muscles, organs, and Coelom
coelomates
have an enclosed body cavity completely lined with mesoderm (eg. earthworm)
acoelomates
have no enclosed body cavity
eg flatworms
pseudocoelomates
have an enclosed body cavity partially lined with mesoderm
eg. nematodes (roundworms)
what can an enclosed fluid-filled chamber act as?
a hydroskeleton
two major groups of protostomes
lophotrochozoa and ecdysozoa
what does the lophotrochozoa include?
mollusks, annalids, flatworms, and Rotifers
