Exam 3 Flashcards
what are traits of true sponges?
lack true tissues, can regenerate, filter feeders, sedentary
Cnidarians differ from sponges in that cnidarians have…
true tissues, motile forms, and tentacles
What is most consistent with the hypothesis that the cambrian explosion was caused by the rise of predator-prey relationship?
increased incidence of hard parts in the fossil record
What are characteristics of the body cavity?
acts as a hydrostatic skeleton in soft bodied animals, cushions suspended organs and preventing internal injury, a space lined by mesoderm in coelomates, allows internal organs to enlarge and move independently of the outer body wall
What is true about the animal tissues that develop from embryonic germ layers?
a pseudocoelom has the same functions as a true coelom, in a coelomate the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity, and a diploblast has no mesoderm
what is NOT a characteristic of all animals?
they have tissues, organs, and organ systems
The animal phylum most like the protists that gave rise to the animal kingdom is _____.
porifera
Which of the following is a characteristic of cnidarians?
gastrovascular cavity
The earliest ancestors of about half of all extant animal phyla can be traced back to the ______ explosion
cambrian
An important trend in animal evolution was cephalization. An animals said to show cephalization when it_____
has an aggregation of sensory neurons at the anterior end
Members of the phylum Mollusca_____
are soft-bodied and often covered by a shell
what is thought to be most closely related to humans?
sea stars
What are NOT diagnostic features of the Chordata? a hollow dorsal nerve cord vertebrae muscular, post-anal tail notochord pharyngeal slits or clefts
vertebrae
The diagnostic feature of Chondrichthyes is ______
an endoskeleton of calcified cartilage
Most members of which group are most closely associated with wet or moist environment?
amphibians
what characteristic only of truly terrestrial animals with no need to return to water at any stage of the life cycle?
amniotic egg
There are three major groups of mammals, categorized on the basis of their _______
method of reproduction
Which chordate group lacks a post-anal tail and a notochord as adults?
tunicates
The common ancestor of all these chordate groups EXCEPT the \_\_\_\_ probably had paired appendages mammals amphibians lampreys ray-finned fishes reptiles
lampreys
What is the only chordate group that has hair?
mammals
what is the key difference between a coelom and a pseudocoelom?
only a coelom is fully lined with mesoderm tissue
A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A postdoctoral student thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus?
look for cell walls under a microscope
Gastrulation is the process that directly forms the _____
primary germ layers
Which of the following animals does NOT have a body cavity? flatworm clam nematode earthworm mouse
flatworm