Chapter 15: Marine Animals Flashcards
what were the first form of primary producers?
probably an early form of cyanobacteria
what were the first animal-like creatures?
single-celled organisms
what happened during the oxygen revolution?
the activity of photosynthetic autotrophs changed the composition of the atmosphere from less than 1% free oxygen to its present oxygen-rich mixture of more than 20%
what is an animal?
a multicellular organism unable to synthesize its own food and often capable of movement
what is a phylum?
a group of animals that shares similar architecture, level of complexity, and evolutionary history
more than __ of all living and fossil animals including all of the earliest multicellular animals are categorized as invertebrates
90%
what are invertebrates?
generally soft-bodied animals that lack a rigid internal skeleton for the attachment of muscles
many possess some sort of hard, protective outer covering
what are the most primitive true animals?
sponges (Porifera)
what are the few basic shapes of sponges?
branching, vaselike, encrusting
what do suspension feeders do?
strain plankton and tiny organic food particles from the surrounding water
what organism belongs in the phylum Porifera?
sponges
what organisms belong in the phylum Cnidaria?
jellyfish, sea anemones, and corals
cnidarians exhibit ____ symmetry
radial
what is radial symmetry?
when body parts radiate from a central axis like the spokes of a wheel
what are hermatypic corals?
corals that contain masses of symbiotic dinoflagellates
what are ahermatypic corals?
corals that lack interior dinoflagellates
what is bilateral symmetry?
the body has a left side and a right side that are mirror images of each another
the worm body plan exhibits a ____ symmetry
bilateral
what are the most primitive organisms with a central nervous system?
flatworms
what are the first animals with a flow-through digestive system?
Nematoda
what are the most successful of the worm phyla in every imaginable terrestrial, aquatic, and marine habitat?
roundworms
what are the most evolutionarily advanced worms?
Annelida
what is metamerism?
a convenient strategy for increasing the size of an animal simply by adding nearly identical units
what animals are part of the Gastropoda class of mollusc?
snails
what animals are part of the Bivalvia class of mollusc?
clams, oysters, and mussels
what animals are the part of the Cephalopoda class of mollusc?
nautiluses, octopuses, cuttlefish, and squid
what animals are part of the phylum Arthropoda?
lobsters, shrimp, crabs, krill, and barnacles
what are 3 evolutionary advances that have led to Arthropods great success?
exoskeleton, striated muscle, articulation
what is an Arthropods exoskeleton made of?
chitin
what is a water-vascular system?
a complex of water-filled canals, valves, and projections used for locomotion and feeding
what is the most structurally complex animal phylum?
Chordata
