Animal Basics
What three broad characteristics describe animals?
Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers.
What is cephalization?
The concentration of sensory organs and nervous-system structures at the head end.
What two features are associated with the name Lophotrochozoa?
A lophophore or a trochophore larva.
What are flatworms, and what is their phylum?
Flatworms belong to Phylum Platyhelminthes.
What is the tough external coat of ecdysozoans called?
A cuticle.
What does cleavage mean in early animal development?
Rapid cell division without growth of the embryo.
Which germ layers are found in diploblastic animals?
Ectoderm and endoderm.
What are the three main parts of a mollusc body plan?
Muscular foot, visceral mass, and mantle.
Do flatworms have a coelom?
No. They are acoelomates and lack a body cavity.
What is ecdysis?
The shedding of the cuticle or exoskeleton, also called molting.
What is a blastula?
A hollow ball of cells formed after cleavage.
What third germ layer do triploblastic animals have?
Mesoderm, between the ectoderm and endoderm.
What structure do chitons use to scrape algae from surfaces?
The radula.
What feeding structure is found in rotifers?
Cilia draw food and water toward the mouth; food is ground by jaws called trophi.
What are the three key features of the arthropod body plan?
A segmented body, hard exoskeleton, and jointed appendages.
What is gastrulation?
The developmental process that forms an early embryo with germ layers.
What is a true coelom?
A body cavity completely lined by mesoderm.
How are bivalve shells arranged and held together?
They have two shell halves held together by adductor muscles.
What is a lophophore?
A crown of ciliated tentacles around the mouth used for feeding.
What material makes up the arthropod cuticle?
Chitin.
What are Hox genes responsible for?
They regulate the development of animal body form.
In protostome development, what does the blastopore become?
The mouth.
Which molluscs are active marine predators and have a closed circulatory system?
Cephalopods, such as octopuses and squids.
What do earthworms do that benefits soil?
They till and aerate soil as they move and feed through it.
Which three major lineages of living arthropods are described in the slides?
Chelicerates, myriapods, and pancrustaceans.