Biology 211 Exam #2
What are the characteristics of animals? - ANS-- multicellular eukaryotes
- heterotrophic
- obtain nutrients through ingestion
- no cell walls (held together by collagen: a structural protein_
- most possess tissues (sponges are the exception; nervous and muscle tissues - these
are not in plants or fungi)
Animals are... - ANS-monophyletic! they come from a single origin; only one animal
ancestor
What are characteristics of choanoflagellates? - ANS-- protists
- some are colonial
- flagellated
- live in saltwater and freshwater
- closest living relative to animals
What is cleavage? - ANS-mitotic cell division without cell growth and no change in cell
size
What are the stages of early embryonic development? - ANS-- zygote (fertilized egg)
- eight-cell stage
- blastula
- blastocoel
What is gastrulation? - ANS-a rearrangement of the embryo; folds into the blastocoel,
formation of layers
What are germ layers? - ANS-- layers of cells that give rise to various tissues and
organs of the animal body
- formed after gastrulation
What are the types of germ layers? - ANS-- ectoderm: outer covering and nervous
tissue
- endoderm: lining of the digestive tract and organs like the liver
- mesoderm: muscles and most other organs
, What germ layers do diploblastic and triploblastic have? - ANS-- diploblastic: 2, only
have ectoderm and endoderm (cnidarians)
- triploblastic: 3, have all three germ layers (like humans)
What is coelom? - ANS-a fluid-filled body cavity that cushions organs and provides
stability (completely lined by mesoderm tissue)
What is an acoelomate? - ANS-no body cavity
What is an pseudocoelomate? - ANS-- "false" coelom
- not completely lined by mesoderm tissues; formed by the blastocoel
What is the fate of the blastopore in protostomes? - ANS-- the blastopore becomes the
mouth of the digestive system
- cleavage is spiral and determinate
What is the fate of the blastopore in deuterostomes? - ANS-- the blastopore becomes
the anus of the digestive system
- cleavage is radial and indeterminate
What are the 2 major protostome clades? - ANS-lophotrochozoa and ecdysozoa
What are lophotrochozoas? - ANS-- have a "trochophore" larva before metamorphosis
or "lophophore" stage as an adult
- refers to a ciliated tentacle structure
What are ecdysozoans? - ANS-- protostome animals that secrete external skeletons
- as the animal grows, it sheds its exoskeleton and secretes another
What are deuterostomes? - ANS-- blastopore become the anus
- includes the echinoderms (starfish) and vertebrates (fish, amphibians, reptiles, birds
and mammals)
- this group makes up less than 5% of the known animal species on earth
Segmentation - ANS-- arose independently at least 3 times in animals (convergent
evolution)
- allows for specialization
"cute" animals - ANS-- make up only 0.5% of the named animal species
What are the characteristics of animals? - ANS-- multicellular eukaryotes
- heterotrophic
- obtain nutrients through ingestion
- no cell walls (held together by collagen: a structural protein_
- most possess tissues (sponges are the exception; nervous and muscle tissues - these
are not in plants or fungi)
Animals are... - ANS-monophyletic! they come from a single origin; only one animal
ancestor
What are characteristics of choanoflagellates? - ANS-- protists
- some are colonial
- flagellated
- live in saltwater and freshwater
- closest living relative to animals
What is cleavage? - ANS-mitotic cell division without cell growth and no change in cell
size
What are the stages of early embryonic development? - ANS-- zygote (fertilized egg)
- eight-cell stage
- blastula
- blastocoel
What is gastrulation? - ANS-a rearrangement of the embryo; folds into the blastocoel,
formation of layers
What are germ layers? - ANS-- layers of cells that give rise to various tissues and
organs of the animal body
- formed after gastrulation
What are the types of germ layers? - ANS-- ectoderm: outer covering and nervous
tissue
- endoderm: lining of the digestive tract and organs like the liver
- mesoderm: muscles and most other organs
, What germ layers do diploblastic and triploblastic have? - ANS-- diploblastic: 2, only
have ectoderm and endoderm (cnidarians)
- triploblastic: 3, have all three germ layers (like humans)
What is coelom? - ANS-a fluid-filled body cavity that cushions organs and provides
stability (completely lined by mesoderm tissue)
What is an acoelomate? - ANS-no body cavity
What is an pseudocoelomate? - ANS-- "false" coelom
- not completely lined by mesoderm tissues; formed by the blastocoel
What is the fate of the blastopore in protostomes? - ANS-- the blastopore becomes the
mouth of the digestive system
- cleavage is spiral and determinate
What is the fate of the blastopore in deuterostomes? - ANS-- the blastopore becomes
the anus of the digestive system
- cleavage is radial and indeterminate
What are the 2 major protostome clades? - ANS-lophotrochozoa and ecdysozoa
What are lophotrochozoas? - ANS-- have a "trochophore" larva before metamorphosis
or "lophophore" stage as an adult
- refers to a ciliated tentacle structure
What are ecdysozoans? - ANS-- protostome animals that secrete external skeletons
- as the animal grows, it sheds its exoskeleton and secretes another
What are deuterostomes? - ANS-- blastopore become the anus
- includes the echinoderms (starfish) and vertebrates (fish, amphibians, reptiles, birds
and mammals)
- this group makes up less than 5% of the known animal species on earth
Segmentation - ANS-- arose independently at least 3 times in animals (convergent
evolution)
- allows for specialization
"cute" animals - ANS-- make up only 0.5% of the named animal species
