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
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Hkane. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £6.55. You're not tied to anything after your purchase.
