Here is one example of what I would consider to be a complete answer to the invertebrate question. There is no one right answer to these question.  Instead, I will be looking to see that you clearly answer the question, you present and understanding all or most of the information, and are able to interpret it.  Hope this helps.

The distinction between vertebrate and invertebrate may be artificial and is certainly

controversial.  Invertebrates are defined as organisms belonging to the Kingdom

Animalia-multicellular, eukaryotic (cells with cellular organelles present), heterotrophic

(do not produce their own food), and lack cell walls-that do not contain a vertebral

column.  Distinguishing between invertebrates and vertebrates is controversial in part

because it separates less than 5% of all animals and suggests a strong bias towards

organisms that are similar to humans.  Further controversy arises from the fact that all

animals are composed of multiple species.  Thus, even the simplest animals-vertebrate

or invertebrate-are a conglomerate of numerous species.  Dr. Lynn Margulis suggests

that the merging of numerous species is actually necessary for all complex life, stated

formally as the theory of symbiogenesis.  The theory of symbiogenis is supported by the

fact that every know animal is composed of multiple species (about 10% of human dry mass

is non-vertebrate species), survival is know to depend upon these multiple species, and even

the cellular organelles of eukaryotes may have arisen from a symbiotic relationship among

prokaryotes, the endosymbiotic theory.  Thus, dividing the animal world into invertebrates and

vertebrates does not take into account the many other species that make up all higher

organisms-ignoring what may be a critical feature of all organisms-and represents our bias

towards things that are like ourselves.
 

Things I would look for in a complete answer.
1 point: Statement of the problem
1 point: Correct definition of Kingdom Animalia
2 points: Explanations of terms
 1 point: Definition of invertebrates
1 point: Statement why controversial
1 point: Sentence concerning the biased view of dividing the animal world into vertebrates and invertebrates
1 point: Definition of symbiogenesis
1 point: Major proponent of symbiogenesis is Lynn Margullis
3 points: Evidence for symbiogenesis
2 points: brief explanation of endosymbiotic theory
2 points: accurate summary statement
4 points: clarity of thought and overall organization

Total points possible = 20


Syllabus  Schedule  Lessons
Home