Use the Nelson text, "Biology 11", pp. 326-331 to complete the blanks and answer the questions.


The science of ___________________ organisms, called taxonomy, has two main purposes: to ___________________ organisms and to represent ___________________ among them. The Greek philosopher ___________________ proposed that all creatures could be arranged according to their ________________. ________________ and simple organisms occupy the lowest rung, while _______________, occupy the top rung. The dominance of humans over all living things was described as the __________ ________________, or "ladder of ____________".

Read "Classifying Organisms" on pg. 327. For each organism, complete the table below.

Plant or Animal
What test would you use?
Fucus (seaweed)  
Brittle star  
Red alga  
Sea anemone  

Taxonomic Systems

Our biological system of classification was developed by __________ _______________. His system was based on ______________ and ___________________ features and assumed that the more features organisms have in common, the _________________ their relationship.

Linnaeus was the first to use _______________ _________________ which assigns each organism a ____-part scientific name using Latin words. The first part of a scientific name is called the ____________; it's first letter is always ________________. The second part is called the _______________. Living organisms within a ______________ can only ________________ with members of their own species.

In our present classification system, there are ________________ main levels or ____________. List these in order, starting from the most general (largest group) to most specific (smallest group): ______________, _________________, ______________, _____________, ________________, ______________, ______________. Which level of classification always uses a small (non-capital) letter? _______________. Which organism is in the order Diptera? __________________. What kingdom are these organisms in? ____________________.

As new organisms were discovered with new features, a six-kingdom system of classification was devised. Print out this page and complete the table for the six Kingdoms on pg. 329.

Today, most scientists believe that organisms have _______________ over time. The history of the _______________ of organisms is called __________________. Relationships are often shown in a diagram called a _____________________ tree, where the tree starts from the most __________________ form and includes branchings that lead to all of its __________________ (Fig. 1, pg. 330). Which organisms evolved first: basidiomycetes or ascomycetes? ______________________; arthropoda or platyhelminthes? _____________________. Which organisms (in general) are at the bottom of the tree (implying all other organisms evolved from them)? ____________________.

Another system that possibly better reflects the evolutionary history of life uses a __________________-domain classification system. The main groups are: __________________, ______________________, ______________________. Which domain are humans in? ____________________. Which domain are heat-loving bacteria in? __________________________.

Many scientists use classification manuals to identify organisms. Usually, it involves the use of a _________________ key (Fig. 3, pg. 330).