Ch 3.2 - Taxonomy

Question 1

Why do we classify and name organisms?

Answer 1

The total number of species in the world is thought to total between 10 and 100 million. The exact number is not known because with the development of more sphisticated observation and analysis tool, more organisms are found and categorized every day.

As discoveries coutinued, and continue still, scientists are forced to reconsider how to classify organisms.

Question 2

What is taxonomy?

Answer 2

The science of classifying living organisms.

Question 3

Why is classification necessary?

Answer 3

To have consistent communication.

Question 4

Why is Latin used in taxonomy?

Answer 4

• It is not spoken by any country
• Allows it to be universal
• Similar to element/compound naming in chemistry, or metric units in physics/math.

Question 5

What was the earliest classification system?

Answer 5

Developed by Aristotle 2000 years ago, it divided organisms into two kingdoms:
- Plant (Plantae)
- Animal (Animalia)

Question 6

What did the development of the microscope come with? What came as a result and who proposed it?

Answer 6

The discovery of microorganisms, which used different methods of locomotion, food consumption, and energy acquisition than larger organisms.

German biologist Ernst Haeckel proposed that there be placed a 3rd kingdom: Protista.

Question 7

What are the specifics of the current classification system? Name some details about the top level.

Answer 7

The one used today has 3 domains and 6 kingdoms. Domains are above kingdoms.

The three domains: Bacteria, Archaea, Eukarya

Question 8

What is the Bacteria domain?

Answer 8

(Eubacteria)
- Prokaryotic: unicellular organisms
- Lack a membrane-bound nucleus
- Reproduce asexually
- Heterotrophic or autotrophic by chemosynthesis or photosynthesis
- Move by flagella (tail)

Question 8

What is the Archaea domain?

Answer 8

(Archaebacteria)
- Prokaryotic: unicellular organisms
- Lack a membrane-bound nucleus
- Reproduce asexually
- Many are autotrophic by chemosynthesis; some are heterotrophic
Many are found in extreme envrionments (thermal vents, salt lakes):
- Unique rDNA base sequence
- Distinct plasma membrane and cell walll chemistry.

Question 9

What is the Eukarya domain?

Answer 9

• Eukaryotic, unicellular OR multicellular organisms
• Membrane-bound nucleus
• Sexual reproduction
• Phenotypes and nutrition are diverse
• Divides into 4 kingdoms
• Flagella, if present, have a 9+2 organization

Question 10

What is a prokaryote?

Answer 10

“Prologue” -> Before nucleus

NO membrane-bound nucleus (it’s free)

Question 11

What is a eukaryote?

Answer 11

“True nucleus”

Have a membrane-bound nucleus

Question 12

What are the four kingdoms within domain Eukarya?

Answer 12

• Protista
• Fungi
• Plantae
• Animalia

Question 13

What is the Protista kingdom?

Answer 13

• Unicellular or multicellular
• Eukaryotic
• Autotrophic and heterotrophic

Ex: Algae, protozoa

Question 14

What is the Fungi kingdom?

Answer 14

• Sessile (do not move)
• Unicellular or multicellular
• Eukaryotic
• Do not photosynthesize
• Secrete digestive enzymes onto food, then absorb it

Ex: Mushroom, yeast

Question 15

What is the Plantae kingdom?

Answer 15

• (Most) Are multicellular
• Eukaryotic
• Photosynthesize

Ex: Trees, flowers

Question 16

What is the Animalia kingdom?

Answer 16

• Have specialized cells
• (Most) Are multicellular
• Eukaryotic
• Ingest food; heterotrophic
• Mostly motile -> can move

Ex: Donkey, horse, chicken, human

Question 17

How were kingdoms subsequently divided?

Answer 17

To further distinguish between organisms, in the 1700s Swedish biologist Carolus Linnaeus subdivided each kingdom into smaller and smaller groups based on increasing similar physical characteristics.

Question 18

What is a taxon?

Answer 18

A level of classification.

Question 19

How are organisms sorted? List them.

Answer 19

Organisms are sorted into a hiearchial system, starting with the broadest category–domain–and progressing to the most specific category–species.

• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Increasing similarity (from top down). Divisions are based on modes of nutrition, morphology, etc.

(D) Keep Pond Clean Or Froggy Gets Sick

Question 20

Who and what was suggested to name organisms?

Answer 20

Carolus Linnaeus suggest bionomial nomenclature, a two-name system based on the last two levels of classification.
Usually in latin, the two-part scientific names include the organism’s:
Genus species

Genus name is always capitalized, and the whole name is always italicized when typed or underlined when written.

Question 21

What is a dichotomous key? How does it work?

Answer 21

A branched or stepped process that can be used to identify organisms.

The key is a series of comparisons arranged in steps, with each step having a possibility of two choices. With each choice, the comparisons become more detailed until the scientific name of the organism is determined.

Question 22

When constructing keys, what are the five steps?

Answer 22

1. Make a flow chart that keeps seperating organisms based on your criteria
2. All choices should only have two possibilities
3. Keep going with this until all parts of your flow chart are down to only one organism
4. Transfer this information into a key which ahs a series of numbered choices, each identified as “a” or “b”
5. At the end of a line for each division there should be either the organism’s identitiy or a “Go to…” instruction