Feb 12 (Dichotomous Keys)

Feb 12(The Five Kingdoms)

Learning Objectives 

• Use and create a dichotomous key
• Compare and contrast the characteristics of the five kingdoms
  • Compare and contrast prokaryotes and eukaryotes 
  • Identify the characteristics that differentiates the kingdoms from each other

What is a Dichotomous Key? 

• A step-by-step key used to identify an organism, usually a plant or animal.
• Each step presents descriptions of two distinguishing characters with a direction to another stage in the key until the species is identified

Using a dichotomous key is actually quite simple.

1. Start with the organism you want to identify
2. Start with number 1 on the key
3. Identify whether the organism has the characteristic in number one and follow the instructions to a) identify the organism or b) follow the directions and move to the next number.
4. Continue until you arrive at the species.

An example of a dichotomous key for the woodpeckers above may look something like this

1. Is the bird tan-coloured? 
   1. Yes …. Go to number 2
   2. No ….. Go to number 3
2. Does the bird have a red spot on its head? 
   1. Yes… Northern flicker
   2. No … Gilded flicker
3. Does the bird have white wing bars? 
   1. Yes … Go to number 4
   2. No …. Williamson’s sapsucker
4. Does the bird have black bars behind its eyes? 
   1. Yes … Red-naped sapsucker
   2. No …. Red breasted sapsucker

The Five Kingdoms 

The five kingdoms system separates all life on Earth into five categories:

Prokaryotes: are organisms whose cells lack a nucleus and other organelles. They are generally much smaller than eukaryotic cells.
Eukaryotes: are organisms whose cells contain a nucleus and other organelles.

Autotrophic: organisms which are able to obtain their food from inorganic sources such as light and chemicals
Heterotrophic: organisms which obtain their food from organic sources

Inorganic Substances: Non-living substances
Organic Substances: Substances that is derived from something that was or is alive.