Protista

1
Protista
2
Facts

• They are the simplest eukaryotes yet they
  represent an incredibly diverse group
• Some are unicellular some are multicellular

3
Started when

• They became of about 1.7 billion years ago
• Thats about 2.3 billion years after the origin
  of life
• The second major step in the evolution of
  protists from bacteria was the process of
  endosymbiosis

4
The Kingdom Protista is divided into four major
groups, not technical divisions but instead
grouped by lifestyle

• the protozoans
• the slime molds
• the unicellular algae
• the multicellular algae

5
Protozoansinclude all protists that

• ingest their food
• live primarily in aquatic habitats such as
• ponds
• ponds
• the digestive tracts of animals

6
the slime molds
They have unicellular and multicellular stages.
When sufficient bacteria are present, cellular
slime molds are single amoeboid cells however,
when food becomes scarce, they aggregate into
sluglike colonies, which become large
reproductive structures. Plasmodial slime molds
also exist as single cells when nutrients are
plentiful, but each cell can grow into a large,
branching plasmodium, with many nuclei and a
continuous nucleus. This differentiates into
reproductive structures when food is short.
7
Algae

• contain chloroplasts and photosynthesize like
  plants
• these can be unicellular, colonial, or
  multicellular

8
(No Transcript)