Protists. Protists are the Most Diverse of all Eukaryotes Eukaryotes that are not plants, animals or fungi are classified as protists

Protists

Protists are the Most Diverse of all Eukaryotes

• Eukaryotes that are not plants, animals or fungi are classified as protists



• Most protists are unicellular and free living (non-parasitic)




• Some protists are colonial organisms. This means that they consist of many similar or identical cells




• Some protists are colonial organisms. This means that they consist of many similar or identical cells

• Some protists, such as seaweed are multicellular and have relatively complex bodies

Protist Structure

• Protists have a typical eukaryotic cell structure, including a nucleus, internal membrane-bound organelles

The Future of Protists

• Many biologist believe that with sufficient data the protist kingdom will eventually be broken up into several kingdoms within the Eukarya domain

Protists as the Most Complex Cell

• What does this mean?


• What does this mean?• Being mostly unicellular, protists are

considered the simplest form of eukaryotic organisms




• While humans are more complex than protists, human cells are in many ways, less complex than protists




• While humans are more complex than protists, human cells are in many ways, less complex than protists

• Most human cells are highly specialized and carry out specific limited function


• Protists cells must carry out ALL of life’s functions if they are to survive


• Protists cells must carry out ALL of life’s functions if they are to survive

• They must find food, digest it, utilize the nutrients, they must avoid predators, they need to reproduce, manufacture proteins, package and ship them, they must produce energy and dispose of waste

Grouping Protists by Nutrition

• Protists are grouped as animal-like protists, fungus-like protists and plant-like protists



• Animal-like protists are called protozoans



• Animal-like protists are called protozoans• Protozoans are heterotrophs that ingest food



• Animal-like protists are called protozoans• Protozoans are heterotrophs that ingest food• Fungus-like protists are also heterotrophs, but

they mostly feed on decaying organic matter


• Plant-like protists are called algae, they are autotrophs and make there food using photosynthesis just like plants do

Motility in Protozoans

• Protozoans move by one of three different methods: Flagella, pseudopods and cilia


• Zooflagellates move by means of one or more flagella (long, thin, whip-like cellular projections)

• Zooflagellates generally reproduce asexually by binary fission

• Examples of zooflagellates are euglenia, giardia (causes diarrhea) and trypanosoma (causes African sleeping sickness)


• Protozoans with pseudopods• Pseudopodia are temporary extensions of the

cytoplasm and the plasma membrane• The cell moves in the direction of the growing

pseudopod• Amoeba are examples of protists that utilize

pseudopods


• Ciliates are a diverse group of protozoans named for their use of hair-like cilia to move and feed

• Cilia are much shorter than flagella and much more numerous

• Paramecium and stentor are common ciliates• Ciliates reproduce both asexually and sexually

through conjugation

Non-motile Protists

• A fourth group of non-motile protists exists• These protists are called apicomplexans• Apicomplexans have complex life cycles• The most well known apicomplexan is

plasmodium, the protist that causes Malaria (remember Malaria IS NOT caused by mosquito’s)

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Protists. Protists are the Most Diverse of all Eukaryotes Eukaryotes that are not plants, animals or fungi are classified as protists