1. Kingdom Protista
Learning Outcome B1

2. Characteristics Appeared in the fossil record 1.5 billion years ago
Protists have an evolutionary advancement over bacteria, because they have a membrane-bound nucleus.
Protists also have ribosomes, mitochondria and lysosomes
Protists are classified within the Domain Eukarya and Kingdom Protista
Generally microscopic and unicellular
Live in fresh/salt water and shady moist terrestrial environments
Example – plankton

3. Characteristics
Plankton is one of the most important producers and consumers in the food chain
Plant-like protists are heterotrophs, which are organisms that must consume food and
Can not make their own food.
Phytoplankton are photosynthetic autotrophs

4. Protist Diversity There are three major groups: Plant-like protists
Animal-like protists

5. Examples of Plant-like Protists
Phylum Euglenophyta
Example – Euglena

8. Characteristics of the Phylum Euglenophyta
Found mainly in fresh water, especially stagnant water
Over 800 species in lakes and pont
Obtain food via photosynthesis, but during periods of darkness they become heterotrophic (take in food)
Have two distinguishing characteristics: eyespot and flagellum
The eyespot has photoreceptors and plays a role in the organisms sensory motor system
Eyespot allows movement towards or away from light

9. Characteristics of Phylum Euglenophyta
Flagellum is used to propel organism through aquatic environments in a whip-like fashion.
Have large green chloroplasts and central vacuole
Food is stored as starch granule just like in land plants
Reproduce asexually; following nuclear division the rest of the cell divides lengthwise
This is known as longtitudinal fission, this involves a growth in cell circumference while the organelles are duplicated.
During unfavourable conditions Euglena may form thick resting cells similar to an endospore

10. Examples of Plant-like Protists
Phylum Chrysophyta
Example – diatoms
Found in fresh and marine environment
Diatoms are the most abundant plant-like protist
Make up diatomaceous earth, makes up kitty litter and pool filters
Autotrophic
Many are flagellated and encased in shells or skeletons
Shells are made up of silica

12. Examples of Plant-like Protists
Phylum Pyrrophyta
Example – dinoflagellates
Autotrophic
Contains chlorophyll and other green pigments
Major component of oceanic plankton
Large blooms of dinoflagellates cause red tide, which can infect shellfish and poison humans.
These dinoflagellates release a neurotoxin that is harmful to humans.

15. Examples of Animal-like Protists
All heterotrophic
Generally move to find food
Feed on bacteria and other microbes
Holozoic is a term used to describe a microorganisms that obtains their food by engulfing it
Saprozoic organism absorb predigested or soluble nutrients directly through the cell membrane
Can be free living or parasitic
Live in a diverse range of habitats: salt water, fresh water and Most terrestrial habitats
Undergo asexual reproduction by fission
May form a resting cell during unfavorable conditions called a cyst
Range in size – example blood parasites = 2 um vs. Foraminferans = 5 cm

16. Examples of Animals-like Protists
Phylum Sarcodina
Generally free-living
May have a motile adult form and develop pseudopods for locomotion
They also use these finger-like projections o obtain food
This phylum can be divided into 4 groups
Amoeba
Formainferians
Radiolarian
Heliozoans.

17. Amoeba
No shell
Demonstrate cytoplasmic movement, this movement is caused by repeated extensions and retractions of the pseudopods
The cytoplasm has two layers:
Ectoplasm
Thin semi rigid layer under the plasma membrane
Endoplasm
The more fluid part that fills the inside of the cell
Continuous movement of the endoplasm causes the amoeba to change shape constantly as it moves

18. Amoeba Linnaes name the amoeba “chaos chaos”
Engulfing food particles is known as phagocytosis
The food particles are stored within an organelle known as a food vacuole.
A contractile vacuole regulates the amount of water within the amoeba, it has the ability to remove excess water.
As the vacuole expands the water is discharged through a pore in the plasma membrane
Reproduction is asexual through binary fission
Once the amoeba splits in two the organelles grow to their full size although they may split again.

21. Examples of Animal-like Prostists
Phylum Ciliphora
Example - paramecium
Characterized by the presence of hair-like structures called cilia
Cilia may cover the entire body
Cilia also function in motility but are shorter and more abundant
Cilia are synchronized for swimming
In sessile organism such as Stenor or Vorticelli the cilia attach the microorganism to a substrate
Most advanced protist

25. Examples of Animal-like Protists
Phylum Sporozoa
Example – plasmodium
No independent locomotion
Do not have pseudopods, cilia or flagella
Parasitic
Have spore-like stage during their lifecycle
Sometimes involved two or more hosts
Reproduce sexually in one and asexually in the other
Insects are frequently responsible for transmitting sporozoa from one host to another
Plasmodium causes malaria

28. Examples of Fungus-Like Protists
Phylum Gymnomycota
Example – slime molds
Live in cool, shady, most places and are often found under fallen leaves or rotting logs.
Leave a slimy trail as they move
At some stages in their lifecycle slime molds resemble protozoans and become amoeba-like or have flagella, at other times they produce spores similar to fungi