Phyla #4: SarcodinaUse PSEUDOPODS to feed and move around

Ex: Ameoba

Ameboid Movement

Use pseudopods to move and capture prey

Directed cytoplasmic streaming pushes on the cell membrane resembling arms

Ameoba surround their food with their pseudopods – a type of endocytosis creates a food vacuole.

phagocytosis

Ameoba reproduce by binary fission

(these are “shelled ameoba”)

Binary fission - ameoba

Other Sarcodinas1. Heliozoans

2. RadiolariansHave a shell of silica (SiO2)

Are used in geology for relative dating of rock strata.

Radiolarians

3. Foraminifers

Have CaCO3 shells that build up on ocean floor when they die

The Cliffs of Dover are made of foraminifer shells

Parasitic ProtistsPlasmodium (causes Malaria)

Trypanosoma –causes many diseases including African Sleeping Sickness

The Tsetse fly – makes the raising of cattle impossible in some regions of Africa because it passes on trypanosoma

Chagas DiseaseThe only trypanosome native to the Western Hemisphere

Entamoeba

Causes amebic dysenteryConsumes food inside the intestines Attacks the intestinal wall – causes bleeding and weakens the host Passed to other hosts in places were sanitation is poor

Helpful Relationships

Ex. Zoomastiginan Tryconympha

Lives in gut of the termite and helps digest cellulose

Has many symbiotic relationships with bacteria within IT’S gut!

Protists are Food

Both marine and freshwater ecosystems rely on the protists for energy and nutrient sources

Plant-like Protists

3 phyla

Most contain chlorophyll and are autotrophic

Considered to be types of algae (therefore sometimes classified as plants)

Phyla #1: EuglenophytaPhytoflagellates

Closely related to zooflagellates (really just zooflagellates with chloroplasts)

Ex. Euglena

Euglena movementEuglena are excellent swimmers using their long flagellum

When “squished” against a slide, euglena change shape and “crawl” along the slide – a very “animal-like” movement

Euglenoid Movement

Euglena StructureA red-spot (photoreceptor) helps euglena detect sunlight so it’s chloroplasts can make glucose using photosynthesis.

Euglena comparison

Euglena – Autotroph OR Heterotroph or Saprotroph

If no sunlight is available, euglena will eat like other animal-like protists

Euglena will also absorb dissolved nutrients if they are available, as a saprotroph will do

Euglena – plant or animal?

Astasia (a zooflagellate) and Euglena are almost identical – except that Euglena has chloroplasts

Astasia

When Euglena are grown at 25oC or more, their chloroplasts are not able to reproduce. After several generations, the new Euglena are colorless. They never regain the ability to perform photosynthesis.(is that where Astasia came from?)

RRRRRRRRROAR!!

Phyla #2: Pyrrophyta

“dinoflagellates”

Most are autotrophic, some heterotrophic

Swim with 2 flagella – one usually wraps around the thick outer plates

Dinoflagellates are luminescent – they glow when they are moved

Phyla #3: Chrysophyta

Includes yellow-green and golden-brown algae, but most of the species are DIATOMS.

Diatoms have intricate shells made of silicon (very glasslike)

Diatoms are very abundant in the oceans

Fungi-like Protists

(Slime Molds)

1. Acrasiomycota (cellular slime molds)

Cellular Slime Molds

Spend most of their lives as free-living amoeba-like cells

These cells have a very high reproductive rate – they quickly deplete the food supply in the area

When food runs out, the amoeboid cells join together and act as a single organism.

The mass of cells then act as a multicellular organism – it migrates several centimeters and produces fruiting bodies filled with spores

The spores are released and grow into new amoeboid cells

It is unclear how the unicellular organisms communicate in order to migrate and form the fruiting bodies together.

2. Acellular Slime Molds(Mxyomycota)

Also begin as amoeboid type cells

Under stress, the amoeboid cells gather together, and fuse into one large, multinucleate cell called a PLASMODIUM

The plasmodium produces fruiting bodies

The fruiting bodies produce HAPLOID spores

These spores grow into cells with flagella

The flagellated cells swim to each other and fuse to create diploid amoeboid cells

Some Slime Molds

Harmful PhytoplanktonEuglenophytes can act as saprotrophs and absorb nutrients from waste materials and sewageIf there is too many nutrients in the water, the balance is destroyed, and phytoplankton can grow rapidly into over populated “BLOOMS”

The “blooms” will quickly use up all the nutrients and then die – and become waste material themselves

Red tide is a caused by a bloom of a dinoflagellateThis dinoflagellate produces toxinsDuring a red tide, it is dangerous to eat any shell fish or other filter feeders

Red tide

Red Tide

Symbiotic Relationships

Many types of coral house dinoflagellates

The coral gets the products of photosynthesis, the dinoflagellate gets a home and some food

Phytoplankton is responsible for more than 70% of photosynthesis in the world

This provides a huge amount of oxygen and food