Protists on Parade

Living things are classified into Six Kingdoms: • Eubacteria • Archaebacteria • Protists • Fungi • Plants • Animals • We have discussed bacteria, which fit into the first two kingdoms.

• Viruses are non-living, so they are not included in any kingdom.

• Now, we’ll discuss protists.

Protists • Eukaryotes • Mostly Unicellular • Diverse group • Three different kinds of protists: – Animal-like – Plant-like – Fungus-like

Animal-like Protists • • • • Protozoans

Rhizopoda

– Amoeba

Ciliates

– Paramecia

Apicomplexa

– Sporozoans

Plant-like Protists • • •

Bacillariophyta

– Diatoms

Algae

– Green, red, brown algae

Flagellates

– Euglena • Have an eyespot – In light, they’re photosynthetic. In dark, they’re heterotrophic.

Fungus-like Protists •

Myxomycota

– Slime Molds

Different Protists • Can you name some examples of protists?

• Animal-like – Rhizopoda (Amoebas) – Apicomplexa (Sporozoans) – Ciliates (Paramecia) • Plant-like – Bacillariophyta (Diatoms) – Flagellates (Euglena and Dinoflagellates) – Algae • Fungus-like – Myxomycota (Slime Molds)

Protist Reproduction • Reproduce sexually and asexually Sexual Reproduction – Alternation of Generations • Sporophytes – spores grow by mitosis into a gametophyte • Gametophytes – produces gametes that combine to make an embryo

Asexual Reproduction • Some protists reproduce asexually. This process of asexual reproduction should sound familiar. It is called binary fission.

• During this process, two cells fuse and exchange genetic information through “tubes” in their cell walls.

Let’s discuss the different protists in more detail!

Amoebas • Animal-like (Rhizopoda) • Live in Water and Soil • Reproduce by binary fission • Have pseudopodia – Arm-like extensions of cytoplasm • These pseudopodia are used – For movement – To obtain food

Sporozoans • Animal-like (Apicomplexa) • Forms spores • Parasitic • Example: – Plasmodium – Causes malaria – Transmitted by blood feeding insects such as misquitoes

Paramecia • Animal-like (Ciliate) • Reproduce both sexually and asexually – Conjugation!!

• Live in water • Have cilia – Tightly packed rows of short flagella – Used for movement

Diatoms • Plant-like (Bacillariophyta) • Found in water • Asexual reproduction • Diatoms have double shells • The shells are made of silica.

• Used in paint and as a natural pesticide • Important in forensic science • Silica shells are the source of chert (arrowheads)

Euglena • Animal or Plant-like? (Flagellates) • Asexual reproduction • Photosynthetic and Heterotrophic • Eyespot – Light-sensitive organ that helps orient movement • Pellicle – Structure inside cell membrane allows for flexibility

Dinoflagellates • Plant-like (Flagellates) • Reproduce Asexually • Make up plankton in oceans • “Red Tides” – Poisonous toxin – Kills fish and invertebrates – Human health hazard

Algae • Plant-like (Algae) • Microscopic or Multicellular • Kelp • Ingredient in jelly beans, pudding, ice cream, marshmallow, choc. milk • Sargasso Sea – Named for floating masses of

Sargassum natans.

Slime Molds • Fungus-like (Myxomycota) • Produce spores • Look like fungi, but have different cell walls • Cause of Irish potato famine (400,000 people died)

Protists and Human Health • Benefits – Recycle important chemicals like nitrogen – Cattle and cellulose digestion – Most of the world’s photosynthesis (source of oxygen)

Protists and Human Health • Dangers – Cause of disease • Malaria • Up to 300 million people die from malaria every year – Symptoms: – Chills, fever, sweating, confusion, great thirst

Malaria • Caused by

Plasmodium

• Carried by misquitoes • Malaria Infection – Protists are injected by insect – Protists invade liver first and reproduce, destroying cells – Protists invade Red Blood Cells second and reproduce, destroying cells – Victims die of anemia, kidney failure, or brain damage

Treating and Preventing Malaria • 90% of the world’s malaria infections occur in Africa • Quinine (a mild, natural poison) is known to treat malaria in small doses • Before traveling to Africa, be sure to carry anti malaria pills on hand • Malaria can also be controlled by reducing mosquito populations • A malaria vaccine is in the making • Individuals that are heterozygous for sickle-cell anemia are resistant to malaria

Isn’t Science Great?!