Lecture 10: Protists

These flashcards cover key concepts related to protists discussed in Lecture 10, including their classification, roles, feeding strategies, and ecological significance.

What are protists?

Protists are informal eukaryotic organisms that are not classified as plants, animals, or fungi, and include a vast diversity of single-celled and simple multicellular organisms.

What is endosymbiosis?

Endosymbiosis is a relationship between two species where one organism lives inside the cells of another organism (the host), leading to the evolution of mitochondria and plastids.

What are the four groups of Protista?

The four groups of Protista are excavates, SAR (Stramenopiles, Alveolates, Rhizarians), algae, and unikonts.

What are the key feeding strategies of protists?

Protists can be photoautotrophs, heterotrophs, or mixotrophs, employing different methods to obtain nutrients and energy.

What is the significance of diatoms in ecosystems?

Diatoms are important phototrophs that contribute to global CO2 levels through photosynthesis and play a significant role in the carbon pump to the ocean floor.

What are the two types of nuclei found in ciliates?

Ciliates contain macronuclei, responsible for everyday functions, and micronuclei, involved in reproduction and genetic variation.

What causes red tides?

Red tides are caused by blooms of dinoflagellates, which can produce toxins harmful to humans and marine life.

What role do photosynthetic protists play in ecosystems?

Photosynthetic protists are primary producers, carrying out approximately 30% of the world's photosynthesis and forming the base of aquatic food webs.

What effects do increased sea surface temperatures have on phototrophic protists?

Increased sea surface temperatures lead to a decline in the growth and biomass of photosynthetic protists and prokaryotes.

What is the ecological impact of protist symbionts?

Some protist symbionts benefit their hosts, such as dinoflagellates that nourish corals, while others can be harmful parasites like Plasmodium, which causes malaria.

Protists are __ organisms that are not classified as plants, animals, or fungi.

eukaryotic (Example: Amoeba is a eukaryotic protist that exists primarily in freshwater environments.)

The relationship where one organism lives inside the cells of another is known as __.

endosymbiosis (Situation: The mitochondria in our cells are thought to have originated from a free-living bacterium through an endosymbiotic relationship.)

The four groups of Protista are __, SAR, algae, and unikonts.

excavates (Example: Giardia, a type of excavate, can cause gastrointestinal disease in humans.)

Photosynthetic protists are also known as __, as they contribute significantly to the base of aquatic food webs.

primary producers (Situation: Phytoplankton, a group of photosynthetic protists, form the foundation of the oceanic food chain.)

Red tides are primarily caused by blooms of __, which can produce harmful toxins.

dinoflagellates (Example: Certain species of dinoflagellates, like Alexandrium, can cause red tides that affect marine life and human health.)

Ciliates have two types of nuclei: a __ for everyday functions and a micronucleus for reproduction.

macronucleus (Example: Paramecium, a ciliate, uses its macronucleus to control metabolic processes.)

The ecological role of __ protists includes contributing to global CO2 levels through photosynthesis.

photosynthetic (Situation: Diatoms, a type of photosynthetic protist, play a significant role in carbon cycling in marine ecosystems.)

Increased sea surface temperatures can lead to __ in the growth of photosynthetic protists.

declines (Example: Such declines can disrupt food webs and impact the overall health of marine ecosystems.)

Some protist symbionts, like __, provide nutrients to their hosts, benefiting them in the process.

dinoflagellates (Situation: The symbiotic relationship between dinoflagellates and corals supports coral reef ecosystems.)

__ can be harmful parasites, such as Plasmodium, which is known for causing malaria in humans.

Protist (Example: Plasmodium is transmitted to humans through the bite of infected Anopheles mosquitoes