Protists

Question 1

Who are the first Eukaryotes?

Answer 1

Protists!

Question 2

Significant Characteristics of Protists

Answer 2

Organisms with membrane-bound nucleus, other membrane-bound organelles; Approx. 1.5 bilions years old: protist fossils from time resemble early green algae(caused mix up); Super diverse with many independent evolutionary lineages(MEANS THEY LACK SYNAPOMORPHIES: no common, unique characteristics that link they altogether, Mixed in with everyone else)

Question 3

Metabolic Types of protists

Answer 3

Photoautotrophs and photoheterotrophs; Chemoorganoheterotrophs; Mixotrophs: some can use both autotrophy and heterotrophy to get their carbon

Question 4

Major Evolutionary Transitions within Protists

Answer 4

Prokaryote to Eukaryote; Asexual Reproduction to Sexual reproduction; Unicellular to Multicellular

Question 5

Size range of Protists

Answer 5

• Microscopic to massive
• Amoebae to kelp 100-200 ft tall

Question 6

Major Parts of Protists in food webs

Answer 6

Primarily photoautotrophs(primary producers) at base of aquatic food webs- use photosynthesis(which increases O2 production); very abundant, source of 80% of Earth’s O2

Decomposers: in terrestrial and aquatic environments; Break down dead/living organic matter physically and chemically, making nutrients available to food web

Predators/consumers: feeding on bacteria, protists, and other eukaryotes)

Question 7

Photoautotrophic Aquatic Protists

Answer 7

phytoplankton(Translation: “flowering plants”) BUT NOT PLANTS; Catch all group for photosynthetic protists floating around in aquatic; hugely abundant photosynthetic organisms
systems (oceans, lakes, wetlands, rivers)

Always present in aquatic ecosystems; Can have period of HUGE increases in growth and reproduction

Question 8

Process of Photosynthesis

Answer 8

CO2+Water->SUNLIGHT TO AID PROCESS-> O2+Sugars

(80% of Earth’s oxygen from protists)

Process relies on chloroplasts(green, chlorophyll-filled organelles) to drive interaction

Question 9

Habitats of Protists

Answer 9

MANY! VARIETY; Primarily AQUATIC(freshwater, slater water, blood)

Question 10

Phytoplankton/Algal Blooms

Answer 10

**can also include Cyanobacteria(prokaryote)

Driven by Optimal conditions for growth/reproduction: increased nutrient availability(nitrogen and phosphorus), water temperature

made up of green algae and diatoms

Question 11

Green Algae

Answer 11

Unicellular phytoplankton: floating free-living individuals cells and colonial filamentous forms

Some attached unicellular forms, that grow on rocks, sand, wood, etc.

Serves as food and habitat(Critically important because of this!)

Question 12

Diatoms

Answer 12

highly abundant, super0diverse protists; possibly most abundant eukaryotic organism(CRITiCAL FOOD RESOURCE)

Structure: actual unicellular organism lives in a shell of two halves that they secrete

Aspect: each species has a specific environmental tolerance!!!(Salinity, temperature, productivity/nutrients in the system)

Question 13

Frustules

Answer 13

shell made up of two halves that they secrete (made primarily of silica)

have openings, pores that allow water in for carbon dioxide uptake for photosynthesis

when diatoms die, they remain and sink to bottom of lake/ocean where they
become “fossils”

Question 14

Purposes of frustules

Answer 14

Paleontology, commercial products

Question 15

paleontology purpose of frustules

Answer 15

frustules can be identified to species, allowing us to reconstruct ancient diatom communities; each species has specialized environmental tolerances
(relative to water temperature, pH, nutrients)

thus, knowing which species were present allows us to
reconstruct ancient environments/climates

Question 16

Commercial Product Purpose of Frustules

Answer 16

DIATOMACEOUS EARTH/fossil frustules; used in filters used in laboratories and pools, used in kitty litter, used in some toothpastes, polishes & other diverse uses

Question 17

Role of Phytoplankton in Aquatic Food Webs

Answer 17

Eaten by Zooplankton and also Plantivores(fish higher in food web, like basking sharks and baleen whales)

Question 18

Choanoflagellates

Answer 18

Free-living individuals, very mobile(using flagella), also form colonies during reproduction; Predatory unicellular protists in marine/oceanic systems that are chemoorganoheterotrophs

Question 19

Dinoflagellates

Answer 19

unicellular photoautotrophs, some also use chemoorganoheterotrophy(MIXOTROPHS) found in aquatic systems; Group defined by having TWO FLAGELLA(Longer flagella is for movement; Shorter flagella is used for feeding)

EXTEREMELY DIVERSE

Group has possibility to be toxic(Can form red tides, releasing toxins and killing lots of animals) and/or bioluminescent

Question 20

Coral Symbionts

Answer 20

CHoanoflagellate, mutualistic interactions(+,+): Known as Zooxanthellae: attach to coral polyps

Provide energy for coral(from autotrophy); Gain some carbon(as heterotrophs) from coral as well as structure to grow on from coral