Protists Flashcards
Who are the first Eukaryotes?
Protists!
Significant Characteristics of Protists
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)
Metabolic Types of protists
Photoautotrophs and photoheterotrophs; Chemoorganoheterotrophs; Mixotrophs: some can use both autotrophy and heterotrophy to get their carbon
Major Evolutionary Transitions within Protists
Prokaryote to Eukaryote; Asexual Reproduction to Sexual reproduction; Unicellular to Multicellular
Size range of Protists
- Microscopic to massive
- Amoebae to kelp 100-200 ft tall
Major Parts of Protists in food webs
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)
Photoautotrophic Aquatic Protists
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
Process of Photosynthesis
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
Habitats of Protists
MANY! VARIETY; Primarily AQUATIC(freshwater, slater water, blood)
Phytoplankton/Algal Blooms
**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
Green Algae
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!)
Diatoms
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)
Frustules
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”
Purposes of frustules
Paleontology, commercial products
paleontology purpose of frustules
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
Commercial Product Purpose of Frustules
DIATOMACEOUS EARTH/fossil frustules; used in filters used in laboratories and pools, used in kitty litter, used in some toothpastes, polishes & other diverse uses
Role of Phytoplankton in Aquatic Food Webs
Eaten by Zooplankton and also Plantivores(fish higher in food web, like basking sharks and baleen whales)
Choanoflagellates
Free-living individuals, very mobile(using flagella), also form colonies during reproduction; Predatory unicellular protists in marine/oceanic systems that are chemoorganoheterotrophs
Dinoflagellates
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
Coral Symbionts
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
