General Characteristics• First appeared 1.5 billion years ago• First eukaryotic organism• Eukaryotes• Mostly unicellular• Mostly aerobic• Most are motile
• Classified together because they do not fit into other kingdoms, rather than because they are similar or closely related to one another• Most diverse group of eukaryotes
Helpful Protists• Major producers and make up the bulk of the lowest consumer level in aquatic ecosystems.• Used in commodities – Ex. Seaweed is in sushi, toothpaste and paints.
Harmful Protists• Many are parasites• Can cause serious disease – Ex. Malaria and giardiases
The Origin of Eukaryotes• Membrane bound nucleus – Through the infolding of the cell membrane in and ancestral prokaryote in order to increase surface area
The Origin of Eukaryotes• Mitochondria – Through endosymbiosis of an ancestral prokaryote
The Origin of Eukaryotes• Chloroplast – Through endosymbiosis of an ancestral photosynthetic prokaryote
Terms:• Endosymbiosis = a single-celled organisms living inside another organism• Endocytosis = engulfing of particles through the extention of a cell membrane
Examples of some groups: Amoeba NucleusVideo:http://www.youtube.com/watch? Pseudopodia:v=W6rnhiMxtKU extensions of the cytoplasm
AmoebaKey Features• Create pseudopods (extentions of cytoplasm)• UnicellularLocomotion• Pseudopods extend and contractFeeding• Feed through endocytosis• Some are human pathogens (parasites)Ex. amoebic dysentery is cause by an Entamoeba (causes intestinal bleeding)
Key Feature Flagellates• Possess one or more flagella (long whip-like structures)• UnicellularLocomotion FlagellaFeeding Some feed on other protists Some are human pathogens (parasites) Ex. Trypanosoma gambiensis in the tse tse fly causes human sleeping sickness.http://www.youtube.com/watch?v=4aVUrGO97Zg
SporozoansKey Feature• Produce spores• UnicellularLocomotion Non-motileFeeding Parasitic (obtain nutrients from the bodies of their hosts)Ex. Plasmodium cause malaria.
SporozoansWhen red blood cells bursts toxins are released causing chills and feverSome types of malaria can be fatalVery serious world-wide diseasehttp://www.youtube.com/watch?v=RqRuSwZey_U&feature=related
Slime mouldsKey Feature• Their life cycles have unicellular stages and multicellular stagesLocomotion• Flagella or pseudopodsFeeding- Heterotrophshttp://www.youtube.com/watch?v=q6rqyaYYZeo&feature=related