Bio 203 1st Edition Lecture 9 Outline of Last Lecture I. Eukaryotic major cladesII. AmoebozoaIII. OpisthokontsIV. ExcavataOutline of Current Lecture I. Why Care About Algae?II. About AlgaeIII. StramenopilesIV. RhizariaV. AlveolataCurrent LectureI. Why Care About Algae?a. Base of all aquatic food chains (freshwater and marine)b. Algae are more morphologically complex than you probably thinkc. Algae may save our bacon, fuel-wised. Cheaper and more easily-grown source of biofuels than conventional crop plantse. Some algae are bioluminescent!f. Algae are significant contributors to coral reefs, directly and indirectly:i. Coral polyps are colonized by symbiotic algaeii. Many seaweeds have CaCo3 in their cell walls, adding to the reef structureiii. Most common coral endosymbiont is a dinoflagellate (major clade Alveolata)iv. Algae of all the other types, plus cyanobacteria, can be found in coralsII. About Algaea. “Algae” are photosynthetic eukaryotes that are not land plants, and they are NOTa monophyletic group:i. “Algae” is a term that describes a growth form and life style, but does NOT imply relatedness among the membersb. Endosymbiotic theory and origin of the eukaryotesi. A “proto-eukaryote” with an a-proteobacterium (became the mitochondrion)was the ancestor to all eukaryotesii. Well-supported; all eukaryote cells have mitochondria with a remnant genome similar to heterotrophic gram-negative bacteriaThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.c. Plastids have the same membranes and compartments as cyanobacteriai. Chloroplast is one of several types of plastidsd. Glaucophyte algae diverged firsti. Freshwater, only 13 speciesii. Retain peptidoglycan wall between plastid membranes!iii. Blue-green color similar to cyanobacteriae. Red algae are widespread and commoni. Red color comes from evolution of pigments which reflect red wavelengths oflight ii. Many marine forms (“seaweeds”)iii. Multicellular forms have evolved multiple timesf. Red algae produce starch in the cytosoli. Glaucophyte algae, green algae and the land plants produce starch in their chloroplastsg. Ancestor of the green algae possessed a new pigment, chlorophyll bh. Diverse growth forms in the green algaei. Streptophyte green algae share the most recent common ancestor with the land plantsj. SAR has many photosynthetic lineages, and are the major primary producers in some ecosystemsk. SAR Algae have taken endosymbiosis to the next level, co-evolving with a red algae to make a “secondary plastid”l. Brown, Red and Green Algae are useful group names, but not all their members are all “Brown”, “Red” or “Green”III. Stramenopilesa. Named for the peculiar morphology of their cilia:i. Swimming cells have two types of cilia:ii. One large one with lots of hairs that look like “straw”iii. A second that drags behind and is undecoratediv. “Stramenopiles” = “straw hairs”b. Almost all the photosynthetic stramenopiles are in one clade, the “brown algae” including kelps and diatoms:i. Found in almost all ecosystemsii. Multicellularity has evolved multiple timesc. Other strameopiles gave up photosynthesis, now have growth forms and life histories that are similar to fungii. Oomycetes: “water molds”ii. Used to be classified as fungi, but their lifestyle is convergentiii. All of them lost the secondary plastid, and are heterotrophsiv. Though most are decomposers, some cause diseasev. The oomycete Phytophthora infestans causes potato late blightvi. Irish potato famine killed millions in the 1800s, led to massive emmigration toUSvii. Disease is still a problem todayviii.IV. Rhizariaa. Named for their “root-like” pseudopods, but DNA analysis has added many other organisms to the group:i. Complex group with many distinct morphologies: amoeba, slime-molds, and cells with complex shells ii. All have thin feeding appendages (pseudopods) that look like little “roots”b. The Rhizaria form 3 major groups, mostly heterotrophs, two of which are well known for their fossil shellsi. Radiolarians and Foraminifera are common in marine deposits – shells of silicaor CaCO3ii. Living organisms remain common in most plankton communities!iii. Captured a green alga as an endosymbiontiv. Very diverse in morphology and life style; form weblike arraysV. The Alveolatesa. Named for the peculiar organelle that they all shareb. Cortical alveolae = large, flattened vesicles immediately under the plasma membrane c. Support the cell surfaced. In some alveolates, they are filled with material and function as “scales”e. Include photosynthetic and non-photosynthetic organisms, but they are ancestrally