Week 4

Monday: The week began with finishing our trawl reports and turning them in by 9:00. After that we had our final lectures and discussion for the fishes section. At 13:30 study time began and between working on lab notebooks and studying for the section final exam everyone was busily scurrying between the library and the lab.

Tuesday: In the morning there was some time for us to study before sitting down for the exam at 13:00. The general feeling in the room at 12:50 was that we were pretty well prepared yet chronically sleep-deprived. The test went well and afterward students headed to the lab for finishing touches on their lab notebooks due at 18:00

Wednesday: It was time to begin the section on marine macroalgae—after taking the morning off to catch some extra Zs, of course.  We met Allie Barner, the instructor for the section, who enthusiastically introduced us to the different phyla of marine macroalgae and presented their unique evolutionary history and plastid origins. The three phyla of algae evolved from three distinct endosymbiosis events.  The first (primary) endosymbiosis event produced the common ancestor to all eukaryotes.  The second of these events (a second primary endosymbiosis) caused this common ancestor to diverge producing the clade which contains chlorophytes (green algae), rhodophytes (red algae), and land plants. Finally, there was a secondary endosymbiosis event in which a eukaryotic cell engulfed a red algae cell forming the ochrophytes (brown algae).

After that we split into different teams, each tasked with a different set of algae, and prepared for going on a field trip the next morning.

Thursday: Most everyone seemed quite tired as we met up in the lab at 6:00 am to leave on our field trip.  We went to Boiler Bay where each team was tasked with finding a key species of algae and recording is distribution, as well as collecting samples. Upon returning to HMSC, we had a break for elevensies followed by an ID lab and some lectures.  In the lab we were introduced to both micro and macroscopic characteristics used to identify algae using a dichotomous key.  One of these lectures focused on the different life histories found in algae.  

 Identifying the red algae growing on a wall in Boiler Bay's protected intertidal zone.

There are three distinct life history strategies that are observed in algae.  Haplontic life cycles consist of a macroscopic haploid gametophyte, whereas diplontic life cycles consist of a macroscopic diploid sporophyte.  The gametophyte produces haploid gametes, and the sporophyte produces haploid spores.  Haplodiplontic life cycles alternate generations between a haploid gametophytes and diploid sporophytes.  Haploid stages are characterized by having a single copy of each chromosome, and diploid stages are characterized by having two copies of each chromosome.

After our lab and lectures, we learned to press algae for artistic purposes and to preserve specimens.

Friday: Once again we had to get up early in lab by 6:15.  From there we went to Tokatee Klootchman where we collected and took notes on at least two more species of algae in our group.  On this field trip we were shown examples of many of the important algae found in the intertidal.  The rest of the day consisted of one lecture followed by team meetings to design a field study.  These field studies will be conducted on Monday May 1st.

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The three phyla of algae evolved from three distinct endosymbiosis events.  The first (primary) endosymbiosis event produced the common ancestor to all eukaryotes.  The second of these events (a second primary endosymbiosis) caused this common ancestor to diverge producing the clade which contains chlorophytes (green algae), rhodophytes (red algae), and land plants. Finally, there was a secondary endosymbiosis event in which a eukaryotic cell engulfed a red algae cell forming the ochrophytes (brown algae).

The finely branched rhodophyte Ptilota, found by a student at Boiler Bay.

Feather boa kelp (Egregia menziesii), an ochrophyte, found at Boiler Bay.

There are three distinct life history strategies that are observed in algae.  Haplontic life cycles consist of a macroscopic haploid gametophyte, whereas diplontic life cycles consist of a macroscopic diploid sporophyte.  The gametophyte produces haploid gametes, and the sporophyte produces haploid spores.  Haplodiplontic life cycles alternate generations between a haploid gametophytes and diploid sporophytes.  Haploid stages are characterized by having a single copy of each chromosome, and diploid stages are characterized by having two copies of each chromosome.