This is the fourth of a four day lesson plan in the Unit Plankton Ecology. This lesson expands on material covered on the previous lecture, exploring consequences of a heterogeneous ocean on phytoplankton. The distribution, population growth rates and general ecology of phytoplankton is explored as a consequence of the heterogeneity of water masses. Students will learn how the environment determines a species distribution and persistence, with a final discussion and understanding that if and how the ocean changes will include drastic changes to the biological community it holds within. During this classroom activity they will plot and interpret growth rate data, and compare these phytoplankton characteristics among groups, understanding the importance of these within an ecological framework.

  • Plot phytoplankton growth rates and relate the differences among groups to differences in their ecology.
  • Work in groups to both figure out the identity of a phytoplankton group, as well as apply knowledge extracted from worksheets to understand how these organisms ‘make it’ in the ecosystem.
  • Calculate population growth rates, interpret them and understand that large differences exist between species for distinct ecological reasons.
  • The lesson begins by going over a few slides from the previous lecture (these can be found in Phytoplankton growth rates and ecological characteristics), reminding students of the data they plot and what this means. The goal of this activity builds on the information taught the previous class. Students will graph, calculate and interpret phytoplankton population growth rates. Group characteristics are also interpreted ecologically and related to the difference in water column distribution and growth rates.
  • A guide to conducting this lab can be found in Phytoplankton Activity Teacher Instructions. A guide to the instructions student must follow can be found at Phytoplankton subgroup activities. During this activity students take real population growth data, and plot and interpret the graph. Students learn about the different ecological characteristics of phytoplankton that relate both to their growth strategies associated with their distribution in the water.
  • The final activity is the actual calculation of phytoplankton growth rates. Students discuss results from different groups and conclude which phytoplankton grows the fastest. Hypotheses of how this relates to ecology and distributions of phytoplankton are encouraged. Finally the last three slides of the Phytoplankton growth rates and ecological characteristics, show the vertical and horizontal distributions of these phytoplankton groups. A discussion of the previous day can be revisited, now that students have been given more information on the topic in question. Answers to the previous questions of: What if the ocean changes? What if it becomes more stratified? Which groups will be most affected?, can now be addressed with a greater understanding of the ecology of these individual groups. Students can revisit their hypothesis from the previous days and correct their predictions based on the information they have learned in this lesson. The Phytoplankton Key and Data can be projected for a clearer picture of the differences in growth rates among groups.
  • This activity was designed for high school Marine Science and Biology students. The goal of the lesson is to understand, graph and calculate population growth rates, while putting this species characteristic within an ecological context.
  • A Quiz is conducted at the end, which combined with the completed Phytoplankton subgroup activities are the final assessment.



Lesson Materials
Related Phytoplankton Lessons
Lesson Specifics
  • Grade Level: High School Marine Science and Biology Students
  • Time Frame: 90 minutes, can be divided into two lessons of 50 minutes

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