We continued our study of ecology by discussing the concept of trophic pyramid. Trophic pyramids are used to describe the amount of biomass in a given trophic level, with producers (organisms that produce energy through photosynthesis) being a source of food for primary consumers (organisms that eat producers). Similarly, secondary consumers eat primary consumers, and tertiary consumers eat secondary consumers. Decomposers are organisms that recycle waste products back into the ecosystem. Students applied their learning about trophic levels to the Great Salt Lake ecosystem, guided by a worksheet they completed working in small groups.
Category Archives: Ecology
Ecology and Systems Biology: Food Web Game Results
We began the day by revisiting the grass/cow/hamburger slide from yesterday, Students were challenged to apply their understanding of the food web by figuring out how much grass a cow has to eat to produce a hamburger. Understanding that grass is at the bottom of the food chain (like halobacteria in the Great Salt Lake), and recognizing that cows eat grass (like brine shrimp eat halobacteria), students reasoned that it would take 10 times as much mass in grass to produce one hamburger. If a hamburger has a mass of 100 grams, then a cow would have to eat 1000 grams of grass to produce the hamburger. Several students wondered how much land is required to produce 1000 grams of grass, and I encourage all of my students to research that question for extra credit!
We continued our discussion of the food web game by analyzing group results, assembling a table of class results, and calculating the average number of organisms at each level of the food chain. Students observed the 10-fold decrease in organism mass as we move up the food chain, and we connected the concept of biomass with energy. The results for each class period are reported at the end of the slide deck. We also discussed the variables involved in the food web game activity, with students identifying distance from the seed-trading space, number of students per group, and the efficiency with which groups worked as key variables contributing to how many higher-level organisms a group obtained.
After the slide deck and discussion, students worked in groups to complete the back side of the worksheet from yesterday. Students learned that while the amount of matter in a system stays constant, the amount of energy in a given level decreases as we move up the food chain. This is not always obvious, especially because organisms at the bottom of the food chain tend to be very small (yet great in number).
Ecology and Systems Biology: Food Web Game
Today we modeled energy transfer through a food chain. We worked through a brief slide deck and added the words food chain, matter, and energy to our vocabulary list and began thinking about what happens to matter (grass) eaten by an organism (a cow) that does not become food for the consumer of the cow (us, when we eat a hamburger). We then modeled energy transfer through a selection of Great Salt Lake organisms present in a food chain. Using 4 different types of beans, we played the Food Web Game and learned how only 10% of the energy in one level of a food chain is passed along to the next level. The game took us to the end of the period, so tomorrow we will share group data, calculate class averages, and complete page 2 of the Food Web Game worksheet.
Ecology and Systems Biology: Let’s Read!
With short periods today, students selected unit-articles to read from our vast collection of Scientific American magazines. Students wrote summary paragraphs describing each page of the article they read, with paragraphs consisting of the main ideas presented on the page, three things the student learned from the reading, and a list of vocabulary words for follow-up. Have a great weekend!
Ecology and Systems Biology: Extreme Environments
Today we focused on 8 factors that are commonly found in environments we consider to be extreme. Students began the lesson with an introduction to the bell curve and an brief explanation of the mean and standard deviation. Students then silently brainstormed three examples of things they consider extreme, with an explanation about why. During our share out, students were encouraged to consider whether the idea of “extreme” is relative. For example, we might regard a skydiver as someone who participates in an extreme sport. However, the skydiver might share a different perspective. Similarly, we might classify a polar bear as an extremophile, given it’s ability to live in extremely cold temperatures. However, the polar bear, being unable to live comfortably away from the south pole, might consider organisms living in warmer climates as extremophiles. After learning about the 8 factors and exploring representative locations and organisms at those locations (see Power Point slides), students completed their extreme environments critter diagrams from yesterday.
Ecology and Systems Biology: Extremophiles
At the beginning of class yesterday, students were faced with the following scenario: You are an extreme environment engineer. Pick your next work assignment. The options were: The Ocean Floor, Olympus Mons (tallest known volcano in the solar system, located on Mars), Antarctica, and The Moon. Today, students were grouped based on their work site preference. Working in groups of 3 or 4, students then were assigned the extremophiles reading packet. Each group member was assigned a roles (slide 1), with the role rotating after each paragraph was read. The roles were: Reader, Paraphraser #1, Paraphraser #2, and Recorder. The Reader was responsible for reading the paragraph out loud to the group. The Recorder highlighted words that were challenging for the Reader or needed to be defined for comprehension. Paraphraser #1 was responsible for paraphrasing the main ideas they heard from the Reader. Paraphraser #2 paraphrased what they heard from Paraphraser #1, further distilling the key points down to a single sentence or two. Ultimately, those main points served as discussion points for answering the questions on the worksheet. The exercise served many learning purposes. Students practiced reading challenging scientific words and were supported by their group members who might be more familiar with the word or who could help the group find out the correct pronunciation and meaning. Students also practiced listening and paraphrasing, applying those skills to answer specific comprehension questions about extremophiles. Many students were able to complete the reading and turn it in at the end of class. Students needing extra time should complete the worksheet as homework and turn it in at the beginning of class tomorrow. At the end of the class period, students drew critter diagrams (slide 2) in their lab notebooks and filled out the leg corresponding to their chosen extreme environment. The legs represent extreme conditions encountered by life either currently living, or wishing to live, in the group’s extreme environment. Groups will share out their legs of the critter diagram tomorrow.
Ecology and Systems Biology: Great Salt Lake Initial Model
Today we turned our attention to the Great Salt Lake. We learned about the organisms that live in the lake, with students taking notes on a worksheet while we worked through a Power Point slide deck. Students learned that in a food web, organisms are drawn as nodes and the edges represent energy. The direction of the edge indicates the predator/prey relationship, with the arrow pointing away from the prey and toward the predator. Students then used the information from the slide deck to construct a food web on the initial model worksheet. Students had a lot of questions about using the initial model, and it’s important to keep in mind that the model of our understanding of the Great Salt Lake ecosystem will develop over time. Scientists often develop models with incomplete data sets and then use the gaps in their understanding to devise and test hypotheses. As scientists in training, we will also learn to work with incomplete data and we will learn to keep track of our questions and devise strategies for filling in the gaps in our knowledge.
Updated 9/30/14: We completed the initial model today, with students using scientific reasoning to assign units of energy moving through their food webs. Students turned in both the Power Point worksheet as well as the initial model worksheet at the end of class.
Ecology and Systems Biology: Clicker Quiz
We began the day with a quick video about the tardigrade (below). Then, students took their second clicker quiz of the year today. Questions included a review of the metric system, tools scientists use, ecosystem vocabulary, and a question about extremophiles. Have a safe and fun Homecoming!
Ecology and Systems Biology: Ecosystem Preview
Such talented students at Highline High School! With several students out of class today preparing for the Homecoming assembly, and short class periods, we reviewed the concept of ecosystem. We integrated biotic and abiotic factors (two vocabulary words learned yesterday). We defined an ecosystem as the biotic (living) and abiotic (non-living) factors present in a given space. We constructed a diagram of a model ecosystem, with students recalling that factors such as plants, animals, birds, insects, water, air, soil, rocks, buildings, mountains, and even the Sun can all be considered factors in an ecosystem. We characterized the various factors as biotic (for example, plants, animals, insects, and birds) or abiotic (for example, water, air, buildings, rocks, mountains, and the Sun). We discussed the fact that biotic factors are often found in direct contact with abiotic factors, and both types of factors are necessary for life as we know it. For example, bacteria are commonly found in all of the abiotic factors listed (except for the Sun!). We then watched the first 16 minutes of episode 6 of Neil deGrasse Tyson’s Cosmos series. In the video segment, Dr. Tyson explores the ecosystem of a dew drop. We were introduced to the tardigrade – an instant class favorite! Season 1 of Cosmos is currently available streaming on Netflix.
Ecology and Systems Biology: Networks and Factors
We launched our first lesson of Unit 2 (Ecology and Systems Biology) with an introduction to the SQ3R reading strategy. Details are included in the attached slide deck presented to students before they practiced the SQ3R reading strategy on a reading passage. The reading introduced students to the vocabulary words of biotic factors (living things) and abiotic factors (things that are not living), and related both types of factors to the study of systems. Students who were unable to complete the reading in class should finish it as homework and turn it in at the start of class tomorrow morning to receive full credit.
Science with Swart 