Download Plankton HW

Name ________________________________________________ Date ________________ Tab ________________________ Plankton Background Reading Please “mark-­‐up” this reading. The word plankton is from the Greek word planktos, which means, "wandering.” Although many of these organisms have some form of swimming ability, they cannot move their bodies against the stronger oceanic currents, which means that they drift around the ocean. Some planktonic organisms can be quite large (like jellyfish); however, most are small enough that they have to be viewed under a microscope in order to be identified. Plankton that can photosynthesize are called phytoplankton and form the basis of oceanic food chains. Phytoplankton are most often single celled organisms and can be thought of as the plants of the sea. Zooplankton are tiny animals that feed on other plankton. Zooplankton can be multicellular or unicellular and are heterotrophic. Organisms that spend their whole lives as plankton are called holoplankton. Others that spend only part of their lives as plankton are called meroplankton. Most non-­‐mammal marine organisms (fish, sea urchins, lobsters, etc.) are meroplankton and start out their lives as eggs and larvae dispersed by the currents. Phytoplankton -­ plants Zooplankton -­ animals Marine phytoplankton are also the first link in many marine food chains, just like terrestrial plants are the foundation of many land-­‐based food chains. Phytoplankton obtain the ingredients for photosynthesis from the environment. CO2 and H2O are able to diffuse through the cell membrane from the surrounding ocean water. Sunlight energy is absorbed by the chloroplasts in the phytoplankton. The product of O2 then diffuses out of the phytoplankton, moving into the surrounding water and atmosphere, while the cell keeps glucose for later use. Zooplankton cannot make their own sugars and must consume the phytoplankton, just like grazing animals eat grass, and obtain the stored energy from photosynthesis. In order to do cellular respiration, both zooplankton and phytoplankton must have the ingredient of O2 diffuse into their bodies. In zooplankton O2 moves in through their gills and they are able to get glucose from eating the phytoplankton. In phytoplankton, the O2 diffuses into the cells from the surrounding water. The waste products of cellular respiration, CO2 and H2O, are able to diffuse out of the cell (phytoplankton) or organism’s gills (zooplankton). The energy released from cellular respiration is then used to bind the third phosphate to ADP molecules to create ATP molecules. Phytoplankton obtain energy from the sun. Zooplankton then eat the phytoplankton and get the stored energy. Small fish consume the zooplankton, medium fish eat the smaller fish, larger fish eat the medium fish, and the biggest fish eat the larger fish. As each organism is consumed, they pass on energy that they obtained from their original food to their predator. Therefore, all of the energy transferred from prey to predator originated from phytoplankton absorbing energy from the sun, storing it, and the passing it on up the food chain. Believe it or not, the majority of oxygen produced on the Earth comes from phytoplankton photosynthesizing in the ocean. In fact, scientist guess that 50% – 85% of the oxygen in our atmosphere comes from phytoplankton. Phytoplankton require sunlight for photosynthesis, so they must stay within the photic or euphotic zone, the top 200 meters of water. Under the right conditions light can reach to 1,000 meters, but this is not enough light for photosynthesis. Appropriate light levels are only available so far into the water, because light only has so much energy to move through the water (which is thicker than air and requires light to exert more energy to move through it). Therefore, photosynthesis levels of light only reach to depths of 200 meters in the ocean. Zooplankton depend on phytoplankton and other zooplankton for food, so they must also stay in the photic zone. Anything below 200 meters does not receive enough sunlight for photosynthesis to happen and any organism dependent on photosynthesis or photosynthetic organisms must also stay in the photic zone. Therefore all plankton must avoid sinking too rapidly away from the sunlit surface waters. Plankton avoid sinking in a variety of ways: -­‐Their small body size helps them remain lightweight. -­‐They increase the surface area of their bodies in order to increase drag and slow down sinking. Many phytoplankton have flattened bodies, spines, and other projections to slow sinking by adding surface area without increasing density. -­‐Phytoplankton also avoid sinking by forming chains with other cells, which also increases drag. -­‐The use of low-­‐density substances like oil or fat helps increase buoyancy and can serve as food reserves for some species. -­‐Some species of phytoplankton have flagella or cilia, which they use a motor to help them sink slowly. Common Structures of Marine Phytoplankton -­‐ What do you notice about the shapes and the adaptations of these cells based on what you just read about slow sinking? Plankton Wars!
In the upcoming design challenge, known as Plankton Wars, your
task is to design a phytoplankton that sinks the slowest. You will be
provided with materials and have two class periods to design and test
your plankton.
Materials:
• Yarn • 2 Paper clips • 1 Plastic bag • 4 Toothpicks • Tin foil • 2 Straws • 2 Popsicle sticks • 2 Rubber bands • 1 Index card • 30 cm of tape • A piece of an egg carton -­‐ This will be a 2-­‐day design challenge in class on Wednesday February 5 and Thursday February 4. -­‐ The final products of this assignment for you and your partner include: 1. Data sheet to record your sink times from ALL trials and designs of plankton 2. An overview of your design process DESIGN PROCESS INCLUDES: -­‐Changes made to your plankton design -­‐Success of each design -­‐Reasons behind the changes Ways to present your design process: -­‐Daily written journal with sketches describing events in class, changes made to your plankton, and level of success -­‐Photos on an ipad accompanied by spoken descriptions of your trials and designs (Explain Everything type thing) -­‐Poster that includes sketches or images of your plankton in a timeline of design with notes -­‐Power Point slides that describe each design and your process -­‐iMovie video with images of your plankton and spoken descriptions DUE ON THURSDAY 2/11 Homework Brainstorming – look at the materials list and images of phytoplankton in this
article. Begin sketching out preliminary designs