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Bellwork : Fri. May 5 , 2017. Write the following classification in your bellwork: Kingdom: Animalia Phylum: Platyhelminthes Class: Turbellaria Order: Tricladida Family: Planariidae Genus: Dugesia Species : tigrina. Remember yesterday’s bellwork. “ Red Yucca ” Kingdom : Plantae
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Bellwork: Fri. May 5, 2017 • Write the following classification in your bellwork: • Kingdom: Animalia • Phylum: Platyhelminthes • Class: Turbellaria • Order: Tricladida • Family: Planariidae • Genus: Dugesia • Species: tigrina
Remember yesterday’s bellwork “Red Yucca” Kingdom: Plantae Phylum: (clade) Angiosperms Class: (clade): Monocots Order: Asparagales Family: Asparagaceae Subfamily: Agavoideae Genus: Hesperaloe Species: parviflora
http://www.youtube.com/watch?v=MeJQdbMge84 • http://www.youtube.com/watch?feature=endscreen&v=A6N8KZqGAJg&NR=1
Observing Planaria Laboratory Investigation
What are Planaria? • Freshwater flatworms: (phylum: Platyhelminthes) • Live in freshwater under leaves and stones • Avoid light (“negative phototaxis”) • Free living – not parasites • Carnivores – eat decaying meat, insects and larvae (egg yolks or liver in the lab) • 1-20 mm in size • Long lived • Use sexual or asexual reproduction This picture has been released it into the public domain.
Planaria are complex organisms Gastrovascular System
Nervous System
Reproductive System
Excretory/Osmoregulatory System
Planaria have an amazing ability to regenerate parts of themselves Planaria regeneration is a great model for demonstrating stem cell function and complexity of tissue regeneration They can grow easily in the lab Why study Planaria 1/279th
Neoblast = Planaria Stem Cell • 20-30% of all the cells in a planaria are Neoblasts. • Neoblasts divide by mitosis and can make more of themselves. They are the only dividing cells in planaria. • When a planaria is wounded, neoblasts migrate to the site and begin dividing • Neoblasts can become ANY cell the planaria needs—nerve cells, flame cells, reproductive cells… Ann. Rev. Cell. Dev. Biol. 20:725-757, 2004
“Totipotent” Stem Cell Blood Nerve Skin They can become any cell type in the body In Humans: Totipotent cells are limited to early embryonic division In Planaria: Neoblasts are always present Neoblasts and Stem Cells are Totipotent
Care and Feeding of Planaria • The water is very important! Fresh water from a pond, stream or lake is best; spring water is adequate • Keep cultures in a cool, dark place • Feed planaria at least once a week • Change the water twice a week, especially after feeding • After cutting them, the cultures should not be fed
Laboratory Investigation Each team will receive 1 planaria:
Planaria Regeneration, Days 1 - 14 Slide courtesy of Dr. Sánchez Alvarado and Dr. Kyle Gurley
Bellwork: old final review hypothesis theory Independent variable qualitative https://www.youtube.com/watch?v=cHoAFihJGbM You may use a word once or not at all: write eachstatement Independent variable Hypothesis Theory Quantitative Qualitative 1. Testable, scientific explanation for observations:__________ 2. Well-tested explanation supported by many observations_________ 3. Variable that is deliberately changed in an experiment: ______ _________ Variable that changes because of the independent variable is the dependent variable 4. Data not involving numbers, but descriptions:______________