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

Laboratory Investigation 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.

Overview of Brown Planaria Dugesia tigrina

Planaria are complex organisms Gastrovascular System

Nervous System

Reproductive System

Excretory/Osmoregulatory System

Why study Planaria 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 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

Neoblasts and Stem Cells are Totipotent “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

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:

Plenty of Planaria

Planaria Regeneration, Days 1 - 14 Slide courtesy of Dr. Sánchez Alvarado and Dr. Kyle Gurley

Slide courtesy of Dr. Sánchez Alvarado and Dr. Kyle Gurley

Slide courtesy of Dr. Sánchez Alvarado and Dr. Kyle Gurley

Bellwork: old final review You may use a word once or not at all: write each statement 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:______________ hypothesis theory Independent variable qualitative https://www.youtube.com/watch?v=cHoAFihJGbM

https://www.youtube.com/watch?v=7G9Jozhr7H0