Happy Friday everybody, I hope you got a lot out of class today. Today we filled out part of a KWL chart about worms. We only filled out the K (what you think you know), and the W (what you would like to know) part of the chart. I will be collecting the chart at the end of class on Tuesday so be sure to bring it to class and be ready to fill out the L (what you learned) part.
In our discussion about worms several of you had some great questions and we were able to get some of them answered. Let's start with some general characteristics of worms like we did for the sponges and cnidarians earlier in the week.
A worm's body structure is that it is
- an invertebrate
- bilaterally symmetrical
- contains cells/tissues/organs
- long and narrow without any legs
Worms reproduce both asexually and sexually. There are some species of worm that are hermaphrodites – contains both female and male sex organs – while in other species there are separate male and female animals. Hermaphrodites do not usually fertilize their own eggs so most of the time asexual reproduction refers to when a worm breaks into pieces.
Flatworms as you would imagine are flat and as soft as jelly. Some important words when it comes to flatworms are
Parasite – an organism that lives inside or on another organism.
Host – the organism that the parasite lives on or in.
Free-living organism – one that does not live in or on another organism.
Scavenger – An organism that feeds on dead or decaying material.
The two types of flatworms we talked about in class were planarians and tapeworms.
Planarians are interesting little creature that feed almost like a vacuum cleaner. Planarians swim up to food, stick their feeding tube into the food, release digestive juices into the food that begins to break down the food, and then they suck in the partially digested food. It is a pretty interesting process.
Here is a cool video on the process with the scientific terminology - http://www.youtube.com/watch?v=w0QzSYQGsnA
Tapeworms are the second kind of flatworm we looked learned about. These bad boys are a kind of parasitic worm that can live in more than host during their lifetime. The two videos I listed below I found interesting.
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