Fall2011_Lab4

Here is the lab worksheet if you haven't bought the book, yet: (this includes the animal diversity lab for your presentation).

=Lab 4=

- We will research an animal and present the information on Wednesday. We will not get through all the presentations on Wednesday, but all worksheets will be due on Wednesday. The worksheet is 20 points, and the presentation is 20 points. We will have a quiz at the beginning of class. The quiz will be half over the conceptual questions from quiz one, and the other half will be over plant and fungi material from Lab 3.

- Presentations will be about 4-5 minutes, and the presentation must present all the information from the worksheet. If you have a powerpoint, please email it to me before class. - You need 5 citations, at least 3 from print sources with an author, publishing organization, and publishing date. - If you are looking for information on your species, but cannot find the particular information, you can **give information for your Phylum instead**.

How to find sources:
 * If you are good at googling, you can go to books.google.com and search for scientific books that might be helpful for your research. For example, if you are looking for info on the Phylum Arthropoda, you could google "Arthropoda" in books.google.com. You should find books that are recent (published in the last 20 years).
 * Scientific papers also give good information, usually in the introductory paragraphs. You can google things in scholar.google.com, but these sources are usually harder to understand.

- __Most important__: **Biological level of organization**.
This means, "how is the organism built? How is it organized?" Imagine what it's like to be a single-celled organisms (amoeba, paramecium) compared to being a multi-celled organism (fungus, tapeworms, etc.). Even though both organisms are "alive", single-celled organisms eat, excrete, multiply, and do everything else in life with only one cell. Multi-celled organisms do it with a bunch of cells, not just one cell that does everything.

In multi-celled organisms, there are two types of organisms: some have lots of one type of cell (a cell type that can perform all the physiological functions of the animal (digestion, circulation, sensation, excretion, etc.)) and some have lots of many types of cells.

What is the difference between a bunch of single-celled organisms living together and a multi-cellular organism which is just a collection of similar cells? Well, not much. Take "volox" organisms. This organism can live in isolation or they can live as a colony of single cells that work together. Check out volvox Volvox photo. Volvox video. In other cases, multi-celled organisms are made of different types of cells. Here, each cell type specialize in some physiological function. Some of their cells specialize in excretion, some in sensation, some in digestion. These specialized groups of cells are called 'tissue' (like skin, nerves, muscle). The heart, for example, is not a tissue, it is a collection of different tissues, and this is called a organ. An organ performs a physiological function with the use of multiple tissue types.

So how do you categorize an organism in terms of "biological levels of organization"? Since each level builds on the one before it, you describe it in terms of the highest level that you can describe.

If the animal has specialized cells, it's at least at the level of organization of "Tissue". If, on the other hand, these tissue types can work together to perform a physiological function, it's called an 'organ'. An example is an eyespot in some worms, that can sense light. It's not a single tissue that reacts to light, instead it's a structure that is made up of different parts, and each part is a different type of tissue. Together, these organs perform a sensation function. Therefore the eyespot is an organ. Organisms that have any kind of organs are at least at the level of "Organ".

The last and most complex is 'organ system'. If a group of organs work together to perform a physiological function, then this is a system of organs and the level of organization is "Organ System". An example of this is our digestion system. We have a mouth, a stomach, an intestine, etc., and these are separate organs that cannot digest by themselves, but digestion includes more than one organ. Organ system.

- **Germ layers**
- These are the first tissues that come about during development in some animals. This only occurs in animals that are at the biological level of organization of tissue or higher. There are at most three different kinds of germ layers, but all tissue-level animals have at least two types of germ layers: endoderm (inner layer) and ectoderm (outer layer). Some other animals have a third, middle layer: mesoderm. Each layer, whether it's the endoderm or the mesoderm or the ectoderm, will be the basic tissue that will eventually turn into specific organs. For example, if the animal has a mesoderm, it will always give rise to the stomach. The mesoderm also gives rise to other digestion-related organs. Ectoderm gives rise to skin, for example.

- **Coelom** (pronouced see-lum).
The ceolem is a cavity in the animal, but it is a different cavity than the central tube (central tube is usually the 'gut'). All animals have a central tube, but not all animals have an additional air cavity. We have lungs, which are a type of air cavity. Earthworms have air cavities that provide internal resistance and create a hydrostatic skeleton.

- **Symmetry**.
Is it possible to split the animal in half and then get two halves that are the same? If there is only one way to split the animal and get two equal halves,the animal is bilateral. If there are lots of ways to do this, the animal is radial (starfish). If there is no way to do this, the animal is asymmetrical (sponge or ameoba).

**-Life history.**
If you are born into this world, you eventually develop into an adult. The stages of life from conception to death are considered the life history of an organism. For example, frogs begin life as a tadpole and then some grow into frogs as adults. Humans, on the other hand, do not go through these kind of changes. But humans do go through development during puberty. So both animals develop, but they go through different life stages. Thus they have different life histories.

- **Tie all of this into classification!**
How do scientists use these different classification traits to explain whether two species are closely related to one another? Think about what we talked about with plants compared to fungi (fungus and mushrooms), and angisperms (flowering plants) compared to gymnosperms (cone plants). We used the similarities of the organisms, and said that when species share more similar traits, that they are probably closely related to one another. So out of fungi, gymnosperms, and angiosperms, which two share the most traits? Whichever two you think share the most traits, these should be the two most closely related species.

**QUESTIONS:**
- "I can't find some particular info on my specific species. So should I skip this part?" No, you should instead answer the question with respect to the Phylum instead of the species. But you should know why you should do this. So ask youself and your friends: Why research good is the Phylum information if you are studying a specific species? If you couldn't find the biological info on your specific species, why was it important to at least report the biological information of the phylum of your organism?