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Go back and look at the list you created for question #4 (above). What's wrong with that list?
b. CON: There's nothing wrong with that list; the instructions say to name ten animals, and those are indeed ten animals.
c. PRO: there is a problem with that list -- everything on it is a vertebrate (animal with a backbone), but vertebrates only represent less than 5% of all animals.
The answer to #7 shows that humans tend to have a __ towards animals that are most like us, even if these are in actuality the minority of animals.
The animal kingdom is often divided up into two major groups: __ which have backbones, and __ which don't. (Note that those that have backbones are a "sub-phylum" of chordates).
Why is this a weird way to divide up the animal kingdom?
It is technically correct to say that some organisms have backbone, and some don't, but to do this, we pick one characteristic of one small group of animals, and say that those that don't have it are all in a group.
Another characteristic that divides some animal phyla from others is symmetry. Animals that lack symmetry entirely are said to be __ ; examples of this kind of animal are sponges (phylum Porifera). Animals that can be divided into many approximately equal halves through a central point (like a wheel) are said to be __; examples of these are __. All other animals are __ symmetrical, which means that they can be divided into two approximately equal halves along a central axis.
Asymmetrical, sponges (phylum Porifera), radially symmetrical, jelly fish(phylum Cnidaria) and starfish (phylum Echinodermata), bilateral.
Traditionally, zoologists (animal biologists) have grouped animals into phyla, classes, etc. based on characteristics such as symmetry and other easily observable characteristics. More recently, it has become possible to directly examine organisms' __ to make comparisons. For the most part, these comparisons have supported the traditional classifications, but occasionally they lead to surprising discoveries as well.
Most animals show symmetry; those that don't are said to be __. Of those that are symmetrical, members of two phyla are __ symmetrical, while all the others are __ symmetrical.
asymmetrical, radially, bilaterally
Having bilateral symmetry creates an orientation of the animal with its environment, with anterior, posterior, dorsal, and ventral parts. At the anterior of an animal is often a __ where the sensory organs and brain are found.
Multicellular organisms may be organized to different extents. The simplest arrangement is the __. At this level, the animal may have specialized __ that perform different functions, but these cells are not organized into __. At the __, tissues are groups of cells of a particular type that work together for a specialized function, like muscle tissues or nerve tissues. At the __, animals have __ that are composed of two or more types of tissues that function together, and __ that are made up of two or more organs that function together.
cellular level, cells, tissues, tissue level, organ and system level, organs, organ systems.
Why do you think organs and organ systems are an advantage to those animals that have them?
Because of Health and Multitasking with the organs
Animals at the tissue level of organization and above (therefore, not __) have either a __ body plan or a __ body plan. A sac body plan is like a bag, or sack or (see picture) a balloon. In these animals, there is only one opening to the __ (where __ takes place) that serves both as the point food is taken in, and where any undigested waste is expelled. Animals with tube body plans have two separate openings into the gut, a __ (through which food enters) and an __ (through which undigested waste is released.
sponges (phylum Porifera), sac, tube, gut cavity, digestion, mouth, anus
Why do you think the tube body plan is an advantage to those animals that have one?
So the animals can absorb minerals, make digestion easier, waste elimination, and so animals can eat more.
Some animals have another body cavity, separate from the __ (sometimes simply called the "gut") discussed above. This other space is called the __, and it is not connected to the outside environment (unlike the gut). Instead, it is the space in which many of the internal organs are contained. (Note that sometimes our internal organs are informally called "guts," and to remove these organs of an animal like a fish before cooking it is called "gutting." But be careful of the distinction between "gut" -- which is the space inside the digestive tract -- and "guts." And keep both of these terms separate from "body cavity" and "coelom.")
gut cavity, coelom
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