User:Katelyn R. Porter/Notebook/Biology 210 at AU/2014/07/15

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0715, T4, Invertebrates

Purpose: to understand the importance of invertebrates and to learn how their simple systems have evolved into more complex systems.

Acoelomates, Pseudocoelomates, and Coelomates

Materials and Methods

Cross sections and whole mounts of Planaria, nematodes, and Annelida were observed under a microscope.

Data and Observations

The cross section of the Planaria showed the ectoderm and endoderm germ layers. It did not contain a fluid filled cavity, the coelom, and the pharynx and simple digestive tract were visible in the whole mount of the organism. Planaria exhibit a slow creeping motion, which was unable to be seen because the organisms were dead. They exhibit this motion because of their long, wide, flat body structures and less developed muscular system. A cross section and whole mount are depicted in Figures 1 and 2.

Figure 1:

Planaria cross section.JPG

Figure 2:

Planaria whole mount.JPG

The cross section of the nematode depicted its more complex pseudocoelom and muscle layers, including the endoderm, ectoderm, and mesoderm. These exhibited a slithering motion because of their slimmer, more cylindrical bodies and more developed muscular system. These organisms exhibit the most primitive form of a circulatory system. A cross section is depicted in Figure 3.

Figure 3:

Nematode cross section.JPG

The Annelida earthworms depicted its ectoderm, endoderm, and mesoderm layers, as well as its fully developed coelom. The muscle layers were depicted in pink. Annelida have the most developed muscular system, which allows them to exhibit a faster slithering motion. A cross section is depicted in Figure 4.

Figure 4:

Annelida cross section.JPG

Analyzing the Invertebrates Collected with the Berlese Funnel

Materials and Methods

The Berlese set up was broken down and the top organisms were poured from the tube into a petri dish, then the bottom organisms were poured from the tube into a different petri dish. Both dishes were examined under a dissecting microscope

Data and Observations

Transect invertebrates table.png


Flea T4.JPG


Spider T4.JPG


Spider 2 T4.JPG


Fly T4.JPG


Egg T4.JPG

The organisms ranged from about 1-2 mm. The Arthropoda insecta and Arthropoda arachnida were the largest and the egg was the smallest. There were many different organisms present in the leaf litter, but the Arthropoda arachnidas appeared to be the most common. Most of the organisms were found in the bottom of the tube with the soil.