Bio 111 Lab 7

Phylum Mollusca includes a variety of animals such as snails, slugs, shellfish, octopus, and squid. It is characterized by an open circulatory system (except cephalopods) and does not have segments like some other animal phyla.

The scientific name for the Brown Garden Snail is Cantareus aspersus, not Gastropoda aspersus, Helix aspersus, or Achatina aspersus.

Snails do not use wheels, jet propulsion, or hovering for locomotion. Canterus demonstrated the use of waves with various patterns like monotaxic, orditaxic, direct, and retrograde.

Geotaxis refers to movement relative to gravity, while the other options refer to movement relative to light, chemical sources, and water currents respectively.

Mollusks respire in different ways depending on whether they are aquatic or terrestrial. Aquatic mollusks use gills, while terrestrial mollusks exchange gases across their mantle. In both cases, the environment must be moist for respiration to occur properly. Some terrestrial mollusks also have a pneumostome, which is an opening to a 'lung' for gas exchange.

In gastropods, particularly snails, the 'love dart' is used as a means to increase the chances of successful reproduction by aiding in the survival of injected sperm.

Phylum Arthropoda is characterized by specific features including bilateral symmetry, segmentation, cephalization, exoskeleton, and jointed appendages. The incorrect answers provided do not accurately describe the unique traits of arthropods, highlighting the importance of understanding these defining characteristics.

The correct answer explains the structure and function of crayfish appendages, specifically mentioning the 3 parts of each segment and the presence of a seminal receptacle in female crayfish. The incorrect answers either misrepresent the structure or function, or provide inaccurate information about crayfish biology.

Serial homology is the presence of similar structures in different segments of an organism, which may have different functions, highlighting the concept of repeated elements in a single organism.

The Crayfish Respiratory System primarily relies on gills for breathing, which are attached to the gill chamber under the carapace. They can also breathe on land for a bit because water gets trapped in the gill chamber allowing for the diffusion of gases.

In the crayfish circulatory system, oxygen is carried by Hemocyanin, which is an oxygen-carrying pigment found in the blood plasma of arthropods, including crayfish. This is different from Hemoglobin, which is the oxygen-carrying protein found in human blood. The pharynx is part of the digestive system in crayfish and is not involved in carrying oxygen. Mandibular muscles are responsible for chewing food in crayfish and do not play a role in carrying oxygen.

Crayfish have an external reproductive system where males release sperm through genital pores located on the 5th pair of walking legs, while females release eggs through genital pores on the 3rd pair of walking legs. The seminal receptacle is located between the 4th and 5th pair of walking legs for the storage of sperm after mating.

Male and female crayfish can be distinguished by the differences in their swimmerets and walking legs, as well as the presence of a seminal receptacle in females.

The main components of the crayfish digestive system include the mouth, esophagus, cardiac stomach, pyloric stomach, and digestive glands. The tail, antennae, and legs are not directly involved in the digestive process.

The Crayfish Nervous System consists of the CNS with ventral nerve cord and brain, along with statocysts filled with fluid chamber allowing them to detect position.

The correct components of the Crayfish Excretory System are the Green glands and Nephridiopores. Red, yellow, and blue glands do not play a role in crayfish excretion.