A is For Arthropods
Arthropod Dissection PreAP Biology March 14, 2014- GABI MATA
What's an Arthropod?
An arthropod is an invertebrate animal having an exoskeleton, a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda, which is divided into five different subgroups. The arthropod body consists of repeated segments, each with a pair of appendages. Their versatility has enabled them to be one of the most extensive members of most environments. They have over a million described species, making up more than 80% of all described living animal species, so they can adapt and evolve and can easily take on any niche, depending on their environment.
Evolutionary Relationships
Ecological Adaptations
Ecological Niche
Arthropods are one of the most diverse group of animals on the planet, proven so as, for example, the number of insects alone is greater than all the other animals combined. Their diversity is attributed mainly by their ability to evolve rapidly to take advantage of changing environmental conditions and fill new or empty ecological niches. Basically, because of their large diversity, arthropods can exploit nearly every niche on Earth.
Today's Objectives
The Crayfish and the Grasshopper
Astacoidea
A crayfish is a part of the Crustacean sub phylum of Arthropoda and are closely related to lobsters, crabs, and shrimp. They are found in bodies of fresh water that do not freeze to the bottom, and which have shelter against predators. Most crayfish cannot tolerate polluted water. They have ten legs; the front two have developed large claws called chellae. Crayfish use their chellae not only to defend themselves, but also to attack their prey (an assortment of an animals and plants, such as worms, insects (and their larvae), certain plants, and eggs of fish, frogs, toads, and salamanders, as they are omnivorous) and pick things up. However, their claws cannot always protect them from their many predators, including raccoons, opossums, snakes and muskrats. The crayfish's ecological niche is that it is an omnivoric scavenger that likes to eat aquatic plants and small invertabrates like insects and is eaten by many other animals. It evolved from ancient species of crustaceans.
Caelifera
Arthropod Dissection 101
External Anatomy:
Watch This!
Grasshopper Dissection: http://www.youtube.com/watch?v=LlipwN_5zlM
Crayfish Dissection: http://www.youtube.com/watch?v=W7F0jZgdc8A
As you watch these, make sure to write down any keynotes or questions you have. My question is: why were the people doing the dissections in each video NOT wearing gloves? Ew. Talk about gross.
Residing in the Respiratory System
Respiratory System of a Crayfish
Crayfish breathe using its gills. The gills, located between the carapace (a part of the crayfishes exoskeleton) and the lateral body wall, in the branchial chamber, exchange carbon dioxide and oxygen between a crayfish's blood and the water across the surface of the gills. At the same time, water is circulated through the branchial chamber through the beats of the gill bailer on the second maxilla.
Respiratory System of a Grasshopper `
The exchange of gases in a grasshopper happen through its specialized respiratory system called the tracheal system. The process begins at the spiracles of the animal where air is taken in. This system contains ten spiracles located in the abdominal area while the rest are located in the thoracic region. A few of the spiracles are involved in the expiration of air as well. Oxygen diffuses into cells into the atmosphere and ends the grasshopper’s respiration process. The air sacs that the tracheal system works to store carbon dioxide and oxygen when the respiration is taking place.
Respiratory System in Both Animals
If You're Interested....
Crayfish and Grasshopper Virtual Labs
http://crescentok.com/staff/jaskew/isr/biology/biolab46b.htm
A is for Arthropod Quiz: Let's See What You've Learned!
Works Cited
http://comparativeanatomybiology.weebly.com/grasshopper-anatomy.html
http://a-z-animals.com/animals/grasshopper/
http://evolution.berkeley.edu/evolibrary/article/0_0_0/arthropods_02
http://www.fcps.edu/islandcreekes/ecology/crayfish_(cambarus).htm
http://www.geology.wisc.edu/~museum/old/arthroinfo.html
http://en.wikipedia.org/wiki/Arthropod
http://crescentok.com/staff/jaskew/isr/biology/biolab46b.htm
http://www.ent.iastate.edu/ref/anatomy/ihop/
http://www.animalearn.org/links.php#.U0M8UvldWSo
http://www.infovisual.info/02/025_en.html
http://www.biologyjunction.com/crayfish_dissection.htm
http://www.uwlax.edu/biology/Zoo-Lab/Lab-08/Crayfish-Internal-Anatomy-1.htm