Arthropod Dissection Lab

By:Arlenn Maldonado PAP GUzman P.7


I will be learning about the external and internal anatomy of a lamprey.I will focus on the organs, structures, and functions of the excretory system. I will also understand the ecological role of the lamprey.

Arthropod Information

The arthropods constitute over 90% of the animal kingdom and are classified in the phylum Arthropoda. They are distinguished from other animals by:

  • an exoskeleton (a skeleton on the outside of the body)
  • body divided into distinct parts
  • jointed legs and appendages
  • bilateral symmetry (both sides of the body are the same)
  • Arthropods (Arthropoda) are a group of invertebrate animals that includes centipedes, millipedes, spiders, mites, horseshoe crabs, scorpions, insects and crustaceans. There are more than one million known arthropods species and many millions more that have yet to be named. Scientists estimate there may be as many as 30 million species of arthopods (most of which are insects). Arthropods are a highly successful group of animals. They evolved more than 500 million years ago and are still going strong. They have colonized a vast variety of ecological niches around the globe and have evolved into a multitude of forms.

Arthropod Excretory System

Crustaceans and arachnids possess paired excretory organs (maxillary, antennal, or coxal glands) that open at the bases of certain appendages. Myriapods, insects, and some arachnids, such as spiders and mites, possess another type of excretory organ, Malpighian tubules, which open into the intestine. Thus in these animals both excretory and digestive wastes exit from the anus.

Arthropod Facts

Arthropods have been on earth since about 428 million years ago. They are among the oldest known animals to have lived on land, and they comprise over 90% of the animal kingdom.

All arthropods have a thick exoskeleton, which protects the body and retains water. The Arthropods' exoskeleton is made of a compound known as Chitin, which is present in the form or plates with joints in .

between. The word arthropod means 'jointed feet'.

All arthropods have bilateral symmetry. They also have an open cavity in their bodies that is called hemocoel. Blood flows through this body and covers the organs and tissues. Arthropods do not possess blood vessels.

Arthropods can be divided into chelicerates and mandibulates. In chelicerates, the head and thorax is fused, whereas in mandibulates, there is a separate head, thorax and segmented abdomen.