Lab 8: Phylum Arthropoda Flashcards
What clade do arthropoda belong to?
Protostomes
What three criteria make arthropoda the most successful group of animals?
-Diversity
-Abundance
-Distribution
What percentage of arthropoda are insects?
90%
What is the arthropoda cuticle produced by; what is is composed of?
The epidermis; chitin
Why is the cuticle so flexible?
There are so many kinds of arthropoda that it can be modified for their environment
Ex: crustaceans that live in water have a thick cuticle because they live in water so that can support a heavy exoskeleton
What functions does the exoskeleton (cuticle) provide?
-structural support
-attachment for locomotion
-protection against predators of the same scale
-prevention of water loss (desiccation)
Which subphyla of arthropoda have the most well-developed cuticle waxy layer?
The terrestrial arthropods (land) because it prevents loss of water
Is the exoskeleton living or nonliving? Does it shed?
It is nonliving so it must shed as the animals grow
What constraints does the cuticle impose?
-when the cuticle is shed, its soft which makes the arthropod vulnerable until it hardens
-it is not easy to get out of the old exoskeleton (some may die because they cannot molt successfully)
-muscles attach to exoskeleton and use it for movement, soft exoskeleton is no good for this
-exoskeleton limits size of arthropod’s; cannot support weight when first molted
Body in arthropods is divided into a linear series of modules called _____
segments
What is tagmatization?
The fusion of segments during development into specialized functional units
What are the specialized body functions formed; what appendages does it include?
Tagmata; walking legs, antennae, mouth parts, reproductive structures, and wings
What are the four different schemes of tagmatization we will be studying for the four subphyla of arthropods?
-head and trunk
-head, thorax, and abdomen
-cephalothorax and abdomen
-prosoma and opisthosoma
What is the main body cavity in arthropods?
The hemocoel
How is the coelom greatly reduced in arthropods?
It only consists of the cavities that house the reproductive organs and some glands
Is the arthropod bilateral?
Yes
What gives them a hydrostatic skeleton?
Their freedom of movement is provided by their joints
How are muscles arranged in arthropods? Is it similar to our own muscles? What makes it different?
As localized bands of muscles and organized into antagonists at joints such as flexors and extensors; it is similar to our own muscles but in arthropods the muscles are attached to the inside of the skeleton
What kind of digestive tract do arthropoda have?
complete with regional specialization
What are the three parts the digestive tract in arthropoda?
-The first part of the digestive tract is responsible for ingestion and mechanical digestion
-The middle part is the site of chemical digestion and absorption
-The last part absorbs water and forms feces
What form of nitrogenous waste do arthropoda excrete?
It depends on whether they are aquatic or terrestrial
-Terrestrial arthropods must conserve water so they excrete nitrogenous waste in the form of uric acid, which is solid
-Aquatic arthropods excrete ammonia because it can be diluted easily in the water
What are the the requirements of gas exchange?
-A gas exchange surface of adequate dimensions relative to the volume of the organism
-A means of keeping the surface moist
-A means of protecting the fragile gas exchange surface from mechanical injury and desiccation
-A method of transporting gases between the area of exchange with the environment and the more internal cells
What are the four gas exchange structures?
-Gills
-Book gills
-Book lungs
-Tracheal system
What are ocelli?
Simple cups with pigments in them that are light sensitive; they allow the animal to detect direction and intensity of light
What are the antennae in arthropods used for?
touching, smelling, and feeling vibration. Can also act in place of the eyes in some insects
Describe the nervous system in anthropods?
The brain is connected by a nerve ring to two ventral nerve cords with segmental ganglia. Touch receptors are attached to bristles that extend through the exoskeleton. They also have sensory receptors that respond to vibrations, gravity, chemicals, and sound waves
Fertilization is often internal in arthropods. What does this mean? List two meanings.
-the male places sperm into the female
-male places sperm sac with a protective covering on the ground and the female picks it up and places it internally.
What is the solution to the challenge of dessication?
waxy exoskeleton
What is the solution to the challenge of obtaining gases directly from the air and preventing gas exchange surfaces from losing too much water?
Modification of respiratory structures; book lungs, tracheal system
What is the solution to the challenge of support without the aid of buoyancy of water?
Exoskeleton
What is the solution to the challenge of loss of water with excretions?
Nitrogenous excretion in the form of uric acid
What is the solution to the challenge of release of gametes into dry environment?
Internal fertilization
What are the phyla that molt the cuticle?
-Arthropoda
-Nematoda
What fluid fills the hemocoel of arthropods?
Blood
What other phylum has a hemocoel as its main body cavity?
Mollusca
What type of circulatory system is associated with a hemocoel?
Open circulatory system
What are all of the clades that Arthropoda belongs to?
-Bilateria
-Metazoa
-Eumetazoa
-Ecdysozoa
-Protostomia
Book Lungs and Book Gills are structurally similar and blood transports oxygen from the gas exchange surface to the cells in both. But there are differences in their gas exchange strategies.
Which is located inside the body?
Book lungs
Oxygen moves from air to blood and then blood to cells in which strategy?
Book lungs
True or False: Book lungs and the Tracheal System are both strategies used by terrestrial arthropods.
True
True or False: Blood carries oxygen from Book Lungs to the cells but air carries oxygen through the Tracheal System to the cells.
True
Which phylum is Arthropoda most closely related?
Nematoda
Which arthropod subphylum does not have mandibles?
Chelicerata
Which arthropod subphylum has two pairs of antennae?
Crustacea
Which arthropod subphylum has Head and Trunk as its tagamata scheme?
Myriapoda
Which arthropod subphyla have a well-developed waxy layer in the cuticle?
Hexapoda and Chelicerata
Which arthropod subphylum has Head, Trunk, Abdomen as its tagmata scheme?
Hexapoda
Which arthropod subphylum has no antennae?
Chelicerata
