Biology Quiz - Crayfish Flashcards
What are Crayfish
Crayfish are arthropods, which are the most diverse and abundant group of animals on earth. There are more species of arthropods than all other animals combined.
Arthropod Characteristics
- Jointed appendages – bend to move in specific directions and specialized for specific jobs
- Exoskeleton – hardened cuticle, which is an outside layer of skin; it is nonliving tissue called chitin that does not grow with the body and must be removed for growth in a process called molting (shedding)
- Body segmentation – specific regions
Telson & Uropods
The telson and uropods form the flipper-like structure at the end of the abdomen (tail); used to propel the crayfish in a backward direction by whipping the tail forward
Maxillipeds
3 pair of larger appendages near mouth; handle food
Mandibles
Jaw like structure; breaks food apart; move side to side
Anus
Complete digestive system
Male
First 2 pair of swimmerets are hardened/enlarged (copulatory swimmerets); used to deposit sperm from opening of sperm duct to seminal receptacle of female
Female
Has a seminal receptacle which is an opening to the female reproductive system (eggs expelled and held by swimmerets after they are fertilized)
Gills
Feather-like structure (inceased surface area) used for resperation; remove oygen from water
Heart
(May be attached to the carapace) Open circulatory system; keeps blood moving under low pressure
Digestive Gland
Produce enzymes to digest food; also absorption of nutrients
Ganglia
Nervous tissue
Stomach
Storage and digestion – 2 chambered: cardiac stomach is anterior (closer to the mouth), has a gastric mill which is a teeth-like structure used to break food into smaller pieces; pyloric stomach connects to the intestine
Antennal Glands (Green Glands)
Paired; excretion of body wastes
(equivalent to urine) “Near the head”
Intestine
Passage of undigested food from the stomach to the anus (complete digestion)
