Transcript crayfish dissection - Solon City Schools

CRAYFISH
DISSECTION
Animal Groups
Image from: http://ology.amnh.org/biodiversity/treeoflife/pages/graph.html
ARTHROPODA
“Arthro” = jointed
“pod” = foot
Arthropods
Structures to identify in lab
• All terms in the PowerPoint that are printed
in RED.
Classifying
Kingdom:
Phylum:
Class:
Crayfish
ANIMALIA
ARTHROPODA
CRUSTACEA
EXOSKELETON- Outside body; NON-LIVING
Made of CHITIN (polysaccharide with some nitrogen)
All animals with an EXOSKELETON
must MOLT (shed their exoskeleton)
to grow bigger
SEGMENTED BODY
like earthworms
Fusion of smaller segments to make
one bigger section
Head + thorax = cephalothorax
CARAPACE
Part of exoskeleton that
covers the cephalothorax
CHELIPED = Pincher (defense; capture food)
ROSTRUM = “visor” protects eyes
COMPOUND EYE
HAS MULTIPLE LENSES
ANTENNAE- touch, taste
ANTENNULES- touch,
taste, & equilibrium
DECAPODS (10 legs)
(4 pair walking legs + 2 chelipeds)
SWIMMERETS (5 pair)
SWIMMERETS
Aid in reproduction
In males – transfer sperm
In females – carry eggs/young
Create water currents
Telson
Uropods
Uropods
Uropods
Telson
MAXILLA – Manipulate food
LAST PAIR of MAXILLA = “BAILERS”
Keep water moving over gills
MANDIBLE
Appendages
1.
2.
3.
4.
5.
6.
7.
8.
Walking legs
Cheliped
Maxillipeds
2nd maxilla
(gill bailer)
1st maxilla
Mandible
Antenna
Antennule
APPENDAGES
ANTENNA
ANTENNULE
MANDIBLE
Touch, taste
Touch, taste, equilibrium
Chew food
MAXILLA
Manipulate food
Last pair “bailers”Move water over gills
Touch, taste, manipulate food
MAXILLIPEDS
CHELIPED
WALKING LEGS
SWIMMERETS
UROPOD
Capture food, defense
Locomotion,
move water over gills
Move water over EGGS,
transfer sperm (males)
carry young/eggs (females)
Propulsion during tailflips
Is it a MALE OR FEMALE?
MALES:
first two pair
of swimmerets
form a channel
to transfer
sperm to female
seminal receptacle
SWIMMERETS
MALES
Top pair
make a
“V”
Females “in berry”
carry developing embryos on swimmerets
REPRODUCTIVE
SEPARATE SEXES
Male and Female
EXTERNAL FERTILIZATION
sperm & eggs join outside body
INDIRECT DEVELOPMENT
Starts as a larva
Examine the inside
of your crayfish
RESPIRATORY
GILLS (#2)
Exchange gases
Remove nitrogen waste (AMMONIA)
What keeps water moving over gills?
“BAILERS”
WALKING LEGS:
are attached to gills so walking moves
water
Image from:
http://www.aa.psu.edu/div/mns/biology/crayfish/crayfishtable.htm
INTERNAL
Heart
Stomach
Digestive gland
OPEN CIRCULATORY SYSTEM
HEART with openings (OSTIA)
ARTERIES leaving heart but NO VEINS to
return hemolymph
OSTIA
ADDUCTOR MUSCLES
run mouthparts
STOMACH
PYLORIC
CARDIAC
GASTRIC MILL
“teeth” inside stomach
DIGESTIVE GLAND
Makes bile; finishes digestion; absorbs nutrients
GONADS (produces sex cells)
Females:
OVARIES – make eggs
SEMINAL RECEPTACLES - store received sperm
Males:
TESTES – make sperm
VAS DEFERENS- tubules inside that carry sperm
from testes to exit opening
ENDOCRINE SYSTEM:
controls sexual development
Also: molting, heart rate
ABDOMEN
INTESTINE (#4) – finish digestion; absorb
nutrients; collect & remove feces
GREEN GLANDS (#2) - collect and remove excess
water & nitrogen waste (ammonia, NH3)
NERVOUS SYSTEM
like earthworms
VENRAL NERVE CORD
CEREBRAL GANGLIA (brain)
GANGLIA along body
VENTRAL NERVE CORD
CEREBRAL GANGLIA =
BRAIN
Nerves connect
the eyes, antennae,
and antennules
to the brain.
Brain
Brain
AUTOTOMY &
REGENERATION
Crayfish have the
ability to
“self amputate” parts
to escape predators
and regenerate to
repair injuries
THE END