Invertebrates: Phlyum Mollusca-Class Cephalopoda- (EXAM 2)

Question 1

class Cephalopoda

Answer 1

• under phylum Mollusca
• ex) octopus, squid, cuttlefish
• occur mostly in marine environment

Question 2

funnel siphon

Answer 2

foot modified as this for expelling water (water jet propulsion) and tentacles: suction disks/ hooks (chitin) used for capturing prey

Question 3

mouth

Answer 3

parrot like beak

used to crush prey items

Question 4

Well developed senses

Answer 4

• large brain
• complex eye (includes cornea, lens, retina)
• Squid has largest eye
• octopus used arms for tactile exploration

Question 5

closed circulatory system

Answer 5

two gill hearts move blood through the capillaries of the gills, a single systemic heart then pumps the oxygenated blood through the rest of the body

Question 6

chromatophores

Answer 6

special skin cells that allow the organism to change color, and are used for communication and camoflauge

Question 7

Ink gland

Answer 7

dark fluid released when alarmed, creating a “smoke screen” which allows the animal to escape predation

• octopus: black ink
• squid: blue-black ink
• cuttlefish: brown ink

Question 8

ink gland 2

Answer 8

• contains a chemical compound called tyrosinase that impairs a predators sense of smell and taste
• contains dopamine which may serve to alert other cephalopods to the presence of other predators
• some deep ocean cephalopods secrete a glowing curtain compound of mucus and bioluminescent bacteria

Question 9

chambered nautilus

Answer 9

adjusts buoyancy by pumping gas (argon-nitrogen mixture) and water into chambers of shell via the siphuncle. the nautilus shell presents one of the finest natural examples of a logarithmic spiral (a special kind of spiral curve that often occurs in nature)

Question 10

siphuncle

Answer 10

tube connecting the chambers

Question 11

cuttlebone

Answer 11

a chambered, gas-filled shell used for buoyancy control (in cuttlefish)

Question 12

rhinophores

Answer 12

detects chemicals= olfaction and chemotaxis to find food

Question 13

countershading

Answer 13

shell exhibits this to avoid predation

Question 14

squid pen

Answer 14

a feather shaped internal structure that supports the squids mantle and serves as a site for muscle attachment; composed of chitin-like substance, it is the remnant of the squids shell

Question 15

reproduction

Answer 15

spermatophore: package of sperm delivered to female (other males may “flush” out previous spermatophores)

Question 16

Blue Ringed Octopus

Answer 16

recognized as one of the worlds most venomous animals (no known antidote)
-toxin is created by bacteria in the salivary glands of the octopus and is five times more powerful than cyanide

Question 17

blue ringed octopus (other)

Answer 17

has evolved a symbiotic relationship with the bacteria, providing them with ideal living conditions while using the toxin they produce to subdue prey and as a part of their highly advertised defense