Cuttlefish Case Study

A. Why was there evolutionary pressure for shell to evolve to a pen?
There was evolutionary pressure for the shell to evolve into a pen for locomotion, propulsion, movement, and protective reasons. The pen can be seen in modern cuttlefish, squid and octopods. The pen was more beneficial than the shell because it is now internalized and doesn’t weigh down the organism, the organism is now able to float horizontally in water and allowed the organism to develop fins for better locomotion. The loss of the shell also allowed the organism to have a highly contractible mantle cavity to squirt out water violently, moving the animal by jet propulsion, this further insured the organisms safety by allowing it to travel faster and further. The adaptation
The ganglion within the worm serves as the brain and receives stimuli like heat, light, and vibrations then takes the information and relays it to the worms’ specialized segments. The ventral nerve cord runs down the entire length of the worms body starting from the ganglionic mass then it branches off into lateral nerves in each segment. The direct path of impulses from the cerebral ganglion to the segments proves that the worm has no need for a more complex structure such as the brain, the cerebral ganglion suffices.
C. Explain the behavior of the cuttlefish mating. How did his behavior come about and how is it evolutionary advantageous?
Small male cuttlefish can disguise themselves as females by using their chromatophores to change color and by pulling in some of their legs. This disguise gets them past the big males that are fighting to get a chance to mate with the females. This is advantageous because the small males are no match for the big males in a fight. This camouflage has proven to be evolutionarily advantageous as the female cuttlefish will select the crossdressing male’s sperm packet seventy percent of the time.
D. Detail out the life cycle of malaria. Why are parasites difficult to control for in the preventative health
The parasites are so difficult to control because of how they are transmitted (through humans, meat etc.) and if we were to try to eliminate them it could pose more harm to us because it could lead to a drug resistance. Parasites are difficult to control in the preventive health setting because they adapt and change when their environments change, and most parasites don’t harm their host so they don’t even realize they have a parasite.
E. How do protozoan model multicellular organisms yet remain single cellular? Why is there an evolutionary advantage to be multicellular organism?
Protozoan model multicellular organisms yet they remain single cellular because their body plan wouldn’t support them being larger so even though they have the mechanisms they don’t have the means. They also exhibit all of the functions of life such as; having a metabolism, the capability of reproduction, and the ability to synthesize DNA and RNA all while they remain unicellular. Multicellular organisms are more advantageous because they are larger, live longer and can specialize cells to perform various functions.
F. What is ADH? How is this related to