What are the differences between fleas and ticks and how do they affect my cat?

First and foremost, fleas are insects, while ticks are arachnids, so ticks are cousins to spiders. The big difference between fleas and ticks is that fleas will build cities and skyscrapers on your animal, and ticks will not. The life cycle of a flea consists of finding your pet, biting your pet, eating your pet, laying eggs, the eggs hatching into larva, the larva turning into pupa, and the pupa turning into adults, perpetuating the cycle. Ticks' life cycle actually happens off of your pet. They only feed off your pet, and after they're done eating, they drop off and continue to propagate and wait for something else to come by.