LIFE CYCLES


The life cycles of living things differ in a many ways. Some organisms need to live inside of other organisms in order to survive. The protozoan which causes malaria must live inside of a specific mosquito, invade a human liver, and eat the protein (hemoglobin) of human red blood cells as a part of its life cycle. Since this protozoan causes harm--sometimes resulting in human death, the protozoan is a parasite. The human functions as a host because he / she provides the raw materials need for the protozoan to live. AND the mosquito serves as the vector (vehicle that moves the protozoan from place to place). The mosquito bites and infected person drawing in the protozoan only to move on to an uninfected person to inject the protozoan with the next bite!




Some life cycles like that of the mushroom involve periods of sexual (joining male & female cells) reproduction and asexual reproduction (spreading spores). In certain jellyfish life cycles, there are periods of free-swimming individuals and periods of time when the organism is attached to the sea floor.



The birth, growth, reproduction, and death of organisms within a species occurs at regular predictability. When scientists are confronted with life cycles that are not well understood...like the Ebola virus...the life cycle of such a parasite becomes important to study. Once scientists know the steps in the cycle, like they do for Lyme's disease, then prevention and intervention steps can be taken to keep the parasite from spreading!