Amoeba (Protozoan) Movies

Amoeba Video No. 1 - An amoeba engulfs a food item in a process called phagocytosis; under phase contrast illumination at a magnification of 400x with a playing time of 20.8 seconds. Choose a playback format that matches your connection speed: 28.8k (modem), 56.6k (modem), or T1/Cable/DSL, or download this video clip in MPEG format (8.72 MB).

Amoeba Video No. 2 - Pseudopodia, or false feet, extend and retract as this amoeba moves across the microscope field; under phase contrast illumination at a magnification of 100x with a playing time of 15.5 seconds. Choose a playback format that matches your connection speed: 28.8k (modem), 56.6k (modem), or T1/Cable/DSL, or download this video clip in MPEG format (6.51 MB).

Amoebas are primitive organisms characterized by their flowing movements, extending cytoplasm outward to form pseudopodia (false feet); this type of movement is considered to be the most primitive form of animal locomotion. Pseudopodia are also used for feeding. In response to chemical stimuli from smaller organisms, pseudopodia are induced to envelop the organism, at the same time forming a vacuole (cavity). Digestive enzymes are secreted into the cavity and the nutrients diffuse from the vacuole into the cytoplasm. Undigested food and wastes are eliminated through the ectoplasm. The ectoplasm also performs respiration, absorbing oxygen from the water and eliminating carbon dioxide. Amoebas reproduce asexually by binary fission.