Final answer:
Animal-like protists or protozoa are single-celled eukaryotes with heterotrophic nutrition. They include flagellates with flagella for movement, ciliates that move with cilia, and sporozoans that produce spores and are non-motile.
Step-by-step explanation:
Characteristics of Animal-like Protists (Protozoa)
Animal-like protists, commonly known as protozoa, are a diverse group of single-celled eukaryotic organisms which share some traits with animals. They are distinguished by their heterotrophic nutrition, meaning they consume other organisms rather than producing their own food through photosynthesis. Protozoa come in various forms, each belonging to different phyla with unique modes of movement and life cycles.
Flagellates
Flagellates are characterized by one or more flagella, whip-like structures that propel the organism through its environment. An example of a flagellate is Trypanosoma, which causes African sleeping sickness.
Ciliates
Ciliates use tiny hair-like structures called cilia to move and to feed. A well-known ciliate is Paramecium, which uses its cilia to swim.
Sporozoans
Sporozoans are non-motile protists that produce spores. An example of a sporozoan is Toxoplasma.
All these protozoa are usually found in aquatic or moist environments, and some can be parasites, forming symbiotic or pathogenic relationships with host organisms. Understanding the key characteristics of protozoa phyla helps elucidate their vital role in ecosystems and their evolutionary significance.