Unit 3 Flashcards
(10 cards)
What are protists?
Protists are a diverse group of eukaryotic organisms, mostly unicellular, that do not fit into the plant, animal, or fungi kingdoms.
How are protists classified?
Protists are classified into four main groups: Excavata (e.g., Euglena, Giardia), SAR Clade (includes Stramenopiles, Alveolates, Rhizaria), Archaeplastida (includes red and green algae), Unikonta (includes amoebozoans and opisthokonts).
What are the key characteristics of protists?
Protists are: Diverse: Can be unicellular or multicellular. Feeding: Autotrophic (photosynthetic), heterotrophic (phagocytic), or mixotrophic. Locomotion: Use flagella, cilia, or pseudopodia.
How do protists reproduce?
Protists reproduce through: Asexual: Binary or multiple fission. Sexual: Some have a haplodiplontic life cycle. Conjugation: In ciliates for genetic exchange.
Can you give examples of protists?
Some examples are: Protozoa: Amoeba, Paramecium. Algae: Volvox (green algae), Phaeophyta (brown algae). Slime Molds: Physarum (plasmodial slime mold).
What is the ecological importance of protists?
Protists are crucial in: Serving as the base of aquatic food webs. Recycling carbon. Forming symbiotic relationships, such as corals and dinoflagellates.
How do protists differ from other eukaryotes?
Protists are more diverse and lack the specialized tissues and organs seen in plants and animals.
How did protists evolve?
Protists likely evolved from a common ancestor of eukaryotes, around 1.5-2 billion years ago, and their evolution is linked to endosymbiosis (e.g., mitochondria and chloroplasts).
What are some diseases caused by protists?
Some diseases caused by protists include: Malaria (caused by Plasmodium), Amoebic dysentery (caused by Entamoeba histolytica), Sleeping sickness (caused by Trypanosoma).
What is the endosymbiotic theory?
The endosymbiotic theory suggests that mitochondria and chloroplasts originated from free-living prokaryotes that were engulfed by early eukaryotic cells.
