Skip to content
Login Register

#nutrition modes

2 public questions tagged with this topic.

Animal Classification

Mode of nutrition in animals is mainly

Nutritional mode in Animalia predominantly holozoic involving active capture, ingestion of solid or particulate organic matter, extracellular digestion within specialized lumina where hydrolytic enzymes secreted, absorption across microvilli enhanced by increased surface area, and egestion of indigestible residue via anus or osculum. This contrasts holophytic photosynthesis in plants using chlorophyll, saprophytic absorptive nutrition in fungi releasing exoenzymes, and holosaprobic bacteria. Evolution from phagocytic choanoflagellate collar feeding expanded into muscular pharynx, gut regionalization, accessory glands and peristalsis coordinating food processing throughout metazoa.

Ref: Campbell Biology 12th ed. Chapter 41 Animal Nutrition; NCERT Class 11 Biology Chapter 4 Heterotrophic Nutrition

View Details
General Biology of Protists

Protists show all modes of nutrition EXCEPT

Protists exhibit remarkable nutritional diversity including photoautotrophy via chloroplasts, heterotrophy through phagocytosis, osmotrophy absorbing dissolved organics, and mixotrophy combining photosynthesis and ingestion in genera like Euglena and Dinobryon. Chemoautotrophy, however, involving oxidation of inorganic substrates such as ammonia, hydrogen sulfide, ferrous iron to generate energy for carbon fixation, is restricted to prokaryotic Bacteria and Archaea including nitrifiers and sulfur oxidizers. No free-living protist employs inorganic chemical lithotrophy for autotrophic growth, marking absence of chemoautotrophic protists and metabolic boundary between eukaryotic protists and chemolithotrophic bacteria.

Ref: OpenStax Biology 2e Chapter 23 Protist nutrition modes chemoautotrophy absent; Raven Biology chemoautotrophs prokaryotes nitrifiers

View Details