Transfer of Energy and Matter Flashcards

Vocabulary flashcards covering the key concepts, definitions, and mechanisms of energy and matter transfer in ecosystems based on IB Biology Topic C.4.2.

Food Chain

A diagram that represents the flow of energy based on feeding relationships, where arrows show energy passing to the next trophic level.

Trophic Level

The position or role an organism occupies in a food chain or food web, such as primary producer, primary consumer, secondary consumer, or tertiary consumer.

Autotroph

An organism that makes its own food by synthesizing organic molecules like glucose using external energy and inorganic compounds such as $CO_2$ and $H_2O$.

Photoautotroph

An autotroph that uses sunlight as its energy source to fix inorganic carbon ($CO_2$) into organic carbon compounds.

Chemoautotroph

An autotroph that uses energy from oxidizing inorganic compounds found in rocks and soil to fix inorganic carbon ($CO_2$).

Heterotroph

An organism that hunts its own food by obtaining energy through the consumption of other organisms.

Holozoic Nutrition

A form of heterotrophic nutrition involving internal digestion through four steps: ingestion, internal digestion, nutrient absorption, and cell assimilation.

Biomass

Organic matter that stores energy within organisms or trophic levels in an ecosystem.

10% Energy Transfer Rule

The rule stating that only approximately $10$\% of the energy in one trophic level is stored as biomass and becomes available to the next trophic level.

Pyramid of Energy

A diagram showing the amount of energy flow at each trophic level in a food chain, expressed in $J/m^2/year$, which always maintains a pyramid shape with producers at the base.

Detritivore

A heterotroph that ingests detritus (dead organic matter) internally and digests it using holozoic nutrition, such as earthworms or woodlice.

Saprotroph

A decomposer heterotroph that secretes digestive enzymes externally onto dead organic matter and absorbs the digested products.

Food Web

A diagram showing multiple interacting food chains and relationships within a community, where organisms can occupy more than one trophic level.

Mixotroph

An organism that uses a combination of different modes of nutrition, functioning as both an autotroph and a heterotroph.

Facultative Mixotroph

A mixotroph that can switch between autotrophic and heterotrophic nutrition strategies based on environmental conditions.

Obligate Mixotroph

A mixotroph that requires both autotrophic and heterotrophic modes of nutrition to survive.

Euglena

A microscopic freshwater protist that acts as a facultative mixotroph, photosynthesizing in sunlight and absorbing organic matter when light is scarce.

Obligate Aerobe

An organism that must live in the presence of oxygen to survive.

Obligate Anaerobe

An organism for which oxygen is toxic, requiring oxygen-free (anaerobic) conditions to survive and reproduce.

Facultative Anaerobe

An organism that can survive and carry out life processes with or without oxygen.